Man's extension into the sea transactions of the joint symposium, 11-12 January 1966, Washington, D.C

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SCIENCE DIO

1966

I TRANSACTIONS OF THE JOINT SYMPOSIUM
11-12 JANUARY 1966, WASHINGTON, D.C.
man's extension into the sea

mUNIONGEY IL
* ffii_

'Copyright

�Marine Technology Society

1966

This publication may be obtained from Marine Technology Society,
The Executive Building No. 828, Washington, D. C. 20005. Price $4. 00.

Reprints of individual papers may be obtained from Kirby Litho-
graphic Company, 409 12th Street, S. W., Washington, D. C. Prices on
request.

FOREWORD

The symposium on MAN'S EXTENSION INTO THE SEA was held
to spread before a wide audience, the knowledge and experience gained
from SEALAB II and from other recent investigations related to man's
living and working at considerable depths in the ocean environment. The
symposium was sponsored by:

The Marine Technology Society
The American Society of Mechanical Engineers
The Society of Naval Architects and Marine Engineers
The American Institute of Aeronautics and Astronautics
The American Society of Naval Engineers
The American Geophysical Union

in coordination with:

The Special Projects Office, Department of the Navy
The Office of Naval Research, Department of the Navy.

This volume contains the text of the technical papers which were
scheduled and delivered at the symposium. The notable service rendered
by the authors, in reporting so ably the results of their investigations,
is gratefully acknowledged on behalf of all the participants.

Richard C. Steere
Chairman, Transactions Committee

.S. -DEPARTMENT OF COMMERCE NOAA
COASTAL SERVICES CENTER
2234 SOUTH HOBSON AVENUE
CHARLESTON, SC 29405-2413

Property of CSC Library

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TABLE OF CONTENTS

Foreword ......................................... ii

Table of Contents ..................................... iii

Keynote Address
The Honorable H. B. Baldwin .........................

AN OVERVIEW OF SEALAB II
H. A. O'Neal ....................................4

THE DESIGN, CONSTRUCTION, AND OUTFITTING OF SEALAB II
LCDR Malcolm McKinnon, III, USN ..................... 14

SEALAB II LOGISTICS PROBLEMS
Edward P. Carpenter .............................. 39

SEALAB II CREW SELECTION, TRAINING, AND DAILY OPERATIONS
CDR M. Scott Carpenter, USN ......................... 55

PROPULSIVE EFFICIENCY OF MAN IN THE SEA
Robert Taggart .................................. 63

OCEAN ENGINEERING FOR HUMAN EXPLORATION
J. J. Hromadik ................................... 74

PROBLEMS OF DEEP UNDERWATER PHOTOGRAPHY
William J. Bunton and M. Stanley Follis .................. 89

HUMAN PHYSIOLOGY ASPECTS OF SEALAB II
CAPT Walter F. Mazzone, USN ........................ 102

MANNED ASPECTS OF DEEP SUBMERSIBLES
J. G. Wenzel and W. M. Helvey ........................ 111

SEALAB II UNDERWATER WEATHER STATION
E. A. Murray and W. A. Koontz ........................ 134

THE MEASUREMENT OF HUMAN PERFORMANCE
James W. Miller, Ph.D .............................. 156

VALUE OF EXTENDED DIVING TO THE SCIENTIFIC COMMUNITY
Arthur 0. Flechsig ................................ 170

DIVING AND SALVAGE OPERATIONS ON THE CONTINENTAL SHELF
Keating Keays, J. Vincent Harrington and Edward A. Wardwell... 176

PRESSURE EQUALIZED FLEXIBLE STRUCTURES FOR MANNED
DWELLINGS
Edwin A. Link ................................... 207

UNUSUAL ENGINEERING PROBLEMS IN UNDERSEA LIVING
Berry L. Cannon ................................. 211

KEYNOTE ADDRESS

The Under Secretary of the Navy
The Honorable Robert H. B. Baldwin

It is a distinct pleasure to keynote a symposium which enjoys so dis-
tinguished a sponsorship, and to speak to a subject which commands such
wide scientific and industrial interest. Indeed, many of us in govern-
ment have long held that the beginning of an exciting new era in this
Nation's exploration and exploitation of the ocean is upon us.

In the sessions to follow, you will hear from many of the scientists
and engineers who are pioneering man's extension into the sea. Their
discussions will center on technical problems inherent in this effort, and
on future opportunities for creative science and engineering on the ocean's
floor. But I am sure this question will inevitably be asked: Are the
resources and leadership now available to seize upon these problems?

To this I can confidently say - yes. And that, gentlemen, is a one
word summary of what I want to say today. Yes, the resources for ex-
ploiting the sea are available. Yes, there is leadership to see that the
job is done.

I can speak with confidence because the entire subject of the ocean
sciences, deep submergence, ocean engineering, and related subjects
has just received a comprehensive review at the very highest levels of
the Navy Department. The review has resulted in recommendations, and
I am pleased to report - in positive action that will not only strengthen
ocean technology programs in the Navy, but contribute to the broad
national effort of concern to this symposium: Man's extension into the
sea.

Before announcing these recent and far-reaching decisions, I believe
it essential to provide perspective in which they can be more clearly seen.
Important to this perspective is the Navy's mission with respect to the
ocean sciences and technology. Briefly put, it is first, to advance our
knowledge of ocean, coastal, and seabed areas so we can increase the
effectiveness of naval operations required to fulfill the assigned missions
of the Department of Defense; and second, to provide direct support to
naval systems and ship development and design, by solving immediate
and long-range scientific, engineering problems associated with the
marine environment. In short, our oceanography and ocean engineering
programs are specifically and directly responsive to military require-
ments. We are sponsoring basic research which has relevance to naval
problems. We are involved in deep ocean engineering because it con-
tributes to our assigned missions; we are not in the business of exploiting
the ocean's abundant mineral or living resources. It is clear that our
need to accomplish military objectives frequently coincides with the needs
of other federal agencies, institutions, or industrial firms to achieve
quite different objectives. For example, boring and fouling organisms
cost the Navy millions of dollars each year in damage to harbor and pier
facilities and in the cost of ship maintenance and repair. The same
problem plagues the shipping and sport-fishing industries. What the
Office of Naval Research learns about the life histories and behavior of
these organisms through research sponsored at universities; what the
Navy Bureaus in conjunction with industry develop in the way of chemicals

and techniques to combat attacks by these organisms once they are
better known - while meeting clear military needs - also contributes
directly to the interests of the large port terminal operator and the
owner of a sports marina.

In the emerging field of ocean engineering, the interests of industry
and the Navy are in many instances identical. I rather strongly stated
that we are not in the business of surveying marine mineral deposits.
And clearly, we are not. We do, however, have a requirement for a
long endurance nuclear-powered research and ocean engineering sub-
mersible - the NR-1. The Navy is currently developing this vehicle in
cooperation with the Atomic Energy Commission. The technology that
will result from the design, construction, and subsequent operations of
this first generation vehicle will be of tremendous value to industry for
it is quite probable that the energy and endurance required for deep ocean
mineral exploration and recovery can only be met with nuclear power.

Another example where Navy and industry interests coincide is in
deep ocean salvage. Much of the work of the Deep Submergence Systems
Project is to provide capabilities identical to those needed by commercial
salvaging companies. For example, sustained pressure diving, undersea
vehicles, large and small object location and recovery systems, and
surface support vessels, to name only a few.

I could give many more examples of this identity of interests. In
fact, I would be surprised if there is any Navy ocean engineering project
that does not make direct contributions to the exploitation of the ocean.
This is not to say that industry lacks ocean engineering experience oi/
know-how. The shipbuilding, cable-laying and off-shore drilling indus-
tries have pioneered the way in many areas. But today - the Navy,
because of its extensive and urgent military requirements and its wide
background of experience, has undertaken a far broader effort in ocean
technology than has any single industry. This effort is supported by
widespread facilities, ranging from large model basins and pressure
testing tanks, to underwater test and evaluation ranges, and many spec-
ialized laboratories. These facilities were not designed for deep sub-
mergence, but over the years came into being to provide capabilities for
solving a variety of engineering problems in the ocean environment. The
facilities, in turn, are staffed with experienced scientists and engineers,
and funded at levels commensurate with the extent of their operations.
These, then, are the resources now available for man's extension into
the sea: Existing naval facilities, operating funds, and experienced man-
power engaged in solving naval problems which in many respects are
identical to the broad ocean engineering problems of national interest.

Thus, in our recent review of the Navy's program, it was obvious
that while pursuing military objectives, the Navy has an obligation to the
national interest in ocean technology; that since so many of our defense
interests are identical with those other aspects of the national interest,
we will - within the restraints imposed by cost - accept the responsibility
for helping develop the national technology needed for mastery of the sea.
Mastery in the military, economic, social, and political sense.

We also recognized that to achieve this capability the widely diversi-
fied programs of the Naval Establishment relating to the ocean sciences
and technology must be focused more sharply. Toward this end,

therefore, the Secretary of the Navy has approved excising the Deep Sub-
mergence System Project from the Special Projects Office and estab-
lishing the Deep Submergence Systems Program as a designated project
directly under the Chief of Naval Material. This action will be effective
February 1st.

In a second decision strengthening ocean technology, Secretary Nitze,
with the concurrence of the Chief of Naval Operations, directed the
Assistant Secretary of the Navy for Research and Development, Dr.
Robert Morse, to assume department-wide policy supervision of ocean
engineering and closely related matters. This extends Dr. Morse's
responsibility to include aspects other than and beyond research and
development in this important field of endeavor.

In a third step toward strengthening the Navy effort, Dr. Morse was
designated Chairman of the newly constituted Navy Oceanographic Policy
and Programs Board. Represented on the Board is the Oceanographer
of the Navy, the Chiefs of Naval Research and Development, and the
Deputy Chief of Naval Operations for Development. The reason for the
formation of this Board is that the Navy's programs in oceanography and
closely related matters are growing in magnitude and importance, are
carried out by many diverse administrative components, and increasingly
affect not only the Navy's combat readiness, but also the economic and
scientific growth of the entire Nation.

In making these rather fundamental changes in the management of
our ocean technology program, I want to stress that we have no intention
of building a paper organization with empty boxes and unfilled billets.
Over 2, 000 years ago, Petronius Arbiler stated:

"I was to learn later in life that we tend to meet any
new situation by reorganizing; and a wonderful method it can be
for creating the illusion of progress while producing confusion,
inefficiency, and demoralization."

The Deep Submergence Systems Program is a viable organization. It is
here - today - to serve both the Navy and the national interest.

In my opening remarks I also stressed that the leadership was avail-
able to do the job. Here I want to emphasize that our concept of leader-
ship is leadership by example - showing rather than directing the way. I
have every confidence that DSSP is asserting this leadership by using the
very considerable resources at its disposal to further extend the capa-
bilities of man to his very limit.

In summary, significant strides forward in technology are not made
by empty boxes in organizational charts.

Exploitation of the ocean can only be accomplished through effective
utilization of resources - people, facilities, and dollars - and through
leadership by example.

The opportunities are here; a vigorous cooperative effort on the part
of government, industry, and the scientific community will help realize
these opportunities now.

AN OVERVIEW OF SEALAB II

H. A. O'Neal
Office of Naval Research

SEALAB II, an undersea laboratory experiment in which we tried to learn
more about how man can extend his dominion over the sea.

SEALAB II was one of a continuing series of experiments in this area.
These open sea experiments are based on much continuing work by many
people in laboratories or in other field experiments. The SEALAB series
is necessary to bring together the man of varying disciplines and
capabilities to checkout, as a whole, integrated "systems" of performing
work and to conduct those experiments which require the whole integrated
system.

Man has invaded the sea for hundreds of years, making brief, daring forays
to learn or extract things of value. In general, however, mankind has
feared the ocean depths. Perhaps this is why things nautical are female
gender-this mixture of fear and respect.

In comparison to some fields, conventional diving has progressed slowly
for many years- advances have been made, but few radical innovations have
appeared. I will mention three innovations of importance:

(1) The introduction of helium-oxygen diving reduced the
danger of nitrogen narcosis (or rapture-of-the-deep)
at depths greater than 150 feet and decreased
decompression times of deeper dives.

(2) The second is the introduction of the self-contained-
breathing apparatus, which increased diver mobility by
releasing him from his umbilical cord to the surface.

(3) The third is the concept of saturation living introduced
by CAPT George F. Bond, MC, USN. This concept greatly
increases the ratio of useful working time to
decompression time. The reduction of this concept to
useful practice is the major subject of this meeting.

About eight years ago CAPT Bond and his principal collaborators CAPTAINS
Workman and Mazzone started laboratory experiments using animals, and
later, human volunteer subjects, to determine the effects of living under
continuous pressure. These experiments culminated in 1963 with three men
living for two weeks in a chamber at a pressure equivalent to 200 feet of
sea water.

In 1964, SEALAB I, an experiment to confirm these laboratory findings in
the open ocean, was conducted near Bermuda. Since I am sure that most of
you have read the report on this experiment, I won't bore you with details.
It is sufficient to say that the laboratory findings were confirmed, and
that this crude precursor experiment identified many crucial areas
requiring further work.

Within five months after the completion of SEALAB I, the framework of the
SEALAB II experiment was established. In January, we started assembling
the talent required to carry out this experiment--medical officers,
physiologists, engineers, chemists, physicists, psychologists, photographers,
biologists, master divers, oceanographers, dedicated Aquanauts and many
other specialists.

The major items considered in the planning were:

PURPOSE - To obtain scientific data on human performance of men living

under high pressure saturation in the open ocean under conditions
typical of the continental shelves, and to conduct discrete experiments
made possible by this opportunity to place men on the ocean floor for
significant periods of time.

DEPTH - Increased depth was not a primary objective. A major consideration
was availability of a significant depth range in a small area for excursion
diving to at least two atmospheres (66 feet) greater than habitat depth.

LOCATION - Six sites were reviewed, considering depth availability,
temperatures, visibility, surface conditions to be expected, logistic
support, and scientific interest. A site on the southeast edge of
Scripps Canyon, about 3,000 feet from the end of the pier of Scripps
Institution of Oceanography was selected. (See Figure 1)

PROGRAM

Medical and physiological - The safety and well being of the Aquanauts was
the item of prime consideration throughout the experiment. CAPT Mazzone
will discuss the physiological program in detail tomorrow.

Human Performance - There were several parts to this effort. Definite
psychomotor tests (two hand coordination, touch sensitivity), assembly
tasks, observation of general activity and performance, observation of
inter-personal relationships and pre and post experiments provided the
major data. A later paper will discuss this in detail.

Environmental Sciences - This effort had three goals: First, to investigate
this method of observation and measurement; Second, to provide data on
the environment of the test, and Third, each scientist had particular
experiments which he wanted to conduct during this unique opportunity. The
effort was primarily physical and biological oceanography, highlights of
which you will hear later. (Figures 2 and 3 apply)

Salvage and Tool Test Program - Several discrete experiments were conducted
under this effort, first was the test of the Aquanauts ability to use a
new technique called Foam-in-Salvage. Special materials were injected into
an aircraft hulk to make it buoyant. Several drums were also foamed, and
raised at intervals of a few days to determine the amount of water absorbed
by the foam. (See Figure 4)

Second was the test of a new design of stud gun, designed to make lifting
or other attachments to sunken objects for lifting. (See Figure 5)

Third were trials of the Aquanauts ability to assist in handling
collapsible salvage pontoons.

Fourth were tests of a zero-reaction drill and hole cutter.

Fifth was the test of an experimental suction mining device furnished
by the Bureau of Mines.

Teams - A first decision was two teams of ten men each for two weeks each.
However, as time progressed, the number of highly desirable work items
increased, and the number of men who met all qualifications volunteered for
the program. The plans were changed to three teams, ten men each, two
weeks each, with two men to spend 30 days each on the ocean floor.
CDR Carpenter will discuss this further this afternoon.

A total of about 50 individual work experiments were identified in the
program. Some 75% of these resulted in useful data, the remainder being
aborted or failing because of material failure, lack of time or logistic
problems. While this may sound like a low percentage, it must be
remembered that we had intentionally planned more work than we expected to

T~~~~~~~~~~~~~~~

be accomplished in order to insure full utilization of available time,
and because Murphy's law is still valid at sea.

So, with this program plan, the many groups went to work, and, in August
we were on site with an assembly shown diagramatically in Figure 6.

On 28 August, just eight days later than the date we had projected in
January, the first team entered the habitat.

On 12 October, the last team completed decompression, between these dates:

over 10,000 man hours had been spent at 200 foot depth.

Over 500 man hours had been spent swimming and working.

From this experiment we have learned:

1. Reasonably large groups of men can live for protracted periods (15 to 30
days) at 205 feet, have a large degree of autonomy, accomplish useful work,
be safely decompressed and show no apparent serious adverse physiological
or psychological effects.

2. The U. S. Navy's first experience with no decompression excursion dives
from a starting depth of 205 feet in a saturated state to a depth of 266
and 300 feet were successful. This represents an important addition to
undersea diving technology.

3. There is a clear degree of diver adaptation to cold water as shown by
interviews with the Aquanauts and by pre and post cold water emersion
physiological measurements.

4. Adequate protection against cold water can be obtained for extended
periods by the use of heated suits. Swimmers without supplementally
heated suits are limited to less than one hour of useful work in 470 -
540F waters.

5. A degradation of work capability varying between 17% and 37% as compared
to warm to shallow water capability occurs which is the result of a
multiplicity of environmental and psychological stress factors.

6. Improved tools and techniques show promise for salvage and other
undersea work functions.

7. Based on the analysis of the overall performance of the Aquanauts,
criteria can be developed for the selection of future Aquanauts.

8. The interaction between man and porpoise has shown that to depths of
200 feet the porpoise can be extremely useful to man-in-the-sea operations.

9. In-situ living offers a new and important methodology to scientific,
biological, geological ocean floor investigations.

10. Although vastly improved over SEALAB I, the habitat and much of the
diving equipments are still rudimentary and require extensive development
to enable routine operations.

11. Deep water swimmer communications and ocean floor navigation systems
require an immediate effort to obtain acceptable equipment for future
man-in-the-sea operations.

12. A completely autonomous habitat is awaiting the development of reliable
underwater power package and integrated complete life support systems.

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In sumnary, a step forward has been made in enabling man to move with
greater ease in a hostile environment, and has shown those problem areas
which must receive attention to permit him to work and live more easily,
safely, and efficiently. Through the remainder of this meeting, I would
like you to remember several things:

--Many of the areas are still in the area of art, not science. This
is because the human organism is complex and not well understood, and
because only great efforts by small groups of dedicated men have been
applied to the solution of problems. We hope that the need for man to
invade the sea will be clarified soon, and that more groups, both military
and commercial, will augment the small body of men now carrying the burden
of improving the technology.

--A very wide range of talent is required to build this technology.
The job is not just an engineering task. It is an outstanding example
of an interdisciplinary program. If I had to select the one item about
SEALAB II which impressed me, I would say that it was the harmony with
which this group of people of diverse backgrounds attacked their joint
problems.

--Lest we forget, the success of this venture and all other future
work depend on a few men who will endure hardships- cold, separation from
normal living, etc., and risk health and life to further our abilities
to understand and exploit the oceans. These men, of course, are the
Aquanauts.

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THE DESIGN. CONSTRUCTION. AND OUTFITTING OF SEALAB II

Lieutenant Commander ialcolm MacKinnon III USN
Hunters Point Division
San Francisco Bay Naval Shipyard

I. Abstract

The design, construction, and outfitting of SEALAB II represent a venture
far removed from the standard Naval Shipyard tasks of construction, con-
version, and repair of Naval ships. It made the Hunters Point Division
of the San Francisco Bay Naval Shipyard a key member of a highly complex
project team with the difficult tasks of developing contract and working
plans from a very sketchy set of specifications and completing production
all within a four month period. The nature of the SEALAB project and the
time schedule posed a great challenge to the shipyard, but the challenge
was met and the project completed on time. The basic problems were
further complicated by the fact that ellipsiodal dished heads required
to cap the cylinder were not available commercially. This placed the
shipyard in a new field: The underwater explosive forming of large
steel sections. The successful accomplishment of this feat is in it-
self a major contribution to the technology of metal forming. SEALAB II
is an underwater habitat capable of housing 10 men for a period of 45 days
at a depth up to 250 feet.

II. Desion Philosoohv

In the middle of January 1965, Hunters Point Division of the San Francisco
Bay Naval Shipyard was approached with an interesting proposal. Could it
undertake the design, construction, and outfitting of an underwater habitat
to be called SEALAB II? Acceptance was given even though it was apparent
that this was a marked departure from normalcy. The normal tasks of a
shipyard are the construction, conversion, and repair of Naval ships. There
would be none of the clean cut detailed specifications and contract plans
a shipyard normally receives when embarking on the construction of a proto-
type design.

This project was in the realm of applied research and involved a large
number of activities and people. Extensive studies in many areas for
equipment selection and arrangement were precluded by time and economic
reasons, and empirical results of previous tests were relied on and used.
Naturally, the most significant of these prior tests was SEALAB I. SEALAB I
and the goals of SEALAtD II as set by the Office of Naval Research and the
Special Projects Office provided the basis for the design parameters used
for SEALAB II.

With the initial proposal came several parameters. SEALAB II was to be a
habitat capable of housing 10 men at a depth of 250 feet for a period of
30 days. Thus, complement, working depth, and duration were established
directly from the basic goals of the project.

In addition much experience in the hitherto non-existent field of underwater
habitat design and construction was obtained by the Navy's Mine Defense
Laboratory through its efforts in support of SEALAB I. The assistance and
guidance provided by MDL in early design phases were invaluable. Many
equipment and installation specifications came direct from MDL.

A great deal of the equipment utilized in SEALAB I was "off-the-shelf"
and of the mail order house variety. The fact that it functioned well
in SEALAB I and a tight budget and schedule for SEALAB II influenced
selection in many instances.

The effect of feedback from SEALAB I on basic design was considerable
and the following major design parameters were obtained, most resulting
from operational difficulties experienced in SEALAB I;

1. SEALAB II was to be a pressure vessel, capable of being pressurized
prior to submergence to bottom pressure.

Reason: SEALAB I was a non-pressure vessel and was flooded more than
once trying to lower, keeping internal gas pressure higher than external
hydrostatic pressure.

2. Submergence and bottom emplacement were to be done with SEALAB II
in an unoccupied condition.

Reason: There would be less danger of personnel casualty from any
malfunctions during pressurization and lowering. The importance of
personnel safety was to be held paramount throughout all phases of the
operation.

3. The pressure vessel was to be cylindrical, approximately 50'
long and 12' in diameter.

Reason: The size of SEALAB I and the complement of SEALAB II, already
fixed, indicated this should be close to an optimum size and shape.

4. The arrangement should include four separate areas: entry,
laboratory, galley, and living space.

Reason: This basic arrangement worked well with SEALAB I.

5. The atmosphere was to consist of approximately 85% helium, 4%
oxygen, and 11% nitrogen.

Reason: Controlled experiments and experience in SEALAB I confirmed
this to be a proper mixture to minimize narcosis, support life and preclude
complete air purging.

6. Certain effects of helium were to be accounted for, primarily in
the heat transfer area; the coefficient of heat transfer of helium being
approximately seven times that of air. Extra insulation must be provided.

Reason: Heat losses were not calculated in SEALAB I and no controlled
tests were run. The refrigerator, a thermal electric type, never operated
satisfactorily.

7. Temperature was to be held at 880 and humidity at 60% relative.

Reason: These seemed comfortable in SEALAB I.

8. Primary power was to come from the shore, secondary power from the
surface staging vessel as part of the umbilical cord. Communications,
secondary gas supply and sampling, and compressed air for external tool
use were also to come down the umbilical.

Reason: Assuming the integrity of the primary power source, the
staging vessel could depart and not cause an immediate abort or dangerous
situation. Primary gas supply was to be from an external bank of bottles.

SEALAB I was terminated due to impending heavy weather. This would make
SEALAB II less weather dependent.

9. There were to be a maximum number of portholes with the capability
of seeing the bottom periphery of SEALAB II.

Reason: A near fatal accident occurred in SEALAB I. An unconscious
man was rescued only when his bottles bumped the side of SEALAB I, he was
not visible from within.

10. The atmosphere-water interface was to be as close to the bottom
as possible.

Reason: With no good data or information as to the extent of excursion
dives deeper than saturation pressure, deeper depths could be reached from
higher saturation pressure.

11. Reduction of the interior cubic was to be made wherever possible
by use of interior tanks, dead spaces, etc.

Reason: Any decrease in interior cubic was a decrease in the amount
of helium required and thus a cost savings.

12. SEALAB II was to be painted white.

Reason: The international orange of SEALAB I would not have the acuity
that white does underwater, for easier sighting in marginal visibility
conditions.

There were a few other more minor considerations but the aforementioned
were about the extent of information the shipyard received in the form of
design parameters.

It became apparent very early that the biggest problem area in SEALAB I
was in the submerging operation. Railroad axles at 300 lbs each were used
as variable ballast. These were loaded by hand and when sufficient negative
buoyancy was reached, lowering was by a sling and whip arrangement from a
crane on the surface. A 9 Inch nylon line was used and the effect was a
huge yo-yo on a rubber band. Once on the bottom, additional axles were
added to increase negative buoyancy. To eliminate this unwieldy method of
ballasting, SEALAB II was designed along submarine principles. The
variable ballast would be sea water, stability would be maintained during
all phases of the submerging operation, and negative ballast on the bottom
to insure firm seating would also be sea water. NOTS Pasadena developed
a winch - counterweight lowering system that made lowering against negative
buoyancy feasible and desirable. Flooding had to be controlled simply and
externally since SEALAB in this phase of operation was unoccupied and sealed.

The condition requiring full working pressure internally at the surface
made the SEALAB II cylinder an internally pressured non-fired vessel
under the ASME Boiler Code. The code governs the structural design,
construction, tests, and inspection. The tables in the code indicated one
inch thick mild steel was sufficient for a working pressure of 125 psi,
ample for the desired 250 feet. A structural strength test, hydrostatically,
to 1J times working pressure was also required. The end cappings for the
cylinder were required to be ellipsoidal dished heads of proper curvature
and depth. Their unique method of fabrication will be discussed later.

The use of water as variable ballast and the desire for reduction in
internal cubic to save helium combined to provide internal ballast tanks.
These were built into the overhead of the cylinder with sufficient capacity
to allow proper reserve buoyancy on the surface and adequate negative

buoyancy on the bottom as previously discussed. The structural details
necessitated making these tanks "soft", i.e. incapable of withstanding
pressure differentials in excess of 15 psi across their lower boundary.

To preclude the necessity for a porthole (viewing port) capable of with-
standing full internal pressure and to allow large (24 inch) ports, structur-
al covers were provided internally to constrain the pressure. When opened
on the bottom they then exposed the port viewing glass to a pressure differ-
ential of slightly over 6 psi. This allowed the use of 1" plexiglas as the
viewing glass material.

Previous data on equipment behavior in helium existed only in what could
be obtained from Mine Defense Laboratory observations during SEALAB I.
Many commercially obtainable items functioned well and this fact was
accepted, tempered wherever possible by actual tests prior to any oper-
ational certification. As an example, commercial dehumidfication units
were used apparently successfully in SEALAB I. The same type units were
procured and tested in helium at the SEALAB II working pressure. It was
noted during operational test that the compressor motor did not function
properly. The malfunction was traced to a metallic relay in the motor
start circuit that apparently changed its characteristics operating in
helium. Replacement with a sealed unit relay restored normal operation.
The rated capacity of 47 pints/day was never conclusively checked, however.
A standard Navy-type refrigerator-freezer was procured, additional insu-
lation added, and the unit was tested in helium at working pressure. The
thermal sensors in the refrigeration compartments were of the fluid filled
bulb type and would have crushed under the extreme pressures. Consequently
once these were replaced with thermo-couple-type sensors the refrigerator
and freezer functioned properly. No data was available on heat losses and
heat input during SEALAB I, although qualitatively the aquanauts seemed
comfortable at a temperature of 85"- 900 at relative humidities between 60% -
70%. It was obvious that these observations were all that was readily avail-
able to design the heating,dehumidification, and insulation systems. A
psychrometric chart for a He-N2- 02 atmosphere was non-existent. A quali-
tative analaysis indicated that since ambient temperatures for SEALAB II
would be 20 - 30oF cooler than for SEALAB I a much higher heating capacity
(needed also to allow for many more men and a larger volume) and more
insulation were required. Consequently, 25kw of heat were provided and 2
inches of cork insulation on the inner surface of the shell were installed.
These, perforce, were based on the most rudimentary qualitative analyses.
A concrete deck was used for several reasons:

1. Structurally simple and economical
2. Provided additional ballast
3. Reduced further the internal cubic
4. Provided insulation
5. Enabled the use of radiant heating by embedding several runs of
mineral insulated (MI) heating cable in the concrete.

Additional heating in the form of household convection baseboard and over-
head radiant heaters were installed.

The ventilation system was modeled after a standard submarine system.
Atmosphere treatment was determined to be sufficient if lithium hydroxide
(LiOH) C02 scrubbers and charcoal filtration were used. The major effort
in this regard was to properly channel the supply and return atmosphere to
optimize treatment.

Thus it is seen that the design philosophy involved in the development of
SEALAB II was very loose and flexible, based on a few supplied parameters
and tempered by empirical data, ecomonics and time. Since SEALAB II was
a complex total project, very few design decisions were independent; most

effected many other project team members, making this a good problem in
systems engineering. Time and geographic distance precluded lengthy con-
ferences on design decisions. Mostly a decision was made locally, members
of the team informed, and if no objections were heard in a reasonable
length of time, production commenced. The results of these philosophies
and decisions, the vessel itself and its characteristics, will be dis-
cussed in succeeding sections.

III. Details of Construction

The construction of SEALAB II was generally a routine shipyard task with a
a few interesting exceptions. The production schedule was extremely tight
but not unlike any other more conventional shipyard projects. Standard
shipyard organization and practices were used throughout.

The ASME Boiler Code under which the main cylinder was constructed provides
for certain procedures to be followed in assuring adequate quality. The
steel selected for the main structure was 1 inch thich mild steel, Grade M
of Military Specification NIL 5-16113 and, as such, received extensive
testing at the rolling mill. The plate was ultrasonically inspected locally
to check for laminations and other specifications were spot checked, Weld-
ing was performed in accordance with current procedures for mild steel (AISI
1015-1025). All welds were radiographed and films were evaluated per the
latest standards. All welds were defect-free.

After fabrication of the basic structure a hydrostatic test to 1 times
working pressure(l190 psi) was applied to test for strength. This was done
prior to outfitting, with fresh water, to minimize any harmful effects.
After installation of all piping systems and upon completion of all hull
penetrations tightness test at working pressure was conducted using air.
Helium was not used due to economic and time restrictions.

In general standard shipyard procedures were used in all phases of con-
struction and testing. Quality control procedures commensurate with those
employed on normal shipyard work were invoked.

As mentioned previously the schedule was very close and would surely have
been missed if it were not for the rapid solution of many production and
procurement problems. Fabrication of the large (24 inch) portholes was
extremely difficult as tolerances were very close and hard to maintain in
the face of normal welding distortions. Not the least of the procurement
problems was the ellipsiodal dished heads used to cap the main cylinder.

Once design specifications were set, contract bids were let to the normal
suppliers of these large dished heads. The production schedule demanded
a 30-45 day delivery. None of the major steel companies, the normal sources,
could begin to touch this time frame. The large size of the heads coupled
with a rash of back orders due to an impending steel strike made normal
procurement impossible. The earliest delivery that could be expected was
5-6 months, or after the scheduled submergence of SEALAB II.

Fortunately the shipyard maintains the Navy's West Coast Shock Testing
Facility and thus has had a fair amount of experience in underwater explosions.
The use of the energy of an underwater explosion to form metal is a novel idea,
used sparingly in the past to form relatively small and simple pieces. The
energy of explosion is transmitted as a pressure pulse through the water
forming the steel against a female die. The forming process lasts only a
few milliseconds. The employment of this process to form large and complex
sections like these dished heads was hitherto never attempted anywhere.
Expedience and necessity being the parents of invention, the decision was
made to attempt this quantum jump in the technology of metal forming.

Immediately several problems became apparent: die design and construction

including curing of the concrete, handling and rigging, and configuration
and size of the explosive charge. briefly, a large die, 14Y feet in
diameter and 5$ feet high filled with a special formula quick curing con-
crete, was designed and built. A blank of steel was placed over the die
and a vacuum drawn under the blank. This is extremely important as any
entrapped gas would have to vent, wrinkling the edges of the piece. One
hundred pounds of C-4 plastic explosive were distributed in two concentric
rings and a lumped central charge. The calculations for charge configuration,
size and stand-off distance were extremely complex and important, as was the
selection of proper depth of water at detonation.

The entire assembly, weighing 60 tons, was lowered 30 feet beneath the
surface of San Francisco Bay using the shipyard's large gunning crane. There
the explosive was detonated and in approximately .004 seconds the first
dished head for SEALAI II was formed.

The results were phenominally good and only minor straightening in certain
areas was required. The heads checked dimensionally within 1/16 inch on the
diameter and within 4 inch on the contour, well within specifications. The
metal did not thin at all and thickening by approximately .075 inch occurred
at the rim where stresses were highest.

A detailed metallurgical analysis was conducted comparing the stock plate,
the plate after forming, and the plate after stress relieving. As expected
the severe cold working of the explosive forces embrittled and toughened the
plate. Stress relieving restored most of the original metallurgical properties.

The expense of die fabrication was considerable, but once made it can be
reused. Die life can be made excellent and once eight heads are formed the
process becomes attractively competitive.

The significance of this feat can best be illustrated by excerpts from a UPI
story in the Berkeley, California, Gazette dated November 18, 1965:

"Denver (UPI) - A metal shaping process......is being studied
by Martin Co. and Denver University scientists for possible use
in forming missile domes, side plates for ships, and other
large structures.

The technique was demonstrated Wednesday with the production of
.....ash trays.

It involved the placing of a sheet of metal across a die or mold,
then submerging the mold and metal in water, An expldsive charge
was detonated a few inches away, beneath the water, causing a
shock wave to blast the metal into the mold.

The experiment is being conducted under a one million dollar
government grant by DU's Denver Research Institute and the
Denver division of the Martin Company. It is expected to
take three years to prove or disprove the process."

Figures 1 through 9 on the succeeding pages illustrate the process.

FIGURE 3

FIGURE 4

FIGURE 5

,--- - - - - - - - - - I . --

z~~~~~~~~~~~~~~~~~l!~ , 2,

I
1 I

I-

LID
m

now

ww - ---w-

28~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

IV. SEALAB II Characteristics

(Figures 10, 11, and 12 apply)

A. Hull Exterior. SEALAB II is essentially a non-propelled submarine
built to withstand an internal working presssure of 125 psig. It is a
cylinder of one inch thick mild steel, 12 feet in diameter and 57j feet
long. The cylinder is surmounted by a conning tower 8 feet in diameter
and 7l feet high. The conning tower provides dry access when surfaced
as well as reserve buoyancy during the pressurizing operation, but is
designed to withstand aap of only 15 psi.

The cylinder is set in a cradle-like structure with trays underneath for
permanent lead ballast stowage. A walking flat is provided around the
conning tower and extending fore and aft. Variable lead ballast is stowed
under this flat for ready access to adjust final trim if necessary.

Access while on the bottom is through a 48" diameter hatch aft. Entry is
from the sea, into a protective anti-shark cage, up a sloping ladder,
through the water-atmosphere interface in an 8 foot square access trunk.
and into the main cylinder. The water level in the access trunk is main-
tained by regulating the internal SEALAB pressure. The trunk is designed
to allow sufficient volume to accommodate the severest expected tidal
change.

Emergency exit isforward through a 30 inch hatch. Access on'the surface
is through the upper conning tower hatch, a 30 psi surface ship weather
deck hatch, and the lower hatch, a 30 inch hatch. The 48 inch main access
hatch was specially fabricated, while the two 30 inch hatches are standard
submarine escape trunk side hatches.

Lifting pads are provided for both the dry maximum weight lift and the
negative buoyancy lowering. Special slings are designed for each operation.
Towing chocks are provided fore and aft.

When on the bottom SEALAB II is 13 tons negative and the bearing surfaces,
two pads extending athwartships fore and aft, are designed for 300 psf,
the bearing strength of the bottom at the site. Corner spades 15 inches
in depth allow a firm implacement and increase resistance to sliding. No
provision is made to level the pads, such leveling is the task of the
occupants if possible by a washing process using compressed air and water.

Stowage racks for 24 - 1300 cubic foot gas bottles are provided port and
starboard forward. The bottles contain make-up helium (10), make-up
oxygen (11) and a helium-nitrogen-oxygen mixture for emergency breathing (3).

There are 11 viewing ports each 24 inches in diameter. These ports are
designed to withstand 15 psig internal pressure and are protected at full
internal pressure by hinged steel covers. An equalizing line allows main-
tenance ofe:p=0 across the glass while submerging. This line is capped
at depth and the steel covers opened.

B. Hull Interior. The variable water ballast tanks are three feet deep
a n d located in the overhead. These tanks are "soft" tanks, i.e., the
bot tom boundary cannot withstand asp o f greater than 15 psi. These tanks
provide, with the conning tower, the negative buoyancy necessary for initial
submergence and lowering, and the negative buoyancy necessary for firm
seating on the bottom.

The deck is made of poured concrete two feet in depth and comprises a
portion of the permanent ballast. The deck and overhead ballast tanks
reduce the usable internal volume and consequently the amount of helium
needed to fill the atmosphere, an important economic consideration.

UP~PER ACCE5 TC LIFIING PADSII

VIEW O~ TOP SIDE G A BOLES

_ ~~~~~~~~~~~~~~~~~TOWING
Milli 71 7H ~ ~ ~ ~CROCK
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MAIN CYLINDER

LDOE ~ B ALL AST TlyI GAS BOTTLE RACK .p/s ~ ESCAPE HATCH
ANTI -11SHAk 1jCAE ~j UPPORING STRUCTURE

SAND SPAV E , ELEVATION -STARBOARD SIDE FGURE 10

DE.SIGNED AND CONSTRUCTED AT
SAN FRANCISCO BAY NAVAL SHIPYARO
HUNTERS POINT DIV15ION UPPER ACCESS
jar
OFFICE OF NAVAL RESEARCH
WASHINGTONJ DC.

WATER WATER - , ,TLR
BALLAST BALLAST BALS BALLAST

CID =All~~~~~~~~~~~~~~w REE~~~~~~EFER
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rv~~~wrlrarlo~~~LABRATRY REA - .COCREEBA BEH ND NON RE
UNDER WaER AESS

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~~~~~~~AND I ��
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DOOR 1 cnrra~~ ~~ ESCA~PE
ANTI- SHARK
CASE

SEALAB Il
INTERIOR ARRANGEMENT

e SECTION LOOKIN4G TO ST F U.
~~~~wo ~~~~~~FIGURE II

/ T \ lT T

I -eo I (Ore. I)

'*.sflO fi LAR BENC GALLEY ;oILB E NCH

SEALAB T:
INTERIOR ARRANGEMENT
TOP REMOVED - LOOKING DOWN

DES IGNED AND CONSTRUCTED AT
SANFRANCISCO BAY NAVAL SHIPYARD
HUNTER5 POINT DIVISION
/or.
OFFICE OF NAVAL RESEARCH
FIGURE 12 WASHINGTON,D.C.

This usable internal volume, 7 feet in height, is divided into four
separate areas. The aftermost area is the entry and contains 2 tubshowers
to aid in regaining body heat after a sortie in 50�F water, as well as
stowage for wet-suits and breathing apparatus.

The next area forward is the laboratory, separated from the entry by a
3Y foot watertight dutch door which gives an extra margin of safety if the
water level should rise in the entry trunk into SEALAB itself. The labora-
tory contains counter and stowage space, a sink, a cable trunk, instrumen-
tation racks, the communications center, and the fan room, heart of the
ventilation system.

Next forward is the galley area, containing stowage and counter space, an
electric range, a refrigerator-freezer, wash basin and water closet, and
the main power transformer enclosure and distribution panels.

Finally, forward most is the berthing area with ten bunks, a dropleaf
table, locker and stowage space. Access to the emergency exit hatch is
through a removable cover in the deck.

C. Mechanical/Electrical.

1. Ventilation System. The system consists of a central fan room with a
250 cfm capacity, recirculating centrifugal fan discharging through ducting
to the berthing, galley, laboratory, and entry areas. Return atmosphere is
drawn into the fan room as follows:

60 cfm directly through a LiOB C02 scrubber, with the remaining 190 cfm
by-passing the scrubber through a duct in the water closet bulkhead. The
combined 250 cfm is passed through an activated charcoal filter, where
noxious hydrocarbons are removed, and thence to the fan inlet. Bracket fans
are utilized to aid circulation. The pitch on the fan blades and the
impeller configuration are modified to allow for the reduced density of the
atmosphere as well as its increased pressure.

2. AtmosDhere Control. The atmosphere in SEALAB II is comprised of 80% He,
15% N2 and 5% 02 by volume at the proper pressure, i.e. hydrostatic pressure
at the depth of the air-atmosphere interface. Initial pressurization is at
the surface and consists of two parts, initially with air to give approxi-
mately the proper amount of 02 and then with helium to reach final pressure
and mixture composition. Care must be taken to avoid overpressurization of
the internal ballast tanks. They must either be properly equalized or
completely filled with water.

There are two gas lines in the umbilical cord, a gas supply line to provide
make-up helium and a gas sampling line to provide continous atmosphere
monitoring for analysis and also to provide an alternate means of oxygen
make-up.

Primary oxygen and helium make-up are from the gas bottles stowed externally.
The oxygen bottles are manifolded dually to a pressure regulator inside SEALAB
which automatically replenished oxygen to the atmosphere, responding to a
specially designed sensor (Krasberg). The helium bottles are piped into a
manual regulator. All gas supply,make-up, and sampling valves and fitting
are centrally located inside SEALAB II on a single gas control panel.

Three external bottles are filled with a pre-mixed supply of 95% He and 5%
02 piped into a regulator on the gas control panel which supplies eight
four outlet manifolds to which standard SCUBA regulator-mouthpiece units can
be plugged. This comprises the emergency breathing system, (Bibbs System),
and is to be used in case of severe atmosphere contamination.

In the overhead of the entry area two supply compressors and two vacuum
pumps are installed. Their function is to supply SEALAB atmosphere through
an external hose to the breathing gear of a swimmer on sortie and return
exhaled gases back to SEALAB. This is called an Arawak or "Hookah" system
and is very desirable for short sorties in that it frees the swimmnner from
cumbersome SCUBA devices.

3. Atmosphere.Treatment. In addition to the control of C02 and hydrocarbon
content, means are provided to regulate the temperature and humidity of the
SEALAB atmosphere.

There are thermostatically controlled baseboard convection heaters in each
area except the entry. Radiant heaters are provided in the entry area,
non-thermostatically controlled. Imbedded in the concrete deck is a
mineral insulated (MI) electric cable, with its own independent thermostat
control. The maxium total heating load is 25 kw. Normal design temper-
ature is 88OF.

Eight commercial dehumidifier units are installed, each with a capacity of
47 pints/day to keep the relative humidity at 60%. Each is controlled by
a humidistat.

The increased heat transfer characteristics of the helium atmosphere
require two inches of standard submarine cork insulation on the hull and
one inch on the overhead.

Direct reading and remote transmitting temperature and humidity sensors
are installed.

4. Fresh Water and Plumbina Systems. A boosted fresh water supply con-
sisting of two one-inch PVC pipes laid from the shore to SEALAB II is the
primary source of fresh water. Demand is based on a maximum usage of 10
gal/min at 50 psig. In addition, a line from SEALAB II to the staging
vessel on the surface provides a means for topping off its tanks during
periods of low SEALAB usage.

An emergency fresh water tank is installed with a 150 gallon capacity in
the overhead of the laboratory area. Also in the laboratory is a 50
gallon hot water tank with a short recovery time.

The plumbing system consists of one small boat-type water closet, two tub
showers, a washbasin and two sinks, one in the galley and one in the
laboratory.

Drainage is designed to be aft towards the entry area where a sump and
overboard connection are installed. Hoses are installed externally to
carry the drains away from SEALAB. The water closet has its own salt
water flushing and overboard discharge connections.

5. Electric Power Distribution. Primary power is led to SEALAB II via
an underwater 2300-440V transformer from the La Jolla power system. A
300 foot cable carries 440V, three phase 60 cycle power into SEALAB
designed for a maximum of 75 KVA. Alternate power is available via a
cable in the umbilical. This is also 440V, three phase, 60 cycle.

The 440V supply is used directly for the hot water, baseboard, and deck
heaters. 440-120V and 440-208V transformers handle the remainder of the
loads. Standard protective distribution panels, circuit breakers and
switches are utilized.

A transfer panel enables transfer from normal to alternate power.

6. The Umbilical. The services from the staging vessel are brought down

hoses and cables nested in what has become known as the "umbilical."
Secondary power via a 3 conductor cable, a multichannel communication
cable, a gas supply hose, a gas sampling hose, and a compressed air hose
for external tool use make up the umbilical. The SEALAB terminations
for these lines are centrally located at the conning tower. The lines
are brought together and lashed in a canvas jacket every few feet to form
a nest. The staging vessel terminations are hooked up prior to lowering
SEALAB to allow complete systems check-out.

7. Communications

a. Via Umbilical: There is a Helium Speech Unscrambler on the
staging vessel modulating and converting the helium distorted speech of
the subjects and is fed via one channel with transmitting stations in
the laboratory, galley, and berthing spaces in SEALAB II. A two way
electrowriter is also installed between SEALAB and the staging vessel.
Four TV cameras mounted in SEALAB II transmit their output to monitors
on the staging vessel. In addition a TV receiver for entertainment as
well as closed circuit monitoring is provided in SEALAB. A two way
intercom system is available in the laboratory to the staging vessel.
There it may be patched into the Helium Unscrambler. Another two way
intercom channel is alloted but this passes through SEALAB for further
transmission to shore. An FM entertainment receiver, a wedge spirometer
output (measuring subject respiration remotely), and 02 partial pressure
sensing comprise the remainder of the channels in the communications
link in the umbilical.

b. Via the Benthic Laboratory: Scripps Institute has developed an
underwater multichannel data transmission station, called the "Benthic
Laboratory" which is situated on the bottom close to SEALAB II. A
trunk is provided in SEALAB aft on the portside of the laboratory which
can be opened and through which cables can be passed. These cables then
can run to and from Benthic to provide the link with a shore based
Benthic control station. The link is audio, visual (TV), and digital
and analog data transmission.

D. Buovancyv and Stability.

The following tables should illustrate the various conditions of buoyancy
and displacement:

Refer to sketch, figure 13

Structure weight (less ballast, including outfit) 119 tons
Fixed Concrete Ballast 29 tons
Fixed Lead Ballast 31 tons
Variable 5 tons
Surface Displacement = Total Weight 184 tons

Submerged Displacement (defined as volume of
Conning Tower, Main Cylinder, Entrance
Skirt, and Appendages): 209 tons
Ballast Tank No. 1 9.5 tons
Ballast Tank No. 2 14.0 tons
Ballast Tank No. 3 9.5 tons
Conning Tower 11.0 tons
Total Water Ballast 44.0 tons
Entrance Skirt 6.0 tons

The net buoyancy of SEALAB II under various ballasting operations is as
follows:

Net
Buoyancy
Weight Tons

Condition I Surface Displacement 184 tons 425 tons
1' 8" freeboard
Flood tanks S1 and 33 +19 tons

Condition II SEALAB II Floating at 203 tons +6 tons
Mid-height of Conning
Tower

SEALAB II was pressurized
with Helium (Tank Nr. 2
and main cylinder).
Flood Conning Tower +11 tons

Condition III SEALAB during lowering 214 tons -5 tons
operation.
Set SEALAB on Ocean Floor
Flood Tank Nr. 2 +14 tons

Condition IV SEALAB on Ocean Floor, 228 tons 19 tons
Tank Nr. 2 flooded
Blow entry trunk -6 tons

Condition V SEALAB ready for entry 222 tons -13 tons
and occupancy.

Stability at each Condition:

Condition

I GM = 2.29 ft
II GM = 1.87 ft
III BG = 2.21 ft

BG at Condition III included the effect of the lowering whip as buoyant
force. Conditions IV and V are on the bottom and bottom reaction would
increase stability. Curves of forms, though academic, were prepared.

CONNING TOWER

1I1.0
TONS
VAR, LEAD BALLAST VAR. LEAD BALLAST
2.5 TONS 2.5 TONS

TANK 3 TANK 2 TANK *1
9.5 TONS 14.0 TONS 9.5 TONS

FIXED CONCRETE BALLAST 29TONS

ENTRY SKIRT FIXED LEAD BALLAST 31 TONS
6.0O TONS

FIXED AND VARIABLE BALLAST

FIGURE 13

V. Conclusions and Recommendations

It becomes very apparent in retrospect that a remarkable experiment,
SEALAB II, was successfully conducted in spite of several salient facts.
Severe time and schedule limitations coupled with a very close budget
precluded orderly progression and thorough investigation of many important
engineering areas germane to underwater habitat design. Nonetheless,
though lacking perfection of design in several areas, SEALAB II functioned
well as a habitat for 10 men for 45 days at 205 feet. It supported life
safely and relatively comfortably.

Experience gained in the progress of the design, construction, and out-
fitting of SEALAB II as well as in its operation and overall project organi-
zation, will aid immeasurably in further man-in-the-sea operations. This
has been just a whistle stop on our excursion down the continental shelves.

For the record, several conclusions can be drawn and recommendations made
from the vantage point of the author. These reflect his opinions and
analysis and may or may not be included in the official summary report of
the project.

1. A Naval shipyard can be expected to respond and undertake a
project of this nature and deliver hardware on time and at a competitive
cost. The Navy does have an in-house capability for underwater habitat
design and construction.

2. A significant contribution to the technology of metal forming was
made in the development and perfection of the technique of underwater ex-
plosive forming of large steel sections.

3. Engineering studies in the following areas must be undertaken at
once:
a. Atmosphere treatment to insure comfort and safety. Phychrometric
charts for an He-02 atmosphere must be developed and adequate dehumidification
devices be designed.

b. An intergrated gas supply and ballast control system to allow
controlled descent and pressurization from within, much as a static sub-
marine dive. Once perfected this would preclude heavy pressure structures.

4. The interior arrangement of future habitats must be developed
from the standpoint of Human Engineering, wherein careful functional analyses
are made. In particular, attention must be given to the entry and diving
station area.

5. A means for leveling the habitat is a necessity since it became
obvious a level site is an impossibility to find.

6. Communications and monitoring equipment must be improved.

7. For succeeding man-in-the-sea operations realistic schedules must
be developed. Expedience must never be a substitute for quality.

In conclusion appreciation must be given to the fine people connected with
SEALAB II project, and in particular the men and women of the Hunters Point
Division of the San Francisco Bay Naval Shipyard. All of them made SEALAB
II and this paper possible.

SEALAB II LOGISTICS PROBLEMS

Total Logistics Provide System Integrity and Complete
Operational Support to Maintain Life, Well
Being, and Incentive For SEALAB II Aquanauts.

Edward P. Carpenter
U. S. Naval Ordnance Test Station
Pasadena, California

ABSTRACT

The logistic requirements for SEALAB II involved the provision of system
integrity and complete operational support. To meet these requirements
a staging area was established at the Long Beach Naval Shipyard (LBNSY),
site investigation and system installations were accomplished, and opera-
tional surface support at the site was provided.

SEALAB emplacement was accomplished with a counterweight lowering
system and shore cable connected components were placed with the assist-
ance of the Scripps Institute of Oceanography (SIO). Surface operational
support consisting of surface craft operation and surface diver support
was provided by both military and civilian personnel.

The requirements for supporting a Man-In-The-Sea type operation were
successfully met; however, the need for certain improvements for future
operations became apparent. A significant advancement in the handling of
large objects in water from a floating support was also achieved.

INTRODUCTION

The logistics problems of keeping ten men alive, happy, equipped, and in
the mood to do useful work, while on the floor of the ocean involved the
provision of system integrity and complete operational support. As applied
specifically to SEALAB II, the logistic requirements can be grouped into
two general categories. First, the provision of a suitable bottom site as a
base of operations with all necessary components and equipment installed
and in working order, and secondly, the provision of adequate surface
support.

The Naval Ordnance Test Station's (NOTS) responsibilities were in the
logistics area as here defined and are the basis of this paper. These
responsibilities were:

a. provision of surface support vessels

b. system integration and checkout

c. site surveys and on-site installations

d. operational support.

The success of the SEALAB II operation resulted from the combined efforts
and cooperation of many activities in providing not only the logistics as
discussed herein, but also the necessary engineering, planning, direction,
training, and construction.

GENERAL DESCRIPTION

Planning and preparations were commenced early in 1965 when the site
location at La Jolla was announced and responsibility assignments for the
project were made. A staging area at the LBNSY was established and
design work started for rehabilitating and modifying the Polaris Pop-Up
staging vessel for use as the primary surface support vessel. Also during
the summer, site surveys were made for detailed site selection.

The site, near Scripps Canyon at La Jolla, is shown relative to the
San Diego area in Fig. 1. It is noted that although the site was only 3,000
feet from the end of Scripps Pier, the nearest protected boat landing was
about 10 nautical miles distant at Mission Bay. Fig. 2 shows the bottom
topography and plan of the site installation. Fig. 3 is a schematic of the
installation.

Operations commenced 28 Aug 1965 when the first team of aquanauts
entered SEALAB II and terminated 10 October when the third team was
brought to the surface.

SURFACE SUPPORT VESSELS

A primary surface support vessel was required to carry the SEALAB
command center, a 10-man decompression complex, and several other
supporting subsystems. This vessel, moored permanently above the
SEALAB, was connected to the SEALAB by a multipart umbilical cable.
In addition, approximately twenty other units of auxiliary surface support
craft were employed during the operation. These auxiliary craft included
small outboard work boats, LCM's, an AVR, harbor tugs, LCU's, a YO
for fuel replenishment, and the salvage ship USNS GEAR. No particular
further comment will be made regarding the auxiliary craft other than to
say that they were provided by various activities including the Eleventh
Naval District, the Naval Electronics Lab, the Amphibious Training
Command, SIO, and NOTS.

Specifications for the primary surface support vessel called for a capability
of providing - in addition to the command center and the 10-man decompres-
sion complex - a system for lowering and raising SEALAB, a shop for ser-
vicing and repairing Mk VI breathing equipment, storage space for breathing
gas, food, and baralyme, an alternate power source for SEALAB, and the

necessary berthing, messing, conference room, and office spaces. To
meet these requirements the staging vessel, which had been built as part
of the facilities for the Polaris Pop-Up testing program conducted at
San Clemente Island was utilized. This craft, heretofore known simply
as the "staging vessel, " was popularly called the "BERKONE"1 as it was
used for SEALAB Li.

The BERKONE consists of two 110' X 34' YC barges spaced about 22Z feet
apart and connected together with a covered structure at one end, to give
a rigid platform with approximate overall dimensions of 110' X 90' with
an open well at one end.

As configured for the Pop-Up tests the BERKONE consisted of the open
well with an underwater hinged platform for launcher loading operations;
an open missile bay on the port barge for missile handling; and the
machinery, equipment, galley, dining and storage spaces. Principle
items of machinery include three AC generators, two winches, one high
pressure and one low pressure air compressor, and a 50-ton crane.

To adapt this vessel for SEALAB II use, several modifications were made.
The underwater hinged platform was removed. A portion of the missile
bay was roofed over and the enclosed space used as a divers ready room.
The remainder of the missile bay was used for the installation of a 10-man
Deck Decompression Chamber (DDC) as part of the decompression complex.
The old electrical shop was converted to the Mk VI shop and two vans were
installed on the 01-level for the Command Center.

A number of operational support subsystems were also provided on the
BERKONE. These subsystems included a dumb waiter for transporting
both dry and wet items between the BERKONE and SEALAB; a counter-
weighted lowering system for lowering and raising the SEALAB and the
Personnel Transport Chamber (PTC); a diving bell for transporting divers;
a mooring line tension measuring and recording system; an acoustic posi-
tioning system; a breathing gas storage and distribution system; and,
interior and external communications.

Recreational and entertainment features were provided for use by the
SEALAB occupants including the installation of FM and commercial TV
tuners, with antennas, on the BERKONE, and the related monitoring
equipment in the SEALAB. The TV monitor in SEALAB was encased in
an acrylic pressure housing provided by SIO to prevent implosion of the
picture tube.

An amateur radio receiver was also installed on the BERKONE for recre-
ational use by the aquanauts, however, it was never used as such because
of their daily routine schedules and other conflicting interests. Commer-
cial telephone circuits were made available to the SEALAB on occasions
for personal telephone calls.

1This name came into being as a combination of the names of
Berkich and Mazzone - two prominent people stationed aboard.

The generators, air compressors, crane, and other pieces of machinery
were used for SEALAB without modification. A photograph of the
BERKONE as used for SEALAB operations is shown in Fig. 4.

In all, a total of about twenty major modifications or installations were
made in converting the staging vessel to SEALAB use.

SYSTEM INTEGRATION AND CHECKOUT

While the BERKONE was undergoing modifications at LBNSY, various
other components of the project were in preparation elsewhere. Between
mid July and mid August 1965, all of these components were shipped to
the staging area at the shipyard where the system integration and checkout
were accomplished. This work consisted first of making final assembly of
sub-components, including modifications where necessary, and secondly,
in testing these components, insofar as possible, for their circuitry,
strength, and designed function. The component testing was followed by
similar tests on the various systems and subsystems as the integration of
the components progressed. The success of the integration and checkout
came only as a result of the cooperative efforts of all personnel on the
project including representatives from each of the activities responsible
for the various components, and the three teams of SEALAB aquanauts.
A total of about forty five major items of system integration and checkout
were accomplished in preparation for SEALAB operations.

SITE SURVEYS

Several considerations were involved in the selection of the SEALAB site.
Cold water and reduced visibility were sought to more nearly represent
the world's oceans than did the ideal conditions at Plantagenent Bank during
SEALAB I operations. Areas of oceanographic interest in proximity to
existing shore based support facilities were also desired. In view of these
considerations the decision was made by the program management to select
the Scripps Canyon area at La Jolla, California. With the general area
selected, surveys were then made to pick the specific point at which to
place the SEALAB.

The Marine Physical Lab (MPL) of SIO made a bathymetric chart of the
general area at La Jolla based on an acoustic locating system for horizontal
control and on echo sounding for depth information. From the chart thus
produced, a tentative site for SEALAB on the south side of Scripps Canyon
at a depth of 210 feet was selected. The MPL then made a more detailed
survey of this tentative site by using spotters on shore for horizontal con-
trol and lead-line soundings for depth information. The chart produced as
a result of this detailed survey was the one used for the SEALAB operations.

The NOTS YFU-53 with its underwater frame mounted TV, cameras, and
lights, and also the tethered, unmanned, CURV vehicle, were used to make
visual inspections and photographs and slope measurements of the bottom
in the vicinity of the site. This survey showed the bottom to be generally
silty sand with some rock outcrop near the edge of the canyon. Bottom
slopes in the most likely position for SEALAB were found to be 5� to 6�.

A series of three anchor pull tests were conducted on the north side of
the canyon using the USS COCOPA (ATF) with an 8,000 pound anchor. The
holding force of the anchor was found to be seven times its own weight in
two of the pulls and ten times its weight in the third pull.

A series of bottom samples were procured over the general area which
verified that the bottom was quite uniformly a silty sand and indicated that
a bearing pressure of 300 pounds per square foot could safely be used in
the design of the SEALAB footings.

ONSITE INSTALLATIONS

Installation of project components at the site at La Jolla included the
placement of a 5-point moor for the BERKONE; putting the BERKONE in
the moor; placing the MPL Benthic Lab and Power Transformer Unit with
cables from each to the shore; laying of miscellaneous communications
and TV cables between the BERKONE and the shore; and the placement of
the SEALAB on the bottom.

A 5-point moor was designed for the BERKONE to give a measure of added
holding capacity in the event of a severe storm or other emergency. Each
leg of the moor consisted of a 13,000 pound anchor, three shots (or 270 feet)
of 2-inch chain, a 10,000 pound steel clump, and 1-1/4 inch wire rope run-
ning to the BERKONE. A line from each clump to a spud buoy on the surface
provided a series of auxiliary moors in the area for general usage.

The moor functioned satisfactorily under the conditions imposed upon it
during the operations. No significant movement of the vessel occurred
except when a supply ship or other vessel was moored to the BERKONE
thus exerting an outside force upon it. Under these conditions, move-
ments of 5 to 20 feet occurred depending upon the magnitude of the pull.
This displacement caused no particular problem since it was within the
tolerable limits of the operating conditions. Strain gages in each leg of
the moor indicated normal tensions of about 10,000 pounds and a maximum
of 55,000 pounds in one leg during a period of high sea state.

The Benthic Lab and the Power Transformer units, built by MPL of SIO,
each housed in cylinders about five feet in diameter and six feet high,
were placed on the bottom by the BERKONE's crane. An LCU, provided
by NEL, laid electrical cables and two 3/4" plastic pipes for fresh water
from these units, to the end of Scripps Pier. Shore power was brought
out at 4,160 volts to the transformer unit where it was stepped down to
440 volts. Transformers inside of SEALAB stepped the 440 volts down to
208/110 volts for the house circuits.

Placement of the SEALAB IT on the bottom was accomplished with a
counterweighted lowering system designed to remove the surging effect of
the BERKONE. It was anticipated that a maximum relative motion between
the BERKONE and the SEALAB of about 10 feet could be expected during a
wave half-period of about 5 seconds. Accordingly the counterweight system
illustrated in Fig. 5 was designed in which the spacing between the sheeves
supporting the counterweight was 60 feet and a counterweight of 14,000
pounds (in water) was selected for the SEALAB negative buoyancy of 10,000
pounds during lowering. In operation the tension fluctuation in the lowering

line due to wave motion as measured by a "pass through" type tensiometer,
was about hO10 to 15% of the nominal load. This compares to a fluctuation
of nearly 5000% experienced while attempting to lower SEALAB I directly
from the YFNB-12 at Argus Island in 1964 with no provision for allowance
of wave action. Fig. 6 is a curve showing the static characteristics of the
counterweight system.

During any operation, the counterweight is handled by a tending line and
winch operated independently from the main support line and winch. To
raise an object from the bottom the following procedure is followed. With
the main support line attached to the object but in a slack condition, the
counterweight is lowered by its tending line to a depth of about 40 to 50
feet. While lowering the counterweight the main support line is kept
slack by paying out as necessary. When the counterweight depth is
reached, the tending winch is secured. Hauling in on the main support
line is begun and tension is gradually built up as the counterweight trans-
fers from its tending line to the main support line. With the counterweight
now on the main support line its tending line becomes slack and sea motions
are absorbed by the counterweight action. The transfer of the load in
either direction between the main support line and the tending line is thus
accomplished smoothly with no shock loading on either line. There are,
theoretically, no points of discontinuity, or conditions that would produce
shock loads on the line, between the load range of zero to infinity. This
is not strictly true in actuality, of course, since at low loads, fluctuating
between 0 to 500 pounds at the BERKONE' s natural pitch period, the
counterweight' s response would not match the vessel's motion due to its
own inertia. Operation in this range (0 to 500 pounds) was required on
occasions to keep a slight tension on the line to the PTC while the PTC
was sitting on the bottom. This condition was met by placing a small aux-
iliary counterweight directly on the main support line and completely
removing all effect of the main counterweight. Both the auxiliary and the
main counterweight systems performed extremely well in all respects.

Lowering - When the SEALAB was ready for lowering, the USNS GEAR
moored itself fore and aft between the spud buoys on legs 1 and 2 of the
BERKONE moor and ran a third mooring line from its starboard beam
to an auxiliary moor. The SEALAB was then brought into a position
between the USNS GEAR and the BERKONE about 40 feet aft of and paral-
lel to, the BERKONE's fantail. Lines were run from both the bow and
stern of SEALAB to both the BERKONE and to the USNS GEAR thus placing
it in a 4-point moor at its lowering position. In this position the lowering
wire from the BERKONE was attached to the lowering sling on the SEALAB
and the prescribed procedure for flooding ballast tanks was commenced.
Upon completion of the flooding of tanks 1 and 3, the SEALAB waterline
was on the conning tower at a point which indicated that, when the conning
tower was flooded, the SEALAB would be approximately 10,000 pounds
negatively buoyant. The counterweight was lowered to about 50 feet depth
keeping the main support line to SEALAB slack. As the conning tower,
which is ballast tank No. 4, was flooded, the SEALAB began to sink. The
tending lines to the USNS GEAR were held taut to prevent the SEALAB
from drifting in to the BERKONE. After the SEALAB had reached a
sufficient depth to clear the BERKONE the lines to the USNS GEAR were
slacked off to allow the SEALAB to hang on the main support line directly
below the BERKONE. As the SEALAB sunk it gradually applied tension
to the main support line which in turn brought the counterweight into action

from its tending line. As the SEALAB was lowered to the bottom the tag
lines to the USNS GEAR were used to prevent rotation and to make final
orientation for touchdown. The SEALAB was designed for internal pres-
surization with helium prior to lowering thus eliminating the necessity for
continual pressure equalization during the lowering (and raising) process.
As it was thus pressurized it was found that the internal pressure covers
on three of the viewing ports developed leaks as full pressure was
approached which allowed the helium to escape through the vent tubes
venting the space between the pressure cover and the transparent acrylic.
These leaks were considered tolerable and the lowering operation was
commenced in the knowledge that the differential pressure would reduce
at depth thus reducing the gas flow and, once upon the bottom, the port
vents could be closed to stop the escape of helium altogether. Immediately
upon reaching the bottom divers went down and closed the vents as planned.
The SEALAB came to rest on the bottom with a 100 bow-up pitch and a 100
roll to port. In order to remove this roll and pitch it was intended that the
SEALAB be lifted a short distance off the bottom, rotated slightly with the
tag lines to the USNS GEAR, and set back down in the most level orientation.
With the viewing port vents having been capped, however, it was soon real-
ized that the internal differential pressure was now bearing directly on the
acrylic plates of those ports with the leaky internal pressure covers. A
limitation was thus placed on the height to which the SEALAB could be lifted
off the bottom, since the acrylic could withstand only a limited differential
pressure. Reduction of the internal pressure would allow lifting SEALAB
to a greater height but it would also present the undesirable possibility of
unseating the main access hatch. As a result the SEALAB could not be
raised high enough to clear its bow end from the ground without exceeding
safe limits of viewing port differential pressure and the decision was made
to set it back down in its same position without reorientation. Ballast tank
No. 2 was then flooded and the entry procedures were commenced. The
slopes were finally determined to be about 60 both fore and aft and athwart-
ships and they proved to be tolerable though somewhat annoying to the
aquanauts. A leveling provision was not made for the SEALAB base since
site surveys showed that the bottom slope would be in the order of 50 or 60

Raising - Problems were encountered in raising the SEALAB in that, due
to its 6 slope, ballast tank No. 2 could not be blown completely free of
water. The weight of the water remaining in ballast tank No. 2 plus the
weight of some additional material that had been placed in the SEALAB
during the operations plus the possibility that some bottom breakout resist-
ance had developed over the 45 day operating period, all combined to
increase the lifting force required to get SEALAB off the bottom to more
than twice that of its negative buoyancy when it was lowered. A lifting
force varying from 20,000 to 30,000 pounds was applied for over an hour
without moving the SEALAB. The water from ballast tanks No. 1 and 3
was then blown out in an attempt to lighten the SEALAB. The SEALAB
weight was thus reduced to the extent that it was lifted with a line tension
of 20,000 pounds but because tanks No. 1 and 3 could not be blown symmet-
rically an unbalance existed and the SEALAB arrived at the surface at an
angle of about 40� bow up. After blowing the conning tower and leveling
the SEALAB with an assist from the crane all remaining water in the ballast
tanks was removed and the vessel prepared for tow to LBNSY.

SURFACE OPERATIONAL SUPPORT

The primary surface support functions were provided by contract and
military personnel. Contractor personnel were employed for:

a. operation of the BERKONE

b. instrumentation and communications installation and maintenance

c. photographic coverage (for NOTS)

d. messing, berthing, and housekeeping

e. spotting for BERKONE position keeping

Military personnel provided:

a. surface support diving

b. operation of auxiliary surface craft

c. watch standers on BERKONE

A total of approximately 40 civilian contractor personnel and 40 NOTS
military personnel were used in the above functions. In addition, the
aquanauts, not in SEALAB, and other project, military, divers performed
surface functions relating directly to the support of the SEALAB aquanauts.
Two 1Z-hour shifts were established for all surface operations. Most of
the operating personnel were quartered ashore; however berthing for up
to 40 people was provided aboard. An average of about 80 people were
aboard during the day.

Among the more interesting of the operational procedures was the handling
of the PTC. It was originally thought that the PTC might be lowered to the
bottom directly by the crane on the BERKONE. Wave action caused heavy
loading, however, and the PTC was therefore lowered with the counter-
weight lowering system. With the counterweight system employed, the
aquanauts stated that they felt no accelerations nor other sensation of
movement while being raised to the surface. At the surface the PTC was
transferred to the crane, lifted out of the water, and set on the 01-level
where its ballast tray was removed. Using the crane the pressure capsule
was then moved to the mating hatch on the DDC. Control of the PTC while
on the crane was by four tag lines. At the DDC the tag lines were replaced
with four sets of block and tackle for better control during the mating oper-
ation.

NOTS surface support divers, available on a 24-hour basis, operated from
their diving boat (LCM-3) and were capable of making scuba or deep sea
dives. A total of more than 1,000 man-minutes of diving time were logged
for 30 scuba dives and one deep sea diver.

Although not specifically assigned the responsibility for photographic and
TV coverage, NOTS obtained some documentary coverage for both above
water and underwater operations. For underwater photography and TV
coverage a frame in the form of a tripod which had been previously

developed for underwater work was used. A remotely operated pan and
tilt platform was mounted within the tripod in such position that it would
afford a view downward and outward between the legs of the tripod. On
this platform were mounted two 16mm motion picture cameras, a 35mm
still camera, two 1,000 watt incandescent lights, a strobe light, and a
high resolution TV camera - all remotely operated from the BERKONE.
The tripod was handled with the crane on the BERKONE and could be
placed on the bottom at any point within a radius of about 100 feet and
outboard of the vessel.

An interesting, thbugh annoying, phenomenon occurred in the use of the
underwater TV cameras when they were installed inside of SEALAB II.
It was found that they lost focus after operating in the SEALAB atmosphere
for varying periods of time ranging from a few hours to a day or so.
Apparently the helium was leaking past the seal in the camera's pressure
housing resulting in a change in characteristics of some of the electronic
components which presumably are pressure sensitive. This problem was
avoided by mounting the cameras outside in the water looking in through
the viewing ports. Preliminary tests indicate that the problem is caused
by a pressure buildup inside of the camera housing and not in the presence
of helium per se.

It is estimated that the AVR-10 in making personnel runs between the
BERKONE and Mission Bay covered a total distance of 9,000 miles. The
LCM-6 in making runs to the NEL waterfront and elsewhere probably
covered Z,000 miles. Diesel fuel consumption for the auxiliary surface
craft and the BERKONE's crane and generators averaged 4,000 gallons
per week. Fresh water consumption on the BERKONE averaged 9,500
gallons per week. This fresh water was supplied by the two 3/4-inch
plastic pipes from Scripps Pier and does not include that used in the
SEALAB II. It is estimated that a total of about 10,000 meals were
served aboard the BERKONE during the project.

CONCLUSION AND GENERAL COMMENT

In general conclusion, it is felt that the problems of staging and supporting
a Man-In-The-Sea type operation, such as SEALAB II, have been defined
and successfully met. SEALAB II operations have shown, however, that
some improvements could be incorporated in future Man-In-The-Sea exper-
iments. These improvements would include: a remotely controlled ballast
flood and vent system capable of operation at steep angles of SEALAB roll
and pitch; the provision of more cold storage in the habitat to reduce the
number of dumb waiter transfers required; a method for leveling the habitat
to compensate for bottom slopes; an improved method of transferring items
from the surface to the habitat; provision of shore power to the surface
support vessel, if practicable, to eliminate noise and generation of carbon
monoxide; an improved above water handling system for the PTC; and
greater sophistication in communications to the habitat especially in the
area of helium speech unscrambling.

It may be found, in the application of the Man-In-The-Sea concept to actual
salvage or other type operations, that an independent, underwater power
supply will be required in the event that the surface vessel should have to
be removed and shore power is unavailable. A habitat design that would

permit raising it to the surface tending craft each night might be desirable
under certain applications particularly if the nature of the job required
short stays at various locations.

A significant advancement in the handling of large objects with high mass
and drag in the water column from a floating support was achieved in the
SEALAB II operations. The counterweighted lowering system used for
lowering and raising the SEALAB II and the PTC completely eliminated all
adverse surging effect of the sea.

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SEAFLOABOGRIH
SIT-

MILE

22 NAUTICA
MILES

FIG. 1. SEALAB II Site Vicinity.

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FIG. 2. SEALAB Operational Configuration La Jolla, California
.Aug - Sept 1965.

FIG. 3. SEALABUI Installation La Jolla, Calffornia.

FIG. 4. SEALAB nI Primary Surface Support Vessel -
"The Berkone".

SEQUENCE OF LOWERING OPERATION-

1 2 ~~~~~~~~~~~~~~~3

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OR OR OR
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FIG. 6. Counterweighted Lowering System - Static Characteristics.

SEA LAB II

CREW SELECTION, TRAINING, AND DAILY OPERATIONS

Commander M. Scott Carpenter, USN
NASA Astronaut

ABSTRACT

This paper deals briefly with crew selection criteria for the Sea Lab Pro-
ject, and with the training activities during the 6-month period preceding
the Sea Lab II experiment. In the section on daily activities during sub-
mersion the scientific investigations are enumerated, some of the Sea Lab
and diving equipment is explained, and a number of the problems encoun-
tered with design and procedure are discussed.

INTRODUCTION

Any manned operation involving exploration or exploitation of a foreign
environment is customarily subdivided into two separate but related
endeavors:

1. The design, fabrication, and testing of the machines that will be
required.

2. The selection, training, and testing of the men who will participate.

Although this discussion is limited mainly to the activities of the crew, it
necessarily includes some of the hardware development endeavor because
during the period immediately preceding the dive our training consisted
solely of redesigning, modifying, completing, and testing the Sea Lab, per-
sonnel transfer capsule, and the deck decompression chamber. Consider-
able work was done on the surface support vessel as well, in order to make
her compatible with our needs.
SELECTION

To treat the problem of Sea Lab crew member selection, it is necessary to
go back in time to Sea Lab I or perhaps even project Genesis, which was a
2-week 100-psi chamber test prior to Sea Lab I.

In Genesis, Captain Bond selected from among his diver acquaintances men
who he intuitively felt were well-qualified to withstand the rigors of isola-
tion and prolonged exposure to high atmospheric pressure. All did exceed-
ingly well. Although I have not discussed the matter in detail with
Dr. Bond, I am sure that he agrees with Captain Cousteau, who feels that
elaborate selection criteria and testing procedures are unnecessary for se-
lecting small crews. Further, Captain Cousteau says that given the oppor-
tunity to talk to a prospective crew member through a 2-hour luncheon he
can know beyond any shadow of doubt whether or not that man would make a
good member of his team. There is certain merit to this system, but it
has shortcomings. Two notable quotes bear on this subject. Sargent
Shriver said in Congressional testimony: "Our psychologists have said,
and our experience has borne them out, that a selection process must de-
pend on a conglomeration of considerations. No one test nor any one pro-
cedure can be counted upon." Dr. Abraham Carp, psychologist with Peace

Corps, backing up Shriver said: "The selection of people is a young
science. No one selection tool even begins to be perfect. That is why
Peace Corps selection is deliberately structured to bring to bear many
different selection tools. As Mr. Shriver testified, no one element of
this process is determinative, but each makes a definite and distinctive
contribution to the process. "

If there is to be a larger program of manned undersea research under-
taken by this nation, then we need not only more crewmen but also they
must come from a younger age group than the present one, and there-
fore, out of reach of the personal acquaintance of the current principals
in the program.

For instance - with a few exceptions - the Sea Lab II diving team was
composed of the crew and surface divers from Sea Lab L By and large,
these men were senior divers with many years experience. Experience
is always needed, but there is also a need to enlist younger men to re-
place, as time wears on, the seniors. This will require a selection pro-
gram which takes into account interest, age, education, and motivation
as well as physical condition and past experience, but with less emphasis
on the last.

TRAINING

Training activities for crew members began April 1, 1965, in Panama
City, Florida, nearly 6 months prior to the scheduled beginning of the
underwater experiment. Classroom work included diving physiology and
physics, detailed study of the Mk VI semi-closed circuit breathing appa-
ratus which was used throughout the operation, underwater photography
techniques and equipment, and familiarization with the hookah breathing
apparatus or "arawak. " In addition, many hours were spent becoming
familiar with the Mk I SPU or swimmer propulsion unit and other auxil-
iary equipment, such as test kits and gas charging pumps for the MK VI
tanks.

Underwater audio communication equipment, handheld active and passive
sonars were studied and operated, and many hours were spent in the div-
ing locker designing and building equipment to support our operation, mix
our gas, store and ship our gear. Divers, in addition to being a very spe-
cial breed are, by necessity, jacks-of-all-trades.

Classroom familiarization with the Mk VI breathing apparatus took 1 week.
This may seem excessive, but the Mk VI is not the simple open-circuit
scuba gear that most people associate with diving. Figure 1 shows the gas
bottles and carbon dioxide absorbent canister worn on the back. The con-
trol block or pressure and flow regulator is shown above the center can-
ister. Figure 2 shows the Mk VI vest which is made up of an inhalation
bag on the divers right side and an exhalation bag on his left. Hoses and
a mouthpiece connect the two and on the upper part of the exhalation bag is
an exhaust valve which can be adjusted in the water by the diver. Adjust-
ment of this valve regulates the amount of each exhalation that is exhausted,
usually about one-third, and this is what qualifies the Mk VI as a semi-
closed circuit breathing apparatus. This valve, used in conjunction with a
bypass valve on the control block, also controls the degree of inflation of
the breathing bags. This gives the diver some control of his buoyancy
which is very useful when he works at varying depths.

We began our actual use of the equipment in the swimming pool. After two
1-hour sessions, we took to deep water where we conducted the rest of the
diving training. One day was spent diving in 30-foot water, 4 days in
60-foot water, 5 days in 100-foot water on nitrogen-oxygen mix, and an-
other 5 days in 200-foot water on helium-oxygen mix.

We were led to believe by some of the divers with hard hat helium-oxygen
diving experience that the use of the helium mix would result in much more
rapid loss of body heat and more rapid onset of the shivers because of the
substantially higher thermal conductivity of the helium. If this was so, it
went unnoticed by us.

A good portion of our time was spent in becoming familiar with the phys-
iological and psychological testing equipment and procedures. This was
necessary in its own right, of course, but it also provided good base-line
performance data on each man. In addition, a day was spent at the Pen-
sacola Naval Hospital with EEG, ECG, cardio-pulmonary function, long
bone X-rays, and other physiological base-line studies.

Unfortunately, the entire Sea Lab team was not available for training at
the same time which necessitated conducting all of the training at least
twice. This, plus the lack of fast surface transportation to deep water,
which was quite a way out, made for a not-too-efficient use of our time
during this phase of our training.

Throughout the 3-month training period at Panama City there was little
opportunity to learn much about Sea Lab II herself, or the two decompres-
sion chambers we would be using. When the crew moved to Long Beach
in July, we saw for the first time the nearly completed Sea Lab and be-
came busily engaged in learning her functions, valving procedures, mech-
anisms, and idiosyncrasies. Under the critical eyes of this crew, and
those of Captain Walt Mazzone and Joe Berkich of the Naval Ordnance Test
Station (NOTS), many design changes were proposed and incorporated.
Serious, potentially fatal deficiencies, involving the design and fabrication
of both decompression chambers were uncovered and corrected. Testing
procedures had to be devised, operating instructions drawn up - and all by
trial and error - before training in the proper use of the PTC and DDC
could be conducted. Throughout this period, much time was spent doing the
back labor required to get our home ready for the sea floor. The time
might have been better spent in study of procedures, blueprints, system
operation, and continued on-site deep water exposure with the Mk VI. This
however, would have required more men, more time, and of course, more
money than we were allotted.

Each day of the 6-month training period was started with 30 to 40 minutes
of compulsory physical training in the form of running and calisthenics.
I firmly believe that this was one of the most valuable activities in the en-
tire training syllabus. We all needed the exercise, it always got the day
off to a good start, it gave the crew a chance to engage in some idle chatter
and horseplay as a unit, and it gave everyone something to complain about.
All of these, in proper measure, are important to sailor morale.
DAILY OPERATIONS

The lowering operation went off with only one hitch - the loss of one lab-
load of 100-psi helium through improperly sealing port covers. Once this
was overcome, the lab was lowered smartly to the bottom, ballasted, mon-
itored for a day, and the occupation began. It was not really that simple
at all but the NOTS lowering scheme worked so well that it appeared to be.

The first two divers of the first team opened and inspected the lab. The
second two opened and inspected the PTC. When these two jobs had been
accomplished, the surface was advised and the other six crew members
joined us. Then the work began.

Our first tasks involved unsecuring all of the equipment that had been
lashed down for the tow from Long Beach to La Jolla and restowing it so
that there was room enough for the ten men. The water lines, safety

anchor line, sewage lines, drain lines, diving light leads, benthic lab
lines, "arawak" hoses and guide lines had to be connected. All drain
plugs, external and internal port covers, and lowering lines had to be re-
moved and stowed. Logistic support from the surface required tremen-
dous expenditures of time and energy both on the surface and below. And
so it went throughout the experiment - housekeeping and supply, through
pots --- for dry equipment, and baskets --- for wet equipment, consumed
altogether too much time.

Once the lab was reasonably habitable, all of our spare time in the water
was devoted to the scientific programs and equipment evaluations. This
included the erection of the strength test platform and associated torque
wrenches, the two-hand coordinator, the current meter, underwater
weather station and sound range, visual acuity range, stationary target
array, water clarity meter, pneumofathometer, fish cages, homing bea-
cons, compass rose, external TV cameras, bioluminescence meter, foam
and salvage project equipment, bottom current trailers, underwater stud-
gun equipment, photo and diving lights, bathythermograph, wave gage, and
anti-torque underwater tool test equipment.

Interesting work was done with electrically heated suits. The power was
supplied by a battery pack worn around the diver's waist in lieu of his
weight belt, or by an umbilical cord leading back to the lab. These suits
need considerable refinement before they are completely satisfactory, but
they are indispensable to the efficient use of a saturated diver in cold water.
Compression of the standard type of wet suit is anotherproblemthatneeds
solution. The surface divers who visited the lab were easily spotted by
their paper-thin wet suits. Ours had been in the lab long enough to absorb
the high-pressure helium and expand to their normal size, but when they
were sent to the surface they suffered an embolism of a sort and needed
a like period to contract to their original size. Needless to say, the ther-
mal barrier a suit provides degrades as the suit is compressed and one
answer to the cold water might be a suit filled with an incompressible
fluid which would help the suit maintain its original thickness.

Our daily jobs consisted of repairing diving lights, adapting equipment to
the list and pitch of the lab, replacing leaky valves, cooking, cleaning up,
inspecting all equipment for signs of deterioration, repairing "arawak"
pumps and gages, improving drainage, setting up the Mk VI breathing
equipment and drying all the Mk VI vests and personal equipment. All
this is in addition to the activity associated with getting each man into the
water at least once each day.

Before and after each dive, strength and manual dexterity tests were per-
formed in the water with the aid of equipment designed specifically for this
purpose. Each evening we did daily activity and mood check lists, and oc-
casionally worked with brain teasers and simple arithmetic tests to get a
feel for the effect on the higher thought processes the elevated atmospher-
ic pressure might have.

The outside "arawak" hoses continually fouled and kinked and had to be
straightened almost daily. And throughout it all, the constant battle with
pots and baskets raged.

During the third teams' tenure on the bottom, the storm of activity center-
ed around resupply abated somewhat because of the installation of a high-
pressure helium -oxygen mix line in the lab. This line, supplied by pumps
on the surface ship, permitted recharging of the Mk VI bottles in the lab
instead of sending them topside for refilling. It not only reduced the work-
load on the men and saved a great amount of time but also was kinder to
the equipment.

Although some of us had spent more than one full week practicing with the
swimmer propulsion unit (SPU) Mk I, these units were not used during
this experiment. Control of this unit is not good and degrades when two
men are riding it. That fact, coupled with the very poor visibility and
unreliable homing equipment, made the disorientation of a team of divers
a likely event. This would be acceptable for surface divers, but for men
saturated at 200 feet it would be fatal.

This type of equipment is very definitely needed for future work of this
sort, but it needs considerable refinement also before it can be used with
any degree of safety by saturated divers.

A substantial amount of time was devoted to physiological studies which
are the subject of other papers. We recorded EEGs both inside the lab
and on free swimmers. Blood samples were reluctantly given daily by
some, and on a less frequent basis by all. Saliva and urine samples were
morefreely donated. Pulmonary studies continued on a daily basis as didthe
recording of blood pressure, pulse rate, body temperature, and weight.
Although we all ate much more and used more oxygen than we normally
did on the surface, we all lost weight. There were no serious medical
problems however. The ear infections were easily controlled by medica-
tion and drying. The skin rash was not so easily controlled, but not par-
ticularly bothersome.

I think the synergistic effect of pressure, humidity, ventilation, and the
helium atmosphere was responsible for the fitful sleeping at first, but we
acclimated in a few days and the problem disappeared.

Tuffy, the porpoise and the most popular member of the crew, performed
very well. He showed himself to be a very fine and funny fellow and
proved that he could not only function as courier, but that he could easily
locate two separated divers in dark water. A porpoise with this training
provides a very effective method for locating a disoriented diver, and
showing him the way home by means of a line trailing from his harness
and attached to the lab. When Sea Lab Ill is on the bottom at 450 feet, she
will be beyond the reach of surface scuba divers and the value of an animal
with this training is greatly enhanced.

CONCLUDING REMARKS

Sea Lab II was a great step forward in man's attempts to colonize the
ocean floor. We found there were a number of things we do not need to
worry about that we thought we might. For instance, the submerged crew
did not experience any marked psychological breakaway from the surface
as they were expected to do. They responded to direction from the sur-
face and from the submerged team leader with even more gusto than they
did on the surface. Morale was exceptionally good and, except for rare
instances, camaraderie flourished everywhere. Further, there was no
evidence that I could see of a general slowing down of movement and think-
ing, and we did not require more sleep than normal plus an afternoon nap.
Subjectively, there was really no way to be aware of the strange environ-
ment except by looking out of the port holes or by listening to your own
voice. We also discovered many things that must be done before we pur-
sue this course much further. Among them:

1. Develop a reliable diver-diver-surface-sea lab communication system,
one that does not compromise the breathing apparatus and does not encum-
ber the diver with wires. It must also incorporate integrally a helium
voice unscrambler.

2. Develop a reliable, durable, easily donned and doffed heated suit.

3. Develop a self -contained closed circuit breathing apparatus which
carries enough gas to support a diver at 1000 feet for 3 to 4 hours. Cryo-
genic storage may be required, and new methods for monitoring carbonI
dioxide and oxygen are definitely needed.
4. Develop small, reliable, light-weight sonar equipment as part of the
communication equipment. This is an absolute requirement if we are to
have any reasonable diver mobility in dark and dirty water.
Perhaps the most important need that became apparent after the success -
ful completion of Sea Lab II is that of better public recognition of its mean-
ing. The whole endeavor is not yet well understood. Knowledgeable engi-
neers still come to me and say, "Didn't you feel awful cooped up inside
that thing?" - or - "Were you ever able to get out of it?" Many people

with above average awareness think Sea Lab U1 was just a submerged pres-
sure chamber test and have no inkling of its essence.
The essence of man-in-the-sea, in my opinion, is twofold. First, it is to
ficiency, endurance, and reliability comparable to that of a man working
on dry land. Second, it is to allow him to exploit the ocean floor, and haer
it is necessary to make people aware of the tremendous potential for ex-
ploitation that awaits us on the sea floor. Conservative estimates show
that the bottom of the ocean holds riches beyond measure in the form of
diamonds, gold, copper, manganese, oil, fresh water, artifacts, and yes,
even pirate's treasures. The paradox is that most of this wealth lies with-
in a scant 1000 feet of a luxury liner's dance floor, and yet it is farther
from the state-of -the -art to attain than it is to prospect the far side of the .
moon - 240,000 miles away. Great benefits await no matter where we ex-
plore, but it is clearly apparent that the most immediately available are
waiting for us underwater.

t~~~~~~~~~~~FGR

61~~~~~~~~~~~~~N~

I
i

I
I
i

i
i
4

I
I

FIGURE 2

I I
4

1
r,

PROPULSIVE EFFICIENCY OF MAN IN THE SEA
Robert Taggart -- A,1NE
Abstract
M,,an is capable of self-propulsion in the water but his effi-
ciency is much lower than when on land. This inefficiency is
reflected in the consumption of large amounts of oxygen per
unit of distance covered. Because in underwater work he must
carry his oxygen supply with him his inefficiency is greatly
magnified. It is proposed that his oxygen consumption per
mile be used as a measure of propulsive efficiency. Analysis
shows that without some form of prdpulsive aid man's perform-
ance in deep water is severely restricted. An available source
of auxiliary power is the expansion of gas from the compressed
air tanks he carries. A concept is suggested for using this
power for swimmer propulsion. The exploitation of this power
source for amplifying man's underwater propulsive capability
isstrongly recommended.

The f/an in the Sea progran is intended to develop man's under-
water capabilities to the point where he can perform useful
and effective work in this unnatural environment. If he is
toperform efficiently he must have mobility. He must be able
to move from one location to another and do so in a reasonable
amount of time without depleting his capacity to fulfill mis-
sions. This paper attempts to analyze man as a self-propelled
underwater vehicle and to indicate the environmental factors
which impose limitations on his capability.
The major problem encountered with men working underwater is
that of supplying them with the oxygen necessary to sustain
life. Oxygen, man's fuel supply, is in continuing demand
place. The greater the energy output the greater is the
demand for oxygen and so the quantity of oxygen required can
serve as a scale to measure the cost of any task performed.
Performance of a mission with a minimum of oxygen consumption
is essential to the efficient operation of man in the sea.

Fortunately, for an engineering analysis, man's oxygen con-
sumption can be directly translated into power. One cubic
foot of oxygen consumption per minute is equivalent to about
13 horsepower. There are definite limitations on man's ability
to consume oxygen and to transform it into propulsive power.
He can put out large bursts of power for a short period of
time but then he must replenish the supply of oxygen expended.
His maximum power output over a given period of time is con-
trolled by his oxygen debt limit and by the rate at which he
can replace the expended oxygen. Sustained exertion requires
that his oxygen replenishment rate be continuously equivalent
to his power output.

Using available physiological data it was possible to derive
the power-endurance curve shown in Figure 1. First a relation-
ship of power consumption versus speed for well-trained and
conditioned surface swimmers using the crawl stroke was extract-
ed from published data. Then it was assumed that champion
athletes tailor their performances to put out the maximum power
for the length of time necessary to cover a prescribed course.
Swimming time records for distances from 100 meters to 40 miles
were examined and the results were combined to develop Figure 1.
This can be considered a near maximum performance curve for
athletes in excellent physical condition.

j ~~~~~~~~~~~~63

Using this curve as a basis
it is possible to compare
,1 | !|the sower requirements for
OK ' ~IA I ~other human activities.
.12 ,~~~\ I Figure 2 shows the derived
ol�0~ ~\ ~~ lspeed-power curves for rec-
a \ Iord performance in other
sports. These curves indi-
cate that man's speed in the
a - water is far below his speed
I "| --_ on land. They also show the
7 2 1 ~ ~----S possibilities of mechanical
7 El1 2 6 6' 8 Z S, N2 60F amplification of speed capa-
END.URANCE 1. MINUTES bility. It is interesting
to note that the speed in-
HU.MAN POWERXENIEREUAFUNCTIOFENDURAN.E crease ratios between rowing
FGURES and swimming and between
bicycle riding and walking
are on the order of three to
one. In other words, given the proper vehicle and mechanism for
the task to be performed man has the capability of a threefold
speed improvement in self-propulsion.

In Figure 3 these data have been converted to fuel rate versus
speed. Fuel rate is expressed in oxygen consumption per mile.
The low point on each curve indicates the most efficient speed
for the particular activity. It can be seen that the optimum
speed is about one knot for swimming, 3.5 knots for walking
and rowing, 4.5 knots for skiing and running, and 12 knots for
bicycle riding. The optimum fuel rate varies from a high of
4.2 cubic feet per mile in swimming to a low of 0.53 cubic feet
per mile when riding a bicycle.

The swimming curve used previously was derived from data on
surface swimming using the crawl stroke. Figure 4 shows how
this stroke compares with other surface swimming strokes for
overall efficiency. The percentages given are ratios of the
power required to tow a man through the water to the power
equivalent to his oxygen consumption in covering the same dis-
tance at the same speed. They are overall efficiencies based
on fuel energy rather than propulsive efficiency. It has been
estimated that in movement across solid ground man's efficiency
ranges from 22 to 41 percent
as compared with maximum
:,, :: swimming efficiencies of
A ... --EE _ J_,,UIEC-MIINA i / Aabout two percent. This
6 OSRCM& u'/ / indicates that man is ex-
, I I ELERC1INI/ ~tremely inefficient in
P 52 17 / / / converting fuel energy to
_~I / .',- /1 propulsive energy in the
�0 10 / ~/ /AI: O-,- water. As a comparison a
�~ 3- - - - .. ~ modern cargo ship utilizes
A'-+-At- - = -7' ...... O 20 to 25 percent of the
K - - N-;! _ energy in its fuel when
3 I-/Y~R /~ ~moving through the water.
.,-1ff.i@ _~ It will be noted that the
addition of swim fins
,,I .3. AB.lIN A A A MS M 123 results in a doubling of
WEED. IN NOTS swimming efficiency. It
is quite evident why this
S ROYEEDPOWER CESFORNVUANSIESFMN O propulsive device has been
FIGURE2 adopted for all underwater
swimming.

In surface swimming the sup-
ply of oxygen is limited
only by the amount which
-E, R'UEA ...I.... the swimmer is capable of
E 1 11.II I ~consuming. Endurance is
3 R ,WoNIN.G'I S7tiNq limited by his skill in
'. v 3 ~ j;.: |1 expending the available
2 I '>-L ,''UNING fuel and by muscular fa-
!b=. I li vtigue. When he goes below
E-310 ... --3 an | the surface he must carry
.R ... E . 'his oxygen with him. This
E 1ll | 1llI means that his displace-
". .2 .3. . . . 2 3 6 O A ment and drag are increased
SPEED IN KNHOTS
and his endurance is limit-
FUELRUESFUR AUCTUTERFAN ed by the quantity of fuel
FUEL RATE CURVES FOR VARIOUS ACT1ILTIES OF .1 e a cry Asa rea
he can carry. As a crea-
FIGURE3 ture of the atmospheric
environment man is accus-
tomed to using great quan-
tities of free air to extract the amount of oxygen which he
actually needs. His bodyinsists upon having this air supplied
at a regular rate. Under normal circumstances his air usage
is about twenty times his oxygen requirement. Carrying all of
this excess air with him involves a considerable loss of pro-
pulsive efficiency.

Much work is going into the improvement of this situation.
The Mark VI semi-closed circuit breathing apparatus used in
the SMALAB II project extends the air supply by recycling and
filtering; further developments along these lines will undoub-
tedly be forthcoming. In this discussion, however, it is
assumed that underwater swimmers are equipped with SCUBA using
either air or an oxygen-helium mixture in an open circuit sys-
tem. It is further assumed that the swimmer is operating from
an underwater structure and no consideration will be given to
problems of descending to working depth or ascending to the
surface.

When a swimmer is operating at depth there are certain append-
ages which are necessarily added to his hull. These include
protective clothing, face mask, knife, flashlight, back-rack,
and weight belt. These basic appendages increase his under-
water volume by about 20
percent and his drag by
about 30 percent. The
volume and drag of his air
supply tank are then super-
3-2 3 .....N._ imposed.
'N / ; The drag, or resistance to
3 2 / RAOSTROE motion of a body in water,
X U=~- ~varies considerably with
., / z - akO !i-the size and configuration
2RRuASTn S of swimmers and their gear.
Average values resulting
2o from towed swimmer tests
R.IN.RIRFEEDI .KNOTS3 indicate that for a fully
equipped swimmer without
RELATIVEEFFICIENCCY OFVARIOUS STROKES IHNSURFACE RSMUNR air tanks the drag in
FIGURER pounds is equal to the
square of his speed in
feet per second. The
addition of air tanks

E.0 increases this drag by a
factor equal to about 0.7
2.A,.CC, percent of the rated vol-
20~ ~~~4
TO�-// / usme of the tank in cubic
1.5 '~ // feet of air at atmospheric
pressure. As an example,
a single tank which has a
I ~xx nominal capacity of 70
cubic feet will increase
the swimmer's drag from
'9 / 1.007)2 to 1.490 where
7) is the speed in feet
per second.

.4 .5 .6 .7 .E . 1.0 . 2 10 Numerous experiments have
IEPEEDIN KNOTS been conducted by the U.S.
Navy and the British
Admiralty relative to
FIGURES oxygen and air consumption
of underwater swimmers at various speeds, at work, and at rest.
Figure 5 shows curves of horsepower versus speed which have
been derived from these test results. Starting with averages
for swimmers at a depth of 16 feet carrying three 35 cubic
foot air bottles and assuming the same efficiency versus speed
for all cases the curves were developed to show the effect of
the fuel tank drag on the speed-power relationship. It can be
noted that at a speed of one knot the horsepower expenditure
increases from 0.80 to 1.10 when an air supply of 210 cubic
feet is added.

These speed-power curves can be converted to fuel rate curves
as shown in Figure 6. The speeds at which the minimum oxygen
is consumed range from about 0.9 knots when carrying a 210
cubic foot air supply to about 1.3 knots when carrying no air
supply. The latter condition is included only to illustrate
what a swimmer could accomplish if he were not burdened with
the drag of his supply tanks. Note that the swimmer's oxygen
consumption at the optimum swimming speed is 4.7 cubic feet
per mile when carrying a 210 cubic foot supply, 4.4 with a
140 cubic foot supply, 4.0 with a 70 cubic foot supply, and
3.5 cubic feet per mile with no air supply.

The real measure of effi-
ciency is how far can a
swimmer actually travel
on the air supply he
carries with him. This is
shown in Figure 7. To
i // / develop these curves it
-~~-/// has been assumed that the
.I: -. A, I . I .AF:IT -DU INC EET 0107/ / oxygen needed by the swim-
/,<e// / mer demands a supply of
.=~ air equal to 21.2 times
the quantity of oxygen
required. It has also
been assumed that the en-
tire rated volume of air
in the tank has been con-
sumed with the swimmer
UNDERWATER SRI.MER FUEL RATE AT IA FOOT EpTH breathing at a depth of
16 feet.

The optimal swimming

speeds range from 1.1 knots
NOMINAL 0 060 CAl 6000 ....T\cu i
.NO..A. FEECA ACIT| when carrying a 35 cubic
foot air tank to 0.9 knots
1.0 ,3 l < I ~ -'> when carrying 210 cubic
'f 7 ~~- - \'\\ feet of air. The distance
_7 /~- > k \\ which can be travelled does
J36/ D ~~ a \\I\ not increase linearly with
-<S H| \ \ \T the amount of air carried.
With a 35 cubic foot tank
the maximum range is 0.3
tTg ~/ - \miles whereas with six
OTIUR...EED times the amount of air in
the 210 cubic foot air sup-
~/ |~ |~ , \ ply the distance is in-
. .3 ., .3 .6 .7. .1.0 1.5 2.0 3.0 creased by only 4.7 times
SPEIOEED RIoNMERT to 1.4 miles.

RANGEERATIFORATERWINNERATFOOTDEPTH en the swimmer is work-
FIGURE ing at greater depths the
optimum speed versus fuel supply relationship remains the same.
However his air supply is depleted at a greater rate due to the
fact that he maintains approximately the same breathing rate
and volume but extracts the air at an increased ambient pres-
sure. Figure 8 shows the distance which can be covered as a
function of tank capacity for different depths of operation.

From an examination of these curves it is obvious that as a
self-propelled vehicle in deep water man leaves much to be
desired. Although operation on semi-closed circuit breathing
apparatus can multiply these distances by a factor of two, the
results are still not impressive. If man is to be able to
operate and work over any reasonable distance on the sea floor
he needs some form of propulsive assistance.

One direction to follow in providing this assistance might be
to develop mechanical means of amplifying man's speed capa-
bilities in the water. Earlier it was shown that rowing and
bicycling provided efficient speed amplification in surface
travel. In the files of the Patent Office there are many
swimmer assistance devices from which to choose. At the turn
of the century inventors turned their talents to assisting
survivors of ship disasters in getting ashore. Some of the
more interesting inven-
tions which resulted are
TO [ / shown in Figure 9. Some-
I.S ,OOSUOFACE vwhat more practical de-
,j ~ ~~vices for aiding the under-
_130 , water swimmer are being
3. 7 // 2S . a -proposed today.
t3.3 / / /
214 / / '0/ / - There is one source of
1,.3 / / / /power available for swim-
mer propulsion which is
being completely wasted
in modern SCUBA. Until
~~/.~// ~ man is able to extract
N0M IN 13ACAFC FEEOT oxygen directly from the
water this source of power
UNDERW.ATER-SWiiNG.RANGEATOPTiMUASEED will be carried on his
AS A U.TION OF TANK CAFACIT A.. DEP1T back. This power is con-
F-RE 8 tained in the compressed
gas from which he obtains
his needed oxygen.

It is customary to provide
an underwater swimmer with
one or more tanks of air or
gas mixture which are ini-
tially charged to a pres-
19 A | - I sure of around 2400 p.s.i.
In a double stage system
this gas is supplied
through a reducing valve
to his breathing demand
regulator at a pressure of
about 160 p.s.i. As he
breathes from the regula-
tor, gas is supplied to
his mouthpiece at ambient
vorg pressure. In the expan-
sion of the gas from tank
P4TMTE. CO.CEPTSOOF SWAER PROPULSION pressure down to ambient
ASSISTANCE DEVICES pressure there is a large
FIGCUREE amount of energy which
could be recaptured.

In Figure 10 is shown an idealized pressure-volume diagram of
the gas expansion which takes place during one respiratory
cycle of a swimmer. The numbers in parentheses are the pres-
sures and volumes representing a fully charged air tank. The
swimmer is assumed to be resting at a depth of 100 feet. The
upper line A-to-? represents the volume o, extracted from
the tank at tank pressure for each breath taken by the swimmer.
This expands to the volume v2 at the regulator pressure v2
along the hyperbolic curve 9-to-C . The regulator demand
valve releases this volume to the mouthpiece and the pressure
drops from the regulator pressure to ambient pressure along
the line C-to-V . The swimmer extracts this tidal volume
from the mouthpiece at ambient pressure represented by the
line D-to-F .

The shaded area under the curve is a measure of the work done.
This work is given in the equation at the upper right. For a
single breath under the conditions shown the work done is 1653
foot pounds. At an average resting respiratory rate of 15
breaths per minute this is equivalent to 0.75 horsepower.

Of course as the tank pressure drops and as the ambient pres-
sure increases with depth
the available work will be
-* W RK r,(Io -,=
AMMO$RN .,., -P less. The variation of
EDE DI.I 5R IDEIS available power with tank
TAREPRESSUSEF. 5 .B I,,,.,,o.... pressure and depth of
...... -,oo , ( - swimmer is shown in Figure
11. The lower set of
xONSM\_curves gives the horse-
, <_C:NSTApower available when the
REOULOR PR.ESSURE swimmer is at rest breath-
......se ioo,| ing at his basal rate. If
AMBIERT PRESSURE p' E
IRSS;. ,' D' the swimmer increases his
respiratory rate and vol-
TIDAL.OLU.EM0.02 I.. . ume the available power
increases as shown in the
upper set of contours of
PEURE-�OLUE DIAGRA 0P UNDERfATER Figure 1 1 . These upper
REUATVGU COOLS Ocontours represent the gas
URE10 expansion energy available

when the respiratory minute
volume of the swimmer has
increased to that required
~ I t I I I -- to swim at a speed of one
03*D AISuURFACE knot. The dashed line in
,4~ 1f- ........ AT 0 KNOT the center of the graph
~z0o shows the oxygen horsepower
o]S ///~ I I I expended by the swimmer in
HO R0SEPDEER EXPDED S! SIAID ]propelling himself at a
speed of one knot. It can
be seen that the energy
5 I-i --t�-T/ I wasted in gas expansion is
0.4 /A/-fl EEE~hI4NDTBSAOLRATE greater than that required
"~ /7/X I I I for self-propulsion.
,3 0 0 100 10 00
INITIAL TAqlC PRESSURE IN POUNDS PER SQUARE INCHi
A question naturally arises
HORSEPOERNVA.ILA.L FORPROPUL510NAUSSIST,.CE as to how to recoup this
FMouRE,, power loss and to utilize
it for swimmer propulsion.
The expansion of gas can be
used in a variety of power conversion devices such as turbines
or reciprocating engines. However there are certain disadvan-
tages to employing these mechanisms. First the gas to be used
is that which the swimmer must breathe and therefore it cannot
be contaminated by any form of lubricant. Secondly the mecha-
nism will be operating in a difficult environment which requires
a minimum of moving parts, extensive corrosion protection, and
maximum simplicity. Finally the respiratory rate at which the
gas is expended is very low and any efficient rotating device
revolving at this speed would be of a cumbersome size. Taking
all of these factors into consideration it is my conclusion
that a flexible fin propulsion system could most efficiently
convert the available power to propulsive thrust.

Fin propulsion is by no means a new concept but it has never
been exploited to the extent of its possibilities. Although
the same basic principle is involved when swim fins are used,
a swimmer cannot undulate his fins in a very efficient manner.
Figure 12 shows a fin propelled boat proposed some years ago
by Mganfred Curry. An adaptation of this boat was used by
Australian Commandoes in Burma during World War II. The fin
provides quiet, efficient propulsion when undulated at rates
commensurate with normal breathing rates. Furthermore an
extremely simple mechanism can be used to convert the expand-
ing gas energy to propulsive energy in this type of device.

A possible configuration
of a flexible fin propul-
sion assistance device is
shown in Figure 13. The
auxiliary propulsion unit
is mounted on a pair of 70
cubic foot gas tanks car-
tied on the swimmer's back.
The leading edge of the
FLEXIL-E FINl IROPELED MOUT PRDPOSED BY MANPRED CURRY fin is oscillated from side
to side by means of a pair
of bellows in which the gas
is expended. The bellows
are encompassed in a sur-
rounding tank which acts as
a gas reservoir. Pressure
within the reservoir is

maintained at an ambient
level by a diaphragm and
demand valve mounted in
the nose of the reservoir.
The breathing hoses are
fitted with check valves
-g 1 _ so that one hose acts as
a supply or inhalation
hose and the other acts
as a discharge or exhala-
X [ > , u X 1\ \ tion hose. W''hen the swim-
mer inhales, high pressure
gas is admitted to the port
bellows and gas from the
starboard bellows is dis-
charged to the reservoir.
..~ u \~ X?1When the swimmer exhales,
high pressure gas is ad-
mitted to the starboard
bellows and the port bel-
lows discharges to the
reservoir. The reduction
of ambient pressure during
inhalation and the increase
of ambient pressure during
AIRDRIVENFLLEXFIN FORUNDERWATOIUER SI1.OFULSION exhalation are used to con-
FIOuRE13 trol the gas flow to and
from the bellows so that
one complete breathing
cycle is equivalent to a complete fin oscillation cycle. Thus
the drive system has the characteristics of a double-acting,
double-expansion, reciprocating engine.

Not shown in the sketch are internal first stage expansion
chambers within each bellows which accommodate the reduction
from tank pressure down to about 500 p.s.i. The gas is dis-
charged from these chambers into the bellows where the second
stage of expansion takes place.

The combined volume of the two bellows is greater than the
maximum tidal volume (volume per breath) of the swimmer. The
total stroke will be a function of the volume of gas used by
the swimmer with each
breath and the rate of
fin motion will be equal
to the swimmer's respira-
tory rate. Thus speed is
controlled by the regu-
lated breathing of the
swimmer.
FIN CONFIGRATION
El[ I ~ The fin itself can be
EJOER IImade of two layers of
L AI A IRDAPEE/ rubberized fabric with
NMIS I I |F1 RE-I-RE,/ Ithreads of the fabric
� ~1t ~ Ia ~ L | |connecting the two layers.
Ir I~--- L I 1_ -1 I The space between the
X IS D IS 45 layers can be pressurized
FIN LADING EDGE ANLE IN DEGREESOFFCENTERLINE from the gas bottles
through a reducing valve
FINDRIVIN PRESSUR DIAGRA which is preset to pro-
FIOGEI vide an optimum fin stiff-
ness. The fin can then

be depressurized for ease
in stowage when not in
use, In fact the reser-
WE . EbEXN~ ED BYSIad RIICKINGOIM. FIBNSTO YOUET voir can have walls of
,~~eE FLEXILE...O~UO, , Fl
30Y IB ROFULBICI Isimilar construction so
that the whole unit can
1S,.25 be collapsed.
B ROPELLE ' I FLEXIB E FIN ONLY
XI2 I BNYBINY B ALBAYB The rate at which the fin
is driven will not be
sinusoidal with time be-
cause of the manner in
0.5 I U 00 5 0 which the gas expands.
o.S 1.o 1.5 Mo 3.0
RANGEINAUITICL ILES The maximum force will be
exerted when the high pres-
ESTIANTED SIMINO RAN4GES WHEN pROFELLEO BY FLEXIBLE FIN IB sure gas is a dmitte d; it
MAIUNER CARRYINGTNO70CUBIC FOOT AIR TANISKIOO -ue gas is a dmitted; it
FIGUES vill drop off in a hyper-
bolic curve in accordance
with Boyles Law. Figure 14
shows the approximate fin motions and a plot of the pressure on
the driven area of the fin. There is an advantage to this
characteristic of the drive cycle in that the maximum force will
be applied during the part of the cycle when the fin is capable
of producing the most effective forward thrust.

There is insufficient information on fin propulsion to estimate
what sort of propulsive efficiency could be obtained with such
a device. But it can be very conservatively assumed that it
would be possible to recapture at least ten percent of the
energy available in the expanding gas. It is interesting then
to see what this can provide in the way of increased swimmer
range.

With the flexible fin aiding in propelling him through the
water the swimmer may relax and let the propulsion system do
all of the work or he may gain additional speed by kicking his
swim fins. As he applies this self-propulsion power his breath-
ing rate and volume increase which in turn increases the power
input to the flexible fin propulsion system. Although he can
attain a higher speed by kicking his swim fins in conjunction
with the flexible fin he exhausts his gas supply more rapidly.
Figure 15 illustrates the results.

These curves are calculat-
ed on the basis of a flexi-
II I I V-HI ble fin propulsion system
-aving an overall efficiency
20 .,"~"";"c'~P'"~ / ---~ -"-"-' of ten percent being used
I2 'Y fl ] -" by a swimmer at a depth of
--F"l I 100 feet. The swimmer is
0 ...., u - carrying two 70 cubic foot
-~ ,, Xl x - ~ gas tanks. If he kicks
I Iv / "00w 1 his swim fins with such
-- I/t XI ' - y- I vigor that he is expending
/1/3 1 / tf I I [ oxygen at a rate equiva-

[I1//x//2/ I Ilent to 1.25 horsepower he
311 YB /l 1 82, IWO4 can make an initial speed
NOINALYT*ANCAPACITYIBNCUBIC FEET through the water in excess
UNDERWATER RANGEONAIRRIENFLEXIBLE of three knots. H owever
FIN BREBATYIG NT BASAL RATE his gas supply is used up
FINuYe very quickly and the total
distance he can travel is
less than one mile. If,

on the other hand, he relaxes completely and breathes at a low
respiratory minute volume the flexible fin will propel him at
an average speed of about 1.5 knots. Under these conditions
his gas supply will last long enough for him to cover a dis-
tance of 2.75 miles.

Without the aid of the flexible fin propulsion system and pro-
pelling himself with swim fins alone this swimmer could have
covered a maximum distance of 0.37 miles. In spite of the low
efficiency assumed it appears that this flexible fin propulsion
system has the capability of providing a sevenfold increase in
swimming range.

This brief analysis of an auxiliary flexible fin propulsion
system has depicted a unit attached to the swimmer. For some
underwater situations it might be preferable to have a separate
vehicle which the swimmer could ride to his destination. Such
a vehicle could be basically a large compressed gas tank fitted
with a flexible fin and drive system. It could serve as the
oxygen supply for the swimmer when underway with his breathing
cycle furnishing the necessary speed control. From an overall
efficiency standpoint it is believed that a vehicle propelled
in this manner could be far superior to the battery powered
swimmer propulsion units now in use.

It is evident that on the basis of the distance which can be
covered the swimmer would do much better to relax and let his
auxiliary propulsion system do the work. Figure 16 shows the
potential range of a ten percent efficient propulsion system
as a function of depth and tank capacity when the swimmer is
essentially at rest. The tank capacity varies from that which
a swimmer might carry on his back to that of an auxiliary
vehicle. For all depths and tank capacities these ranges are
about seven times what a swimmer could accomplish on swim fins
alone. These results can be compared with the possible three-
fold improvement achievable by mechanical speed amplification
devices discussed earlier. It appears that on a relative
basis the air driven flexible fin has the greatest potential.

As long as a man underwater requires an external supply of
oxygen every effort should be made to use the power which com-
pressed gas can furnish. This applies not only to propulsion
but also to the accomplishment of other forms of underwater
work. In addition this power might conceivably be converted
into heat to provide the warmth so essential to a man in the
water.

In the foregoing discussion I have attempted to develop a
means of analyzing the propulsive performance of underwater
swimmers. ~Man in the sea, as on land, is a highly unpredict-
able creature. His adaptability to other unfamiliar environ-
ments has exceeded expectations and therefore this analysis is
perhaps unduly pessimistic. However under the best of circum-
stances it does not appear that without aid man will ever
approach the propulsive performance of the animals which make
their home in the sea.

It is apparent that if he is to be capable of transporting him-
self from one place to another along the ocean floor with any
reasonable degree of efficiency he must be provided with some
propulsive aid. This aid may be in the form of mechanical
amplification of his propulsive capabilities, better utiliza-
tion of the power already available to him, or providing him
with a transport vehicle. Whatever this means may be it is
evident that the development of propulsion assistance devices
must be encouraged if we are to obtain optimum performance
from man in the sea.

References

1. Breder, Jr., C. E. and Edgerton, H. E., "An Analysis of the
Locomotion of the Seahorse, Hippocampus, by Means of High Speed
Cinematography", Annals of the New York Academy of Sciences,
Vol. XLIII, Art. 4, pp. 145-172, June 20, 1942.

2. Brett, J. R., "The Swimming Energetics of Salmon",
SCIENTIFIC AMERICAN, August 1965.

3. Garrick, I. E., "Propulsion of a Flapping and Oscillating
Airfoil", Report No. 567, National Advisory Committee for
Aeronautics, 1936.

4. Gero, D. R., "The Hydrodynamic Aspects of Fish Propulsion",
American Museum Novitates, No. 1601, American Museum of Natural
History, New York, N. Y., December 11, 1952.

5. Lambertsen, Christian J., "Effects of Oxygen at High Partial
Pressure", Chapter 39, Handbook of Physiology-Respiration II.

6. Osborne, N. F. Y., "The Hydrodynamical Performance of
Migratory Salmon", Journal of Experimental Biology, Vol. 38,
pp. 365-390, 1961.

7. Rosen, Moe William, "Experiments with Swimming Fish and
Dolphins", The American Society of Mechanical Engineers, Paper
No. 61-W'A-203, 1961.

8. Saunders, Harold E., Capt., USN (Ret.), "Some Interesting
Aspects of Fish Propulsion", The Society of Naval Architects and
Marine Engineers, Chesapeake Section, 3 May 1951.

9. Yao-Tsu Wu, T., "Swimming of a Waving Plate", Journal of
Fluid Mechanics, Vol. 10, Part 3, pp. 321-344, 1961.

10. National Research Council Committee on Amphibious Operations,
"Report of the Cooperative Underwater Swimmer Project", NRC:CAO:
0033, January 1953.

11. World Almanac, 1962.

OCEAN ENGINEERING FOR HUMAN EXPLORATION

J. J. Hromadik
U. S. Naval Civil Engineering Laboratory
Port Hueneme, California

Abstract

An up-to-date review of many of the engineering problems associated with
manned and unmanned underseas facilities is presented. Included is a
progress report on the current efforts in The Bureau of Yards and Docks
Deep Ocean Engineering Program directed to provide the Navy with a
capability for designing, constructing, maintaining and operating fixed
installations, structures and equipments in an ocean environment. The
paper introduces the reader to developmental and test information on
work now in progress on sea floor soil mechanics, anchors and anchor
systems, and materials for underwater constructions. A brief report on
the Deep Ocean Environmental Simulation Laboratory that utilizes sea
water as a pressurizing medium with working pressures to 20,000 psi is
included.

INTRODUCTION

Human exploration implies that man will go down into the ocean and ob-
serve and perform that function or functions he considers necessary to
complete his exploration. Ocean engineering for human exploration means
providing man with the capability to do his exploring, whatever the rea-
son for his compulsion to do so. Some of his explorations in shallower
depths will expose him directly to the undersea environment; this paper
is not addressed to that aspect alone.

Of equal importance is man's extension into the sea with vehicles and
structures that will also place him at the site - or maybe, only through
remote controlled equipment and optics, that will place his capabilities
at the site, while he remains at the surface. This paper takes a brief
look at some of the technology aimed at achieving means for this explora-
tion. It is to these ends that the Bureau of Yards and Docks has imple-
mented an R & D program encompassing 7 technical areas: (i) site selec-
tion and survey, (ii), bottom soil properties and foundations, (iii)
construction equipment, (iv) anchors and moorings, (v) design and con-
struction, (vi) power sources, and (vii) support systems. Much of the
work is carried out by or through the Naval Civil Engineering Laboratory
(NCEL) at Port Hueneme, California.

FOUNDATIONS

Soil investigations in shallower depths can rely to a certain extent on
current technology, as developed by the off-shore oil industry. But
man's exploration into the deeper oceanic regions is presented with an
appreciably different, and most difficult, set of circumstances. Usable
exploration techniques are still in the formative stage and reliance on
past experiences is an event of the future. Soil investigative tech-
niques for these deeper regions have advanced little beyond the prelim-
inary stage. There is a difference of opinion among notables in the
field as to a suitable means of obtaining an undisturbed sample, most
realistic testing method, and the translation of the findings into usable
design criteria.

Until recently, examination of oceanic sediments as a foundation support
material has provoked only little interest. Heretofore, most sea floor
sampling was for oceanographic and geological purposes, of academic
interest totally unrelated to foundation investigations. Man's desire
to explore, and exploit, innerspace has presented him with a need-to-
know, and the interest in sea floor foundations is on the rise. To date
at the NCEL, hundreds of soil samples from ocean basins have been analysed
for physical properties. Tests essentially follow those standardized for
terrestial soils.

There are various types of coring tools in common use today. It is be-
lieved that the characteristics of the coring tool exert an influence on
laboratory findings. Also in question is the degree of induced distur-
bance resulting from the coring operation, and unknown changes that must
occur in the sample being brought from great depths at high pressure to
the surface, and the influence that transportation and storage may exert
on the sample before testing. Moreover, the shallow penetration depths
from which the core samples are taken are usually inadequate for founda-
tion analyses. Only in rare instances do the penetrations exceed ten
feet. Understanding the behavior of sea floor sediments may lie in per-
fecting techniques for strength measurementsin-situ.

The work at NCEL is directed not only towards improving coring methods
to obtain undisturbed samples...and longer ones, but also towards deter-
mining the influence of pressures on soil strength and developing tech-
niques for in-situ testing.

One task currently underway has as its objective the performance of shear
strength and consolidation tests on typical sea floor soil samples in a
high pressure environment. Tests will be conducted in a pressure vessel
with the pressures ranging from atmospheric to 10,000 psi. In this way
it may be possible to determine the effects of the deep ocean environment,
primarily that of elevated pressure, on the engineering properties of
these sediments. The shear strengths of samples will be measured using
both vane shear and direct shear devices. The former will have a vane
rotational speed of 60 per minute (clock motions speed) for tests on
cohesive soils; the latter will accommodate both cohesive and non-cohesive
sediments. The consolidation tests will be performed with a consolidometer
of the conventional fixed or floating ring configuration. A sufficient
number of soil types will be used to obtain some representation of ocean
sediments. The total number of tests to be performed on each soil will
be adequate to allow analysing the influence of the high pressure environ-
ment, and to determine this influence for variations in pressure.

A second program underway has as its objective the development of devices
for carrying out in-place strength tests of sea floor soils. The first will
be a plate bearing device. Basically, as designed, it consists of a large
hollow piston with a plate attached at the end of the piston rod. This
piston is supported and guided, and its displacement is controlled by
three small hydraulic cylinders. The submerged weight of the piston can
be varied from its tare weight of about 300 pounds to 5,000 pounds by the
addition of lead weights. The device will be lowered on a tether line
from a surface ship. When in contact with the sea floor, the device will
be supported on three pads having a total bearing area of about 30 square
feet. When tension is removed from the tether line the piston will force
a given size bearing plate into the sea floor to induce a shear failure.
It is planned to use different size plates to evaluate footing sizes ver-
sus bearing capacity. It is recognized that this first generation device
may not reveal the presence of compressible strata, but this is a problem
for a later day. The instrumentation system provides four channels of
read out via an acoustic signal. The parameters to be monitored are
plate displacement into the sediment, total load on the plate and inclina-
tion of the device from the vertical. The fourth channel is a calibration

Until recently, examination of oceanic sediments as a foundation support
material has provoked only little interest. Heretofore, most sea floor
sampling was for oceanographic and geological purposes, of academic
interest totally unrelated to foundation investigations. Man's desire
to explore, and exploit, innerspace has presented him with a need-to
know, and the interest in sea floor foundations is on the rise. To date
at the NCEL, hundreds of soil samples from ocean basins have been analysed
for physical properties. Tests essentially follow those standardized for
terrestial soils.

Two types of coring tool are in common use today, the gravity and the pis-
ton varieties. It is believed that the characteristics of the coring tool
exert an influence on laboratory findings. Also in question is the degree
of impressed disturbance resulting from the coring operation, and unknown
changes that must occur in the sample being brought from great depths at
high pressure to the surface, and the influence that transportation and
storage may exert on the sample before testing. Moreover, the lengths of
obtained core samples are usually insufficient for a proper foundation
analysis. Only in rare instances do the penetrations exceed ten feet.
Understanding the behavior of sea floor sediments may lie in perfecting
techniques for strength measurements in-situ.

A second program underway has as its objective the development of devices
for carrying out in-place strength tests of sea floor soils. The first will
be a plate bearing device. Basically, as designed, it consists of a large
hollow piston with a plate attached at the end of the piston rod. This
piston is supported and guided, and its displacement is controlled by
three small hydraulic cylinders. The submerged weight of the piston can
be varied from its tare weight of about 300 pounds to 5,000 pounds by the
addition of lead weights. The device will be lowered on a tether line
from a surface ship. When in contact with the sea floor, the device will
be supported on three pads having a total bearing area of about 30 square
feet. When tension is removed from the tether line the piston will force
a given size bearing plate into the sea floor to induce a shear failure.
It is planned to use different size plates to evaluate footing sizes ver-
sus bearing capacity. The instrumentation system provides four channels
of read out via an acoustic signal. The parameters to be monitored are
plate displacement into the sediment, total load on the plate and inclina-
tion of the device from the vertical. The fourth channel is a calibration

circuit. The instrumentation system was successfully tested in a pressure
vessel to a maximum pressure of 6200 psi, and at temperatures as low as
0�C. It is planned to begin developing an in-situ vane shear device early
this year.

In conjunction with this program NCEL is developing a deep ocean test
instrumentation placement and observation system (DOTIPOS). Essentially
this piece of hardware will be a platform that can be lowered on to the
sea floor to conduct the in-situ testing, observe and photograph the
tests, provide power to them and transmit commands to them and receive
data from them. The system will also be operated from a surface ship
and will include all the necessary cables, deck viewing control console,
a support structure for the in-situ test devices and an underwater view-
ing and lighting system.

In addition to the sea-floor soil mechanics studies the NCEL is studying
concepts of anchorages and means of improving these for deep water appli-
cations. One of the tasks deals with evaluating propellent embedment
anchors and the techniques and equipment necessary to their effective
placement and employment. The propellent embedment anchor, also commonly
termed explosive anchor, is a self contained bottom penetrating implement
similar to a large caliber gun consisting of a barrel, a recoil mechanism
and the projectile which is the anchor. These anchors have found limited
application in shallow waters. Preliminary tests at the NCEL include
testing vital components in a pressure vessel. The components of one
anchor passed the test to 10,000 psi. In addition to shallow tests, five
firings have been made in deep water, two each at nominally 1100 feet and
2500 feet and one at 6000 feet. Although the anchors exhibited high
holding power in shallow water tests, about 150 per cent of the rated
capacity, the holding powers in deep water tests were only one half of
the rated capacity. The reason for this degradation at the greater depths
is not known at this time.

In another study the NCEL is investigating the application of these
anchors to an anchorage complex for bottom mounted structures. The
anchor complex is a tripodial frame terminating in articulated, steel
bearing pads, each pierced by a vertical component carrying a propellent
embedment anchor. (Figure 1) Each anchor is attached by cable to a
battery-powered motor in the central portion. Once the complex is posi-
tioned on the sea floor, the three embedment anchors are fired. The
cable arrangement for payout is shown in Figure 2. The anchors are then
tensioned by cables winding on drums in the central compartment. This is
accomplished by a rewind mechanism driven by the electric motor. The
rewind mechanism has a 1356 to 1 gear ratio that is capable of developing
a 10,000 pound line tension. The anchors are individually tensioned.
Although the capacity of the complex depends upon the soil conditions,
it is estimated that in a reasonably competent soil the complex will sup-
port 80,000 pounds in bearing, a pullout force of 40,000 pounds and an
overturning moment of about 120,000 foot pounds. In recent shallow water
tests all components functioned satisfactorily.

SUPERSTRUCTURES

An extensive research task that is underway at the NCEL is concerned with
the long-term behavior of various materials of construction for underwater
structures. Because the program is extensive and since various aspects
have appeared in print,1,2,3,4 it warrants only brief conmment here. The
program includes the exposure of a variety of metallic and non-metallic
materials in ocean depths of nominally 6,000 and 2,500 feet for extended
periods of time to determine the corrosive and biological degradation of
construction materials exposed to an ocean environment. These depths
were selected because (i) the 6,000-foot depth represents a sea environment

on the edge of a major basin, and although it is an unprecedented depth
for present construction-type operations, it appears to be attainable in
terms of mid-range objectives; (ii) the 2,500-foot depth represents the
level of minimum oxygen concentration, off shore at NCEL. The work in-
cludes monitoring the environment at the sites. Figure 3 shows the night-
time recovery of a recent test rack from 6,700 feet.

NCEL's deep ocean simulation facility plays an important part in the
structures studies. The facility consists of six 9-inch ID pressure
vessels and one 18-inch ID vessel. (Figure 4) All vessels have a 20,000
psi safe working capacity, use sea water as the pressurizing medium, and
are equipped with refrigeration coil permitting experiments at any temp-
erature from ambient room to 0� centigrade. Provisions have been made
for optical viewing, internal lighting, environmental monitoring, and
instrumentation connection inside these vessels. The smaller vessels
were fabricated from 16-inch high capacity naval projectiles5 and have
an inside usable length of about 26 inches. They are permanently mounted
in vertical orientation. The large 18-inch vessel was fabricated to
specifications and has an inside usable length of 36 inches. It is gim-
baled for operating in any orientation.

In looking at broad objectives one may tend to overlook a small but sig-
nificant component; perhaps it may be a window. It is a fairly reasonable
assumption that manned-ocean structures at all depths will be provided
with ports or windows for optical purposes. There is but a dearth of
design data on materials used in windows exposed to high hydrostatic pres-
sures for short and extended durations. "What constitutes a safe design?"
is one of the questions NCEL hopes to answer. An experimental program is
in progress to determine the safe operational parameters for glass and
acrylic windows that can be used in external and internal pressure vessels.
The first phase of the study is directed towards determining the strength
of acrylic windows subjected to short-term, hydrostatic loads at room
temperature. Tests have been completed on window specimens having 30-,
60-, and 90-degree included angles, i.e., the windows are frustums from
cones having these angles. The windows, machined from grade G acrylic,
were tested to failure in one of the shell-converted vessels, as shown
in Figure 5. In the tests the windows were flange mounted in the vessel
cover, seated with silicone grease in matching conical seats, Figure 6.
The load was applied at a rate of 600 to 1000 psi per minute. The experi-
mental conditions and results of the 30-degree window tests on some 50
specimens are given in Figures 7 and 8. Figure 7 defines the critical
pressures plotted as a function of the ratio dimension t/D, window thick-
ness to internal diameter. The results are based on average values for
five specimens for each t/D ratio. The region of failure for these win-
dows is well defined in the figure.

The mode of failure in all the 30-degree windows tests was an explosive
ejection of the specimen, which shattered into many fragments upon being
ejected. The load-strain relation is defined in Figure 8 for the various
t/D ratios. It was noted from the tests that the window with the higher
t/D ratios extruded quite uniformly with both faces remaining virtually
parallel throughout the tests, thus retaining their optical properties.

The 60- and 90-degree windows were tested in similar manner. However,
their mode of failure was somewhat different from the 30-degree windows.
At low t/D ratios failure was characterized by an ejection of the central
portion of the window as a conical fragment, while the remainder of the
window was retained in the flange. A typical failure is shown in Figure
9. At high t/D ratios, nominally in excess of 1/2, the failure was char-
acterized by complete fragmentation, similar to the 30-degree windows.
Preliminary findings indicate that under short-term loads the 60-degree
window is substantially stronger than the 30-degree, and that there is
but little difference in strength between the 60- and 90-degree windows.
At the time of this writing tests are underway on the 120- and the 150-

degree windows; other tests have been initiated to study the long-term
effects of hydrostatic pressure as may be imposed on permanent ocean-
floor structures. So far, in the latter tests, five acrylic windows
have been exposed to 20,000 psi pressures for 1000-hour periods.

A few exploratory tests on 30-degree windows at 35-40 degree temperatures
of the pressurizing medium indicated the failure loads to be about 20%
higher than at the 65-70 degree temperatures. Other exploratory tests
were conducted on glass windows, (30-degree included angle, one-inch
thick, with a t/D of 0.445). These windows were seated with a plastic
gasket. Ultimate failure of these windows by ejection occurred in the
neighborhood of 5000 psi, but cracking was in evidence at pressures as
low as 1000 psi.

The research program on windows is young; much more data will be required
before it will be possible to recommend rational designs. Generalizing,
it can be said that acrylic windows failures are characterized by plastic
extrusion under short-term loads and by creep extrusion under long-term
loads. The former is illustrated in Figure 10, which shows the result of
a test on a 60-degree, one-inch, acrylic window. It was removed from the
flange at 50 per cent of the critical pressure. On the other hand, while
glass windows did not show any creep extrusion, they did fail by cracking
at lower pressures than did the acrylic windows of the same dimensions.

To this day little consideration has been given to the use of concrete for
pressurized structures. In the shallow to medium depths, say 3000 feet or
less, this material may find a place. To this end exploratory experiments
are in progress at the NCEL on 16-inch OD, 14-inch ID, hollow concrete
spheres.

Each sphere was cast in two halves in hemispherical steel molds, Figure
11. After proper curing and preparation, strain gages were mounted on
the inside surfaces of two hemispheres, the edges were ground smooth, and
the two halves were bonded with epoxy. Subsequently, strain gages were
mounted on the exterior surface and the entire sphere was coated with a
water-proofing compound. Three such spheres were prepared for short-
term tests. In each test the sphere with its sample control cylinders,
cast with the parent member and cured under the same conditions, was
placed in the pressure vessel and loaded at the rate of 1000 psi per
minute. The spheres imploded at hydrostatic pressures of 3050, 3100,
and 3200 psi; or nominally at about a 7000-foot ocean depth. Table I
gives the test and cure data on the spheres and the sample cylinders.
At the 3200 psi ultimate load the maximum biaxial stress generated in
the concrete (inside surface) was 14,500 psi; the stress on the exterior
surface was 12,900 psi. Sample control cylinders exposed to the same
test pressure environment failed in uniaxial compression at about 9400
psi. Those that were not exposed to the pressure environment failed at
about 9950 psi.

At the time of this writing, some preliminary tests on permeability are
completed. The first experiment consisted of subjecting an uncoated 16-
inch concrete sphere to a sustained hydrostatic pressure of 1,500 psi
and measuring the leakage rate of sea water into the interior. This was
determined to be 0.0057 cubic inches per hours per square inch of surf-
ace for the 1-inch thick shell. The test was concluded at 94 hours, at
which time the pressure was increased until the sphere imploded at a
hydrostatic pressure of 2,850 psi. Other tests underway are demonstrat-
ing that the permeability of concrete exposed to a sea pressure environ-
ment is quite variable and time dependent. In one test, at 750 psi,
leakage into a sphere was in evidence for several weeks, then stopped.
Thereafter, the sphere remainedwatertight even though the pressure was
increased to 2200 psi. In another similar test, leakage was detected

initially. After the test the sea water was analysed and it showed a
decrease in salinity. The sphere was then dried out and retested. No
leakage was detected on the retest.

This is just the beginning. The questions come fast and easy, and in
great numbers. Questions like: what will be the effect of surface dis-
continuities, as windows and hatches? Are dissolved salts retained by
the concrete voids or combined physically with the concrete to make it
watertight? Or is it watertight indefinitely? Will a cylindrical struc-
ture with hemispherical ends show promise? What are some of the fabrica-
tion problems? What will the underwater structures look like? The
answers will cone with time and research. Perhaps the answer to the last
question may be found in Figure 13.

Table I. Data On Concrete Sphere Specimens

Cure (days) Compressive strength Hydrostatic
of control cylinders pressure at
(psi) implosion
Sphere1 2 3 (psi)
100% rh 20% rh dry wet

23 18 9025 8400
22 18 9460 93100

24 26 9700 9050
23 26 9780 9123050

35 13 9970 9770
34 13 9930 93200

Notes: 1. The two rows of data for each sphere represent the two
hemispheres.

2. Cylinders not exposed to test pressure environment.

3. Cylinders exposed to test pressure environment; tested
after removal from pressure vessel.

REFERENCES

1. Reinhart, F. M. "First Results - Deep Ocean Corrosion," Geo Marine
Technology, vol. 1, no. 9, September 1965.

2. "The Recovery of STU 1-1," Naval Research Reviews, June 1965.

3. Burkart, W. F. "Deep Ocean Engineering At BuDocks," Trans. Joint
Conference and Exhibit, Ocean Science and Ocean Engineering, vol. 1,
Wash D. C., 1965.

4. Jones, R. E. "Deep Ocean Installations," Trans. Joint Conference and
Exhibit, Ocean Science and Ocean Engineering, vol. 1, Wash D. C., 1965.

5. Gray, K. 0. and J. D. Stachiw. Technical Note N-755: The Conversion
of 16-Inch Projectiles to Pressure Vessels, U. S. Naval Civil Engine-
ering Laboratory, Port Hueneme, California, June 1965. UNCIASSIFIED.

Figure 1. Bottom-mounted complex utilizes
explosive embedment anchors to
lock the bearing pads to the sea-
floor.

Figure 2. Cable arrangement for easy payout.

Figure 3. Recovery of submersible test rack
from 6700 feet after one-year
exposure.

Figure 4. Deep Ocean simulation laboratory. Bank
of 9-inch I.D. vessels at right. 18-
inch I.D. vessel at left. One half of
18-inch vessel is below floor level.

Figure 5. Window experiment in shell-
converted pressure vessel.

Figure 6. Pressure vessel flanges for mounting
acrylic window.

32 .,,,,!!..,,,,,,,,,,,,,,,,,,,,,,,
NOTE:
' Material - Plexiglos "G"
Thickness tolerance -- 5% of nom. thickness
28 Rate of pressurization - 600-1, 000 psi/min
Water tenperature - 65-750F

4HHi 20 H S" rilrzm - . ,
I.. ::::::: :..............
;oW . .... ...
:a I.'---- 30--ce-30. ' -

O 16 -. l ll| .. ... -
124 "

(D
i6 .r250

rp m 0.999

scotter of esperimental overage of::
data from 5 windows 5 windows::

Critical Pressure of Acrylic Windows
Under Short Ter. Hydrostatic Pressure
30 Cones

0 0.1 0.2 0.3 04 05 06 0' 0.8 0.9 1.0

t/D

NOTE:

to Th~~~~~~~~~~~~~~~~~~Iiatnerifolem -+5%eom.tlsickness
42~~ ~ ~~~~~~~~~~~~~~~~~ I I I11 111 I iii I II I(1(1 TIcIkIesIsI oIeranceI
C ~~~~~~~~~~~Ill II 11111 mli {1I IlII

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t/D i.970 VWater temperaturex-glas"G"
, ThickneDisplacement - A- ia' movementof the -
':;:;:' ' 'L r:: '' ' '''center point on window's low pressure fce-
,- , Displacement points are avemge values of
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Displacement (in.)

Figure 9. Typical failure of 600 acrylic windows
with low t/D ratios.

Figure 10. Typical plastic extrusion of 600
acrylic windows under short-term
loads.

Figure 11. Hemispherical mold for casting
of concrete specimens.

Figure 12. Concrete sphere with sample
control cylinders ready for
test.

Figure 13. Engineer's concept of a
submerged concrete habitat.

PROBLEMS OF DEEP UNDERWATER PHOTOGRAPHY

William J. Bunton and M. Stanley Follis

Abstract

SEALAB II confirmed with startling reality the problems of obtaining
consistent underwater photographic results in deep dives. Deep diving
from the surface with complicated mixed-gas apparatus, or total satur-
ation involving living and working from an underwater habitat, create
many photographic problems which cannot be entirely overcome. The
paper (1) discusses the adverse environmental conditions directly affect-
ing the diver's skills in underwater photography; and (2) describes the
development of a multiple-exposure 70-mm still camera, the PC-770,
designed to overcome many of the problems of underwater use by divers.

Acknowledgements

The authors wish to acknowledge the assistance of Robert Briggs and
other members of the Oceanographic Engineering Corporation in the dev-
elopment of the PC-770 camera; the project was conducted in very close
cooperation with the authors and other engineering representatives of
NEL. OEC is continuing the development and is currently manufacturing
the PC-770 camera.

INTR ODUC TION

The advent of mixed-gas diving, utilizing self-contained underwater
breathing apparatus, and placing of pressurized habitats on the ocean

floor, have for the first time allowed man to work at great depths for ex-
tended periods of time. Now that these goals have been reached, all
efforts must be made to provide the necessary tools capable of withstand-
ing the ever-increasing environmental rigors that man will encounter and
compensate for the deficiencies of man himself in the environment.

The difficulties of underwater photography by divers at depths in excess
of Z00 feet are well known. However, little or nothing has been done to
solve these problems. The lack of cameras designed for underwater use,
the greatly reduced natural light, and the difficulty of the diver in functicn-
ing under adverse conditions are only a few of the problems.

GENERAL DISCUSSION OF THE PROBLEM

Under ideal conditions, in shallow water, most cameras can be used
merely by building a watertight housing designed to conform to the fea-
tures of the camera. Tripods, light meters, flashbulbs, floodlights, and
other auxiliary equipment normally used for surface photography can be
utilized. Pictures can be planned unhurriedly; stages can be set and dir-
ections readily followed; cameras and film can be replaced with minimum
effort, merely by surfacing for short intervals of time and later making a
repetitive dive. For the most part, all of the techniques of surface photo-
graphy can be employed with excellent results.

Brief excursions to great depths (beyond 200 feet) have occasionally re-
sulted in the taking of a satisfactory picture, but seldom with consistency

or quality. Most underwater photography is done in water of 100-foot
depth or less. At these shallow depths where conditions are less severe,
underwater photographers can function according to the dictates of their
training as photographers first, and as divers second.

However, the photographer who has achieved excellent results in shallow
water finds, as he descends to greater depths, a combination of environ-
mental problems which make heavy demands both on his own skill and
stamina and on the operation of his equipment.

One of the formidable problems in deep water is the lack and unpredicta-
bility of light. It cannot be better than at the surface, but only worse,
eventually becoming total darkness. This must be accepted, as by one
who suddenly becomes blind and has to grope around on his hands and
knees to find his way home. As the light diminishes, it becomes increas-
ingly difficult to make proper settings for correct exposure. Reduced
visibility makes visual contact and communications virtually impossible.

As pressure increases with depth of dive, the controls on the camera's
underwater housing may jam and become inoperative. The cells of the
diver's rubber suit begin to collapse, making his buoyancy excessively
negative. He cannot hold his position for mid-water pictures without in-
creased effort. He may possibly descend deeper than originally planned
and thereby complicate decompression, which is so critical at these
depths. The diver must be tethered to his diving partner who invariably
will be in his way, stirring up the bottom sediment or fouling the buddy
lines connecting them. Low water temperatures quickly fatigue the body,
slowing mental processes and making each assignment a task of persever-
ance. In such a situation, photography becomes a secondary concern,
with the diving operation taking precedence and no longer merely a tool
for the accomplishment of a task. The photographer can no longer con-
centrate entirely on f-stops and shutter speeds. His mind is now filled
with exacting details of decompression stops, accurate depth, and time on
the bottom (which must not exceed the dive plan). He must be aware of
his own and his partner's well-being, and of gas supply and consumption
rates, malfunctioning diving equipment, and all the other hazards of deep
diving. Only by long training and experience can the diver develop the
skills and techniques to withstand the hostile environment of deep water.

Obviously, the diver's equipment must be as specialized as the man him-
self must become. Self-contained cameras must be developed specifical-
ly for underwater use, incorporating features essential to the diver -- not
equipments primarily designed for surface operations and then taken be-
low the surface when a need arises for underwater photographs.

An underwater photographer should have the same diving buddy whenever
possible. They learn to work as a team, forming techniques that enhance
the chances for better pictures. A good diver, knowing little or nothing
about underwater photography, might act as an asset for safety reasons,
but be a liability in obtaining a quality picture. For example, he might
assume the leadership on a dive and approach the object to be photograph-
ed from the wrong direction, not realizing that the stirred-up sediment
from his movements will soon engulf the object. In water with even the
slightest current, the object should be approached with the current in the
diver's face. The photographer should always lead the way. In this man-

ner, he can shoot his longer shots and work his way in for close-ups with-
out fear of cloudy pictures caused by an exuberant but unknowing dive
buddy. Limited bottom times do not usually allow a second chance.

Many underwater assignments involve both work and photography. Pre-
dive plans should establish which is to be done first. If photography is
considered secondary, it should be pointed out that the results will usual-
ly be of poor quality. If cooperation exists between teams and their lead-
ers, and the work is not urgent, the photography should be done before
the movements involved in the work assignment have stirred the sedi-
ment. Forethought, planning, and cooperation between divers can mini-
mize this problem.

Deep diving from the surface is hazardous. Saturation dives from a pres-
surized habitat, at a distance greater than one can swim by holding his
breath, can be dangerous because of the complexity of the self-contained
units used for mixed gas. Unfortunately, the problems that can develop
with this equipment are such that there is little warning, if any, and a
diver must constantly be on guard for the slightest sign of a malfunction.
In many instances, others may have set up his unit for him; this can be a
disturbing thought. On a saturation dive he must be tethered to the habi-
tat to keep from getting lost on long excursions. As a safeguard against
accidental ascent, he ties knots in his weight belt, usually adding a few
pounds of lead, and discards all flotation devices. He now knows that in
case of an emergency he cannot surface without meeting certain death. He
can no longer take his diving apparatus for granted, and years of training
and his own instincts are contradicted. This condition creates a mental
hazard which burdens the diver's mind and, in varying degrees, can de-
tract from his functional capabilities.

There is no easy answer, either mechanical or technical, to the environ-
mental and psychological problems involved in deep-water photography.
Only desire, conditioning, and as much experience as possible can develop
optimum skill in the diver. A camera which will minimize the demands
made upon the diver is obviously desirable.

DEVELOPMENT OF A DEEP DIVER'S CAMERA

Photographic documentation at the Navy Electronics Laboratory has been
of paramount importance. Many scientific programs involving research
rely on the evidence from pictures taken by divers. NEL, because of its
many involvements in oceanic problems, has sent diving expeditions
throughout the world. From these assignments many photographic prob-
lems arose that caused loss of time and money. This led to the eventual
development of a self-contained multi-exposure still camera, the PC-770,
which was specifically designed and built for underwater use by divers
(Fig. 1). During SEALAB II operation it more than proved its capabili-
ties with consistent results to depths of 300 feet (Figs. 2, 3).

Following are some of the design criteria and construction details in-
volved in the PC-770.

Selecting the Film Size

PROBLEM: In dark waters it is impossible to compose the picture before
shooting, since in many instances the diver has only marginal vision or

none at all. It is therefore desirable to have the largest practical nega-
tive format and a wide angle lens so that the desired details will be re-
corded and not lost in the grain of a small negative.

SOLUTION: A 70-mm film, 2-1/4 by 2-1/4 inches, was selected as the
best compromise between bulkiness and image size. This provides an
image area of 5.06 square inches - almost 3-1/2 times larger than the
35-mm film format. More detail is possible, allowing enlargements of
considerable size without loss of resolution. Negatives and positives can
be examined without viewing aids.

The larger image area is also valuable when it is necessary to force-
process the film. Since the image area is greater than three times that
of 35-mm, to obtain the same image size on a projection screen, the
2-1/4 by 2-1/4" image must be magnified less than one-third as much as
a 35-mm slide. When it is necessary to force-process the film to gain
film speed, the granularity of the emulsion is also increased. Since the
projection magnification, for the same screen size, is less than for 35-
mm, the apparent grain size will be less.

Forced processing of Ektachrome MS, essentially the same as Ekta-
chrome X in 120 roll film, has been found to be quite satisfactory. When
shot at its rated exposure index of ASA 64 this film provides excellent
color and resolution. The grain structure cannot be observed in normal
viewing conditions. When this film is shot at an exposure index of ASA
250, the color is good and resolution only slightly poorer than when pro-
cessed normally. Ektachrome High Speed has been tried and is consid-
ered less desirable than Ektachrome MS, even compared to EHS at its
rated exposure index of ASA 160 to EMS at an exposure index of ASA 250.

For black-and-white photography, Tri-X film appears to be adequate in
film resolution and granularity without pushing it beyond its rated speed
of ASA 400.

Tri-X can be pushed to ASA 1600 (two f-stops). Usually the results are
poor and excessively grainy. If quality and detail are not of importance,
black-and-white pictures can be taken with surprising success in dark
waters with limited ambient light.

Although Plus X film has a finer grain, its reduced film speed of ASA 125
makes it unsuitable and nothing is gained by pushing this film in compari-
son to Tri-X film. Occasionally on deep dives the need will arise for
pictures utilizing natural light.

The importance of additional film speed is apparent when, with a 100-
watt-second strobe and a film with an exposure index of ASA 64 is used,
it is necessary to use the maximum aperture of f:3.5 when photograph-
ing an object six or seven feet away from the light. By using film speed
of 250 the lens can be stopped down two full stops, thus improving the
resolution and depth of field of the lens. The improved depth of field is
particularly important since the diver, preoccupied with thoughts of self-
survival, diving mechanics, and the safety of his buddy, must estimate
the distance and set the camera, while he and the object are being acted
upon by oceanic conditions.

The increased image area of the 70-mm film is desirable to obtain finer
resolution. This is a particular advantage when it is necessary to force-
process the film.

Film Capacity

PROBLEM: Inadequate film capacity characterizes most commercial
cameras. The lack of sufficient exposures in existing conventional
2-1/4" by 2-1/4" format cameras has been the single most important
problem confronting underwater photographers. This is even more pro-
nounced in deep diving. Repetitive dives for film reloading are imprac-
tical and extremely hazardous.

An assignment may extend into several days because of the required
waiting periods between dives. * Bad weather can create further post-
ponements, upsetting boat schedules and causing expensive delays. Be-
cause of the constantly changing environment in the ocean, the diver has
no assurance that the object to be photographed will be there at a later
dive. It is also possible that the location would not be found again because
of a change in visibility or foreign bottom terrain. Film capacity of suf-
ficient quantity minimizes the photographer's concern with the amount of
film remaining, minimizes inadequate coverage, allows bracketing ofex-
posures, and insures the best quality picture. Occasionally, opportunit-
ies for pictures of great scientific value will present themselves, but the
diver will find he is out of film or has only one or two exposures left.

SOLUTION: The PC-770 was designed to use a 100-foot roll of 70-mm
film, which provides a capacity of about 400 shots.

Sighting and Viewing

PROBLEM: Sighting the camera and viewing the scene to be photographed
through the lens is difficult in limited light conditions and adds bulk and
complexity to the camera.

SOLUTION: The PC-770 does not include any provisions for reflex view -
ing. The complexity of the arrangement would complicate and make the
camera larger than it presently is. The optimum requirement of sim-
plicity of operation makes through-the-lens viewing of questionable virtue
in dark water.

Film Advance and Shutter Cocking Mechanisms

PROBLEM: It is desirable to have the camera as nearly automatic as
possible so that the diver may operate it with a minimum of thought, and
if necessary, with one hand.

SOLUTION: The PC-770 is provided with automatic shutter cock and
automatic film advance with a recycle time of four seconds, powered by

*The Repetitive Dive Table included in the U. S. Navy Diving Manualpre-
scribes minimum waiting periods between dives, as a protective measure
because of the slow elimination of inert gas from the diver's body.

rechargeable nickel-cadmium batteries.This is advantageous when a
diver has only the use of one hand (for example, in deep dives in dark
waters or in strong currents where a descending line must be used and
held onto). Also, rapid-fire sequence to capture time-lapse effects or
bottom mosaic sequences is possible.

The use of a wide-angle lens and fully automatic operation and the pro-
vision of ample film capacity make it possible to shoot many pictures in
a short time so that difficult adjustment for any single shot is not re-
quired (Fig. 4).

Control Design and Placement

PROBLEM: In limited visibility, focusing, shutter speed, and f-stop
controls should be Conveniently accessible without moving the camera
axis from the subject. Having controls with positive detent positions,
one can feel, rather than see the proper settings and even operate the
camera in total darkness. One of the greatest problems with previously
existing underwater cameras is that the controls bind or jam at pressure
depths.

SOLUTION: The controls on the PC-770 are all conveniently located on
the back panel. They have large knobs and positive detents so that they
can be operated in the dark if necessary. A special ball-bearingpres-
sure seal was developed so that the controls will operate as freely at
great depths as at the surface.

Lens Selection

PROBLEM: A wide-angle,large aperture lens was desired which would
be dimensionally compatible with the camera housing and window.

SOLUTION: A Nikkor (Bronica) 50-mm, f:3.5 lens was chosen for the
PC-770. This lens provides a 76-degree uncorrected angle of coverage
on the diagonal of the film format. This angle in the water is approxi-
mately 57 degrees. This is a moderately wide-angle lens for underwater
photography.

Pictures shot with this lens show good field of view and generally are
quite sharp; however, there is a certain amount of distortion, or a tear-
ing of the image at the extreme corners of the format. This is not a func-
tion of the lens itself, but rather a problem of light going through an un-
corrected plain glass port, found on most underwater housings. Correc-
ted ports are available and advantageous, and a study is now being con-
ducted at NEL to determine the feasibility of incorporating them on our
existing underwater cameras.

The maximum aperture of the f:3. 5 lens is considered relatively fast for
underwater use with the 70-mm film; f:3. 5 gives the benefit of consider-
able latitude in exposure; however, faster lenses are always desirable.
This is particularly true when working with natural light.

Underwater Illumination

PROBLEM: The problem of underwater illumination is a critical one.
More light would permit smaller f-stops, and consequently require less

attention by the diver in focusing and less necessity to push the film speed.
Two alternative types of light sources may be considered - electronic
strobe and flash bulbs.

The main advantage of a strobe unit over conventional flash bulbs is sim-
plicity of operation, since flash bulbs require a time-consuming bulb-
changing process. The diver must interrupt his concentration after each
picture and tediously make a replacement. For multiple-exposure cam-
eras, large quantities of bulbs are needed. This creates buoyancy prob-
lems as the bulbs are used and discarded. Flash bulbs occasionally im-
plode upon firing at depths in excess of 200 feet. Removing the bulb stub
underwater is difficult and at times impossible.

The problem with underwater strobe units of sufficient light intensity is
only one of size. Because of the number of components and the size of
the batteries required, they represent more bulk than is desired, espe-
cially on deep dives.

SOLUTION: Although not entirely satisfactory from the point of view of
bulk and intensity level, the illumination requirement was solved by dev-
eloping a strobe light compatible to the PC-770 camera. This unit, the
PF-100 (Fig. 5), has a light output of 100 wattiseconds which roughly is
equivalent to a Number 5 flash bulb in lighting intensity. Two 510-volt
dry-cell batteries provide 800 shots with a recycling time of 10 seconds.
Once turned on and synced to the camera, the PF-100 requires no fur-
ther attention. The unit is 18 inches long, 5-1/2inches in diameter, and
weighs 12 pounds in air. It is mounted to a support column attached to
the camera and located 18 inches from the camera axis. The direction
of the strobe light can be controlled by a pivot on the supporting column
and allows the diver some choice in lighting the object.

CONCLUSIONS

The specifications listed above were the main criteria in development of
the first 70-mm hand-held camera, exclusively for underwater use, capa-
ble of taking 400 single exposures. Its usefulness, especially in deep
water, has been amply demonstrated. For example, a dive to 250 feet
for five minutes bottom time has produced 50 good pictures. To gain the
same results with a conventional 12-exposure camera would take one
diver at least four days. The additional cost for such dives, in person-
nel, equipment, and time, would more than represent the cost of a PC-
770 Underwater Camera as specified.

This should not be construed as meaning that the PC-770 represents the
optimum solution to the need for a deep-sea camera. The following de-
sign improvements will be sought in the near future.

Pressure Valve

It was not realized during the early design of this camera that it would be
used during the SEALAB II experiment. Had that been known, pressure
equalization valves would have been incorporated, allowing the camera to
be opened in a pressurized habitat and eliminating the necessity of send-
ing the camera to the surface for film changes, or minor repairs if the
need arose.

Improved Strobe Configuration

Presently we are considering developing a strobe unit of ZOO-watt-
seconds contained in a miniaturized package, and placed in the support
column separating the camera from the strobe light. At the end of the
column would be only a reflector and bulb. By eliminating the bulk on
the end, it would now be possible to lengthen the column considerably.
This would increase the angle of light from the camera axis and allow
pictures at greater distances without "back scattering" caused by the re-
flection of light. Another possibility under consideration is placing the
strobe components in the form of a weight belt. This would make the
weight of practical value and remove the bulk entirely from the camera.
The disadvantage of this method is the necessity of a connecting cable be-
tween the shutter synchronization and the weight-belt components. The
added lighting power of a ZOO-watt strobe would allow shooting at smaller
aperture openings. This would eliminate the present need to force-
process film beyond its rated ASA speed, increase the depth of field, and
make focusing less critical.

Corrective Port for the Lens

Although in most instances the distortion introduced by the use of the un-
corrected lens in water is negligible, there would be significant value to
the inclusion of a corrective port on future models of the PC-770. The
corrective port would reduce the distortion in the corners of the picture
which is occasionally apparent and would restore the normal angular field
of view. Investigation of corrected lenses and corrective ports is cur-
rently being conducted.

W. J. Bunton is an Experimental Test Mechanic (Diver) for the U. S.
Navy Electronics Laboratory, San Diego, California; M. S. Follis is a
Motion Picture Production Specialist at the same Laboratory.

Figure 1. The PC-770 camera showing the control plate with detent stops for focus, f-stops,
and shutter speed. The small window at the top is an exposure counter. The camera
is 20 inches long and weighs 20 pounds.

Figure 2. A SEALAB 11 diver determining the orientation of a gorgonian coral (Eugorgia Rubens
Verrill). Water depth, approximately 270 feet. Film, 70-mm Ektachrome MS, force-
procesmed to an exposure index of ASA-250.

- - - - - - - - - -- -- - - -

r -- -- - -_ -I

Figure 3. A SEALAB II diver suspended over the rim of Scripps Submarine Canyon (off La Jolla,
California). Water depth approximately 250 feet. Film, 70-rmm Ektachrome MS,
force-processed to an exposure index of ASA-250.

Figure 4. The PC-770 camera with housing removed, showing the 50-mm, f:3. 5 lens, shutter-
speed and focus tie rods, metering roller switches, battery charger and strobe
terminals, and trigger in aft hand grip. This trigger magnetically actuates a reed
switch inside the housing.

"Ill .- _ -- _ - - - - w

Figure 5. The PF-100 strobe unit attached to the 70-rmm camera by an 18-inch arm. The self-
contained strobe has an on/off switch and is synced to the camera's shutter. The
housing and support arm are of anodized aluminum.

HUMAN PHYSIOLOGY ASPECTS OF SEALAB TWO

Walter F. Mazzone, CAPT MSC USN

Abstract

A background of saturation diving is presented, drawing on the findings of Project
GENESIS and SEALAB I. SEALAB II is discussed, with emphasis on environmental
contrasts with SEALAB I. The physiological testing program of SEALAB II, much
more extensive than that of SEALAB I, is presentedwith regard topurpose, methods
and preliminary results in eight areas of study. Difficultieswhicharoseincarrying
out the studies under field conditions are described, with a recommendation that
future studies be made under laboratory conditions insofar as possible. It is noted
that "normal" values for these measurements in man under hyperbaric, synthetic-
atmosphere conditions have yet to be established. Some alterations in pulmonary
function tests did occur, as would be expected in the prevailing atmospheric condi-
tions. Some serum enzyme elevations were seen, which are most interesting, but
as yet, inconclusive. The data obtained indicate that no major physiologic changes
occurred in the Aquanauts of SEALAB II.

SEALAB II was conducted during the months of August, September, and October
1965. This experimental project is rapidly assuming a position as a milestone in
the historical development of man's quest to inhabit the ocean's floor. In retro-
spect, 1965will be rememberedby those individuals whohave dedicated their efforts
toward extending man's capability for prolonged excursions into the sea as the
start of a new era in oceanology. Exciting scientific findings have been produced
by the SEALAB Project, and by similar endeavors by researchers in this and other
countries. These findings will go a long way toward enabling man to inhabit the
continental shelves of the world within the near future. It is the hope of all who
work in this area that, when man can both easily and safely explore and exploit the
natural resources indigenous to the continental shelves, there will accrue a benefit
of great import to all mankind.

The purpose of this discussion is to present those physiological facts which relate
to man's adaptations to, or the pathological changes occurring from, a prolonged
exposure in a sea habitat environment. Realizing that this audience is not made up
of physiologists, I will secularize our findings in the hope that a greater interest
may be served.

We are now at the dawning of a new era in deep diving research. Through the cen-
turies, man has been imbued with a strong and compelling urge to explore under
the sea, yet he has made few advances in this technology over the past two hundred
and seventy-five years. However, a renaissance is now upon us, and more advances
in diving techniques have occurred during the last decade than during any other
period in the history of diving.

Interest in deep diving is no longer the hallowed ground of the hyperbaric physiolo-
gist, that is, of those scientists interested in the physiological effects of exposure
to high pressures. The materialistic values to be realized from man's ability to
explore and exploit the continental shelves of the world have already stimulated keen

102

interest and motivation in industry. Therefore, at this very time, the problems
that we face in achieving our goals are being attacked on an ever-widening front.

SEALAB I, the first of the U.S. Navy's open sea experiments, validated the basic
concept that man could be placed on the ocean's floor at depths approximating two
hundred feet, subsist for a prolonged period of time in an artificially produced
hyperbaric atmosphere, and subsequently be returned to the surface without ex-
periencing any untoward effects. To insure optimal control in this first experi-
ment, good environmental conditions were considered essential, in terms of bottom
topography, water visibility and water temperature. Water depth - 193 feet; Visi-
bility - 50--150 feet; Water temperature - surface 790F., bottom 69�F.; Bottom
topography - hard, flat coral.

SEALAB II, building on the shoulders of SEALAB I, was in many respects substan-
tially more sophisticated. However it cannot be said that SEALAB II represented
the ideal, for neither our earlier laboratory experiments nor SEALAB I provided
sufficient criteria for the optimal engineering design.

SEALAB I had proved the basic tenets of saturation diving, but it had not provided
information as to the type of person who should be selected for this kind of work,
and more importantly, it had not determined whether man could perform useful
work once we had placed him on the ocean's floor in a sea habitat. Therefore,
SEALAB II was designed as a severe test of the functional capabilities of the SEA-
LAB concept. The experimental design emphasized the evaluation of multiple team
participation and physiological and psychological studies to determine just how
much, and what types of useful work man could perform under these conditions.

If we can imagine a spectrum of undersea environmental conditions, SEALAB I was
at the optimal end. However, to afford more definitive proof of the concepts to be
tested in SEALAB II, we selected an environment at the other extreme: Water
depth - 205 feet; Visibility - 0 to 25 feet; Water temperature - 44'F. to 560F.;
Bottom topography - very uneven, with six or more inches of silt.

The severity of these conditions must be experienced to be fully appreciated, yet
to increase the adversities amongst which the divers had to subsist, the resting
position of their habitation on the bottom was such that it had a six degree up angle
and a six degree list to port. The light level in'the water during the day was ex-
tremely poor, requiring constant use of underwater lights.

SEALAB IU posed this set of extreme conditions in order that we might: (1) Evalu-
ate the multiple team participation concept; (2) Conduct both physiological and
psychological studies to determine man's effectiveness while on the bottom; (3)
Determine the engineering criteria for the optimal structure in support of this
particular system of oceanology.

The diving concept involved in the SEALAB Project differs greatly from the tradi-
tional diving approach. In order to provide a clearer understanding of certain
terms of reference, let us look at some of the basic differences between the phys-
iological considerations in deep sea diving and "saturation" diving as employed in
either manned undersea dwellings or surface/pressure facilities.

Conventional deep sea diving, except for the breathing media used, is approximately
One hundred and thirty-four years old. The deep sea diver, properly attired in
"hard-hat" dress, is lowered to a prescribed depth for a relatively short period of
time. At the end of the stipulated period on the bottom, the "hard-haft diver must
be brought back to the surface under very close control, utilizing the procedures

103

of stage decompression, a procedure in which ascent to the surface is interrupted
by stopping for relativelylong periods at prescribed depths. Under such conditions
of diving, the various tissues of the diver's body are only partially saturated with
inert gas. Saturation, or in other terms, gas uptake, is a function of time and
pressure.

Henry's Law states that the volume of gas which will go into solution is directly
proportional to the ambient pressure of that gas. Thus, as the blood absorbs the
excess inert gas which can be taken into solution as a result of the increased pres-
sure, the tissues of the body absorb their share of the increment until, with the
passage of time, they come to be in equilibrium with the gas content of the blood
and the ambient atmosphere--this saturation of the tissues being an exponential
function. Since the degree of tissue saturation varies with the duration of the dive
(unless full saturation is reached) decompression requirements also vary according
to the duration of the dive. Therefore, for the hard-hat diver to obtain a reason-
able working time on the bottom, he has an increasing penalty of decompression
time to pay back.

In saturation diving, the diver is exposed to pressures past the time at which com-
plete saturation is assumed to have taken place. It is estimated that when a diver
has been exposed to a specific pressure for twenty-four hours or longer, every
tissue of his body will have absorbed at least 98.5 per cent of all the inert gas that
it is capable of absorbing under the stipulated conditions. In terms of the decom-
pression penalty that this saturated diver will eventually have to pay back, it makes
no difference whether he stays on the bottom a day or a month beyond the point of
saturation. It is apparent that the type of diving involved in the SEALAB program
is saturation diving.

Let me reemphasize the gross limitations that decompression puts upon the tradi-
tional form of surface-based diving, for example, if a deep sea diver were to spend
twelve hours at a depth of 300 feet, he would be required to spend a minimum of 60
hours undergoing stage decompression. However, a diver exposed to this same
depth within the framework of the saturation diving method for 24 hours, several
weeks, or for that matter for several months, would only be required to pay a de-
compression time penalty of approximately 55 hours, by undergoing a "constant
rate of ascent" type of decompression. The decompression requirement relative
to the length of time which the diver can stay on the bottom is the dramatic effect
which the SEALAB Project emphasizes.

The respirable atmosphere of SEALAB has evolved directly from laboratory-con-
trolled experiments, and its make-up was as follows: Oxygen - range 188 to 268
millimeters of mercury partial pressure (mm Hg pp); Nitrogen - below 965 mm Hg
pp; Carbon dioxide - below 22 mm Hg pp; Helium - balance, to total pressure of
5358 mm Hg. If calculated in per cent, the figures would appear as: 02 - 3.5 to
5 per cent; N2 - less than 18 per cent; CO2 - less than 0.4 per cent.

Although the above percentage figures appear low, it must be rememberedthat these
are actual figures at depth and, in the case of SEALAB II, must be multiplied by a
factor of seven to obtain the sea level equivalent value.

What do we mean by sea level equivalent? Is this an actual concentration? Sea
level is taken to be 760 mm Hg total pressure, thus a sea level equivalent would
require the use of this figure as a denominator. If, for example, we take a partial
pressure of 02 at depth to be 188 mm, then on the surface, at one atmosphere ab-
solute, this would represent: 188 x 100 = 24.7%
760

104

whereas at a depth of seven atmospheres, a total of 5, 320 mm Hg total pressure
(7 x 760) would serve as the denominator:

188 x 100 : 3.5%
5320

or in verification, 7 x 3.5 = 24.5%

The physiological and medical testing program established for SEALAB II was based
on those areas of human physiology which previous experiments have indicated
would be most susceptible to change, whether it be a true adaptation or singular
environmentally precipitated alteration. The following areas, though not totally
inclusive, will be discussed herein: (a) Inert gas uptake and elimination; (b) Oxy-
gen toxicity; (c) Respiration; (d) Hematology and blood chemistry; (e) Urine anal-
ysis; (f) Electrocardiography; (g) Electroencephalography; and (h) Daily vital
signs - pulse, temperature, and blood pressure.

The following are examples of related studies which were included as convenience
would allow: (a) Exercise tolerance; (b) Effects of cold water, and (c) Radioiso-
tope-tagged iron for plasma turn-over and erythropoiesis.

INERT GAS UPTAKE AND ELIMINATION: In saturation diving, unlike conventional
deep sea diving, the rate of compression is not a consideration. When divers leave
the surface to take up residence in an undersea habitation, the need for rapid com-
pression is not urgent. In deep sea diving, if fairly rapid rates of compression are
utilized, the uptake of inert gas is minimized during this period, allowing for more
time on the bottom without increasing decompression time. Descent time is taken
into consideration as time on bottom when calculating decompression schedules.

The determination of the inert gas content of various tissues of the body would, of
course, be of great concern to the physiologist or diving medical officer. To date,
however, we have no simple method for measuring the amount of gas within the
body tissues.

DoctorJackSwinnerton of the Naval Research Laboratory was made available to the
SEALAB Project to conduct an evaluation of the dissolved gases contained in urine,
utilizing a gas chromatographic process whichhe andhis co-workers have developed
at NRL.

The equipment consists of a glass sample chamber in which the dissolved gases are
stripped from solution by an inert carrier. A four-way valve and a commercially
available gas partitioner with a one-millivolt laboratory recorder complete the
system. Calibration for routine work is accomplished by carrying out the deter-
mination on a sample of water, saturated with pure inert gas at a known tempera-
ture and pressure. In this work, argon was utilized as the carrier gas, making it
possible to analyze for helium and nitrogen.

Upon a review of the curves which have been plotted, it would appear that this sys-
tem gives an excellent correlation between ambient inert gas and urine-dissolved
gas. However, the sampling procedure is not sufficiently sensitive to detect dif-
ferences which might reflect quantities of gas released by the body. Physiologi-
cally, it appears that urine-dissolved gases come into almost immediate equilib-
rium with arterial gas, and thus with alveolar gas levels.

Inert gas uptake by the tissues of the body on entering a hyperbaric atmosphere is
extremely important. In an effort to study the rate of inert gas uptake over time,

105

one subject was selected to devote complete attention to providing the necessary
alveolar gas samples. These samples were collected in evacuated stainless steel
bottles, transported to the support vessel, and analyzed on a gas chromatograph.

The large number of samples required during the first two hours of such a study
made it necessary for immediate transfer of the bottles to the support vessel and
return. For each transfer of samples, it was necessary for a diver in SEALAB to
enter the cold water, go out through the protective skirt and shark cage in order to
attach the pressure pots to the elevator system. Since, prior to this sampling
period, the diver-subject had not been exposed to cold water sufficiently to develop
some degree of adaptation to cold, it was necessary for him to dress completely in
the underwater protective clothing. This fact in itself has a tremendous detrimen-
tal effect on motivation to be a good giver of alveolar samples.

Although the gas uptake studies are very important, other priorities necessitated
that they be curtailed prior to completion. This curtailment was justified since the
results analyzed were. at best, marginal. The obtaining of true alveolar samples
requires a meticulous sampling technique, which would be affected by motivation
and morale.

The scrubbing of this test from the decompression phase, the gas elimination cycle,
was dictated by a mechanical inadequacy. The environmental control system for
the deck decompression chamber failed to perform adequately. Therefore, as sub-
ject morale varied inversely with the temperature and humidity levels, it was
deemed to be in the best interest of the program to cancel the tedious sampling
procedure during this phase. This program, in the event better systems are de-
veloped, can be better carried out in laboratory-controlled experiments.

OXYGEN TOXICITY: though a greater and more direct hazard in those areas of
deep sea diving and saturation diving which utilize exceedingly high partial pres-
sures of oxygen, is of considerable interest in the SEALAB program.

Under conditions of increased atmospheric pressure, the physical and chemical
behavior of a gaseous component of respirable atmosphere may differ from those
under so-called normal conditions. Although oxygen was maintained at less than
35 per cent (sea level equivalent), consideration was given to the possibility of
gradual development of pulmonary damage. Would there be evidence of damage in
the tissue structure of the lung as a result of irritation due to these levels of oxy-
gen being breathed over long periods of time? Since pulmonary damage is a definite
hazard under these conditions, consideration was given to means of attempting to
assess the effects of this exposure. We selected three serum enzymes for study:
(1) Lactic dehydrogenase (LDH), by the modified method of Caboud-Wroblewski;
(2) Serum glutamic-pyruvic transaminase (SGPT), by the modified method of Reit-
man-Frankel; (3) Serum glutamic-oxalacetic transaminase (SGOT), modified method
of Reitman-Frankel.
LDH is found in considerable quantity in many types of cells, including liver cells,
heart muscle, skeletal muscle cells and the red blood cells. Injury to any of these
types of cells may cause release of LDH into the blood plasma. SGPT levels in
serum may increase dramatically with liver cell injury. Since this study was one
designed to observe, in a small way, cellular behavior, SGPT measurement was
considered of value because of its reported role in maintaining a balance between
anabolic and catabolic pathways. SGOT activity in serum is markedly increased
following damage to liver or heart muscle cells. The extent of the increase is a
measure of the degree of cell damage. Also, it has been reported that increased
SGOT is manifest following prolonged, strenuous, physical exercise.

106

The results of this study, based on three selected individuals in Team One, cannot
be considered conclusive, although they are of extreme interest. SGPT activity did
not exceed normal limits, therefore, one might make the following assumptions:
Significant liver damage did not take place; balance between anabolic and catabolic
metabolic pathways was not affected. SGOT activity exceeded normal limits on the
fifth day under pressure, but by a very small margin. It is doubted that this single
excursion above the normal range is of significance. On the other hand, it could
possibly be indicative of cellular involvement. Further studies must be carried
out under controlled laboratory conditions.

The level of LDH activity is of most interest and perhaps of greatest significance.
On the basis of a daily plot of mean values for Team One, it appears that LDH
values rise during the first week of exposure to pressure, peaking at approximately
September 2nd, the sixth pressure day. However, by the end of the first week, all
values were back within normal limits. After a review of the many possible causes
for elevated serum LDH levels, the cause of the elevations observed is still un-
clear. Other serum enzymes indicate that liver damage did not occur. Therefore,
we must look elsewhere for an answer. Apart from leakage due to cell damage,
LDH activity may rise due to increased formation of the enzyme, or possibly due
to mobilization of stored enzyme.

LDH from heart muscle cells can be identified as such by its relatively thermal
stability, whereas LDH derived from skeletal muscle and liver cells is not stable
when heated. Electrophoresis of serum LDH shows it to be made up of several
forms. Although one form of the enzyme may occur in more than one tissue, and
one tissue may contain more than one form of the enzyme, the electrophoresis
technique may help to localize the source of the rise in activity. Although neither
of these techniques was used in SEALAB II, they will be used in subsequent studies.

PULMONARY FUNCTION STUDIES: These studies were carried out using a wedge
spirometer inside the SEALAB habitat. A cable incorporated in the umbilical cord
connected the spirometer to an amplifier and a camera-equipped oscilloscope aboard
the support vessel. The oscilloscope was equipped with a 'storage' screenwhich
allowed the trace to be held on the screen long enough for photographs to be made.
When the prescribed respiratory maneuvers are performed, the oscilloscope trace
takes the form of an asymmetrical loop, from which can be calculated a number of
respiratory volumes and flow rates. Among the most important of these are: Vital
capacity, maximum expiratory flow rate, and tidal volume. Measurements were
made almost daily during submergence on all members of Team Two, and the re-
sults were compared with control measurements of the same subjects at the sur-
face and breathing air, after the end of their stay in the SEALAB,

Tidal volume, or the depth of breathing, is an important measurement with regard
to estimating the actual volume of ventilatory exchange in the divers. Blood levels
of oxygen and carbon dioxide are importantly affected by the amount of gas moving
in and out of the lungs in a giventime interval. Unfortunately, subjects consciously
breathing into a machine and trying to perform a test tend to breath more deeply
than usual. All of the tidal volumes obtained were much greater than the generally
accepted average of about 500 ml. What is of interest, however, is the change in
tidal volume under pressure. Seven of the ten subjects showed a decreasedtidal
volume while on the bottom, and the average for all ten was nine per cent less than
the control values on the surface. If this is indication of a decrease in respiratory
minute volume, it is significant, particularly with regard to CO2 elimination. It
must be remembered, however, that accurate respiratory rate measurements were
not made on the bottom. If the increased ambient CO2 caused an increase in res-
piratory rate, the tidal volume change may have been compensated.

107

Vital capacity was decreased by an average of about 14 per cent on the bottom.
Vital capacity is the maximal volume of gas that can be expelled from the lungs by
forceful effort following a maximal inspiration. It varied from day to day, being
most depressed in the mid-portion of the run and showing some return toward con-
trol values during the second week. There are not sufficient data to say whether
this represented an actual adaptation to the environment or not.

Maximum expiratory flow was markedly decreased by an average of 46 per cent.
This measurement also showed day to day variation, but without any obvious trend.
Since the flow of gas in the tracheobronchial tree is more or less turbulent at high
velocity, it should be inversely proportional to the density of the gas. The SEALAB
atmosphere at seven atmospheres absolute had approximately twice the density of
air at one atmosphere absolute, and the flow rate decrease seems quite compatible
with this.

Further, more elaborate studies are certainly needed to measure changes in the
work of breathing, actual respiratory minute volume, CO2 elimination, and other
important respiratory functions. These should bedone under laboratory conditions.

HEMATOLOGY AND BLOOD CHEMISTRY: Studies were scheduled to be conducted
on venous blood drawn at least every other day. To minimize the amount of blood-
letting, it was decided that three subjects from each team would be studied. The
study areas were rather routine, consisting of red blood count, white blood count,
reticulocytes, sedimentation rate, platelets, hemoglobin, hematocrit, serum elec-
trolytes (sodium, potassium, calcium and chloride) and carbon dioxide. The serum
enzymes were discussed earlier in this report.

The same sample transfer problems as were encountered in the gas-uptake study
hindered this endeavor. In addition, the dry transfer pot seemed to take delight in
upending whenever biological specimens were involved in a transfer. It is worthy
of note that the problem of dry transfer of materials between the SEALAB and the
surface is one of the most persistent and troublesome problems in the Man-in-the-
Sea Program.

All the data which have been determined from the samples left for us to analyze
have been reviewed. At the moment, it would appear that all values determined fall
within normal ranges. There are no grossly adverse findings. However, some
values do appear to shift from mid-range to high normal ranges. It is suggested
that hematological studies be continued in a controlled laboratory situation, but that
considerable thought be given prior to their inclusion in open water test programs.
If it is necessary to monitor hematology and blood chemistry, then we should con-
sider the feasibility of conducting such tests within the confines of the sea habitat
itself.

URINE ANALYSIS: Renal function studies and urinalyses were accomplished daily
for Team One and at least every day for Team Two. In view of the difficulties of
collecting twenty-four hour samples of urine for analysis, three individuals were
selected from each team to be the subjects for these studies.

Experience in underwater work has shown that even limited exposure to a watery
environment can result in an increase in urine output. In early works on under-
water swimmer's protective devices, it was suggested that urine elimination be
utilized as a secondary heat source. Although the thought lacks aesthetic appeal,
nonetheless, it has assisted in prolonging total exposure time.

Complete urinalysis was done, includingdeterminations of urine electrolytes as well

108

as a microscopic examination of the urine sediment. A review of the findings fails
to show any gross alterations in urine electrolytes, and all microscopic examina-
tions were essentially negative with regard to indicating renal complications. As
expected, urine output, though possibly incompletely measured as a result of use as
a heat source in cold water exposure, was above values normally expected on the
surface.

The true value of the renal function studies and urinalyses may be questionable,
since it was impossible, under field conditions, to maintain an accurate record of
fluid intake for each subject. Fluid balance studies, under adverse environmental
conditions, seem to lack enthusiastic support of the subject, concerned only with
rewarming as rapidly as possible after coming out of the cold water.

As laboratory experiments are performed at deeper depths, baseline urine values
should be derived as a result of closely supervised fluid balance studies. In open
water experiments, this imposes problems detrimental to the interest of high morale.
It must be recognized, however, that it is difficult to reproduce in the laboratory
the conditions of immersion and cold encountered in the open water experiment.

ELECTROCARDIOGRAPHY: All subjects had electrocardiograms made as a part of
their physical examinationbefore being accepted as subjects for SEALAB II. During
the submergence, 4-lead electrocardiograms were taken on the subjects in the hab-
itat, using a regular Sanborn Portable Electrocardiograph. Examination of these
tracings and of others taken after decompression showed no significant change from
the control tracings.

Further experiments were carried out with a sonar telemetry system for recording
either in the habitat or on board the support vessel, the electrocardiogram of a
free-swimming diver. The equipment used was designed and provided by the Phila-
delphia General Hospital. Although several problems were encountered with the
equipment, some useful tracings were obtained. The method shows considerable
promise for recording EKG's and other physiological data without encumbering the
diver with cables.

ELECTROENCEPHALOGRAPH AND NEUROLOGICAL EVALUATION: Pre-submer-
gence and post-submergence EEG neurological studies were made on nearly all the
aquanauts by Dr. L. C. Johnson of the Neuropsychiatric Research Unit at U. S.Naval
Hospital, San Diego. Evaluation included electroencephalograms and autonomic
nervous system measurements, at rest, under intermittent flickering light stimula-
tion, and during hyperventilation. Comparison of the pre- and post-dive studies
showed no significant neurological, EEG, or psychophysiological change as a result
of the stay in SEALAB II.

In addition to these studies, EEG recordings were made on one aquanaut during his
submergence by Dr. K. W. Sem-Jacobsen, using his miniaturized on-person re-
cording technique. These recordings were interpreted as showing increased fre-
quency of alpha waves. The significance of this alteration is uncertain at present.

VITAL SIGNS: Blood pressure, pulse, and body temperature were monitored on a
daily basis by the team medical officer. The pulse rate, though showing daily vari-
ations around the mean, did not show any particular trend. The body temperature,
measured orally, generally considered to be normal at 98.6�F., rose above this
value after the second day under pressure. The mean body temperature was 99.8�
F., approximately 1.20 above normal.

It could be postulated that the thermal effect of helium might be responsible for such

109

a finding. The high thermal conductivity of helium accelerates loss of body heat.
In increasing metabolic heat production to compensate for this, the body may over-
compensate somewhat, with a resultant increase in body temperature. More lab-
oratory work will be required in order to validate this theory. Helium as the res-
pirable inert gas, may cause a diminished peripheral blood flow, thus causing the
internal temperature of the body to increase slightly. This, too, must await lab-
oratory validation under closer supervision.

In a review of the blood pressure, a downward trend in systolic pressure was ob-
served during the first half of the bottom time, the systolic pressure climbed slightly
above the mean, but did not show a continuing upward trend. The diastolic pressure
though showing daily variations, does not appear to show any particular trend.

CONCLUSIONS: Since we have just taken the first steps across a new threshold in
deep diving, it would be incongruous to summarize by saying, "in conclusion ..... "
As one reviews the various findings, however, there are certain basic conclusions
that one may draw. It is apparent that man, when subjected to severe environmental
stresses in SEALAB operations, did not manifest untoward responses indicative of
biological rejection of a new mode of life, --life under the surface of the sea.

The factors which have been studied were studied under prevailing conditions at 205
feet. Man will attempt to go deeper for longer periods of time. If extrapolation is
to be the rule, then caution must be exercised. In this new endeavor, extrapolation
must give way to actual experiments under laboratory conditions. As sea habitats
are placed deeper and deeper, toward the limits of the continental shelf, open water
testing and evaluation programs become increasingly more difficult.

Above all, one must exercise extreme reluctance in accepting superficial interpre-
tations of results. Although for SEALAB II all results were essentially within nor-
mal limits, it must be remembered that these normal limits have been stipulated
for conditions on the surface, with a normal atmosphere, the design criteria estab-
lished for the development of man.

As man in the beginning came from the sea, the surface environment became the
evolutionary design criteria, --as we enter the program of retrogressive evolution,
we must proceed with utmost care. We must set aside the urge to race to the bot-
tom of the sea with reckless abandon, an approach which often prevails in programs
of this magnitude, interest, and almost limitless military and economic potential.

110

MANNED ASPECTS OF DEEP SUBMERSIBLES
by
J. G. Wenzel, Manager, Ocean Systems & Deep Submergence Programs
and
W. M. Helvey, Manager, Biotechnology
Lockheed Missiles & Space Company
Sunnyvale, California

ABSTRACT

A brief overview of the history-of manned submersibles, the need for man being
aboard, the primary missions he will perform, and the design considerations im-
plied by his presence in future deep submersibles have been given. Only during
the past 30 years have manned submersibles been able to penetrate ocean depths
below 300 feet, but during this period rapid advances have been made. A depth
of nearly 36, 000 feet has been reached, but submersibles capable of such a de-
scent have limited mobility and endurance. Man's presence in deep submersibles
is responsible for two principal areas of design considerations - crew health and
safety, and useful work performance. In the former category are the follow-
ing: 1) need for pressure capsules that achieve structural efficiency at design
depth and also provide good habitability for the crew, 2) need for a suitable life
support system, 3) need for safety systems that provide crew protection under
emergency conditions. In the area of useful work performance, these design
items must be considered to allow efficient crew performance: 1) need for
mobility and efficient controllability, 2) need for high-level visibility at both
short and long ranges, 3) need for effective manipulators to permit useful work.

INTRODUCTION

History of Manned Submersibles

The history of interest in manned submersibles can be traced back to at least the
16th century when a two-man, closed submersible was demonstrated for Charles V
(Fig. 1). In conducting basic research in life support - specifically on the renewal
of air that had become foul by respiration - Halley built this bell about 1715. The
atmosphere within the bell was rejuvenated by fresh air lowered from the surface
in casks.

111

Fig. I

A valve at the top of the bell permitted stale air to be forced out as the new air
entered. By this means, the air inside the bell could be refreshed almost indefi-
nitely. Halley also contrived a wooden helmet arrangement, connected by a hose
to the bell, which permitted a diver to leave the bell and perform useful work.
With this device, Halley successfully dove to 65 feet (with four assistants) and re-
mained there for 4 hours.

Essentially all diving, in submersibles or otherwise, was limited to depths less
than 300 feet until the early 19301s, when Beebe and Barton made dives to approxi-
mately 3, 000 and 4, 500 feet, respectively, in Bathysphere-type devices shown in
Fig. 2. The advent of the Bathyscaphs after World War 11, such as the Navy's
familiar Trieste I and II (Fig. 3), made a quantum jump in depth achievement,
particularly when Walsh and Piccard conquered the Marianas trench, at 35, 800
feet.

The history of man in submersibles, then, (Fig. 4) shows a very slow rate of
progress until the last 30 years. Although progress in these last years has been
tremendous, and in spite of the highly developed military submarine, there is
much work to be done before a truly efficient, manned deep submersible workboat
can become operational.

Definition of Deep Submersibles

Before going into the design implications and problems of man in deep submersi-
bles, it may be worthwhile to review briefly some of the specific missions in which

112

Fig. 2

Fig. S

these vehicles will be applied. Basically, these missions can be broken down into
two relatively broad general classes, on the basis of the type of vehicles required -
namely (Fig. 5) relatively small vehicles (2-4 personnel) having a relatively short
endurance of, say, less than 24 hours submerged, and the larger vehicles with
crews of up to 25 -35 men and submerged endurances in excess of 30 -60 days.
The smaller vehicles have become typified by the term "work-boats," and include
missions such as those shown. (Fig. 6).

c. 3363 PERIOig.EA
Mission~~~~60 apliaton for70 3th0 larger essti l 300ite enduanc crft(Fg.70
whic arethedeepsubersile outras oftecretncerpwrdsb
marines,~K ar lagey miiayixaue uha isielucltom.Hw
evrocanmiinstdy fthe aiso h ca ihppltos n ie

W~~~~~~114

SMALLONS

SEARCH & RESC
a RECOVERY. OF AE ~Fig. 6
* UNDERWA T'ER MSUPPORT

o CABLE IN.sPECTitOADElPAlONR
*S ;40 < S 00i tMARI NE ARCHEOLOGY
* UNDERSEA CONSTRUCTION
* SALVAGE

Fig. 6

l "BOTTo:M:::M!OB"LE;MISSILE~ LAUNCH PLATFORMS
* UNDERWATER SURVEILLANCE
El ANTI-SUBMARIN E 'WARFARE
El COMMAND & CONTROL STATIONS
El DEEP OCEAN BOTTOM SURVEY AND MAPPING

8 HOMESTEADING

Fig. 7

Why Man?

When one faces the issue of utilizing man in missions associated with the ocean
depths, a first thought may be "why put man there in the first place?" This is an
argument not unlike the man-in-space or wing planform discussions of the past and
probably will be equally short lived.

115

Other than the thirst for first-hand knowledge and the spirit of adventure, the pres-
ence of man in deep submersibles has advantages that are both economic and state-
of-the-art oriented. The cost of remote-controlled equipment with equivalent
versatility and capability is high and in many areas not presently within the state-
of-the-art. The problems involved lie in observation and response. To observe,
one must sense and relay what the submersible "sees" to a remote station. And
to respond, one must relay control information to the submersible guidance and
propulsion mechanisms, all of this through the limitations of a wire or a very poor
communication medium. In addition to the economic and "state-of-the-art" advan-
tages, there is the fact that man is an extremely versatile machine by himself,
either as a subsystem within the submersible, or as a working diver.

Man is presently essential in re-usable closed systems, such as in certain military
applications where remote control would degrade security or tactical reliability. He
is also essential in those military or commercial applications where maintenance of
the system and vigilance directed toward the accomplishment of a series of tasks
are a necessary and continuous operation. In summary, then, man's presence in
deep submersibles, whether necessitated by the state-of-the-art or by his versa-
tility, has inherent advantages in the area of observation, control, decision-making,
computation, and maintenance.

The requirements unique to the utilization of man in deep submersibles are many.
Some of these requirements are equivalent to those of man-in-space, and thus a
great deal of the human engineering that has been developed and applied to space
vehicles will apply directly to deep submersible systems. Among these require-
ments are life support systems, integrated controls, and long-endurance power
systems. Certain similarities also exist between lunar surface exploration craft
and deep submersibles in the area of manipulation, sampling devices, and the like.
Habitability needs are quite similar and are largely determined by length and com-
plexity of the mission and size of the crew.

To facilitate a more specific review of the requirements unique to man, two general
categories of design considerations can be established - namely (Fig. 8) man's
ability to survive, i. e., crew health and safety within the foreign environment of
great depths, and his ability to perform useful work in carrying out his mission
while confined to his protective shell. An interesting hybrid is the vehicle used to
support the working diver in relatively shallow (i.e., less than 1,000 feet) water
depths.

116

Fig. 8

MANNED ASPECTS

Crew Health and Safety

Structural/Habitabilitv Considerations. in considering the health and safety of the
crew, the design of the pressure capsule is of primary importance. Pressure hulls
of modern submarines are highly efficient stiffened steel cylinders. In designing
for extreme depths, it is desirable to achieve structural efficiency high enough to
permit the hull to carry a significant payload, and a shape that is hydrodynamically
efficient and at the same time provides good habitability for the crew.

Existing deep submersibles have largely utilized a single monoceque steel sphere.
It can be shown easily that for a given total volume a single sphere results in the
lightest pressure hull weight. However, from a hydrodynamic standpoint, the
sphere is grossly inefficient. In small manned vehicles, where usable internal
volume, power, and endurance requirements can pose great problems and where
efficient mobility is vital for search and rescue, a complete systems approach must
be taken in defining the pressure hull shape. Considering the vehicle as a whole,
hydrodynamic efficiency, the ratio of habitable to total volume, and power system
weight become important factors.

This problem was addressed in early studies at LMSC, where pressure hull shapes
varying from cylinders to spheres and toroids were considered. Typical spherical
structures designed for 20,000-foot depths are shown in Fig. 9.

117

,�!:~,~ ~ � PRESSURE HULL SHAPE

Fig. 9
Upon comparing single and bi-spherical pressure hulls of the same total volume
and for a given total mission endurance, it was found that the bi-spherical hull pro-
vided more usable volume, better habitability, and a lighter total system weight.

As more efficient power plants become available, such as fuel cells or isotope
engines, mission durations of 24 to 100 hours and above will become feasible.
However, this additional duration will require that increased volume be made
available for crew habitability. Over-restrictiveness adversely affects man's
activity, his flexibility of performance, and his ability to adapt to his working envi-
roument. On the other hand, volume in excess of the minimum functional needs of
the crew will penalize the system by increasing weight and cost.

In considering volumetric requirements, a distinction must be made between total
volume and free volume. Free volume refers to that space not occupied by instru-
mentation and other internal hardware and which is actually available for crew
occupancy. Figure 10 provides typical comparative data on a number of volume-
limited systems. Based on studies of this nature, it appears that an allotment of
approximately 50- 60 ft3 volume per man would be a reasonable value for a long-
endurance, deep submergence vehicle.

Establishing endurance, and hence constant propulsive power or equal drag as a
basis for comparison, the relationship between total and free volume of candidate
hulls can be examined. Shown here (Fig. 11) is a comparison between a single
sphere and a nested bi-sphere, each with an optimized fairing for minimum drag.

COMPARISON OF VOLUMES OF UNDERSEA & SPACE'
VEHICLES

MISSION EST. TOTAL CREW FREE VOL.
(DAYS) VOL. (ft3) SIZE PER MAN

>KU? ii ; '106 48

: A14 i 175 2 % 6 5306

9 A LO 15 '365 3 75

',,,POLAI SUB] 60 15,3930 120 4,36

Fig. 10

1lFig. 111CPP9A

The increase in available free volume from 145 ft3 to 256 ft3 clearly i ndicate s the
superiority of the bi-sphere.

Mission duration and adequate provision for crew work/rest cycles play a major
role in determining crew size. For missions of the order of 24 hours, a four-man
crew is highly desirable. These same data also show the free volume available per
man for three- and four-man crews and the greatly improved (by almost a factor of
2) habitability and endurance growth potential of the bi-spherical pressure hull.

119
119

It was convictions developed through studies such as these plus the desire to proof
test a full-scale operational pressure hull of this type that led to choice of the bi-
spherical pressure hull for the Deep Quest research submarine. This hull, fabri-
cated of an improved 200, 000 psi yield maraging steel is shown here (Fig. 12) in
final assembly.

An interesting question relative to habitability is raised when one considers the
larger bottom mobile systems of the future. The question is one of the desirabil-
ity, need, and usefulness of viewports. Related to this question are such factors
as depth and structural weight, turbidity and visibility, ancillary mission require-
ments, and emergency control considerations, as well as the effects on habitability.

Life Support. In addition to protection from high ambient pressures, man in a deep
submersible must obviously be provided with a suitable life support system, giving
consideration to the factors shown in Fig. 13.

With the great deal of work that has been done for space vehicles and conventional
submarines, this represents no significant problem in the design of deep submers-
ibles. However, the type of system will depend somewhat on the endurance
requirements.

The straight open systems (Fig. 14) utilized by divers where exhaust gases are dis-
charged directly into the sea has little application to deep submersibles. The
quantities and storage volume of gas required for any significant endurance is

Fig. 12

120

Fig. iS

Fig. 14

prohibitive. For example, the helium required by two divers for 24 hours at
1, 000 feet would require a storage capacity equivalent to a 9-foot sphere.

The replenishable system is the most attractive for the small submersible. In
this semi-closed recycling system, oxygen is added and CO2 and odors and/or
contaminants are removed. Consideration of very long endurance missions in-
troduces the completely closed ecological systems being developed for space, and
the application to submersibles is direct.

121

An interesting life support problem is introduced in the hybrid vehicle mentioned
earlier, where the vehicle must support underwater diver operations. (See Fig. 15.)
Relative to life support, the crew and equipment chamber will operate at atmos-
pheric pressure and on a standard Oxygen/Nitrogen mixture. The diver's quarters
or decompression chamber will operate on a Helium/Oxygen mixture of proportions
and pressure varying with depth.

In a small, relatively short-endurance vehicle, the divers would normally remain
in the diver's quarters at all times with the pressure lock only being used for
emergency purposes. For large, long-endurance craft such as an ocean mining
support vehicle, more spacious quarters would be required, and egress to the
atmospheric pressure quarters would be more common for extended rest.

To get a feel for the life support and design requirements for a small diver support
research vehicle capable of operating under the extreme conditions of 1,000 feet, for
24 hours, the data shown in Fig. 16 were produced.

The large gas volume requirement, namely 137 ft3 of light helium, which is unique
to this mission, is evident from the figures. Exclusive of the diver considerations,
only 10 ft3 of gas storage is required for the boat's operating crew.

The system utilized is a simple "re-breathing" or "replenishable" system. The
breatheable atmosphere is recycled through lithium hydroxide and activated charcoal
beds to remove CO2 and objectionable odors. The atmosphere composition may be
varied from pure Oxygen to Oxygen/Nitrogen/Helium mixtures. In the diver opera-
tion, the diver himself would be supplied by a self-contained two-gas system using
the re-breathing principle, or by a two-hose hookah system which would exhaust
back into the diver's module.

Helium has a high heat conductivity, which is accentuated with pressure. There-
fore, it is important to insulate effectively the shell around the diver's chamber and
minimize air circulation. A higher cabin temperature, perhaps 900 F, will be re-
quired for comfort.

In order to provide a test bed to develop mobile man-in-sea techniques, the Lockheed
Deep Quest (Fig. 17) has been designed to accommodate a support module for two or
more divers down to depth of 1,000 feet.

Direct access from the pressure hull to the diving chamber for emergency purposes
has been provided via a pressure lock as shown. If the pressure lock should not
prove necessary, its elimination will increase the volume available within the work-
ing chamber. An upper hatch permits transfer under pressure to a personnel

122

RKi

Fig. 15
~iii MA? iAJl'~~ SUPPORT VEHICLE :?.:� ~1

Fig. 1

transfer chamber and hence to a decompression chamber on the surface. Rapid
payload module interchangeability also permits decompression within the chamber
should that prove to be more desirable due to lack of transfer facilities.

Decompression can be controlled from within the ambient pressure bi-spheres by
the chamber operator or from within the diver's module (dual control similar to
surface decompression chambers).

1 23

Fig. 17

Safety. A major and overriding design consideration in any manned deep submers-
ible is that of crew safety. Critical failure modes of all components which would
endanger the life of the crew must be determined, their probability of occurrence
defined, and adequate safeguards provided to preclude the creation of hazardous
situations. Safety considerations for deep submersibles include both quantitative
and qualitative estimates of crew and equipment hazards. Quantitative analyses
are concerned with the establishment of a submarine safety probability objective,
which can be expressed as a safety failure rate. Therefore, submarine safety and

the boat's reliability program are obviously directly related.

In determining the critical safety items for consideration (Fig. 18), a safety philos-
ophy and criteria must be established. For example, top priority is given to struc-
tural integrity of the pressure hull and its penetrations. Adequate life support must
be provided to sustain life within the pressure hull until emergency surfacing or res-
cue can be effected. Assuming that the catastrophe precluded normal surfacing and
that it requires dropping ballast or jettisoning equipment, the appropriate emergency
release circuits and mechanisms must function properly.

Emergency power must be provided to operate the various jettison systems, to pro-
vide minimum illumination, emergency communications, and possibly some control.
All principal subsystems affecting crew safety are so defined and relative priorities
and probability objectives established.

124

CRITICAL SAFETY ITEMS

: � PRESSURE HULL

PENETRATIONS

- LIFE :SUPPORT -

* EMERGENCY RELEASE CIRCUITS/MECHANISMS

: EMERGENCY POWER

.....0 COMMUNICATIONS -

; MAIN/VARIABLE BALLAST SYSTEM

Fig. 18

Qualitative aspects which must be considered include such items as the adequacy of
emergency procedures, minimization of hazards due to human error, adequacy of
training, adequacy of alarm system, and malfunction detection.

Useful Work Performance

Mobility and Controllability. Mobility and controllability are very closely inter-
related, the first being concerned primarily with hydrodynamic lifts and drags and
the latter with the means of obtaining the forces and moments required to control
the various maneuvers. The problem of endurance, the necessity to operate with
a limited amount of energy vs. kilowatt hours, provides a design limitation in both
areas. The mobility/controllability problem can be divided into two general opera-
ting situations, bottom contouring and hovering.

Bottom contouring is associated with search operations, survey work, and various
oceanographic data-gathering missions. Some sonar search gear requires bottom
contouring for providing a precise measurement of the height of the boat above the
bottom. The maneuvering and control requirements, not unlike those of conventional
submarines, are (1) the provision for minimum drag, so that minimum energy ex-
penditure is needed for a given speed, and (2) the provision for a suitable compro-
mise between stability, which generally inhibits turning, and the requirement for
making tight turns to avoid obstacles.

A major problem is that of terrain avoidance. Because the number of operators is
far fewer than on conventional submarines, much more of the control system must

125

be automated. This includes integrating the navigation and sensor equipment with
the controls and displays as well as integrating the ballast and trim systems with
those of the control surfaces. It is not expected that in this type of operation the
operator will be overloaded, even if some of his automatic control loops are not
operative.

The second operation, hovering while working, is a most complex control problem,
much more so than any other vehicle control problem known. The operators must
control 6 degrees of freedom of the vehicle, using dynamic thrusters as well as sta-
tic forces such as ballast and trim. Typically, the accelerations that can be applied
to the vehicle are less than 0.003 g, and at maximum velocities (attainable after
approximately 1 minute) it takes 5 to 10 seconds to move a distance equal to the di-
mension of the vehicle. In addition, one or two manipulators must be controlled,
each with approximately 7 degrees of freedom, and one or more pan-and-tilt TV
cameras must be operated. And all of this must be done by no more than two
operators.

The integration and automation requirements for hovering are much more critical
than for contouring. Hovering requires more power than cruising, since lateral
drags are much greater than longitudinal drags, and thrusters require more power
than control surfaces for maintaining a given moment. A well-integrated control
system will permit the work to be done with minimum energy drain from the batter-
ies. This will increase the amount of time per trip for performance of work, and,
in effect, reduce the cost of each work operation. Thus, automation will be re-
quired, not only because the task is difficult, but primarily because the task needs
to be done efficiently. On the other hand, for emergency purposes these vehicles
must have sufficient controllability to permit the operator to do an effective job even
during manual control. The feasibility of this approach has been attested to by the
work done by various operational craft, as well as by simulations performed at
LMSC.

The control system must be intimately tied in with the display system, particularly
if it is necessary to work in various modes of control. It can reasonably be assumed
that all deep submersibles will utilize TV cameras and that a TV monitor will be in-
cluded at the control station. Integration of controls and displays will involve using
the TV monitor as the control display on a time-shared basis with the TV picture.

A very important design tool being utilized by the Navy and industry in the design of
manned submersibles and their integrated control systems is that of computer simu-
lations, both static and dynamic. Manned simulations provide an accurate, inexpen-
sive, and quick method of evaluating control and display concepts.

126

Figure 19 shows a control display simulator used at LMSC in the design of the con-
trol system for Deep Quest. In addition to basic control system design, such simu-
lators are invaluable for failure analyses, manual control evaluation, and crew
training.

The degree of controllability and hence the amount of simulation work required will
be a function of specific mission requirements. For example, in recovery, setting
the submersible over the escape hatch of the distressed submarine and positioning
sufficiently to gain an effective pressure seal may require vernier controllability

up to 45 degrees of pitch and roll. Such attitudes introduce severe human engineer-
bing problems, which make manned simulations mandatory.

In research program designed to support Deep Quest and DSSP work, Lockheed is
using both full-scale, hard mockups, and simulation. Shown -here (Fig. 20) are
several of the facilities used for human factors research, design, simulation, lay-
out, and arrangement.

One of the first problems encountered was how to seat and restrain operators and

scientist-observers to permit efficient operation at relatively large pitch and roll
angles over the bottom. Due to the pressure of gravity, large attitudes produce
problems not experienced by astronauts or by aircraft pilots. Roll attitudes intro-
duce a tendency to "hang on the stick," thereby resulting in lateral overcontrol.
Pitch attitudes inject requirements for full head and shoulder supports. A complete
special purpose operator's seat has been designed to permit efficient control under
these conditions.

Fig. 19

127

In the layout of an efficient console design for Deep Quest, a seat reference point
(SRP) was chosen as shown in Fig. 21, positioned above the deck, and used to de-
termine the reach and vision envelopes for the 5th and 95th percentile Navy opera-
tors. A preliminary console design was fitted into this envelope, modified by hard-
ware space and volume considerations, and re-evaluated prior to final design. The

:HUMAN ENGINEERING & SIMULATION

Fig. 20

i T* Slh PEERCENTILE OPERAO R

5 t� h PERCENTILE OPERATOR

Fig. 21

128

procedure has ensured operator visual and manual access to all relevant positions
of the control panels.

Visibility. Regardless of the conditions within a work-boat, the operators are
helpless to perform useful tasks unless some form of visibility outside of the craft
is provided to them. There are really two problems here, one of supplying rela-
tively long-range visibility for purposes of search and rapid scanning of large
areas, and the other of supplying very short-range visibility for close-in task ob-
servation or object recognition. Both problems have imposed serious limitations
on submersibles to date. For example, the relatively short ranges of existing
high-resolution sonar, combined with the very slow speeds of craft such as the
Trieste, result in effective search rates that are extremely low. Although search
rate numbers are subject to many qualifications, an area approximately 5 miles on
a side would require about 17 hours to cover. This is obviously unsatisfactory and
incompatible with the endurance capabilities of small work-boats.

Relative to close-in vision, the principal need is to supply the operator (of the work-
boat manipulator) a good visual display of the object of his task and the results of his
efforts. Without such a display, any tool or manipulator to be used in the foresee-
able future will be essentially worthless. This display must in essence be equivalent
to direct viewing so that full advantage is taken of the dexterity capability possible
with man in the loop. The first consideration then is to provide viewports fordirect
vision, located so that the operator's eye is within a very short distance, about 5 to
10 feet, from the object being worked on. Even though full provisions are made for
TV viewing, such ports will be vital in an emergency. Because of the total darkness
at depths, high-intensity lights are mandatory.

A particularly challenging problem is that of vision in the presence of sediment in
the water. Don Walsh in his explorations with the Trieste reported the total lack of
visibility when clouds of sediment were raised upon bottom contact. Sealab II re-
ported similar conditions. A work-boat, hovering and applying power to counter-
balance loads from the manipulator, is certain to stir up sediment, which will ren-
der TV and light systems useless.

A possible solution to the problem of viewing under aggravated conditions is a system
that uses acoustical imaging. This is possible because water is relatively trans-
parent to high-frequency acoustic waves at short range, even in the presence of a
cloud of stirred-up bottom sediment. Figure 22 shows a simplified schematic of
such a system. The object to be viewed is insonified with high-frequency sound in
the low-megacycle range. Part of the energy scattered by the object' s acoustical
features is collected by an acoustical lens, and an acoustical image (in the form of
pressure variations) is created at the front side of an image-converter tube. The

129

Fig. 22

converter tube front plate is a piezoelectric one, with the effect that a spatial
voltage distribution corresponding to the acoustical image is obtained at the back
side of the plate.

In a conventional image-converter tube, the back side is scanned by an electron
beam, with the result that the secondary electron current represents a typical video-
signal that is suitable, after amplification, for display on a TV monitor screen.
Among the problems requiring R&D are the following: The image is degraded in
turbid media due to attenuation, backscatter veiling, and diffuse scattering of sound
after reflection from the object. Resolution is lost because of acoustical lens abber-
ation and diffraction and because of refractive effects of thermal inhomogeneities.
Also, improvements are needed in the field of image conversion.

Backscatter veiling reduces contrast. Under severe backscatter conditions, one can
improve things relatively easily by introducing time gating, i. e. , by' use of relatively
short pulses of acoustical energy. Forward scatter would be detrimental only in the
case of a rather high scattering coefficient. Its effect is approximately 1/5 of the
back-scatter influence under typical conditions. Figure 23 compares theory to meas-
urement results obtained in an optical analog experiment. There is a good agree-
ment except at extremely high turbidity values, where secondary scattering can no
longer be neglected.

The image-converter problem has been addressed at LMSC, and a novel techniqu'e
has been conceived that will improve the resolution of acoustical imaging. In this
improved design, the converter aperture can be made much larger, which permits

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131

Typical tasks to be performed by a work-boat manipulator are shown in Fig. 24.
Because of the scaling problems mentioned, many recovery tasks simply involve
attaching a plate mand/or connecting lines to the object to be recovered. Of the tasks
listed here, cutting and welding possibly require the greatest dexterity.

Increasing the dexterity capability is a complex and involved subject that is beyond
the scope of this paper. In essence, however, the problem is to make available to
the remote operator as much as possible (or practical) of the sensory information
that he would have if the manipulator were replaced with his own arm. This includes

not only proper visual display but feedback data and controls having spatial corres-
pondence mand force reflection. This is not easy nor low in cost mand provision of
this capability must be commensurate with the value of the task. As must be done
in other fields, underwater maintenance tasks must also be designed so that load
and dexterity requirements are minimized.

One final problem worthy of mention is that of training operational personnel. The
use of dynamic simulation, such as that used for training USN submarine personnel,
is one obvious candidate. Also to be considered is the use of the available deep sub-
mersibles themselves. Cost/effectiveness studies must be done to determine the
kind mand amount of training required for personnel manning deep submersibles.

TYPICAL MANIPULATOR TASKS

0 HOOK-UP ASSIST & POSITIONING FOR TRANSFER

* ATTACH RECOVERY DEVICES TO OBJECTS

* CONNECTING LINES OR CABLES

* CUTTIHO & WELDING

* SIMPLE PICK-UP, TRANSFER, AND STOW

Fig. 24

132

Summary and Conclusions

A brief overview of the history of manned submersibles, the why of having man
there at all, his primary missions, and a few of the design implications of his pres-
ence in future deep submersibles have been given. There are, of course, many
subtle design and human engineering factors that are either beyond the scope of
this paper or that will not be uncovered until more operational experience is
gained in this field. One thing is certain, however, and that is that man is not to
be denied the wealth, adventure, and technical challenges of the ocean depths.
Long before effective exploitation of the resources of outer space has begun, pro-
ductive and efficient military and commercial deep sea operations with manned
deep submersibles will be commonplace.

133

SEALAB II UNDERWATER WEATHER STATION

E. A. Murray, D. L. Inman, and W. A. Koontz
Scripps Institution of Oceanography, University of California
La Jolla, California

Contents

Abstract

Introduction

Description of the Area

Instrumentation

Savonius Current Meter
Vibrotron Pressure Sensor
Data Acquisition System

Installation of Underwater Weather Station

Data Results

Presentation of Data
Diver Observations

Bibliography

Figures

1. Index chart showing bathymetry of the continental shelf off La
Jolla.
2. Detailed bathymetry in the vicinity of Sealab II.
3. Schematic diagram of underwater weather station and location of
other instruments.
4. Schematic diagram of the underwater weather station in lowering
position, diver towing position, and installed.
5. Upper (right) and lower (left) current meter packages prior to
installation.
6. Analog records of data recorded on 25 and 26 September 1965.
7. Analog records of data recorded on 22 September 1965.
8. Wave record from the digital wave staff mounted on end of the
Scripps Institution of Oceanography Pier.
9. Power spectra for wave staff (13), current meter (5), and pressure
sensor (7) for 1130-1330 PST, 6 October 1965.

Table

1. Diver Log

Contribution from the Scripps Institution of Oceanography, University of
California, San Diego.

134

Abstract

An underwater weather station was installed and maintained by the Aquanauts
as part of the Sealab II scientific program. The weather station provided
measurements of current speed and direction, temperature, pressure, and
ambient light. The data were recorded in Sealab II for diver use and
through long lines to a shore station where more detailed analysis could be
performed.

The Sealab data indicate that many phenomena contribute to underwater
weather. The identity and relative contributions of the many possible
sources of energy will require more extensive measurement and spectral
analysis. Weather at this depth could not be predicted by simple manipu-
lation of measured surface parameters such as waves and tides.

INTRODUCTION

An underwater weather station was installed near Sealab II and maintained
by the Aquanauts. The weather station measured water current speed and
direction, pressure, temperature, and ambient light. It was intended that
these measurements provide the divers with the most essential parameters
of underwater weather, as well as providing necessary background informa-
tion for other scientific programs undertaken during the operation. In addi-
tion, it was hoped that the underwater weather station measurements, when
compared with similar measurements obtained synoptically elsewhere on
the shelf, would provide insight into the complex phenomena that constitute
underwater weather.

There are almost no continuous observations of the underwater environment
that are of sufficient scope to be considered as underwater weather. Yet,
underwater weather is as important to man in the sea as to man in the
atmosphere. The kinds of parameters to be sensed are similar to those in
the atmosphere: current speed and direction, pressure, temperature, and
light. Their measurement underwater is somewhat more complicated,
principally because water is wet. In addition, the underwater environment
has greater pressure, viscosity, specific heat, and biological activity of
all kinds. The importance of biological activity is frequently overlooked
in underwater instrumentation. Every few days, it was necessary to clean
organic growth and fouling from the current meters. The current measured
underwater appears deceptively weak in terms of air currents. However,
"gusts" up to nearly 2 knots were measured near Sealab and these, because
of the increased density and viscosity of water, would have exerted a drag
on the diver equivalent to that of a 50 to 100 knot wind in the atmosphere.

Sealab II, with three teams of divers and a total underwater occupancy of
45 days, presented an excellent opportunity to obtain long-period continu-
ous measurements of the underwater environment. Sealab II was occupied
by divers from 28 August through 10 October 1965.

135

DESCRIPTION OF THE AREA

The site of Sealab II was the continental shelf just north of La Jolla,
California, where Point La Jolla forms a small hooked bay which opens to
the northwest. The shelf area within the embayment is cut by two main
branches of La Jolla Submarine Canyon (Figure 1). Sealab II was placed on
the rim of the northern branch, Scripps Submarine Canyon, where the rim
has a depth of about 210 feet; and the floor of the adjacent canyon has a
depth of 650 feet. Both La Jolla and Scripps Canyons extend across the
continental shelf and terminate within a few hundred feet of the beach.
The shelf between the two canyons is covered with fine sand in shallow
water and with fine sand and coarse silt at the Sealab II site (Inman, 1953).
Scripps Canyon is narrow and precipitous, and in many places the walls are
vertical as indicated by observations from the diving saucer (Shepard et al,
1965).

For many years it has been known that the heads of Scripps Canyon trapped
sand from the adjacent beaches. This beach sand is eventually deposited
in the deep water of San Diego Trough some 16 to 20 miles seaward. The
mechanism by which the sand is transported through the canyon is not
understood, although the volume of material transported has been measured.
Extensive surveys of the canyon head (Chamberlain, 1960) indicate that
about 200,000 cubic yards of sand is lost into the canyon each year. A
series of current measurements have been made over periods of days and
weeks at several stations within the canyon. One of these stations is
within SCUBA diving depth at 150 feet at the head of the canyon (Figure 1).
Currents have also been measured on the canyon floor just below the
Sealab site at a depth of 650 feet. These measurements were obtained by
sending a self-contained instrument package down a taut wire mooring to
the canyon floor (Figure 3). After a predetermined length of time weights
are released, and the instrument package returns to the surface where it
is retrieved by SCUBA divers. The 650-foot station was not occupied
during the Sealab measurements because of fouling by the mooring lines
from the surface support vessel, BERKONE. However, a taut wire mooring
at a depth of 215 feet just northwest of the Sealab II site was instrumented
during the Sealab operation (Figure 2). This data was compared with data
from the underwater weather station which was at a similar depth on the
rim northeast of Sealab II.

INSTRUMENTATION

Data from all sensors except the two current meters at the bottom of the
canyon was transmitted to a control center (called "Benthic Control") at
the shoreward end of the pier where it was recorded in both digital and
analog form. Pier end data was transmitted by direct cable, but data from
the weather station was transmitted through a telemetry system which had
its seaward terminal in an underwater Benthic chamber. Six 2-conductor
cables and three 4-conductor cables connected the instrument array on the
weather station platform to an equipment rack inside Sealab. The equip-
ment rack furnished power for the sensors and conditioned the signals from
the sensors for transmission via the telemetry system. It was essential
that the variable-resistance sensors receive a constant excitation current.
It would have been impractical to furnish an individually regulated constant-
current supply for each sensor, so a single 300-volt constant-voltage
supply was installed. Individual 300,000-ohm resisters connected to the

136

300-volt supply furnished an excitation current of one milliampere for each
sensor. Since the resistors were mounted in Sealab, the amperage avail-
able in the water was very low. A 12-volt power supply, also mounted in
the equipment rack, furnished regulated, constant-voltage power at about
3/4 ampere for electronics packages incorporated in the current meters and
the Vibrotron pressure sensor and for signal power amplifiers in the equip-
ment rack.

An analog-to-digital converter inside Sealab changed the signals from
variable-resistance sensors to digital form to be transmitted via the tele-
metry system. Signals from the current meters and the Vibrotron needed no
transformation. All sensors except the Vibrotron could be monitored inside
Sealab with Rustrak chart recorders. Digital channels of 12 bits each were
sampled every 6 or 12 seconds by the analog-to-digital converter. Some
of the more important data channels, including the current and pressure
sensors, were connected directly to the telemetry system and could be
sampled as often as desired (within limits imposed by the nature of the
signals). However, analog signals from the variable-resistance sensors
could not be telemetered with any great accuracy due to drift in the tele-
metry channels.

All signals were connected from Sealab to the underwater Benthic telemetry
chamber via a multi-conductor cable. From here they were transmitted to
the shore station via an amplitude-modulated, multi-channel carrier tele-
metry system on a single coaxial cable.

Savonius Current Meter

Accurate measurement and recording of low-period, low-velocity undersea
currents prompted a modification of the reliable and time-tested Savonius
rotor. A miniature model, designed by Mr. I. M. Snodgrass of the Scripps
Institution of Oceanography, was constructed of "Cycolac" plastic sheet
and balanced to be neutrally buoyant in sea water. The rotor was mounted
on bearings of sapphire and tungsten carbide. Sixty equally spaced holes
near the periphery of one rotor end plate interrupted a light beam as the
rotor turned, producing 120 electrical pulses for each revolution. One
pulse was generated as the beam passed through each hole, and another
pulse was generated as the beam was interrupted. This pulsing output
signal has proven to be most reliable in transmitting data over long tele-
metry channels because its information is relatively immune to amplitude
modulation caused by normal noise pickup during transmission.

Several light sources for the current meter were tested during its develop-
ment. The final design incorporated a CM-8 series bulb manufactured by
the Chicago Miniature Lamp Works. The bulb, because of its small size,
was capable of withstanding the high pressure of the environment and
proved to be less susceptible to marine growth than larger lamps which
were tested.

Direction of current flow was indicated by a Cycolac vane mounted on
sapphire pivots and housed axially with the Savonius rotor. Vane position
was sensed electrically by a potentiometer, and its analog readout appeared
inside Sealab. A magnet was attached to the potentiometer shaft and the
unit sealed in an oil-filled canister. A second magnet fastened to the
edge of the vane provided magnetic coupling of vane rotation with

137

potentiometer rotation. The oil damping reduced overswing of the
potentiometer during fast transitions.

Vibrotron Pressure Sensor

The Vibrotron is a vibrating-wire transducer which converts absolute
pressure input to an audio output signal with a frequency inversely propor-
tional to the applied pressure. It was chosen for use at the sea floor
weather station because of its ability to resolve small changes in absolute
pressure while in a very high pressure environment. Excitation and signal
amplification electronic circuitry was modularized and housed with the
transducer in an oil-filled canister. The audio output signal was tale-
metered directly to the data acquisition system on shore where the frequency
variations were digitized and recorded on magnetic tape along with the other
measured parameters.

Data Acquisition System

A system of analog and digital recorders, along with necessary amplifiers,
digitizers, and logic control units, was located in the Benthic Control
Center near the telemetry receiving terminal equipment. A 12-channel
chart recorder monitored analog readouts from the underwater weather
station and from the pier end anemometer. A separate chart recorder
monitored an analog conversion of the output of the pier end digital wave
staff. The chart speed of the latter recorder could be changed as desired
to obtain short records of wave profile (Figure 8), as well as long-term
records of lower frequency phenomena such as tides and shelf seiche.

The telemetry receiving equipment monitored the output of the analog-to-
digital converter in Sealab and recorded the information incrementally on
magnetic tape. Data which was telemetered direct (without conversion)
was channeled into a data acquisition system (DAS) for sampling at shorter
time intervals. Plug-in, printed-circuit logic boards were used in the
acquisition system to digitize the sampled data, to store in memory banks
in binary form information from all input channels, and to present the
information in increments to a high-speed magnetic tape recorder for
permanent storage. The tape record was in standard IBM format and could
be programmed directly into a computer for analysis.

INSTALLATION OF UNDERWATER WEATHER STATION

The underwater weather station platform was lowered to the sea floor from
the staging vessel BERKONE on the evening of 4 September 1965. The
platform in its lowering position (Figure 4) consisted of a central 1-inch
thick steel plate, 32 x 32 inches on a side, to which were welded four leg
guides and two instrument mounting brackets. Other components, including
the taut wire and its float and the flotation equipment, were lashed to the
platform between the four anchor legs, which in their lowering position form
a "teepee" structure. Once on the bottom, the platform was located in the
turbid water by two divers using a 25-40 kc hand-held sonar. A 37 kc
"pinger" attached to the platform provided a target for the sonar.

The underwater weather station was diver-oriented in its design. It was
intended that it be easily moved by two divers after inflating four rubber
tubes to give it neutral buoyancy. The tubes were inflated by bleeding air

138

from a SCUBA bottle into holes cut in the tubes near their point of attach-
ment. This provided the necessary safety control to prevent over-inflation
and excess positive buoyancy. The air in the tubes could be spilled
instantly by squeezing the tube. After inflating the tubes, the platform was
transported 165 feet to the installation site by two divers. The site (Figure
2, position 3), which had been determined previously during reconnaissance
dives, was on a slight rise where currents would be more typical of the
area than in the valley at the Sealab site. The platform was firmly anchored
in place by pounding four anchor legs into the bottom. The taut wire
mooring was then released from the platform and assumed its vertical posi-
tion, maintained in a taut position by the 75-pound positive buoyancy of
the float. At the end of the 45-day Sealab project, all of the underwater
weather station sensors were attached to the taut wire mooring which was
then released from the platform and retrieved on the surface.

Two days were required to install sensors on both the upper and lower
weather station. Conductors were run to the station, and underwater weather
was recorded in the habitat. Two trips were made daily to service instru-
ments and check sensors. Recorders inside the habitat were checked, and
comparisons with observed weather conditions from the 24-inch ports were
made.

DATA RESULTS

Data was recorded in analog form in Sealab II and in Benthic Control Center.
Also, all data transmitted over the Benthic Lab cables was routinely sampled,
digitized, and then stored on the telemetry system's magnetic tape recorder.
Unfortunately, an erratic fluctuation of the time identification channel made
much of this magnetic tape data unintelligible.

The routine analog recording through the long lines of Benthic Lab had high
levels of background noise, as well as long-period, quasi-systematic
fluctuations that partially obscured the data signals. Therefore, it was
not practical to make a systematic reduction of all of the analog data.
Rather, the approach was to (1) analyze those records that presented
synoptic information from a number of stations, such as the underwater
weather station, the 150-foot station, and the pier end (Figures 6 and 7)
and (2) make detailed analysis during times of unusual phenomena, such
as high waves (Figures 8 and 9). Detailed analysis was facilitated by the
use of a high-speed data acquisition system, DAS, (Koontz and Inman, in
press) which stored data of finite length for future spectral and cross-
spectral analysis.

Presentation of Data

Seven days of synoptic measurements of currents at the Sealab II under-
water weather station and at the 150-foot deep station in the head of Scripps
Submarine Canyon were made (22-26 September and 29 September-1 October
1965). Comp arison of currents from both localities during two days when
the currents were most active are shown in Figures 6 and 7, together with
measurements of tide and wind from the Scripps Pier.

Currents at both stations showed a marked tendency for flow directions to
parallel the axis of Scripps Submarine Canyon rather than to cross the axis.
This permitted the currents to be plotted as two-dimensional currents using

139

the notations "onshore" and "offshore", where these notations indicate
flows in the directions of 0600 True and 2400 True respectively. On 25
September 1965, (Figure 6), maximum currents in excess of one-half knot
were measured at the underwater weather station, while those in the canyon
head were in excess of one knot. Currents at both stations were irregular
in speed and showed frequent reversals in direction. The fluctuations at
both stations had periods ranging from about five minutes to over one hour.
It is impossible to determine from these analog records whether there is
coherence in the fluctuations between two stations. It does appear that
the fluctuation frequencies are similar at the two stations, and it is
obvious in this case that the stronger currents occur at the canyon head.
There is some indication, especially at the Sealab station, that the net
current is offshore during ebb tide and onshore during flood tide.

Similar comparisons between the Sealab site and the 150-foot station are
shown for 22 September (Figure 7). These differ from those in Figure 6 in
that the currents were stronger at the Sealab site than at the canyon head.
They're similar in that both records show fluctuations of current with periods
of a few minutes to over an hour and in that the reversals in current were
somewhat more frequent at the canyon head. This data differs from Figure 6
in that the net current appears to be onshore during most of the day.

High waves were observed on 6 October (Figures 8 and 9). Inspection of
the analog record from the wave staff on Scripps Pier, where the water is
20 feet deep, showed that the waves were as high as 6 feet (200 cm) and
had periods ranging from less than 8 seconds to over 16 seconds. The
water was too rough for SCUBA divers to place the current meter in the head
of Scripps Canyon. However, a two-hour record of wave height from the
end of Scripps Pier and current and pressure records from Sealab II were
made on the high-speed data acquisition system. During this run, each
sensor was sampled every two seconds, and the data was processed through
the CDC-3600 computer to obtain the spectra and cross-spectral analysis
for all channels. This data is shown in Figure 9, together with the phase
and coherence between the Sealab pressure sensor (7) and the current (5).
The spectrum from the wave staff (sensor 13) shows the surface wave energy
to be concentrated over a broad band of waves varying in period from about
8 to 16 seconds. It also shows a pronounced long-period spectral peak
with a period of about 105 seconds which appears to represent the "surf
beat" associated with these waves. Both the Sealab current and pressure
also show broad spectral peaks with periods in the range of 10 to 16 seconds,
which are undoubtedly associated with the surface waves. The pressure
record shows a series of spectral peaks, some (periods of 50 and 25 seconds)
having frequencies that are multiples of the surf beat frequency. Others,
with periods of about 7 and 8 seconds, are probably artifacts due to parasitic
disturbances in the data sensing and/or transmission facilities.

The energy density for the signal variations from the wave staff and the
Sealab pressure sensor is expressed in units of cm2 per unit of band width,
Af (Koontz and Inman, in press). The corresponding spectral estimate for
the current is in units of velocity2 per ta. The proper scale in cm2/seconds2
per Af for the current spectra is obtained by multiplying the printed scale by
a factor of 0.41. The product of the spectral estimate (energy density) and
the band width gives the mean square velocity associated with any particu-
lar frequency band. It will be observed that the root-mean-square velocity
under the broad spectral peak of the current is approximately 5 cm per
second.

140

The orbital velocity associated with the passage of a simple wave of
frequency f in still water would show a maximum onshore velocity under
the wave crest and a maximum offshore velocity under the wave trough.
The spectrum for this orbital velocity would show a single spectralpeak
having a frequency twice that of the wave, because the square of the
onshore (positive) and the offshore (negative) orbital velocities has the
same sign in the analysis procedure. However, the spectrum for the
current meter shows good agreement in frequency with that of the surface
waves (center of diagram) and shows little energy at twice this frequency
(right of diagram). This can only be interpreted as an orbital velocity
superimposed upon a net current of nearly the same speed or greater.
Inspection of the analog record of current during this period shows that
the current had a speed varying between zero and one-quarter knot, and
the direction of flow was southwesterly or offshore.

Diver Observations

Observations by divers were made in the vicinity of Sealab and from within
Sealab through three of the 24-inch portholes. The first two days' observa-
tions were made outside the habitat because the porthole protective covers
were in place; but once removed, the forward port, the laboratory space
port, and the starboard portholes were chosen for routine observations.
The underwater weather station was not set up and operational until the
seventh day of occupation.

On the first two days of occupation a swimmer survey of the lab site was
made with MK VI mixed gas equipment. The two relatively higher ridges
of sand that extended from the port quarter and starboard bow were explored.
Divers carried a safety line attached to Sealab and used underwater sonar
that was tuned to the frequency of a pinger previously placed on the Sealab
conning tower.

An area on the port quarter 165 feet from Sealab was selected for the under-
water weather station, and current observations were made here during
each inspection. The weather station platform and its equipment were
placed on a sand slope near the rim of the submarine canyon. Anchor and
nylon safety line were maintained between the Sealab shark cage and the
underwater weather station at all times. Sediment stirred up by the divers
during inspection dives was a problem both for the instruments as well as
for safety and visibility. The distance between Sealab and the underwater
weather station (165 feet) and the capacity of the MK VI mixed gas diving
apparatus limited the time outside to 70 minutes or about two round trips
to the weather station. A very large part of installation time was spent
placing the cables that led from Sealab to the weather station. Once
sensors and cables were in place, daily routine cleaning and inspection
trips were initiated.

During the first four days it was possible to "hear" or feel pressure changes
caused by the passage of surface waves. Simultaneous observations on the
surface and in the habitat showed that occupants were able to sense crests
and troughs of waves passing on the surface.

Observation of fish that set up permanent occupancy near Sealab portholes
showed they definitely oriented with the current. Migratory fish appeared
independent of the direction of current and surge. Usually the orbital

141

motion of surface waves is not apparent from the trajectory of small particles
at this depth,

During the first three to five days of occupancy, surface waves were low;
and tides were near their spring range (about 5 feet). Bottom currents, as
indicated by particle trajectories did not show good agreement with tidal
fluctuations. Erratic fluctuations from onshore to offshore currents were
commonly observed. On the sixth day of occupancy, the height of the
surface waves increased to about 6 to 8 feet; and the waves continued to
be high through the tenth day. The high waves were followed on the
eleventh day by a strong, steady offshore current. This current was also
measured by the sensors on the underwater weather station, which showed
maximum velocities of I knot and 2 knots on the lower and upper sensors
respectively. During the first team's occupancy, each period of high
surface waves was followed by: (1) an increased tendency for offshore
current, (2) increase in water temperature, (3) increase in numbers of
plankton, and (4) appearance of large, migratory fish. Observations over
longer periods are necessary to determine if this is a common trend.

BIBLIOGRAPHY

Chamberlain, T. K. , 1960, "Mechanics of Mass Sediment Transport in
Scripps Submarine Canyon, California" , dissertation for Ph.D. degree,
Univ. of Calif. , Los Angeles, 200 pp.

Inman, D. L. , 1953, "Areal and Seasonal Variations in Beach and Nearshore
Sediments at La Jolla, California", Corps of Engrs. , Beach Erosion
Board Tech. Memo. No. 39, 82 pp.

Koontz, W. A. and D. L. Inman, in press, "A Multi-purpose Data
Acquisition System for Field and Laboratory Instrumentation of the
Nearshore Environment".

Shepard, F. P. , 1. R. Curray, D. L. Inman, E. A. Murray, E. L. Winterer,
R. P. Dill, 1964, "Submarine Geology by Diving Saucer", Science
Vol. 145, No. 3636, pp. 1042-1046.

142

t17-17' 117 16' 117'15'
32'53'

CURRENT

~65OFL~ METER I

E-SEALaB E SCRIPPS
7SITE FIGURE PIER
,2~K '' 5 32'52'

Knl

6ri, N

32-51'

LA dOLLA
CONTOURS IN FEET
0 1o00 2000
FEET

Figure 1. Index chart showing bathymetry of the continental shelf off La
Jolla. The Sealab II site is indicated by the dashed area and its position
and detailed bathymetry are shown in Figure 2. Note the two current meter
stations at depths of 150 feet and 650 feet.

143

SCRIPPS 5
400
390
380
370

? /SUPPORT VESSEL\0

250 50 100

FEET
CONTOURS I N FEET

Figure 2. Detailed bathymetry in the vicinity of Sealab II. Numbers show
the location of: (1) Benthic Lab, (2) power beehive, (3) underwater weather
station, (4) taut wire mooring on canyon rim, and (5) taut wire mooring on
canyon floor.

144

SCRIPPS PIER
ANEMOMETER

TO BENTI COTROL

UNDERWATER WEATHERVIRTO

SELF-CON~~~~~~TATINE
CURR ~ ~ ~ MDATR LMENT LIGTE

Figure ~ ~ EAAB 3.NH ScEmtcdgrmouNdewtrwahrStiOR n oaino
other instruments.~A

UNDERWATER WEATHER STATION

LOWERING POSITION DIVER TOWING POSITION INSTALLED

ANCHORING
LEGS

TAUT WIRE FLATED
FLOAT 30 ft
TUBES
DEFLATED

-~~~~~~~~6 -

INSTRUMENT

LEG GUIDES
LEGS

Figure 4. Schematic diagram of the underwater weather station in lowering
position, diver towing position, and installed. Numbers indicate sensors:
(1) upper current direction vane; (2) upper current speed, Savonius rotor;
(3) compass; (4) upper thermister; (5) lower current speed, Savonius rotor;
(6) lower current direction vane; (7) pressure sensor, Vibrotron; (8) lower
thermister; (9) ambient light.

. 1 . -_W

Figure 5. Upper (right) and lower (left) current meter packages prior to
installation. Photographed in Sealab II by Chief J. D. Skidmore (official
photograph, U. S. Navy).

147

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WIND SPEEO(II) I I 11<

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I I I I I I I I I I I I II I I
0800 1000 1200 400 600 800 2000 2000 0000 0400 0600 0800
'ST.
25 SEPtEMBER 60 26 SEPTEMBER 65

Figure 6. Analog records of data recorded on 25 and 26 September 1965.
Tide, wind speed, and direction were measured from the end of Scripps
Pier; underwater weather station current is from the lower instrument package,
sensors 5 and 6; current from the 150-foot station recorded on a similar
instrument placed by SCUBA divers. Since the current directions were on and
offshore, the data from current speed end direction at both stations is repre-
sented by a single plot of speed vs. time.

+ 10.0o IDE

MLLW 0 -

-5.0
WIN I SPEED(II) I I

.,,~ ,,,~ ,I II ,I I I I

360, --

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I I I i , , I , I I I. I I I I I i , I, I ,
CURRENT- 150 FOOT STATDION

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0 ; i , i i i l'

2400 0200 0400 0600 0800 1000 1200 1400 1600 1800 2000 2200 2400
PST 22 SEPTEMBER 65
Figure 7. Analog records of data recorded on 22 September 1965. Tide,
wind speed, and direction were measured from the end of Scripps Pier;
current at Sealab site measured from taut wire mooring shown as station 5
in Figure 2; current from the 150-foot station recorded on a similar instrument
placed by SCUBA divers. Since the current directions were on and offshore,
the data from current speed and direction at both stations is represented by
a single plot of speed vs. time. Data below threshold value at the 150-foot
station indicates direction only.

250

0
0 50 100 150 200 250 30
TIME IN SEC.

Figure 8. Wave record from the digital wave staff mounted on end of the
Scripps Institution of Oceanography Pier. Record begins 1200 PST,
6 October 1965, and is representative of waves contributing to the spectrum
in Figure 9.

PERIOD SEC
200 I00 50 25 15 10 9 8 7
10- AS-22 , - I
A. 2- ,f.6.25,I0%PcSl .t
% a. "6000 m(400I1U N
IWAVE STUFF

_loo-G S n."nW~ ~ , WA7|35}TF . V ;CURREN 5) -

P80D |PR L.ESSUR E LEADS 180-

' , ' , ' \ ,o . ..

~'tKA\UPRESSURE LEAUDS

0 0.05 010 0.15
FREQUENCY CPS

Figure 9. Power spectra for wave staff (13), current meter (5), and pressure sensor (7) for 1130-1330
PST, 6 October 1965. Lower graphs give coherence and phase between sensors 5 and 7. To obtain
mean square value of spectral estimate of current, in cm2/sec2 per af, multiply energy density
scale by factor of 0.41.

Table 1. Diver Log, 28 August 1965 to 11 September 1965, (E. A. Murray)

1st Day, 28 August 1965

No current observed on the bottom. Visibility 30 feet (porthole covers
still on; all observations today by divers). Two-inch nylon mooring lines
sway slightly with the surge, estimate I-foot swing. No ripple marks in
the silt and sand bottom sediments. Temperature outside about 460F.

2nd Day, 29 August 1965

Removed four starboard porthole covers. Visibility 30 feet. Current obser-
vations by diver - onshore very slight. Observations through Sealab port-
hole - trajectory of plankton past glass port is onshore and up. Trajectory
interrupted by a pause about every 6 seconds during which plankton "sinks"
down, followed by a repetition of the onshore and up motion. Net drift
onshore and up at the rate of 1 foot per 15 seconds. This condition pre-
vailed all day. However, sometime in the late p.m., the direction
reversed and plankton moved offshore and down.

3rd Day, 30 August 1965

No observations this date from inside Sealab. Observations outside show
very slight drift of plankton in a downslope and southwest direction most
of the day, stronger by dark.

4th Day, 31 August 1965

Net drift of current onshore and up. Plankton moves 24 inches in 152
seconds in the a.m. Current decreased in velocity by noon, increased
steadily in p.m. to offshore, 24 inches in 10 seconds by dark. Current
increased near sunset and was strongest at 1800. Current velocity changed
very quickly after dark to a very slight offshore and down movement. There
is still no distinct off and onshore surge as is commonly associated with
the passage of surface waves. However, about 1800, I could "hear" or
distinguish the pressure fluctuations associated with the passage of
surface waves. This was verified by topside watch officer. This p.m.
was the last time I was able to "hear" the pressure change of surface
swell. This is probably because of bad hearing caused by humidity and
ear, infection (?) or low waves.

5th Day, 1 September 1965

In the a.m. net current drift was offshore, very mixed and erratic, from
high waves on the surface last night (?). Plankton move offshore and sink
most of the time. Same condition prevailed all day, current strongest at
dark or about 1800. One observation at 2200 shows slight offshore current,
plankton sinking down. Low waves, no surge, just steady offshore.
Visibility was very good today, and there was no indication of high waves.

6th Day, 2 September 1965

Wind chop on surface following 8-10 foot swell reported at surface. 0800 -
no current; 0900 - slight current flowing to the north and onshore about
0.1 knot; 1000 - current increasing, surge has on and offshore orbital

152

motion, net drift onshore, orbital diameter 4-6 inches; 1030 - current
increased, net displacement of 4 inches onshore during each cycle of the
orbit; 1045 - steady onshore or northern drift broken by irregular periods of
10-12 seconds of offshore surge. Net is onshore about 15 inches in 15
seconds. All offshore motion is erratic. Note: Fish (scorpion or Scorpina
Gattata) orient into the current, as a rule, unless feeding or moving which
is about two to four times a day. Other small fish, E cm-l cm long, and
some large migratory fish have no obvious orientation preference so far as
current direction is concerned. 1057 - slight onshore net drift.

Set five plastic bottom drift indicators outside. In 20 minutes they had
drifted downslope 10 feet. Net drift of sediment is also downslope. A
steady current, enough to clean off large objects on the bottom, is evident.
A 35-pound Danforth anchor on the sand slope has been exposed for two
days. Water temperature is 13.5 0C, well mixed down to 230-foot depth.

1600 - Very steady up and onshore current. Plankton moves 24 inches in
12-15 seconds; 1730 - current changed to offshore, 24 inches in 13 seconds;
1800 - current is onshore, changed direction very quickly.

Visibility reduced considerably today following wind waves. Heavy red
tide this p.m. Sundown at 1900. Visibility 2 feet with hand-held light.

7th Day, 3 September 1965

Mixed current - short on and offshore surge. Plankton moves 24 inches in
20 seconds. Heavy red tide last evening, came down fast from seaward.
Heavy watch day. Very slight onshore current all day. Red tide sinking
to sea floor.

8th Day, 4 September 1965

Little current detected from ports. Fine plankton in early morning drifting
down and slightly offshore - visibility bad. By mid-morning, water became
very clear, the clearest water we have observed, 30 feet visibility with
natural light. Worked locating underwater weather station. Anchored
weather station platform.

1800 - visibility bad again, more red tide. Visibility changed quickly.
Plankton moves 24 inches in 21 seconds with offshore net drift. Continuous
offshore flow with slight fluctuation in velocity. 1800 - dark.

9th Day, 5 September 1965

Dense red tide. Fish fill the ports making current observations difficult.
Slight offshore and down net drift. Clouds of sediment rise 5 feet above
the bottom from divers working on the weather station. Drift is slow to
clear sediment from the area. Set underwater weather platform today.

10th Day, 6 September 1965

Temperature 13.5�0C, warm. Visibility bad. Slight offshore current,
plankton sink slowly. Trajectory is 8 seconds down, 8 seconds off, 8
seconds down, etc. Net offshore, 8-9 inches in 16 seconds. Steady
temperature increase for three days, 46-48-50-550F.

153

sNnows ezMSRm\\-w3 foll o w )inrit n hiz'6nk - trajectory of plankton
snows the following periodicity in cycle: (1) horizontal offshore movement
for 8 seconds, followed by (2) up movement for 8 seconds, etc. The net
drift is offshore and up.

11th Day, 7 September 1965

Upper direction vane (1) and Savonius rotor (2) on weather station in
operation. Rustrak recorders in Sealab are recording. Recorded current of
0.8 knot. During diver inspection, sensor 2 turning one revolution in 2
seconds and direction vane indicated current flow offshore. Sensor 5
turning one revolution in 4 seconds. Analog record of sensor 2 indicates
0.1 knot steady during day, increased at 1700 to full scale (almost 2 knots)
on the upper current sensor (2) and to 1 knot on the lower current sensor (5).
Current direction offshore.

12th Day, 8 SePtember 1965

Lower weather station out of order in a.m. Upper weather station appears
o.k. Installed thermisters - upper temperature 530F (11.50C), lower
temperature 510F (10.05 C).

Sensors 1 and 2 indicate 0.5 knot offshore current; observations from Sealab
port indicate 24 inches in 25 seconds offshore. Decreased to "0" current
by 1200. Plankton sinking down steadily. 1700 - observed very slight
offshore and down current. 1800 - same observation, 24 inches in 30
seconds. Temperature at 1600 was 550F (12.2�C) with thermometer hand
held outside. Thermister records 51�F (10.051C) on line 36 of Rustrak
recorder.

13th Day, 9 September 1965

Temperature 50-51� (thermister o.k. with hand-held calibration). Visibility
poor due to plankton. Current - 0.2 to 0.6 knot on sensor 5. Direction
vane shows offshore flow most of day. Current observations from Sealab
port:

0800 offshore and down
1030 offshore and down 24 inches in 40 seconds
1100 offshore and down 24 inches in 60 seconds
1200 sinking down very slowly
1600 current changed to up 24 inches in 30 seconds

14th Day, 10 September 1965

Visibility poor in early a.m. Current upwelling - up and offshore 6 inches
in 20 seconds. 1100 - sensor 5 indicated 0.35 knot steady. Sensor 2
(upper) off scale on high side. Current direction southwest to south south-
west. 1145 - Sensor 5 reads 0.3 knot, sensor 2 reads off scale on high
side. Current direction southwest. Flying fish came in with upwelling?
Sediment covers rotors in three-day period, Mica and light material deposit
on flat surfaces. Thirty-five pound anchor covered by sediment. One-quarter
inch sediment fill on underwater weather station platform in three days.
Sensor 5 is dirty; sensor 2 is clean and runs faster than 5 on all observations.

154

15th Da, LI1 September 196 5

Visibility very poor, no light. Many fish at the ports. Current is offshore
and up, no surge. Very slight current. Good weather topside for transfer
of personnel.

Diver observations and their comparison with the underwater weather station
recordings show a fluctuating irregular current pattern during periods of
high waves. This is followed by a somewhat more uniform flow during
periods of low waves.

155

THE MEASUREMENT OF HUMAN PERFORMANCE

SEALAB II

James W. Miller, Ph.D.
Head, Engineering Psychology Branch
Office of Naval Research
Washington, D. C.

Abstract

The purpose of the Human Performance Program was to make an overall
assessment of man's behavior while living in the sea. The program was
designed not only to determine how well man can perform specific tasks
of a scientific or operational nature, but also to study broader aspects
of adaptation to life and work in the hostile undersea environment.

The Program began in the early stages of the training period, continued
throughout the divers' stay on the bottom, and concluded with post-dive
interviews, questionnaires, and tests. In addition to specific tests
carried out in the water, there was continual observation, via closed-
circuit television, of each diver's behavior, and his interaction with
the other members of the team. Furthermore, the divers' performance in
the various scientific and salvage programs was noted where possible.

Data was collected on psychomotor tasks, e.g., two-hand coordination and
manual dexterity; visual and auditory functions; as well as demographic
and sociometric characteristics. Although the results indicate a decre-
ment in performance on some of the specific tasks, it should be made
clear that in spite of all the obstacles and dangers present, an unprece-
dented amount of useful work was accomplished. The aquanauts' performance
of scientific and operational tasks demonstrates clearly that man can live
in harmony with himself and with the hostile undersea environment.

156

INTRODUCTION

The purpose of the Human Performance Program was to make an overall assess-
ment of man's behavior while living in the sea.* The program was designed
not only to determine how well man can perform specific tasks of a scien-
tific or operational nature, but also to study broader aspects of
adaptation to life and work in the hostile undersea environment. Before
describing the details of this program, let's consider briefly some of the
general factors affecting performance during SEALAB II.

There can be little doubt that the SEALAB environment was stressful. The
water was cold (46 degrees to 54 degrees) and visibility was poor, deteri-
orating, on occasion, to zero for all practical purposes. Although land-
marks were learned gradually, it always was necessary to follow guidelines
attached to SEALAB to avoid becoming lost. Unlike diving from the surface,
the aquanauts had a single 40-inch hole to which they could return safely.
To surface inadvertently would have meant certain death. This fact always
was foremost in the minds of the divers.

Aside from such discomforts and dangers, there were numerous frustrations
associated with working in the water, Frequently a man would go out to
work on something he couldn't find, or for which he didn't have the proper
tools. Long hours of careful preparation were required to put a man in
the water. To further complicate things, the work schedule constantly was
interrupted, delayed, and revised because of various emergencies or
necessities.

Added to these inconveniences were problems associated with living in the
capsule itself. The helium atmosphere gave speech a "Donald Duck" quality
which, in addition to being amusing, seriously interferred with communi-
cation. Helium, combined with the higher atmospheric pressure and
excessive humidity, may have disrupted the human thermostat, the result
being that the men frequently experienced cold sweats. In addition, most
of the men had great difficulty in sleeping. Also there were nagging
physical complaints in the form of ear infections, skin rashes and
headaches. Towards the end of the submersion period the men anticipated
with some apprehension the dangerous process of transfer from the bottom
to the surface decompression chamber and approximately 30 hours of
decompression in quarters even more cramped than those of SEALAB.

It is essential to take these and related factors into account when inter-
preting the results of the SEALAB program. Although equipment modifications
and advances in technology will alleviate some of these problems, many
new problems will arise as we push further into the ocean's depths.

As with any scientific investigation outside the laboratory, compromises
were made in the SEALAB program in an effort to obtain the maximum amount
of information. The Human Performance Program was no exception. A major
problem was the absence of an on-the-bottom experimenter. In many
instances, carefully laid plans had to be abandoned because of bottom
conditions, emergencies and changes in schedules. Although the cooperation
and effort put forth by the divers was very high and much valuable data
were collected, the absence of a person with the necessary training and
interest to make on-the-spot changes in plans severely limited the

*This presentation, although prepared by the author, represents a program
carried out with the combined efforts of many individuals. The author
gratefully acknowledges the contributions in particular of Dr. Roland
Radloff, Naval Medical Research Institute; Dr. Hugh M. Bowen and Mr. Birger
Andersen of Dunlap and Associates, Inc.; and Mr. Robert Helmreich, Yale
University. The major responsibilities were shared by the author,
Dr. Radloff, and Dr. Bowen.

157

flexibility of the program. These data, along with those of the salvage,
medical, physiological, and oceanographic projects, were coded and entered
on punched cards to permit an overall analysis of the program.

PROGRAM DESCRIPTION AND PROCEDURE

The actual collection of data for the Human Performance Program began in
the early stages of the training period, continued throughout the divers'
stay on the bottom, and concluded with post-dive interviews, questionnaires,
and tests. In addition to specific tests carried out in the water, there
was continual observation, via closed-circuit television, of each diver's
behavior, and his interaction with the other members of the team. Further-
more, the divers' performance in the various scientific and salvage programs
was noted were possible.

The initial data gathering was done primarily through the use of question-
naires and paper-and-pencil tests. In addition to general demographic
statistics, information was obtained on such topics as attitudes, desired
characteristics in teammates, rating of teammates as potential leaders,
evaluation of moods, and vocational interests. Some of these tests were
designed especially for SEALAB while others were standard tests chosen
because of their apparently successful use in programs such as the Mount
Everest and Antarctic Expeditions. The selection of these latter tests
should enable us to broaden our understanding of man's behavior under real
stress as experienced in widely divergent environments.

Data also were collected on a variety of psychomotor tasks. These tasks,
which are adaptations of tests used in other situations, were selected in
order to probe specific features of psychomotor behavior. The modifica-
tions were necessary because of the conditions in the water and the absence
of the experimenter. It should be noted that the tests range from simple
short-term behavior to complex prolonged behavior. The tests (which are
described below) require the direct application of force, manipulative
dexterity, eye-hand coordination, and the cooperative assembly of compo-
nents by several divers.

a. Strength Test - The purpose of these tests was to determine
whether there would be a decrement in strength between dry
land, shallow water, and deep water measures. The tests
utilized two calibrated torque wrenches, one with a scale
from 0 to 800 pounds, the other with a scale from 0 to
1200 pounds. The Lift Test was performed by bracing the
feet on a platform and lifting upwards with both hands on
a handle positioned between the legs about 30 inches above
the platform. The Pull Test was carried out by grasping
the handle with the left hand at about shoulder height (arm
outstretched) while simultaneously grasping a grip with the
right hand (Fig. 1).

These tests were chosen because they are representative of
the actions required when divers are used as primary
power sources, and because they provide data that are
directly applicable to the design of hand tools.

b. Individual Assembly Test - This test measured manual
dexterity and the ability to form spatial relationships.
The test required the diver to assemble three one-foot
lengths of steel plates into a triangle by joining them
with various size nuts, washers, and bolts. In some cases
the location of the holes in the plates determined which
ends of the plates could be Joined together. The challenge
to the diver, thus, was varied in terms of the degree of
fingertip dexterity involved as well as his ability to form

158

I o e- I-~C~-3�C---" -C -- N -T~C~~-T~PT -�- - I . i E

Fig. 1 - Diver Performing Strength Test in Shallow Water

Fig. I1 Diver Performing Strength Test in Shallow Water

spatial relationships. Performance in the water was expected
to deteriorate as compared to dry-land conditions, due to
cold, wearing of gloves, visibility, and general problems
associated with maintaining body orientation. The task
was selected as being representative of those requiring
the assembly, adjustment, and general handling of small
items of equipment.

c. Two-Hand Coordination Test - The purpose of this test was
to measure eye-hand coordination. The test utilized a
specially designed gear box, on which were mounted two
rotatable knobs permitting the user to move a peg along
a track cut in a template located on the top of the gear
box. Turning the right hand knob moved the peg forward
and backward, while turning the left hand knob moved it
left and right. The task of the diver was to move the peg
along the track from one end to the other and return in
as short a time as possible (Fig. 2). In addition to
assessing overall eye-hand coordination, the test was
selected as being representative of tasks requiring con-
tinuous control or adjustment of equipment.

d. Group Assembly Test - The purpose of this task was to
observe the manner in which a group of four men planned
and carried out the assembly of a three dimensional struc-
ture requiring the perception of complex spatial relationships.
The structure was made up of short lengths of 1/2 inch pipe
with appropriate connectors. A drawing showing the final
assembly was provided. The divers were asked to work out a
plan of attack, prior to beginning assembly. The time taken
to execute the assembly was recorded.

In addition to the above psychomotor tasks, tests were administered to
measure visual and auditory functions.

a. Audiometric Tests - Pre-exposure and post-exposure hearing
tests were administered to all divers. Hearing levels (re
American Standards Association, 1951) at 500, 1000, 2000,
3000, 4000, and 6000 cycles per second (cps) were obtained
using a Rudmose ARJ-4 Bekesy-Type Audiometer with Otocups.
Hearing levels were derived from the Bekesy-Tape tracings
in the usual manner of accepting midpoints of the tracings
and recording thresholds in 5 decibel (db) increments.

b. Helium Speech - Although a helium atmosphere has long been
known to have a marked affect on speech, little systematic
data have been collected. With the advent of underwater
living, it is imperative that we study this problem both
from the standpoint of gaining a better understanding of
the underlying mechanism, and providing information for the
design of communication systems. With this in mind,
periodic samples of conversational speech were recorded
in the surface monitoring station. In addition, specified
sentences and word lists were read directly into a tape
recorder inside the habitat. It is planned subsequently
to analyze the speech content of these tapes. Subjective
data were obtained during post-dive interviews and with
questionnaires pertaining to speech communication in the
habitat.

c. Form/Color Test - The purpose of this test was to measure
detection and discrimination of form and color underwater.
Four targets were used; a white square, a black circle, a
white cross, and a yellow triangle. The size, area, and

160

I
i

i i

Fig. 2 - Diver Performing Two-Hand Coordination Test in Shallow Water

161

experimental arrangement of the targets are shown in
Figure 3.* The task of the divers was to swim along the
bottom towards the targets, beside the surveyor's tape,
and note at what distance they could detect the targets
and at what distance they could positively identify the
form. Six different observers were used in this experiment.
A total of 20 observations on each target was obtained.

d. Water Clarity Meter - An Inshore Water Clarity Meter,
developed by the Scripps Institution of Oceanography, was
used during the submergence of Teams 2 and 3. This is an
instrument for measuring scalar irradiance and the
attenuation coefficient. The instrument can produce
profiles of scalar irradiance at depths to 500 feet.
Whenever possible, readings were taken at the same time
that visibility and form/color discrimination tasks were
performed. This is of great importance, as it is the
first time that perceptual measurements have been made
concurrently with optical measurements at such depths.

A test of mental arithmetic was administered to each diver during train-
ing and on three occasions during the submersion period. The test requires
the diver to multiply as many two-digit numbers by one-digit numbers as
possible in a two-minute period. Because laboratory studies have shown
that the ability to perform mental arithmetic is adversely affected by
nitrogen narcosis, it was considered desirable to determine whether
performance would be affected similarly in SEALAB.

Throughout the entire 45-day submersion period the activities of the divers
inside the habitat were observed using closed-circuit TV and open micro-
phones. Observations were recorded pertaining to eating and sleeping habits,
moods, type of activity engaged in, and an overall estimation of motivation
and general espirit de corps. In addition, the divers were requested to
fill out daily forms related to their moods and activities. One of these,
the Sortie Report Form, had questions on it pertaining to activities in the
water, clothing and equipment used, tasks performed, difficulties encoun-
tered, and a description of visibility and general bottom conditions.

Following the period of submersion, each man underwent a thorough
debriefing which included medical examinations, hearing tests, the
filling out of questionnaires and a detailed interview.

RESULTS

Much of the data collected during SEALAB II were recorded on punched cards
and subsequently placed on magnetic tape. A suitable computer program,
prepared previously by Mr. Robert Helmreich of Yale University, currently
is being used for the data analysis at the Yale Computer Center. This is
one of the few times that data have been gathered in an operational setting
which permit cross correlational measures between medical, psychological,
physiological, oceanographic and general performance.

a. Demographic Data - At the present time only a preliminary
analysis of these data has been made. Table I, however,
summarizes some of the background characteristics of the
aquanauts.

*Provided by aquanauts George Dowling and William Tolbert, U. S. Navy
Mine Defense Laboratory.

162

WHITE BLACK WHITE YELLOW
SQUARE DISK CROSS TRIANGLE

Fg.3omooiiity ag

Fig. 3 - Form/Color Visibility Range

Table I
Summary of Demographic Data on Aquanauts

Education
Civilian Navy Average Marital Less Aver. Diving
Divers Divers Age Sin. Mar. than H.S. H.S. Coll. Exper. (yrs.)

10 18 35 4 24 3 12 13 11

It is interesting that the average age and marital status of
the aquanauts is about the same as that of similar adventurous
groups, namely those in the Space Program and the Mount Everest
Expedition. Although the age range is 26 years, nearly half
the men are between ages 35-39. It would appear that rather
than being unencumbered by family responsibilities, the opposite
is true of men volunteering for assignments in adventures of
this type.

Whether civilian, officer, or enlisted man, every one of the
aquanauts in SEALAB was fully committed to his career. In
reply to the question: "In general, how do you feel about
your present occupation?" all men chose the response, "I am
strongly dedicated to a career in my present field." The
unanimous answer to this question probably sums up, as well
as any battery of questions could, why these men were in
SEALAB. In order to gain an understanding of the background
characteristics that the divers themselves thought to be
important, the following question was put on the debriefing
questionnaire: "Based on your experience, which of the
following characteristics do you think most important for
a man to live and work in a SEALAB environment?" The possible
answers are shown in Table II in the rank order in which
they were rated by the divers.

Table II
Summary of Rank Ordering by 28 Divers When Asked for
"Characteristics you Think Most Important for A Man to Live
and Work in A SEALAB Type Environment"

1. Diving experience
2. Willingness to do his share of general work
3. Competence in work specialty
4. Physical condition
5. Sense of humor
6. Has imagination
7. Takes orders well
8. Tries to keep everyone's morale high
9. Is tactful
10. Keeps his mind always on the job
11. Doesn't waste time or energy
12. Ability to mind own business
13. Previous experience working with the team
14. Is the kind of person you could tell your
troubles to if you felt like it
15. Doesn't get too personal
16. Age
17. Has led the same general kind of life you have

164

The high motivation of the divers probably will continue for a
while because the SEALAB program is still new and exciting.
The value of using the above characteristics for selection
purposes will increase, however, as more men are involved
and additional undersea dwellings are utilized.

b. Psychomotor Tests - The preliminary data comparing diver
performance on the psychomotor tasks under three test
conditions are shown in Table III.

Table III
Summary of Psychomotor Data

Dry Land Shallow Water SEALAB

Strength Test (ft. lbs.) Mean N Mean N Mean N
Pull Test 236 15 - - 200 58
Lift Test 626 15 - - 602 60

Individual Assembly
Test Time (Sec.) 76.3 54 91.5 52 120.7 34

Two-Hand Coordination
Time (Sec.) 125.1 45 144.3 14 150.8 6

The data are incomplete in the sense that all divers did not
perform all tests. Furthermore, because of other demands on
their time, and changes in schedules, the tasks were not performed
an equal number of times under each condition. Nevertheless, a
trend is shown towards a decrement in psychomotor performance.
Although the decrement in exertable force was only 4% and 15%
for the Pull Test and Lift Test respectively, the increase in
time taken for the individual triangle assembly test was 37%.
The data also show that performance time increases as the size
of the components gets smaller and greater restriction is
placed on the number of ways to properly assemble the triangle.
The data on the Two-Hand Coordination Test show a 17% decrement
in performance time.

Only one group assembly test was completed outside the habitat.
The time taken was twelve minutes and twenty seconds. However,
the team had practiced assembling the components and had
discussed their strategy immediately prior to entering the
water to do the test. Hence, the time taken may be compared
to the best dry-land time (six minutes), suggesting a marked
deterioration of performance under SEALAB conditions.

Because of the overall difficulties associated with open sea
experimentation, it is difficult to attribute the decrement in
performance to a specific cause. The combined effect of cold,
danger, confusion, etc., all undoubtedly contributed to it.
As our underwater technology and methodology improve, and such
operations as SEALAB become more routine, the more obvious
difficulties with such experimentation will be alleviated, thus
making it easier to establish cause and effect relationships.

Although psychomotor performance in the water did deteriorate,
the results of the mental arithmetic tests show no decrement
between dry-land and SEALAB data. As a matter of fact,
performance actually improved by a small amount, suggesting
a slight practice effect. These data do not demonstrate that
there was no mental deterioration during SEALAB, but only that,
if there was any, it was not gross enough to be detected by
this test. 165

c. Visual and Auditory Tests

Form/Color Study

It will be recalled that the purpose of this test was to
measure detection and discrimination of form and color
underwater. Six divers were used to obtain a total of 20
observations on each of four targets. Table IV shows the
mean detection and recognition distances.

Table IV
Detection and Recognition Distances (in feet)
for the (orm/Color Study
(f=2o)

Targets
Black White Yellow White
Circle Square Triangle Cross

Detection 24.4 18.3 16.7 16.5
Recognition 20.0 14.2 13.5 13.4

It is apparent that the black disc is both detected and
identified at greater distances than either of the white or
yellow targets. This is particularly interesting when
considering that it is the smallest of the four targets in
area. (Black disc = 707 sq. cm., white targets = 900 sq. cm.)
The differences between the detection and recognition distances
of the black disc and the white square were tested and found
to be highly significant (less than the .01 level of confidence).

Previous studies on color discrimination underwater have been
conducted at depths ranging to 35-40 feet. Some of these
studies, as yet unpublished, indicate that fluorescent paints
in the yellow orange region of the spectrum are the most
visible. As greater depths are reached, however, the
advantage of fluorescent material becomes less, due to lower
ambient light levels. One therefore must be careful about
extrapolating from results obtained in shallow water.

A major factor in any underwater operation is visibility.
The selection of the SEALAB site was, in fact,. almost
changed at the last minute because of poor visibility.
Although experiments on the underwater visibility of
lights were not carried out as planned, some data were
obtained during the debriefing interviews. Each diver was
asked to estimate the maximum distance at which he could
see a 1000 watt underwater quartz light under the best
of conditions. For Team I the mean answer was 48 feet
with a range of 30-60 feet. For Team II the mean answer
was 60 feet with a range of 50-70 feet. Team III had a
mean of 95 feet and a range of 40-170 feet. It is clear
that visibility increased during the 45-day period. It
also is apparent, when noting the range of responses, that
controlled experiments are needed if we are going to obtain
reliable data on the visibility of lights.

All 28 divers stated that the white habitat was far more
visible than the reddish orange personnel transfer capsule
(PTC). In many cases the habitat was said to be visible
at two or three times the distance of the PTC. Whether
it would have been more visible if painted black, as
suggested by the form/color study, remains to be determined.

166

The data collected with the Water Clarity Meter during the
last 30 days hopefully can be related to the above observations.

Audiometric Test*

Comparisons between the pre-exposure and post-exposure
audicmetric data were made to detect any changes in hearing
levels resulting from prolonged exposure in SEALAB. The
results show very little change in hearing levels for
frequencies in the speech range (below 3000 cps), but a
trend was indicated for hearing loss at the higher test
frequencies (3000 cps and above).

Hearing levels of divers in general tend to reflect a pattern
of acoustic trauma quite similar to that of personnel exposed
to high intensity noise levels. Divers also are subject to
additional deleterious effects from more than the usual
amount and degree of ear pathologies. Therefore, the need
for a program of hearing conversation for these personnel
is indicated.

Helium Speech

The problem of helium speech to a certain extent plagued the
aquanauts during the entire 45 days. It often was difficult
to communicate a complex idea or set of instructions. However,
for regular conversation regarding food, equipment, etc., there
was a remarkable amount of adaptation. Although post-dive
questionnaires and interviews revealed that 23 of the 28
divers had initial difficulty in communicating, when asked
during debriefing, "How soon were you able to understand all
nine other aquanauts quite well?" the responses showed that
sixteen divers felt they could in 1-2 days, eight more by the
end of 4 days, two more by the 11th day, and one never.

Each diver stated that the voices tended to get lower in
pitch and that the rate of speaking slowed down. Most said
they learned to recognize voices in 2 to 3 days, but that
there always was extreme difficulty in localizing sounds.
Several commented that their voices did not seem to carry
over 2-3 feet. Whether this was due to the high ambient
noise level produced by equipment or to the helium atmosphere
was not determined. A striking example of the extent to
which adaptation took place was brought out when three
members of Team 2 entered the habitat prior to Team 1
leaving. Team 1 had so adapted to each other, over the
15-day period, that they were hardly able to understand
the three newcomers for several hours. The newcomers were
laughed at because of their '"high squeaky voices."

GENERAL DISCUSSION

A great variety of tasks was performed by the aquanauts during the SEALAB
Program. Although a high percentage of these tasks were in the form of
manual labor, several rather sophisticated and complex Jobs, such as the
repair of the underwater weather station, were carried out successfully.
In most cases standard tools and equipment proved to be satisfactory. With
the advent of extended underwater living, however, we must recognize that
tasks of a more sophisticated nature will be undertaken in the near future.
Because of this, a new generation of underwater tools will need to be
developed. A step was made in this direction during SEALAB II with the

*This test was conducted and the results analyzed by Dr. George Harbold, Life
Sciences Division, Naval Missile Center, Point Mugu, California.
167

use of pneumatic tools and explosive stud guns as part of the experimental
salvage program. One of the first operational attempts at using a foaming
device for attaining positive buoyancy also was made. In this instance
positive buoyancy was obtained in an aircraft fusilage by filling it with
a styrofoam type substance.

In addition to improving tool design, better methods of handling and
carrying tools must be developed. Furthermore, the redesign of tanks,
weight belts and other basic SCUBA equipment must be considered. It
does not follow necessarily that SCUBA equipment designed to be used when
diving from the surface is equally as efficient when used for SEALAB type
operations. Advances in the early stages of the space program were slowed
down at times because designers insisted on modifying existing aircraft
equipment rather than standing back and taking a "fresh look." Let's not
limit the performance of 'Man-in-the-Sea" by restricting our thinking about
equipment design.

The above holds equally true with regard to the design of underwater habitats.
The SEALAB II habitat taught us much. The restricted work space in the
diving area was a severe handicap, and work was continually hampered because
of crowded conditions. Workspace layout of future habitats must be based
on a functional analysis of diver activities.

Motivation and Morale

In spite of all the adverse conditions facing the aquanauts while living
on the bottom, motivation and morale was extremely high. The comments of
the divers, upon emerging at the end of each 15-day period, indicated that
they were "amazed that men of such diverse backgrounds and experience could
get along so well under such conditions."

The knowledge that they were part of a project with unlimited potential
and great significance doubtless had a significant impact on most if not
all of the men.

Closely related to the feeling of being involved in a significant project
was a real feeling of accomplishment. Despite disappointments at
accomplishment in relation to expectations, there was the knowledge
that useful work was done and invaluable information obtained in the
face of very trying circumstances. Possibly as important as the feeling
of individual accomplishment was the sharing of this feeling. In talking
to the individual divers there was apparent a sense of shared affect, a
vicarious satisfaction in what the whole group was accomplishing.

Adaptation

In addition to the factors just described, the high morale maintained is
a tribute to man's capability to adapt to almost any situation. There
were, however, large individual differences in adaptability. For example,
during the debriefing interviews, some divers stated that they adapted to
the cold in 2-3 days, while others felt they were still adapting even at
the end of the 15-day period. Interestingly, a few said the water felt
warmer at night, even though the recorded temperatures did not bear them
out. Many reported that their efficiency increased as adaptation took
place, and that, by the end of the 15-day period, they were coming back to
the habitat more because of becoming tired than being cold, as was the case
at the beginning. The fact that general visibility improved, permitting
an increasing familiarization with landmarks, also put the men more at
ease as the days passed. Several divers stated that as a result their work
efficiency was much higher towards the end because of the decreasing pre-
occupation with becoming lost in the water.

168

A phenomena discussed during SEALAB and since its completion is the so-
called "SEALAB Effect." Many reports have suggested that the divers had
short memory losses, that silly mistakes were made, poor planning was
commonplace, and that generally there was much more confusion that would
be expected.

It certainly is true that there was much confusion due to the logistic
difficulties, schedule changes and other factors already mentioned.
Perhaps some of the confusion, mistakes, and memory losses were due to
the stressful situation. It must be kept in mind, however, that diving
requires detailed preparations, and that each diver, in addition to the
Job at hand, has many things to remember, including a constant vigil over
his air supply, his location, and the location and state of his buddy.
Furthermore, the lack of swimmer-to-swimmer communication means that a
pair of divers may have to return to the habitat simply to exchange a few
words or otherwise plan in advance, at great length, what appears to be an
extremely simple task.

In other words, in addition to the multitude of safety precautions, there
were numerous details to contend with in an extremely hostile environment.
With so much on their mind, it is not surprising that some things were
forgotten and that in retrospect, silly things were done and details over-
looked. An additional factor is that, in most instances, it was not
possible to practice each operation in detail or to conduct simulation
training on land. As a result, procedures were not routine to the extent
that performance was automatic. One, therefore, must carefully temper
judgment regarding the effects of stress with the potentially over-
whelming problem of human information-processing.

Another factor, which research has shown can produce some of the symptoms
mentioned above, is sleep deprivation. Post-dive interviews revealed that
almost all divers had great difficulty in sleeping. Some stated they never
slept more than l� hours at one time. If extended periods of time are to
be spent living on the bottom of the sea, the problem of sleep loss must
receive serious consideration. This is particularly important when depths
are reached which do not permit surface support as supplied in the past.
If it is anticipated, in the future, that sustained performance will be
required in a situation in which sleep loss is probable, individual
differences in ability to tolerate sleep loss should be taken into account
when selecting the aquanauts. Research has shown that neurotic, anxious
and less intelligent persons are not as able to withstand sleep deprivation.

In conclusion, it should be made clear that in spite of all the obstacles
and dangers present during SEALAB II, an unprecedented amount of useful
work was accomplished. While some of this work possibly could have been
performed from the surface, a diver, with his inherent flexibility for on-
the-spot decision making and planning, was the essential element in the
program. The aquanauts' performance of scientific and operational tasks
demonstrates clearly that man can live in harmony with the hostile undersea
environment. Having again demonstrated the tremendous ability of man to
adapt, the future of undersea habitation and exploration should be limited
only by our technology and imagination, not by man.

169

VALUE OF EXTENDED DIVING
TO THE SCIENTIFIC COMMUNITY

Arthur O. Flechsig
Scripps Institution of Oceanography

Abstract

Man is a necessary component of any system for studying complex phe-
nomena in the sea, owing to his functional superiority to present day
machines. The kinds of undersea research he is likely to undertake in
the future are probably exemplified by the oceanographic studies
attempted during the Sealab II experiment. These were varied and mod-
erately successful despite the limitations imposed by time. The great
advantage of extended diving, over surfaced based diving, or diving in
undersea vehicles, is the opportunity it offers for long, continuous ob-
servation and experiment. Although this capability makes undersea
laboratories attractive to scientists even for shallow water investigations,
it seems unwise to utilize extended diving, because of the dangers inher-
ent in the system, except in depths greater than about 150 or 200 feet,
where no adequate alternative is available. The combination of an under-
sea research submersible with the extended diving capability would re-
sult in an ideal method for exploring the continental shelves.

The extended diving capability is a new tool to be added to those already
available to the marine scientist. As with most new research tools, we
cannot be certain of its potential until it has been used for some time;
we may get more than we expect; we may be disappointed. Paradoxic-
ally, one of its uses will be to find what use we can make of it, since it
is to some extent a tool that has become available before we are able
fully to exploit it.

There exists today some difference of opinion about the value of putting
man into the sea. I am going to ignore the argument that investigations
of the continental shelves may not be worth the cost in time, effort, and
money, since it is unthinkable that this vast, relatively unknown region
of the world should remain a terra almost incognito now that we have
means of knowing it.

There is sometimes heard, however, a further argument against putting
man into the sea. It is that instruments and machines can be sent in our
stead, to perform as well or better, or, at least, well enough. While it
certainly is unnecessary to use man when one's objectives are sufficiently
straightforward or restricted to permit the use of instruments lowered
from the surface, this contention, when applied to the study of complex
phenomena, is in my opinion sheer nonsense, or more charitably, wish-
ful thinking. For just as the modern man of affairs occasionally finds it
necessary to leave his mail and his telephone in order to fly across the
continent for direct observation, analysis and discussion of problems;
just so, must the modern marine scientist sometimes descend into the
ocean.

Their reasons are much the same. Each is bringing to bear on his prob-
lem a creature that is mobile, adaptable and sensitive; a creature that

170

can compute, record, communicate, make decisions based on an exten-
sive memory bank, change its goals and methods of operation, and con-
tinue to function under widely varying circumstances. Now each of these
things can probably be done better by some machine, but man can do all
of them. And what is more, he is not just "state-of-the-art", he is an
"off-the-shelf-item"! It is neither good sense nor good economics to
leave him out of the system.

I would like now to look at the Sealab II operation per se, as well as in
the light of oltr extensive scientific investigations at SIO using shallow
water diving.techniques and in deeper water using the Cousteau Diving
Saucer.

The oceanographic investigations in Sealab II were planned and conducted
by scientists from the U. S. Navy Mine Defense Laboratory in Panama
City, Florida and from Scripps Institution of Oceanography in La Jolla,
California. The studies undertaken were diverse, ranging through the
fields of biology, geology and physical oceanography. They were se-
lected because we felt that Sealab presented a unique opportunity to study
certain phenomena or certain organisms with greater precision, more
directly and more continuously than is possible from the surface. The
USNMDL oceanographers, George Dowling and William Tolbert, were
additionally interested in what they appropriately termed "upside-down
oceanography". That is, the effectiveness of standard or slightly modi-
fied oceanographic techniques when undertaken from the bottom.

In planning the details of our underwater investigations we found that we
could not predict anything with perfect confidence. Therefore, any prob-
lem that depended for its success on the presence within a practical dis-
tance of a particular species of organism, or on certain water conditions,
or even on Sealab II being placed in a certain location, was a problem
that might have to be dropped. As a result, on the other hand, of the
extensive surface sampling, SCUBA diving, and "saucer" diving that had
been done in the area, we probably knew more about the sea floor off
La Jolla at 205 feet and about the organisms to be found there than would
be known about other areas at the same depth. We, therefore, felt that
we could make sufficiently informed "guesses" about the conditions and
organisms we would encounter to outline a worthwhile scientific program
that could be conducted from Sealab II.

The primary objectives of the program that eventually emerged were the
following:

1. Obtain continuous records of current speed and direction, temperature
and wave conditions at carefully selected depths and locations, with the
intent of elucidating patterns of sediment transport and, perhaps, of cor-
relating biological events with the physical data so obtained. Site selec-
tion, instrument installation and instrument maintenance were all to be
by or under direction of the scientist-diver.

2. Study sediment transport and bottom currents by several techniques
involving direct obsdrvation and manipulation. The techniques involved
included time-lapse photography, the use of vertical stakes for measuring
cut or fill by sediments, and use of several kinds of bottom current
tracers such as dyed sand.

171

3. Determine the identity, their numbers and the distribution of virtually
all the organisms in the vicinity with the intent of discovering both the
normal population composition and changes correlated with the presence
of Sealab II. This required that we collect and count organisms at var-
ious places and at different times of the day and night, and indeed,
throughout the duration of the Sealab experiment. Owing to the wide
range of size, mobility, threshold of disturbance and population densities
in the animals it was necessary to provide a variety of kinds of collecting
and sampling equipment. While small cores of sediments randomly
taken, for example, might well show the distribution of tiny, abundant,
subsurface-dwelling amphipods, they would not suffice for showing the
distribution of a relatively rare, mobile crab or of any of the swimming
organisms, regardless of their density.

4. Observe the overt behavior of the larger organisms with particular
reference to day/night differences and presence or absence of other
organisms. How, for example, do they react to others of their own
species or to other species; does their behavior change when the numbers
of the other organisms change; are any changes in behavior correlated
with changes in the physical environment; does the behavior of any spe-
cies change during the 43-day Sealab project?

5. Study the in situ composition of gases in the gas-bladder fishes and
determine the source of gas bubbles in the eyes of certain fishes.

6. Evaluate Sealab II as an oceanographic platform by conducting instru-
ment observations of such things as temperature structure of the over-
head water column, water clarity, etc.

These objectives were pursued with considerable vigor and some success.
The results in most cases are now being prepared for publication in ap-
propriate journals. The exigencies of time caused our results to be less
complete than we had hoped, but there is nothing intrinsic in a Sealab
operation to cause us to change our objectives. Indeed, I contend that
the research tasks attempted in Sealab II provide a fair sample of the
kinds of research that we can expect to see carried out by extended
diving in the future.

These kinds of research may be categorized as follows:. First, there is
the installation, manipulation and maintenance of equipment. When, in
order to gain certain information, an instrument or a collecting device
must be positioned so critically that this cannot be done from the sur-
face, or when the instrument must be serviced or modified without re-
moving it from the bottom, the obvious solution is a man in the sea.

Another type of endeavor is that involving direct observation, either of
organisms to determine their natural conditions of existence and their
normal behavior in nature, or of physical phenomena such as sediment
transport or localized turbid zones. Physical and biological phenomena
that change in time, or that are of such infrequent occurrence that long
observation is necessary to discover them, are particularly good subjects
for investigation by extended diving.

A third category is that of undersea experimentation. When we wish to
confirm the results of laboratory work, or when it is impossible to

172

create the proper conditions in the laboratory, we will be able sometimes
to conduct the experiment in the sea. But another, highly intriguing kind
of experimental work would involve modifying the environment in various
ways to discover limits and optimum levels for the parameters that gov-
ern plant and animal distributions. We can easily alter the substrate
by providing hard surfaces where there are none, change the amounts
of light and/or falling detritus by providing screens and indeed, even
alter the temperature by transplanting organisms from other localities
where different temperature regimens are encountered.

As we go deeper in the sea we enter a region that is almost completely
unexplored. Yet extended diving, as presently employed, is not a suit-
able method for exploration. It is better suited for exploitation, for in-
tensive study in a limited, managable area. This is partly what I had in
mind at the beginning when I suggested that we were not yet ready to ex-
ploit our extended diving capability to the fullest. We know few areas
well enough to plan really fruitful research projects for them. Without
extensive exploration in the region of an underwater habitat one would
not even know the pertinence of his labors at that single spot to the areas
around him. He would not know whether he was working in an "average"
environment or an anomalous one. This being so, one naturally concludes
that the site for an underwater habitat should be selected only after ex-
ploration of the region with a submersible research vehicle.

Since my experience as a subject in the Sealab'II experiment was pre-
ceded by 14 or 15 years of experience diving from the surface using
SCUBA and some 14 or 15 hours in Cousteau's Soucoupe, I feel justified,
indeed even obligated, to compare these three modes of diving with ref-
erence to their research capabilities, even though most of their virtues
are self-evident.

Free diving from the surface using SCUBA has been in increasingly wide
use for nearly 15 years. It is generally regarded as most useful at
depths of less than 130 ft. since nitrogen narcosis usually becomes a
serious problem at approximately that depth and also because the time
one may spend at the bottom without requiring decompression is re-
duced at that depth to less than 10 minutes. The narcosis may be elimin-
ated by substituting helium for the nitrogen in the breathing gas, but
decompression requirements are still limiting.

The other major limiting factor in diving from the surface is weather.
As Cousteau has pointed out, there are days or weeks or even longer
periods in some regions, when passing through the air/water interface
is impractical if not impossible. On the other hand, the surface-based
SCUBA diver can observe at first hand; he can manipulate, palpate,
prod, poke, dig, install his instruments, and collect his specimens; he
can then return to a laboratory that is full of expensive, space consuming
equipment and reagents and books, where he may work on his specimens,
cogitate, and plan his subsequent dives, whether they be days, weeks or
months in the future.

The scientist who goes into the sea in a sealed vehicle such as the
Soucoupe is not intrinsically limited by depth and he has no decompres-
sion problems. He has some time limits, however; whether they are
imposed by the life-support system or by the power storage capacity

173

depends on the design of the vehicle and on the power requirements on
any one dive. Research submersibles are also limited at the present
time by the weather and its effect on the air/water interface.

Perhaps the most frustrating feature of the undersea vehicle is the in-
ability of the occupants to reach out and touch the objects that they can
see. I had not realized till my first voyage in one that many things are
identified, at least in part, by whether they are soft or slimy or fragile
or have other qualities that one normally determines, almost reflexly,
with one's hand. A remote manipulator with a variety of capabilities
is a sorely needed feature lacking in undersea research vehicles but one
that will no doubt always be inferior to the human hand.

Some other characteristics of undersea research vehicles are their
ability to carry a variety of sensing and recording equipment and their
ability to travel relatively great distances, even though the latter capa-
bility is somewhat degraded by present day deficiencies in precision
navigation. They also serve as nearly ideal camera platforms and in-
strument platforms because they are able to hover off the bottom or at
some level in midwater.

When we come to the undersea laboratory we find really only one great
advantage over other types of diving; the diver may spend almost un-
limited time on the bottom. For the price of one round trip through the
air/water interface he may stay long enough to accomplish what even
hundreds of surface-based dives might not do. Instead of decompressing
many times, he decompresses once.

Still, there are disadvantages. The atmosphere must be tailored to the
depth of the habitat. Great care must be exercised to avoid contamination
of the atmosphere, so some normal laboratory operations become im-
possible. Many sorts of equipment cannot function under elevated pres-
sures unless specially constructed or protected by pressure proof hous-
ings. And one must plan the operation in far greater detail than in other
kinds of diving, simply because there is no early opportunity to return to
a well equipped laboratory to read and think and plan. Neither is there
likely to be enough space for the equipment needed to provide for any
eventuality you can foresee.

If extended diving has one great advantage, it has also one great disad-
vantage. That is the lack of mobility. Divers can move some distance
away, but they are bound to their habitat by the necessity for decom-
pressing slowly. It is, therefore, almost inevitable that we will soon
have undersea research vehicles that carry divers. Just as inevitable,
but somewhat further in the future, are larger vehicles that can stay in
one location for extended periods while its divers undertake longer term
operations.

The oceanographic work in Sealab II was only one of a number of experi-
mental programs during that operation. Many marine scientists are
looking forward to a day when they can participate in a "sealab" with
purely oceanographic aims. Since extended diving is a new tool, the
first oceanographic sealab will be in some ways as experimental as was
Sealab II. It would be natural for the planners of that future operation
to say, "Let us put the first of these at some moderate depth like 40 or

174

80 or 100 feet. Here we can work out the bugs in this new tool without
the dangers and difficulties we would have in deeper water." But that,
I submit, is a fallacy. It is a fallacy because we would have all of the
danger, most of the difficulty, and gain almost nothing!

First, it must be clearly understood that extended diving is hazardous
beyond most human endeavors because the diver in the water has no
counterpart of the parachute or the fire escape. If he gets lost, or if
his equipment malfunctions, he cannot come directly to the surface --
alive. And it makes little difference whether his body tissues were
saturated with dissolved gases at the pressures of 60 feet or 600 feet;
the excess dissolved gases must be gotten rid of, virtually a molecule
at a time. Since it is almost as easy to get lost at 40 feet depth as in
deeper water, and since breathing apparatus can malfunction in shallow
water as easily as in deep water, I cannot see that extended diving in
shallow water is less dangerous there.

Second, there seems little point in braving dangers of extended diving if
one can conduct his investigation by a combination of recording instru-
ments, monitoring cameras, and diving from the surface using SCUBA.
And this he can do, with moderate ease to 130 feet and less easily to
around 200 feet. Extended diving is a tool for deeper water where there
is no other way to learn so much.

175

DIVING AND SALVAGE OPERATIONS ON THE CONTINENTAL SHELF

Keatinge Keays
and
J. Vincent Harrington
Research and Development Department
General Dynamics Corporation
Electric Boat Division
Groton, Connecticut

Edward A. Wardwell
Manager, Development Department
Ocean Systems, Incorporated
1030 15th Street, N.W.
Washington, D.C. 20005

INTRODUCTION

The substance of this paper is based upon the results of a study
conducted for the U.S. Navy Special Projects Office under the
Deep Submergence Systems Program (DSSP). To assist the reader
better in evaluating these results it is important that the
ground rules which guided the study be stated. These ground
rules are as follows:

1. All equipment must be required for, and be appropriate
to, salvage of a submarine (or a "smaller" surface ship) from
600 feet.

2. This same equipment should be adaptable for efficient
deep salvage of airplanes and weapon-sized objects.

3. Harbor clearance and shallow salvage are not a subject
of study.

4. Salvage tools and related equipment should be general
purpose in nature. Special tools would be developed as required
to meet specific salvage situations.

5. Time is not of the essence in salvage.

6. All-weather capability or covertness is not required.

7. All salvage equipment should be of a type that the
Navy could reasonably be expected to own and to operate on a
continuous basis (i.e., preferably no special purpose, high
lift capability crane barges for salvage as are used to support
the oil industry and commercial salvage).

8. Shelf life of salvage equipment should be maximized.

9. The Salvage System should be operational in all
respects not later than 1970.

PROBLEM DEFINITION

The term "Large Object" in this study relates to objects rang-
ing from submarines at one end of the spectrum through relatively
small surface craft to cargo and passenger type aircraft at the
other end of the spectrum. The object of the salvage operation
logically must have some recoverable value, either economic or
intangible. An example of intangible value would be ascertaining
the cause of an accident so that remedial action may be taken.

176

In examining the possible objects of a salvage operation, it
appears evident that submarine-sized objects impose the design
parameters on the Salvage System and the study has concentrated
upon the salvage of these objects.

The salvage problem itself is composed of eight distinct phases.
These are:

PHASE I - Location of the salvage object.

PHASE II - Surveying the object to ascertain its integ-
k ~~~~~~rity, extent of flooding, embedment in the
bottom, and the environment surrounding the
object.
PHASE III - Positioning of the Salvage System with re-
spect to the salvage object.
PHASE IV - Rigging the salvage object for the lift to
the ocean surface.
P ~~~PHASE V - "Bekot"1, i.e., freeing the embedded
object from the suction of the bottom.
PHASE VI - The lifting operation; this includes the
problems of "control". Control means both
the variation of total lift force in order
to regulate the rate of raising the object
as well as the distribution of lift force
over the length of the salvage object in
order to regulate the attitude of the object.
PHASE VII - Rigging the object for tow, and towing it
to shoal waters preparatory to entering
port.
PHASE VITT - Final raising of the object and placing it
in drydock for final disposition.
Phases I and VIII were specifically exempted from the study,
hence, they will not be treated further. Phases IT, IV, and
VI are perhaps the key operations in the Large Object Salvage
operation and are certainly in keeping with the theme of this
meeting, since they are functions to be performed by "man-in-
the-sea."

The most severe restrictions upon the salvage operation are
those of the environment. The environmental factors which were
considered in the study include:

GOOD AVERAGE POOR
FACTOR CONDITIONS CONDITIONS CONDITIONS

Sea state 0-3 3 3-4
Air temperature 50OF or more 500F 500F or less
Water temperature 50OF or move 50`F 50oF or less
Precipitation None None Rain or snow
Visibility at depth 3 ft. or more 3 ft. 3 ft. or less
Current 0.3 knot or 0.3 knot 0.3 knot or
less more

The effects of the environmental factors and the restraints they
impose upon the Salvage System will be discussed as the various
system elements are treated.

177

SALVAGE SYSTEM ELEMENTS

The Salvage System can be broken down into ten separate elements.
These are:

SALVAGE ELEMENT TYPE EXAMPLE

Lift attachment Point Padeye
Line Sling
Area Net

Lift connection Line Wire or chain

Lift force Buoyancy Pontoon or ship
Mechanical Kedging
Lift power Natural Tide or current
Mechanical Winch

Lift control Buoyancy Near surface pontoons
Mechanical Winch
Sensor/communications Wire Telephone
Optical Closed circuit television
Sound Sonar

Tools Hand Crowbar, knife
Powered Explosive, electrical

Divers Tethered "Hardhat", "hookah"
Untethered Scuba, closed circuit

System positioning Static Mooring
Dynamic Dynamic moors

Support vessels Salvage center
Diver support
Logistic support
Lift ships
Small work boats

In reviewing the state-of-the-art in Large Object Salvage, a
number of salvage operations were reviewed and their system
elements analyzed for applicability in extending the salvage
capability to continental shelf depths. Of the salvage oper-
ations which were reviewed, four are of particular interest in
illustrating the Salvage System elements. These are:

1. F-41, the deepest submarine salvage operation carried
out by the U.S. Navy. Divers were used only as visual sensors.
The lift power was supplied by winches on salvage barges,
although kedging was attempted. The value of the salvage object
was intangible (to ascertain the cause of sinking). The system
elements are illustrated in Figure 1.

2. SQUALUS, the most recent submarine salvage operation
conducted by the U.S. Navy. Divers were used to do a rela-
tively extensive amount of work, including attachment. Lift
power was supplied bryrigid pontoons. The value of the salvage
object was economic since it was less expensive to salvage and
refit than to build a new submarine. The system elements are
illustrated in Figure 2.

178

�ATTACHMENT

OSUCCESSFUL INTERMEDIATE ATTEMPT AT
LIFT (WINCH a BARGE)

INITIAL ATTEMPT AT LIFT (KEDGING)

Value - Intangible (determine cause of
loss)
Object - Submarine
Environment - 305-ft. depth (deepest sub-
marine salvage)
Lift attachement - Line - (slings)
Lift connection - (wire rope)
Lift force - Mud scows - (kedging tried
unsuccessfully)
Lift power - Winch
Lift control - Winch
Sensor/Communications - Optical (diver)/
Wire (telephone)
Tools/manipulator - None
Divers - Hardhat - for observation only
Small work vehicle - None
System positioning - Static moor
Support vessels - Mud scows
Dredge
Tug

SALVAGE OF F-4
FIGURE I

Date: 1915
Technical Planner: J.A. Furer

179

W DIGGING TUNNEL FOR SLING
(PIPE,NOZZLE S HOSE)

a' START -

AFTER BREAK-OUT.ILLU$-
TRATING LIFT CONTROL

b IN PROCESS

C.THREADING MESSENGER THRU PIPE
Background Information:
Value - Tangible (cheaper than new
construction)
Object - Submarine
Environment - 240-foot depth
Lift attachment - Sling of wire rope a.
Lift connection - Wire rope and chain PILOTS LIFT PONTOONS
Lift force - Rigid pontoon EFORE BREAK-OUT
Lift power - Compressed air
Lift control - Pilot pontoons (to destroy LIFT
lift after break-out)
Sensor/Communication - Optical (diver)/
Wire (telephone)
Tools/Manipulator - Pipe and nozzle (to
tunnel under sub)
Divers - Hard hat
Small work vehicle - None
System positioning - Static moor
Support vessels - ASR
2 Coast Guard patrol
boats (logistics)
Fleet Tug
Coal Barge

SALVAGE OF SQUALUS
FIGURE 2

Date: 1939
Technical Planner: A.I. McKee

180

3. THETIS, a submarine salvage operation conducted by
the British Navy. Lift power was supplied by the tidal rise
acting on a specially fitted merchant ship hull. Divers per-
formed an extensive amount of underwater work. The value of
the salvage object was intangible, i.e., to ascertain the
cause of the sinking. The system elements are illustrated in
Figure 3.

4. CAPE DOUGLAS, the deepest salvage operation conducted
of a ship (636 feet). A man in a hydrostat was used to verify
the identity of the wreck and to make a cursory survey of its
condition. Divers were not used until the ship was moved to
shallow waters. Lifting power was supplied by winches on a
salvage ship. The value of the salvage object was intangible,
i.e., to obtain evidence for a barratry trial. The system
elements are illustrated in Figure 4.

STATE-OF-THE-ART

In reviewing the state-of-the-art of the various Salvage Sys-
tem elements, it is apparent that only in the field of diving
has there been any significant advance in the past few decades.
The crux of the Large Object Salvage problem is the application
of enormous forces upon an object to raise it from the bottom
to the surface. Buoyancy is still the most promising source of
this force, and anchor chain, wire rope, and other heavy de-
vices are still required to transmit this force to the object
to be salvaged. Although there are means of improving the
Salvage System elements other than the diver subsystem, the
greatest gains for a given level of investment will be made by
pursuing the improvements in diver technique and equipment
which have been started in the years subsequent to World War II.

In recognition of the dominant role that the diver system plays
in the improvement of the Large Object Salvage capability, the
remainder of the paper will deal with the diver subsystem and
the demands it places upon the Naval Architect. The other
areas of improvement in the Large Object Salvage capability,
under the ground rules previously stated, will be briefly
described.

THE DIVER SUBSYSTEM

The major improvements which have been achieved in the area of
diver systems have been the development of the saturation div-
ing technique and the use of inert gas/oxygen atmospheres for
life support. The concept and techniques of saturation diving
have been advanced primarily by U.S. Navy experiments. Captain
R. D. Workman, MC, USN, and Captain G. Bond, MC, USN, have pro-
vided the theoretical and operational proof of the saturated
diving technique.

Captain Bond's SEALAB I and II experiments, as well as similar
ventures by Captain J.Y. Cousteau and Mr. E.A. Link, have
emphasized the advantages, and the problems, inherent in satu-
ration living and diving. From these experiments, it has been
shown that saturation living can be successfully accomplished
either at the diving depth in which the work is to be accom-
plished or in a pressurized chamber at the surface.

181

LOW TIDE Q HIGH TIDE

.cY::i::::>

Background Information:
Value - Intangible (to determine cause
of loss)
Object - Submarine (1000 ton)
Environment - 155-ft depth - in area with
10-15 ft. scope of tide
Lift attachment - Line (slings)
Lift connection - (wire rope)
Lift force - Merchant ship of 3500-ton
deadweight capacity plus self-
generated
Lift power - Tide - (compressed air for
self-generated lift)
Lift control - Tide
Sensor/communications - Optical (diver)/
Wire (telephone)
Tools/Manipulator - None
Divers - Hard hat
Small work vehicle - None
System positioning - Static moor
Support vessels - Diving ship
Lifting ship
Salvage ship
Survey ship

SALVAGE OF THETIS
FIGURE 3

Date: 1939
Technical Planner: A.M. Robb

182

O ON-SITESURVEY
(HYDROSTAT)

/ O NOOSE

LASSO IN PLACE

/ ATTACHMENT

/, _ _~

X > @ ~~~~~~~~LIFT a TOW

Background Information:
Value - Tangible - (recovery of insurance)
Object - 78-foot purse seiner (114 tons)
Environment - Puget Sound - Depth 106
Fathom (636 feet)
Lift attachment - Noose of 1-1/4 inch
cable
Lift connection - 1-1/4 inch steel cable
Lift force - Surface barge
Lift power - Winch
Sensor/Communication - Optical and fath-
ometer
Tools/Manipulators - None
Divers - None
Small work vehicle - Hydrostat for wreck
identification
System positioning - Static moor
Support vessels - Research vessel NEPER
Salvage vessel -
SALVAGE CHIEF (Ex LSM)
Tug - ADAK

SALVAGE OF CAPE DOUGLAS
FIGURE 4

Date: 1960
Technical Planner: F. Devine

183

Sea Hut Versus Submersible Transfer Capsule

In reviewing the advantages of a sea hut for saturation living
at depth and a deck decompression complex for saturation
living at the surface, the advantages of the sea hut appear
to be:

1. Pressurization is automatically maintained by the
captured bubble. (This does not imply that there is no need
for atmosphere control.)

2. The working team may live at depth and not require
being raised to the surface. (The passage of divers and diver
equipment through the air-sea interface is one of the most
difficult and hazardous phases of diving.)
3. Space is available for a plethora of undersea experi-
ments and on-site investigations.

4. There is no space constraint on equipment design.

The disadvantages of the sea hut appear to be:

1. Service personnel, such as cooks, corpsmen, etc.,
must either be maintained at pressure in the sea hut or make
frequent trips through the air-sea interface.

2. Breathing mixture logistics require the use of closed
circuit breathing or recirculating techniques, since the cur-
rent state-of-the-art requires the divers to operate with
hookah gear tethered to the sea hut. Twofold limitations
exist, viz.:

a) To keep the tethers to a reasonable length, the
sea hut must be placed near the area of work. In
the case of Large Object Salvage, this dictates
that the sea hut must be first located near the
bow of the salvage object and later re-positioned
near the stern. This move adds to the underwater
work and to the complexity of the salvage problem.

b) To ensure that there is minimal danger to divers
and the sea hut during heavy rigging operations
(for example, should a large piece of salvage
gear break free and sink), the sea hut must be
placed as far away as possible from the wreck.
The effect of this condition is to dictate longer
hose lengths an the hookah gear and to restrict
further the area of the wrecked ship available
to the divers with a given sea hut position.

3. If heavy weather forces the surface support ships to
abandon the site, the question arises as to whether to leave
the divers in the sea hut or return them to a decompression
complex on the deck of the surface support ship until the
weather abates and the sea hut may once again be inhabited.
Prudence appears to dictate that the divers should be returned
to the support ship in this instance.

Submersible Transfer Capsule (See Figure 5)

The case for the Submersible Transfer Capsule (STO) is best
made by noting that it eliminates many of the disadvantages

184

of the sea hut when employed in Large Object Salvage. Its
advantages are as follows:

1. Since downhaul lines can be rigged throughout the
length of the ship the STC may be lowered to the spot where
work is to be accomplished. Tethers on the hookah gear may
therefore be kept at a minimal length. (See Figure 6.)

2. When diver work has been completed and a heavy rigging
operation is to be accomplished, the divers may be raised clear
of the water.

3. In the event of heavy weather the divers are living
on a surface support ship and will abandon the site automatic-
ally when the surface support ship leaves the area.

4. All service personnel may live on deck under normal
atmospheric pressure, but are immediately available if medical
assistance is required.

In analyzing the specific LOSS operational requirements, it
was estimated that the diver man hours using the STC were only
85 per cent as great as the diver man hours required for Large
Object Salvage using a sea hut. Because of these advantages,
it was decided for Large Object Salvage that the STC, with
saturation living on the deck of a support ship, was the most
promising. Prudence dictates that at least two such transfer
capsules be provided in case of a casualty to one.

The primary characteristics of the STC for use in Large Object
Salvage are as follows:

The STCts primary design function will be to transport four
divers from the surface support vessel to the bottom salvage
site. It can provide emergency life support for four divers
for a 24-hour period without externally supplied aid or
logistics.

The STC must be capable of operation independent of the remain-
der of the diving system in order that day-to-day diving may be
performed from U.S. Navy vessels. In this operational mode,
the STC is capable of supporting two divers for a total of 12
hours, including work and decompression. Meeting these oper-
ational requirements while maintaining STC displacement and
weight at a minimum forms the basic design parameter of the STC.
An internal volume of 40 cubic feet per diver appears to be the
optimum size. This is based upon past operational experience,
engineering layouts, and a mockup constructed by Ocean Systems,
Incorporated.

This volume, contained in a spherical pressure vessel with
cylindrical skirt, results in a configuration as shown in
Figure 5. Such a pressure vessel will basically consist of a
74-inch diameter sphere and will displace about 5.4 tons.

The STC must carry its own helium and oxygen as elemental com-
pressed gases for pressurization and metabolic usage makeup.
Surface-supplied gas at LOSS depths through a hose bundle is
not recommended because of the effects of current drag on large
diameter hoses, the hazards of fouling with other salvage hoses
and lines, and the increased operational and maintenance support
required. Helium can be carried in a torus ring around the
upper circumference of the skirt. A helium booster-pump should

185

;PCC-
SPC CRANE PICKUP
ELECTRIC
CABLE *-z r . HELIUM SUPPLY

X TORUS

RUBBER , /

BUMPER

N
SUPPLY
DDC TRUNK

EESBRWINCHBLE_ PORTABLE STC MOUNT

REEL

SUBMERSIBLE TRANSFER CAPSULE
FIGURE 5

) DIVER SHACKLE STC DOWNHAUL
TO AFT ESCAPE HATCH. -I

GLIFELINES RIGGED AFT TO PROPELLER
Si FWDTO TORPEDO LOADING HATCH.
STC DOWNHAUL RIGGED AT TORPEDO
LOADING HATCH.

~~~~~~~-"
STC AT TORPEDO LOADING HATCH.
LIFELINES e STC DOWNHAUL RIG-
GED AT FWD. HATCH. SURVEY OF RE-
ACTOR COMP., CONTROL COMP.
FWD. COMR.

PRELIMINARY RIGGING
FIGURE 6

186

be supplied with the surface support system to pressurize the
torus ring from shipboard helium supplies.

A unitized cable must be provided to supply electrical power,
wired communications, television transmission, and a strength
member for lifting the STG. The strength member would form the
outer covering of the cable and provide abrasion resistance as
r well as tensile strength. The Strength, Power and Communica-
tion Cable (SPOC) would be powered from and stored on a deck
* reel onboard the surface vessel.
TeST0 should be internally fitted with gas mixing and ana-
lyigequipment, emergency battery power, air purification
unzits, heating, and life support essentials.

The basic SF0 pressure vessel must always be a positively buoy-
ant structure. A ballast weight, to be suspended from a haul-
down winch, would provide negative buoyancy during launching.
The SF0 design must be such that with the ballast weight bot-
tomed, the capsule will be positively buoyant and will rise
above the bottom weight. In this condition, the SF00 can be
slackened slightly so that surface motion is not transmitted
to the ST0.
Both the SF00 and the ballast weight cable should be fitted
with explosive cutters operable from within the capsule. Sever-
ing of these two cables would permit the positively buoyant
capsule to make an emergency free ascent.

In normal operation, the SF0 should ascend or descend by using
the winch to reel in or pay out the ballast weight cable. The
winch must be sized to permit approximately 60 feet per minute
travel in either direction and must incorporate a constant
tension and level wind feature.

The STO double hatch and access trunk arrangement is suggested
to permit vertical mating to the deck decompression complex
and yet allow the SF0 to be used as an independent unit. The
support ship is provided with a mounting stand and a looking
device for the outer hatch so that the cylindrical portion may
be used as an entrance lock.

Refuge and Rest Tent

In exploring the relative advantages of the sea hut versus the
SF0, it waE. discovered that one advantage of the sea hut was
lost in the use of the STC. This advantage was the fact that
the working divers need not penetrate the air-sea interface
so long as the weather remained fair. In order to regain some
of this advantage while using the STC, two schemes were
examined:
1. Use of two STCts at one time. This would permit two
diver teams to be lowered and to work alternately for a period
of approximately twelve hours. The team which was resting
woauld take refuge in its STC. This also provided two havens
atdepth should an emergency render one of the havens uninhab-
itable.

2. The second scheme was provision of a Refuge and Rest
Tent near the wreck (and one of the ST~s) where the unemployed
team could take shelter for rest and warmth while the working
team was on the wreck. In case of an emergency in the SF0,

187

both teams could take shelter in the Refuge and Rest Tent
until the second STO could be rigged and lowered. During
heavy rigging operations the two teams could be returned to >
the surface.
In comparing the two schemes it was estimated that the inter-
face penetrations under adverse environmental conditions and
using one STC and a Refuge and Rest Tent appeared to permitI
a salvage operation to be accomplished with only 7o-So per
cent of the air-sea interface penetrations that were required
utilizing two STOs. Under good environmental conditions both
schemes appeareci to be of equal merit.
It was decided that there was sufficient advantage under poor
environmental conditions to warrant recommending the use of a
Refuge and Rest Tent. The characteristics of this tent are
as follows:
The rest tent should be designed to provide warmth, lifeI
support, and berthing for two divers for 12 hour periods and
to provide emergency life support for four divers for 24 hours
without external aid or logistics. A volume of 60 cubic feet
per diver or 120 cubic feet for the two divers is estimated
to be the minimum size capable of performing the operational
mission. An artist's concept of such a dwelling is shown In
Figure 7. The tent should be independent of the surface in
that all gas and electrical sources are contained on the tent
frame or in the ballast carrier. Since the tent is designed
for positive bottoming, it is not a weight-limited component,
and batteries, gas cylinders, and life support equipment can
comprise a substantial portion of the required four tons of
ballast.
The rest tent is to be designed with a minimum of internal
components which are to be packaged to withstand sea water
immersion. With this provision, the tent can be handled and
lowered in a collapsed and flooded condition. Inflation
would be accomplished by a diver utilizing the tent-carried
gas supplies.
Emergency self-sustaining electrical power can be supplied
from the ballast batteries. In operation as a rest environ-
ment, the tent would be supplied with electrical power through
an umbilical cable from the STC. Wired communications can be
similarly supplied. Battery-powered sonic voice communica-
tions would be supplied for emergency use. The tent gas
supply would be pre-mixed to reduce mixing and analysis re-
quirements. Emergency oxygen should be separately stowed
and piped for internal control.
Deck Decompression Complex
In support of the STC and the Refuge and Rest Tent concept,
a Deck Decompression Complex on the support ship is required.
This decompression complex will permit relatively comfortable
habitation for saturation divers during the lengthy decompres-
sion stage subsequent to extended bottom work. Maximum volume
compatible with the selected ship system is desired, with a
minimum of ship structural modification the primary consider-
a tion.

PORT LIGHT---. I | | i PORT LIGHT

GAS SUPPLY

< ~I /I

BATTERY a BALLAST

DIVER REST TENT
FIGURE 7

189

The Submarine Rescue Ship (ASR) was selected as a suitably
configured vessel for a volume study of a decompression complex
installation. Prior to selecting this specific vessel, an in-
dependent determination of the minimum acceptable volume was
made and a figure of 110 cubic feet per man was selected.
This volume is considered adequate for habitation under high
pressures for periods of up to two weeks. Since the proposed
diving system utilizes eight divers, a total volume of S8o
cubic feet is required. Subsequent layout of this volume
showed that a configuration as shown in Figure 8 was compati-
ble with an ASR and would provide more than the S8o cubic feet
minimum volume. Vertical mating of the STO to either of the
two decompression chambers is accomplished on the support
vessel's main deck. This permits maximum reliability and ease
of operation for topside personnel.

The pressure of the two decompression chambers could be equal-
ized through their common lock and the complex operated as a
single unit. Alternately, either chamber could be pressurized
independently should the operational situation so dictate.
Chamber orientation and arrangement should be designed to per-
mit one operator control of either or both units from a central
panel. Viewing ports and medical access looks are to be pro-
vided at the control station for ease in maintaining surveil-
lance and life support of the chamber occupants.

Each decompression chamber can be divided by a moms tructural
bulkhead into a sleeping area and a general activity area.
Four berths should be provided in each chamber unit. Sanita-
tion and lavatory facilities as well as a recreation area must
be incorporated in each activity area.

orientation of the decompression complex with the ship's fore
and aft centerline will reduce effects of ship motion both for
the mating operation and for personnel comfort.

Tools, Light and Communication

The specific work tasks to be performed by a salvage diver
will vary from one operation to the next. In general, divers
may be expected to perform cutting, rigging, and structural
repair on any salvage task. For this purpose, a general pur-
pose power source is recommended with tool adapters provided
for a specific function to be performed.

Electric, air and hydraulic power supplies were investigated.
Electrical operation was discarded because of the potential
hazard associated with high energy, electrical currents in
sea water. Compressed air was ruled out because of the desire
to eliminate surface-connected hoses to as great an extent as
possible and because it is difficult to develop sufficient
differential pressures to perform useful work at 600-foot
depths.

A compensated hydraulic power source utilizing oil or sea
water offers an efficient and safe power supply. Motive force
for the hydraulic system could be an electric motor on the STC
remote from the actual diver work site. The hydraulic power
head will be provided with various tools to perform cutting,
twisting and wrenching operations.

190

Buoyancy devices can provide the diver with a means of lifting
moderate weights and moving equipment about the work site.
These buoyancy devices might be collapsible containers with
provision for attachment to the object to be lifted. In oper-
ation, the buoyancy bag would be tethered to a horizontal
guideline and then inflated by the diver until the weight is
lifted and restrained by the tether line.

Control and propulsive force in the horizontal plane could be
provided by flooded,low horsepower, low voltage electric motors
controlled by the diver. The motors would need only a minimum
of speed control and steering ability since they would be pro-
pelling a tethered object or diver only in a horizontal plane.

External lighting should be provided on the STC, the rest tent,
and the portable television camera. No attempt need be made to
light the entire salvage area since no wide area work chore is
envisioned.

Primary communications should be a wired voice system utilizing
electronic correction of the speech aberration caused by helium
in a high pressure environment. This system can connect each
diver, the STC, and the surface control station. Wired com-
municaticas need not be provided in the rest tent because when
occupied by a diver he can then use his mask microphone and
speaker. The wired communication system can be a 'party line"
with override from the surface control station.

A battery-powered sonar voice and/or CW system should be pro-
vided in the STC and the rest tent for emergency use. No
helium speech corrector need be incorporated.

Effect of Environment Upon the Diver System

The expected low visibility associated with deep depths and
turbid conditions at the bottom work site will probably neces-
sitate a diver navigation, orientation, and location system
usable in zero visibility. A horizontal touch-coded guideline
system can be used. These guidelines would be rigged between
work areas on and across the salvage object. The guidelines
would also permit more efficient diver horizontal motion than
if he were a free swimmer. The incorporation of vertical
tether lines with the horizontal guidelines would constrain
working divers from dangerous excursions above their saturation
depth. While the danger of a wet suit clad diver losing buoy-
ancy control is remote, a vertical excursion of more than one
atmosphere may cause decompression sickness in saturated divers.
The tether and guideline combination can provide orientation
and direction to divers under zero visibility and high current
conditions.

Cold water and long diver work periods will require development
of a heated and well insulated diving suit. The suit should
provide the joint mobility of a common wet suit while providing
long term warmth and protection for the diver. The suit heating
power supply should be compact and lightweight for transportation
on the diver's person. Radioisotope, chemical, and electrical
power units should be investigated.

Direction and Supervision

Several methods of direction and supervision of the salvage
divers were considered. Provision of a two-chamber STC in the

191

system would permit on-the-scene supervision by a salvage expert
from the upper chamber (at one atmosphere pressure) while the
divers operated from the lower. This method would increase the
weight of the STC with an attendant increase in handling prob-
lems and hazards. Additionally, in low visibility conditions,
the salvage supervisor would be unable to see or actively
supervise the divers at work.

Consideration was also given to having the salvage master actu-
ally be a member of the diving team. Since the two skills,
salvage master and deep diver, require extensive training, it
is felt that the operation of a Large Object Salvage should not
be based on the availability of such a singular person. Also,
it is not advisable to remove the salvage master from the sal-
vage control center and place him in a high pressure situation
where he is not available to the largest segment of the salvage
work, which is normally on the surface vessel deck.

Closed circuit television (CCTV) was selected as the best
method for visual inspection and monitoring by the salvage
master. The CCTV unit would be portable for diver use under
the direction of the topside Salvage Operational Control Center.
A video tape recorder would permit selective recording of vital
salvage sequences and survey points.

Interface Handling Problems

As discussed earlier, every effort has been made to minimize
the size and weight of the STC. Operational planning must be
done to reduce the number of interface penetrations required
for the salvage operation. These efforts will minimize the
operational requirements and hazards of handling diving equip-
ment in and out of the water.

The inclusion in the system of improved deck handling equipment
is considered vital to achieve maximum reliability and effi-
ciency. The design of a stabilized crane for marine use
is recommended for this purpose. The hydro-electric crane
would include a hydraulically controlled outrigger arm or jib
boom capable of reaching at least ten feet below the sea sur-
face. This extension boom should be fitted with a rigid cou-
pling type pickup device to catch and lock, positively, a
matching connection on the STC. With rigid coupling effected
below the interface, the STC could be handled over the side
and on deck with minimum hazard to both the STC occupants and
deck personnel. The crane should be rigged to utilize the
unitized SPCC to the STC as a guideline until rigid coupling
is effected. Continuous power and communication transmission
can be carried on through the SPCC and reel during pickup
maneuvers.

In conclusion, it is interesting to compare the results of the
operational analysis of the recommended Large Object Salvage
System for continental shelf depths with the SQUALUS salvage
operation. Based upon the best information available, it
appears that from the time the salvage operation started until
the SQUALUS was lifted for the first time, the total elapsed
time was 48 days. Rigging required approximately 31 diver man
hours and approximately 340 air-sea interface penetrations
were made by the working divers. For the recommended Large
Object Salvage System it is estimated that the total time re-
quired from the start of the salvage operation to first lift
would be approximately six to seven days. Rigging would

192

require approximately 50 to 55 diver man hours, and approxi-
mately 28 to 36 air-sea interface penetrations would be
required.

DIVER OPERATIONS

Surveying the Wreck

Assuming that a large object has been located on the ocean
bottom and the decision to salvage it has been made, the exact
condition of the wreck as well as the environmental condition
must be ascertained in order that the salvage operation may be
planned and safely executed. Previously, most of the informa-
tion available on the condition of a wreck has been gleaned
from debriefing the survivors. As the object of interest be-
comes more sizeable and possible depths from which salvages
may be accomplished become greater, the need for more specific
information as to hull strength, hull watertight integrity,
and extent of flooding becomes more stringent. The extent
and disposition of flooded compartments determine both the
amount and the relative locations of required lift forces.
Hull integrity determines whether an object may be lifted by
applying force at the two ends or by distributing the force
along the length of the wreck. Partial flooding may cause
loss of attitude control should the wreck be tilted, and if
slings are employed the large object might slip loose.
Bubbled compartments in free communication with the sea but
with a trapped bubble remaining inside will expel water as
the wreck is raised and the bubble expands. The result of
this could be loss of control over the rate of raising the
wreck, permitting it to bob unexpectedly to the surface with
disastrous results to the support system.

In order to determine the exact state of a wreck, as well as
to predict the break-out forces required, divers must:

1. obtain soil cores to permit ascertaining the type
and characteristics of the bottom;

2. accurately measure the depth of imbedment of the
wreck in the bottom;

3. determine whether or not the compartments within
the wreck are flooded and, if so, to what extent;

4. in flooded compartments, determine whether or not
the compartment is in free communication with the sea or
with adjacent compartments; and

5. locate possible attachment points such as rudders,
shafts, or other protrusions, and determine the capacity of
each.

These operations will be required of the divers in the initial
on-site survey, and illumination devices, coring devices,
ultrasonic sounding devices, and possibly pneumatic pressuri-
zation devices must be developed to permit this survey to be
made.

Lift System

Traditionally, Large Object Salvage operations have been con-
ducted using slings and pontoons. In reviewing the state-of-
the-art it was found that the force magnitudes render this

193

approach most attractive. The primary advantages of pontoons
are:

1. the lift may be accomplished with the surface area
over the wreck cleared of all support units, and

2. buoyancy force offers a natural advantage in the
underwater environment and pontoons permit exploitation of
this advantage with a minimum of additional heavy equipment.

The primary disadvantages of pontoons appear to be:

1. the need for diver work in setting each pontoon, and

2. if using compressed air, the time required to blow
the pontoon at continental shelf depths becomes a limiting
factor upon the operation.

Due to the fact that the Navy already has a large investment
in rigid pontoons and that operational experience with col-
lapsible pontoons indicated no clear-cut advantage over the
rigid pontoons, rigid pontoons are recommended as the lift
vehicle in the continental shelf salvage operation.

The diver operations, therefore, center around attaching the
pontoons to the wreck and setting the pontoons upon the cable
or chains used to make the attachment.

In reviewing the state-of-the-art for attachments it was found
that chain slings offered the most tons of lift per diver man
hour of work. The slings, however, require tunneling under
the wreck, which is an operation required of the diver. The
hydraulic lance developed during the SQUALUS salvage appears
effective in bottoms composed of sand, mud, or clay. In
rocky soils or coral, however, some other type of unit will
be required. Recommended for investigation are tunneling
devices utilizing rotary bit or ultrasonic attachment.

To overcome the disadvantages of pontoons, two avenues of
approach are open.

1. To reduce blowing time, larger compressed air volumes
and pressures can be utilized in the near term. For the longer
term, chemical gas generation or liquid gas stowage techniques
may prove attractive.

2. To eliminate the need for re-setting pontoons continu-
ously as the wreck is hoisted to the surface, ships equipped
for bow lift may be substituted for pontoons after the wreck
is clear of the bottom. These bow lift ships can then hoist
the wreck to the surface and the original pontoons re-attached
to the wreck to hold it near the surface for the to-wing oper-
a tion.

Although collapsible pontoons have been seriously considered,
many of their apparent advantages disappear when their size
is increased to provide large buoyancy packages. The collaps-
ible pontoons, in addition, are vulnerable to damage by punc-
turing or chafing. In small buoyancy packages or small lifts,
however, collapsible pontoons are inviting.

194

Demands Placed Upon the Naval Architect

What are the demands which the diver systems and the lift sys-
tems place upon the Naval Architect? In exploring the answer
to this question the diver system will be examined first. It
appears reasonable that the salvage operational center and the
diver support ship are compatible functions and should there-
fore be placed on board the same ship. A volume study was con-
ducted and it appears feasible to contain these functions in a
ship of about 2,300 tons displacement. The ship selected for
this study was a current submarine rescue vessel (ASR). A
sketch of the approximate volume requirements for the diver
system and the Salvage Operational Control Center is shown in
Figure 8. It should be pointed out that this was a preliminary
study only and that the arrangement depicted is not the optimum.
It was generated by eliminating spaces not required for the
recommended Large Object Salvage System and then placing in
these spaces the functions required by the recommended system.
The hydraulic crane depicted has been discussed previously, as
have the submersible transfer capsule and the deck decompres-
sion complex.

To hold the Salvage Operational Control and diver ship in posi-
tion over the wreck while salvage operations are being per-
formed, both static and dynamic moors were considered. For
continental shelf depths the use of a static moor utilizing
four to six legs was most attractive from a cost-effectiveness
viewpoint. The type of moor envisioned is depicted in Figure
9. It will be noted that the mooring for the salvage oper-
ational center leaves the area directly over the wreck rela-
tively free of mooring lines.

Salvage Operational Control Center

The space allocated within the Salvage Operational Control and
diver support ship for the Salvage Operational Control Center
would be equipped to coordinate the various salvage tasks. It
is recommended that it be provided with modern cata recording,
displaying, and computing equipment. This center would take
charge of and perform the following functions:

1. Transmission, receipt, and dissemination of both short
and long range tactical communications associated with the sal-
vage operation.

2. Radio link with shore-based master computer memory, if
this function is required.

3. Data generation and processing for various salvage
problems, including but not necessarily restricted to:

a) Initial moor-laying calculations to determine the
holding capability of the moor as actually con-
figured, as well as to monitor the moor under
existing conditions and to predict the environ-
mental parameters which would dictate temporary
abandonment of the site.

b) Continual monitoring of the diver system environ-
mental conditions, communications, and diver
performance.

195

DIVERS SUPPORT COMPARTMENT AIR STORAGE

CARGO STORES

/X/ /
DDC SALVAGE OPERATIONAL COMPRESSOR ROOM SALVAGE STORES
CONTROL CENTER

SALVAGE CONTROL SHIP
FIGURE 8

SUPPORT SHIP COMMAND SHIP SUPPORT SHIP
SURFACE BUOY

~[CHAIN

CLUMP / ANCHOR
WRECK

STATIC MOOR ARRANGEMENT
FIGURE 9

196

a) Scanning of the wrecked ship's design calculations
to identify by name and location any components
that may present implosion hazards to the divers
during their efforts in rigging for salvage.
d) Transform measurements of water level, pneumatic
pressure, and wreck orientation to arrive at
negative buoyancy predictions and lift distribu-
tion requirements.
a) Prediction of the lift requirement to overcome
the holding power of the bottom.

f) With the attachment points and their capacities
stipulated, calculation of the lift force require-
ments at each point. Consideration of break-out
force, free-surface effects, and free-communica-
tions effects must be included.
g) Monitor the lift system, using the results to
compute and display the lift condition for com-
parison with the predicted lift requirements
obtained in a mcanner similar to that described
in the next section. This would permit early
recognition of considerations which, if uncor-
rected, might lead to the loss of lift control.
SURFACE SUPPORT REQUIREMENTS

A wide variety of surface support ship types could be con-
sidered for salvage operations described here. Within the
context of the prescribed study, existing operational vessels
of the fleet were to be considered for this duty rather than
vessels of new design or types not currently in the naval
service. Within these ground rules, a fleet of three ships
was selected for service on this requirement. Each of the
three ships is configured, in hull shape and size, similar
to an ASR or ARS. The Salvage Operational Control and diver
support ship just described appears to fit within the con-
figuration of a submarine rescue ship (ASR). The other two
support ships appear to fit within the configuration of cur-
rent salvage ships (AilS).
These two salvage ships must be provided with-a large bow lift
capability by virtue of each having two powerful hoisting
winches installed on their forecastle decks. They will pro-
vide the control lift after break-out has occurred as previ-
ously explained. These ships will also tow most of the rigid
pontoons to the site. They will transport all mooring equip-
ment and lay the moor. In addition, they will function as
floating workshops and storehouses. They will tie up to the
surface spuds of the moor in calm weather. Heavy weather may
force them to cast off to insure that the command ship posi-
tion will not be jeopardized. In this case, the lift ships
will steam in the vicinity until normal operation can be

resumed.
This combination of bow lift vessels has the capability of
lifting large weights from any accessible point on the conti-
nental shelves of the world. Additional capacity is available,
limited only by the number of pontoon attachment points and
the number of nontoons that can be made available.

197

Lift Requirement Analysis
In planning a salvage operation, the Naval Architect must care-
fully analyze the lift, control, and break-out problems asso-
ciated with his given salvage task. Each salvage will be
unique, hence, only a guide as to how he approaches this analysis
can be given.
Varying amounts of lift force must be provided during the dif-
ferent stages of raising the wreck to the surface or to a depth
sufficient for transportation. Consider the example of a sub-
marine which has been partially flooded as shown in Figure 10.
It has sunk to the bottom and is resting partially in mud, which
will resist motion of the vessel in any direction. The subma-
rine will have a certain negative buoyancy which may be located
at a certain center of gravity, neither value being known at
the start of the salvage operation.

CG2 o3

CG3

~'2 4W2
3
AP S-,

WI + W2 W
11 - + 12 = 1

WI + W2

ANALYSIS OF LIFT
FIGURE 10

The first objective will be to estimate the over-all weight and
center of gravity of the object to be lifted. This may be
based upon reports from survivors and results of inspection,
and from the data obtained from plans and calculations of the
ship design. Two other items that must be determined include
the amount of partial flooding in any tanks or compartments,
which can cause free-surface effect, and the partial flooding
in any tanksopen to the sea, which implies an air pressure in
that tank equal to the ambient pressure at that depth. Such a
pocket of air will expand as the object is being raised, and
will result in changes both to its weight and its center of
gravity.
A second objective will be the determination of the degree of
imbedment of the submarine in the sea bottom and the physical
characteristics of the bottom. Computations based upon the
remolded shear strength, percolation rates, etc., of the mate-
rial in contact with the vessel and the area exposed to the
material must permit estimation of the force required to break
the vessel loose from the bottom.
198

Returning for a moment to Figure 10, it is possible to estab-
lish a best estimate of both the weight and the location of
the center of gravity of the object to be salvaged. It is also
possible, based upon best estimates and judgment, to place a
margin of probable error both upon the weight and the location
of the center of gravity of the wreck. This will consist of
two parts, first the margin of error in knowledge of the condi-
tion of the submarine immediately prior to the accident, and
the effect of the accident upon the vessel.

Lifting force may be generated in several ways, either by
attaching pontoons to the lifting slings or attachments and
blowing them dry, or by lifting on the slings or attachments
directly via a cable attached to a winch on the surface vessels
above. As a result of recent studies, it has been recommended
that a combination of both methods be used.

The salvor will probably elect to lift the wreck in a series
of stages to permit positive attitude (trim) control over the
object. The first stage will consist of lifting the wreck
clear of the bottom. For the analysis the following nomencla-
ture will be used:

Nomenclature

i W1 - Net weight of object in its normal condition.

W2 - Weight added as a result of casualty or accident.

W3 - W1 + W2 = W3 - Best estimated final weight.

�1 - Distance from after perpendicular to C.G. in operating
condition.

22 - Distance from after perpendicular to C.G. of weight
added by casualty.

3 - (W- ll + W22)/(W1 + W2) = �3 - Best estimated final C.G.

AW3 - Estimated margin for error in W3.

A~3 - Estimated margin for error in �3.

AW - Estimated weight of water that can shift due to free-
surface effect.

-a3S ' Estimated shift in �3 due to free-surface effect.

AW3E - Estimated allowance for reduction in W due to expansion
of air in tanks open to the sea as wre~k is lifted.

A 3E- Estimated allowance for shift in �3 as water is expelled
by expanding air.

B - Estimated force required to break wreck out of sea
bottom.

-B - Distance from after perpendicular to estimated C.G. of
break-out.

AB - Estimated margin of error in break-out force.

Ae - Estimated margin of error in XB'

199

FLM - Lift force developed by Mth lift pontoon.

FCM - Lift force developed by Mth control pontoon.

ELM - Distance from after perpendicular to Mth lift pontoon.
L0M - Distance from after perpendicular to Mth control pontoon.

The situation as it is at this time is diagrammed in Figure 11.
Having made the best possible estimate of the weight (W5) to be
lifted and the location of the center of gravity (23), at must
be recognized that certain margins must be allowed to compen-
sate for inaccuracies in measurements and inspections made.
A margin for error must be assigned both to the weight and the
center of gravity of the ship as it really exists in situ.

If air is contained in tanks closed to the sea, and the pitch
angle of the vessel is changed, there will be a change in
moment due to the shifting of the free surface. An allowance
should be made for this effect on the moment diagram.

If air is contained in tanks open to the sea, water and pos-
sibly air will be expelled as the ship is raised due to de-
creasing pressure and an allowance for this effect, as well as
its associated free-surface effect, must be made.

Finally, a certain force and moment must be exerted on the
vessel to break it loose from the mud which is enveloping it.

By suitable plotting of best estimates of each of these indi-
vidual effects, the diagram of Figure 11, entitled Variability
in Weight and Moment During Break-out and First Lift, may be
established.

In planning the operation the Naval Architect may elect to
make the first lift equal to 40 feet. This is a realistic
lift in order that the trim angle of the salvaged object be
limited to less than that at which the slings will slip.

As a result of analyzing the situation the pontoons would be
rigged around the wreck as shown in Figure 12. They are
divided into two groups called lift pontoons, which are placed
close to the wreck, and control pontoons which are placed close
to the ocean surface. One purpose of this arrangement is to
lift the wreck free of the ocean bottom, and when control pon-
toons reach the surface to stop the lift before control is lost
due to expanding air in spaces open to the sea. This also
provides an opportunity of weighing the wreck so that pontoon
rearrangement for the remainder of the lift may be more accu-
rately established. Finally, the power and time required to
blow pontoons close to the surface is less than the power and
time required to blow pontoons at deeper depths.

Analytically, the problem of lifting with pontoons may be pre-
sented in terms of the following criteria:

m=n m=n
W + AW + B + AB < 2 FLM + o FCM
3 M7m=o m=

200

VARIABILITY IN WEIGHT AND MOMENT DURING
BREAK-OUT AND FIRST LIFT
FIGURE II

~~~~~~PONTOONS

EFEC3 O CNT

c~~~~~~~ONOTS
I\2~ ~FFC OFBWMMNSTAEZBU FE
0~ ~~~PNON PEPNIUA
~~~~~~~~~~~~~~~~~~~~EFCOFA 3A 3EIS-OSHF
U ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~~~~~W ONADN OTELF

z~~ ~ ~ ~ ~ ~ ~ ~ ~MMN -_ F T _ T O NS

If these criteria are not met, the load will not rise. Con-
versely, if the condition

w IW 3 -AW 3E> m F M
m=n
w3 -A3 -W3E > m=Zo FLM

is not met, the load may rush to the surface out of control
once it has broken free of the bottom, causing possible casual-
ties to men and equipment.

It may also be seen that

m=n
Z FCM > B + 2AW3 + AW3E + AB.

The situation with respect to moments may be examined in the
same light. If W3, 23, B, and t$ were known exactly, the ideal
lift situation would be expressed by

m=n m=n
Z FLM LM + mo FCM CM =W3 3 + BBB.

However, there is uncertainty as to the exact values of W3,
B. W ,and BBB, as previously pointed out. These deviations
consst of

AW3 L3 � AW3 S �3S AW3E l 3E � AB AB-

In the worst case, all of these deviations may be additive.
In order to compensate for the lack of precise knowledge of
the moment required, control pontoon capacity must be provided
so that

m=n m=n
Z S LM ILM + mZo FCM CM > W3 23 + B� B + AW3 (23 + Ai3) +
MR=O m_

W3S (23 + A23S) + ALW33 (3 + Al3E) + AB (23 + 2B).

The additional lift capacity of pontoons for moment control
should be provided at the control pontoon level to assure that
after break-out the excess available moment does not cause the
wreck to continue rotating until the longitudinal axis has
attained a vertical attitude.

The range of moment and weight control of the pontoon system
may be plotted on Figure 11, and if properly designed the pon-
toon system should enclose the plot of all uncertainties to be
encountered (in the manner shown).

Figure 11 illustrates the method of determining pontoon place-
ment and arrangement. Situations may arise in which the center
of application of break-out forces is considerably displaced
from the center of the load. Other unique situations not in-
cluded in the figure may arise, but all situations when properly
analyzed by methods similar to the one shown are amenable to
solution.

202

w3~~~

RIG BEFORE BREAK-OUT

FIGURE 12

-SURFACE

RIG FOR LIFT TO SURFACE
FIGURE 13

203

When the pontoons are blown, the assembly shown in Figure 12
will rise until the control pontoons reach the surface, At
this time, based on a knowledge of the condition of the pon-
toons, a revised estimate may be used to more accurately
establish the values of W3 and 23

Description of Salvage Lift Operation

After all the pontoons have been set and the diving officer
has reported the bottom "all clear," the pontoons are blown
with compressed air supplied from the surface. This is the
most critical point in the salvage operation. It is the cli-
max to the major effort of analysis and preparation. The
effort to this point could be lost, should something go wrong.
Successful break-out and initial lift are proof of the engi-
neering assumptions and calculations.

Break-out should occur at some time during the blowing process.
If not, a revised estimate of the situation should be made in
terms of the analysis previously presented, and additional
control pontoons added as required. Bow lift from surface
vessels could be employed by the salvage master at this time
for another increment of lifting force; but this should be
attempted only if surfacing control pontoons will cause no
damage. Once the control pontoons reach the surface, the sub-
marine is clear of the bottom. The salvage master now has the
opportunity to measure the weight of the wreck accurately. He
can measure the draft of the surfaced pontoons and determine
the sum of his lifts. This is the first opportunity to con-
firm the accuracy of previous calculations.

The lift stage of the operation utilizes the two bow lift
ships for control. The slings and lift cables used for the
control pontoons are transferred to the lift ships; the lift
pontoons remain untouched. The cables from the top control
ntoons are picked up by the lift ships. The cable clamps
(flowerpots) are removed from the top of the control pontoons
so that the cable may be winched aboard the surface lift ship
as it runs through the hawsepipes of the pontoons. This
arrangement is shown in Figure 13o

The surface ship can lift the submarine in 70-foot increments
until the lift pontoons reach the surface. These increments
are established by the travel of the tackle used with the lift
system. The lift operation consists of a number of sequences
involving incremental lift, stopping the cable, resetting the
tackle, and repeating the lift increment, Incremental lifts
also afford opportunity for inspection while tackle is being
reset, and insure positive control of the attitude of the rising
load.

During this phase of the salvage operation there are two clearly
identifiable sources of potential danger. The first is a par-
tially flooded compartment and the second is dynamic stresses
in the lifting cables.

A partially flooded cmpartment represents a serious consider-
ation in the control problem. If the compartment is closed,
the problem arises from free surface; but if the compartment is
open to the sea, the salvage master must account for both free
surface and the augmentation of lift caused by expanding air.

204

In the case of a partially flooded compartment closed to the
sea, the amount of flooding water always remains co nstant;
however, its center of gravity will shift as soon as one end
of the submarine begins to rise. Unfortunately, this shift
is in the opposite direction from that desired, causing the
end which is already rising to become lighter and the lower
end to become heavier. This process, if not controlled, can
ultimately result in the submarine being upended in a vertical
position similar to a spar buoy.

The second case is that of a flooded compartment open to the
sea. In this case both the previous problem of a free surface
and an additional problem of expansion result. The water
level is maintained by a bubble of compressed air at the top
of the compartment. As the submarine is raised to the surface,
the sea pressure decreases and the air bubble increases in
size. Conceivably, ,this process can progress to a point where
the negative buoyancy becomes less than the applied lifting
force and the submarine will shoot up to the surface out of
control. It is a necessity that dynamometers be connected
to the bow lifts to insure that the rate of change of negative
buoyancy is monitored, thus insuring negative buoyancy at all
times. If the wreck becomes buoyant, air may be vented from
pontoons to reduce the lifting force.

In controlling the rising load it would be helpful to make an
assessment of Wo and 3 at the beginning and end of each incre-
ment of lift an� run a continuous plot on a diagram similar to
Figure 11, so that blowing or flooding of pontoons in a manner
suitable for retaining control at all times is accomplished.

The other source of potential hazard results from stresses
induced in the lifting cables by wave action. These dynamic
loads on the lifting cables are difficult to determine.
Results of preliminary studies made on this subject show that
the first resonance occurs at the low sea states normally con-
sidered ideal for salvage operations. Also, the closer the
salvage object is to the surface, the higher the frequencies
become, placing them at even lower sea states. Further study
of this subject is required.

CONCLUSIONS

The classical salvage requirements for heavy objects in deep
water involve the making of large, strong attachments to the
object and the applying of sufficient force to overcome its
negative buoyancy. These requirements are unchanged.

However, the tools for meeting these requirements have changed
radically in the past few years. We have an enhanced diver
capability that permits longer and deeper dives than was pos-
sible in the past, permitting the accomplishment of more work
in shorter time on the bottom than was heretofore possible.

The diver has available to him better inspection tools, such
as closed circuit television, underwater lights, and cameras,
and a number of devices under development, such as ultrasonic
liquid level detectors. His other tools include development
of shaped charges for cutting and punching holes and a number
of devices which, while requiring development for underwater
adaptation, appear to offer enhanced work capability.

205

The installation of properly programmed computers in the Salvage
Operational Control Center will permit computation of proper
decompression schedules and gas mixture regimens, and control
to minimize decompression time. These devices may have other
uses on salvage problems as well.

As a result of improvements in the necessary disciplines and
equipment used in salvage operations it may be said that the
ability to conduct recovery of large objects on the continental
shelves has been greatly enhanced in the last decade.

206

A ~~~~PRESSURE EQUALIZED FLEXIBLE STRUCTURES FOR

MANNED DWELLINGS

Edwin A. Link

Chief Marine Consultant

Ocean Systems, Inc.

ABSTRACT

The feasibility of flexible materials for the structural por-
tions of manned undersea dwellings has been demonstrated in
design studies and proven in at-sea tests. Since the maximum
differential pressures encountered are small and are directly
proportional to the height of the pressure equalized flexible
structure, a wide variety of materials such as rubber, nylon,
plastics and other synthetics may be utilized.

Teconcept of flexible structures permits economical solution
to many diverse undersea tasks. Flexible structures offer in-
herent advantages for operation from small research vessels with
a minimum of logistic support requirements and operating person-
nel.

The problems of life support, atmosphere control, biomedical
support and diver safety remain as urgent as those associated
with large undersea dwellings. The use of a small bottomed
dwelling along with a system of "commuter diving" does offer sig-
nificant operational andsafety advantages for certain missions.

Application of this concept to many tasks is envisioned. Among
these are:

Diver Rest and Refuge Stations

Oceanographic Observation Stations

Bottom Sitting Dry Environment Work Areas

Workshops and Storage Areas

Submarine Escape Techniques

In July 1964, the author planned and directed a deep ocean sat-
uration dive utilizing a p res sure equalized flexible dwelling
to support two divers at 432 feet for 49 hours.

CONCEPT

The techniques of saturation living and diving conceived by the
U.S. Navy provided a new method for Man's extension into the sea.
The medical and physiological proofs that Man could exist for
l.ong periods at high ambient pressures gave rise to several dif-
t4~ent engineering approaches to exploit this capability.

The cb22eept of the pressure equalized flexible dwelling resulted
from a d'esire to provide maximum safety and comfort for deep
ocean dives while conforming to the operational capabilities
and limitations of a small diving research ship. Earlier Man-

single diver, had ntbydemonstrated athat properly dvfotplanned satura-
tion diving work could be accomplished from an independent re-

207

search ship. This-experience also showed the need for addi-
tional underwater habitation if the depth, duration or length
of manned submergence were to be increased. A submersible,
portable, inflatable dwelling analogous in many respects with
a tent was determined to best offer a solution to this problem.
DESIGN
The prototype dwelling (submersible, portable, inflatable dwel-
ling (SPID))was designed to be constructed of commercially a-
vailable components. The dwelling portion of the structure is
a modification of a rubber storage bag modified externally with
an access trunk and two view ports on the longitudinal axis.
The usable internal space measured 7 feet in length by 4i.5 feet
diameter.
The 110 cubic foot internal volume was outfitted with two bunks,
gas analyzer equipment, heaters, dehumidifier, C02 removal e-
quipment, lighting, provisions and water, and diver personal
clothing and equipment. The fabric was internally strengthened
to support the loads suspended from it. The dwelling internals
were painted with non-toxic high reflectant paint to provide
maximum internal illumination.
The inflatable dwelling portion was mounted within a pipe struc-
ture frame and restrained by a nylon webbing. Eight compressed
gas cylinders, each with a 24I0 cubic foot capacity were mounted
on the external frame and manifolded for control from within
the dwelling. A bridle was fabricated to fit the frame and pro-
vide a lifting point for the entire dwelling.
Ballast to compensate for the 3.5 tons submerged displacement
and to provide firm anchoring on the ocean floor was contained
in a structural steel basket beneath the dwelling. The ballast
consisted of lead pigs and cast lead shot I inch in diameter.
Use of the lead shot permitted final ballasting of the SPID
while it floated near the surface ship without swimmer or diverI
man-power. The ballast basket further provided a stowage space
for pressure tight containers loaded with life support consum-
ables, provisions and diver clothing.
The SPID as fully outfitted and configured required a deck stow-
age area of 9 feet by 6 feet on the surface vessel deck. Par-
tially ballasted, it required a dry weight lift of only 2 tons,
well within the capability of most research vessel booms and
cranes.
Concurrently with the SPID design and manufacture, a second pres-
sure equalized flexible structure was designed and built. This
unit was designed to provide a completely dry bottom environ-
ment for inspection and work on the ocean floor.
This bottomed work area, nicknamed IGLOO, consists of an 8 foot
diameter hemisphere of nylon reinforced rubber attached to an
external ballast ring around its lower circumference. The bal-
last ring provides external stowage space for compressed gas7
stowage and consumable supplies.
IGLOO was designed for use in two configurations; either-nega-
tively ballasted for semi-permanent bottom installatiQTI'with a
sub-bottom entry passage, or, ballasted to be raisedi'and low-
ered above an anchor by an occupant. In the latter mode, pro-
per ballasting and use of a hauldown device and bottom anchor

208I

permits positioning of the anchor prior to placing IGLOO on the
bottom, Final positioning of the slightly positively buoyant
structure and blowing out the residual water is accomplished by
a diver utilizing conventional breathing equipment or breathing
the mixture entrapped in the IGLOO itself.

OCEAN OPERATIONS

IGLOO, the inflatable bottom-work shop, was operated for 50 days
at 140 foot depths to determine its capabilities. Throughout
this period, diver teams investigated various techniques for
positioning, entry, and use of this dry work area.

SPID, the inflatable dwelling, was integrated into a system for
more extensive deep ocean testing. This deep diving system in-
cluded a submersible decompression chamber (SDC) for diver trans-
port, a deck decompression chamber with which the SDC0 mated for
diver transfer at high pressures, a master control console, and
the SPID.

After operational trials in 80 foot depths, the SPID was lower-
ed to the ocean bottom at 1432 foot depths in late June 1964.
Throughout the descent, internal pressure was measured through
a pneumo-fathometer while a constant water seal was monitored
with closed circuit television equipment. Accurate depth posi-
tioning of the SPID was accomplished by descent line markings
and thorough use of a fathometer which presented a continuous
descent profile. A pre-mixed helium-oxygen breathing composi-
tion was hose supplied to the dwelling to maintain the desired
water level.

The SPID bottomed on an eight degree sloping sandy and coral bot-
tom. Surface supplied gas was secured and the inflated dwelling
remained anchored to the bottom for forty eight hours prior to
the arrival by SDC of the two men who would live in and work from
SPID. Throughout this waiting period, no gas makeup was required.

Concern regarding helium diffusion through the dwelling fabric
was ended. This confirmed earlier tests that has shown the small
pressure differential across the fabric (3.14 psig maximum at the
top of the dwelling) has not caused significant gas leakage.
Subsequent to occupancy of the dwelling by the two divers, Robert
Stenuit and Jon Lindbergh, all gas analysis and makeup of oxygen
and mixed gas for water seal maintenance were controlled by the
occupants.

Throughout the 149 hour bottom dwelling period, the SPID provided
a warm, dry environment for the deepest ocean dwellers to date.
After the ascent of the two divers, the SPID was raised to the
surface and reloaded aboard the surface vessel without incident.

FUTURE CAPABILITIES

The missions Man will accomplish in the sea are many, varied
* and often not yet completely defined. The equipment, living
facilities, and work areas he will require are as varied as his
missions will be. The use of pressure equalized flexible struc-
tures will fill some of these needs just as some will require
larger structural components.

* Some of the future uses foreseen for flexible structures include:

1. Rest and refuge tents for deep dives using a "commuter"

209

technique where the main support facilities are located on the
surface vessel. In this technique, a small bottomed refuge pro-
vides a safe haven for deep divers in the event of a SDC cas-
ualty. Proper design of such a haven will permit its recurrent
use for rest and minor repairs during prolonged bottom work tasks.

2) Oceanographic observation stations which can be main-
tained, launched and recovered by existing research vessels for
many biological, geological and physical oceanography tasks.

3) Provision of a dry bottom environment for cable repair,
pipeline installation and maintenance, extensive bottom construc-
tion work, and accurate in-site bottom analysis.

4i) Underseas workshops and storage areas which are readily
relocated and maintained.

5) Escape from disabled submarines, either military or ci-
vilian, by controlled decompression within an ascending flexible
structure. Once surfaced, the flexible dwelling may be converted
to a life raft for the survivors until aid arrives.

SUMMARY

The economy of manufacture and operation of pressure equalized
flexible dwelling systems have been demonstrated. Increased op-
erating experience with flexible dwellings and workshops will pro-
vide information for future designs and uses.

The continued use of pressure equalized flexible structures for
manned dwelling will permit a multitude of scientists, engineers
and explorers to live in the oceans and perform their specific
tasks.

210

UNUSUAL ENGINEERING PROBLEMS IN UNDERSEA LIVING
Berry L. Cannon
U.S. Navy Mine Defense Lab., Panama Cit~y, Fla.

A wide variety of unusual and interesting problems are encountered
when the engineering requirements for living underwater are
examined. The most obvious problem, increased pressure, creates
some special requirements on most equipment design. Since an
artificial atmosphere is a necessity in undersea living,
maintaining the correct gas mixture requires a specialized air
conditioning and ventilation system. The oxygen percentage
must be rigidly controlled, and all toxic gases removed. Also,
the relative humidity has to be kept within comfortable limits.
If Helium is used as the primary inert gas, communications
require a special approach to reduce the "Donald Duck" effect.
This speech distortion is a serious problem in communications
in general. Even the commonplace problems of logistics demand
some unusual solutions. Transfers of food, clothing or other
articles that must be kept dry require special equipment and
handling.

One of the first questions asked about undersea living is, "H~ow
do you stand the pressure," or "Doesn't the pressure affect
you?" Fortunately, pressure doesn't seem to have any adverse
effects on man, within certain limits. But, pressure is
definitely an engineering problem because of its effects on the
hardware involved.

Any equipment present in the habitat must either be able to
withstand the high ambient pressure or be in a pressure proof
housing. Some of the new solid state electronic components
withstand pressure very well even without encapsulation in
epoxy or some other material. A good example of this is the
PQS-IB hand held sonar that was used on SEALAB 1I. This
transistorized sonar has a pressure-proof housing and could
have been operated with the electronics package sealed at sea
level pressure, but to permit access to the batteries while
the sonar was in SEALAB at depth, the housing was vented as
SEALAB was pressurized. The sonar performed normally with the
components exposed to approximately 90 psig. This same unit
is now at NAVMINDEFLAB where it is working perfectly.

Not all solid state electronics will function normally when
pressurized, however. The TV cameras used for the closed
circuit TV monitors were enclosed in pressure-proof housings.
After being in SEALAB for several days, some of these cameras
would lose their contrast and focus capabilities. The
instrumentation engineers on the surface support vessel were
of the opinion that Helium was leaking past the 0-ring seals
or diffusing through the glass lens cover. The resulting
increased internal pressure apparently caused enough change in
the characteristics of the electronic components to degrade the
picture quality. To solve this problem, a camera was placed
outside in the water with the lens flush against a port looking
in. No further problems were experienced with this camera.

The entertainment TV was an 11-inch transistorized model sealed
inside a pressure-proof container. The picture was visible
through a 2-inch thick plexiglass window with 0-ring seals.
There was no Helium leak into this housing since an internal
pressure gauge, which reflected the differential pressure
between the inside and outside of the housing, remained constant
at about 90 psi.
211

People living in a normal environment rarely give any thought
to their atmosphere or breathing medium. But for the undersea
dweller, the atmosphere is a special one and presents some
unique problems. To avoid the various undesirable effects that
breathing air under high pressure for prolonged periods has on
the human physiology, the undersea habitat must have an arti-
ficial atmosphere. The gases to replenish those present in
this atmosphere must be stored about the habitat or be available
from a surface complex. There are two ways of storing the gases,
either in the gaseous state or as liquids. Storage as a liquid
has the advantage of requiring less storage volume but it
presents more handling problems than does the gaseous state.
The Helium, Oxygen and emergency breathing system mix was
stored in cylinders on either side of SEALAB II.

For reasons of economy, a closed cycle ventilation system is
desirable. It is obviously cheaper to replace the oxygen as
it is used up and remove the carbon dioxide produced than it
is to ventilate the entire volume each time the oxygen concen-
tration gets low or the carbon dioxide content rises to an
undesirable level. By replacing only the oxygen, comprising
a small percentage of the total atmosphere, the initial
quantity of primary inert gas, Helium for- example, is preserved.
Since Helium costs approximately four times as much as oxygen,
a tremendous saving is evident. Removal of the carbon dioxide
can be accomplished in various ways such as cryogenically or
by simple absorption. SEALAB II used the absorption method
and employed lithium hydroxide in canisters as the absorbent.
Charcoal filters were also installed in the ventilation system
to eliminate odors.

The oxygen content must be controlled with precision. To
prevent anoxia, the oxygen concentration has to be maintained
at a level such that the partial pressure is at least .21
atmospheres, corresponding to normal surface conditions. Also,
to eliminate the problem of oxygen poisoning, a partial pressure
of less than .60 atmospheres is necessary. Since SEALAB II was
at a depth of 205 feet, the oxygen concentration had to be
controlled between 3 and 8.5 percent and was in fact maintained
between 3.25 and 5.25 percent.

The makeup oxygen flow was controlled by a solenoid valve. An
oxygen partial pressure sensor was coupled through an amplifier
and control circuit to the solenoid. The control circuit had
variable upper and lower limits. A meter with an appropriate
range marked on the face indicated the oxygen partial pressure.
For safety, a separate sensor, amplifier and meter was provided
as a monitor. A cylinder of calibration gas was available for
periodic checks of the equipment.

One facet of the special atmosphere is the relative humidity.
Humidity is a problem that can be attacked in several ways.
One way is to reduce the moisture input. Because of the
temperature differential that exists between the water and the
interior of the undersea dwelling, condensation is almost
certain to occur. The condensation problem can be reduced by
insulation of the interior surface but not all of the surfaces
can be insulated. Cork has been used but is certainly not the
ideal insulating material. Once the dwelling is pressurized
for a period of time, the cork has a tendency to crack and peel
during depressurization. Also, water crumbles the cork after
a length of time. Some other inputs of moisture which may be
controlled are dripping wet suits, hot showers and open cooking
pots.

212

Another way of attacking the humidity problem is by actually
removing unwanted moisture from the atmosphere. The standard
dehumidifier, commercially available, works well, even under
high ambient pressure. In SEALAB II, the relative humidity was
kept within the range of 60 to 90 percent. A good cork
insulation and four dehumidifiers were used.

Directly related to the relative humidity is the question of
heat. The temperature in a Helium atmosphere must be maintained
near 85OF for comfort because of the increased thermal conduc-
tivity. There are several types of elect;~ic heaters that can
be used. The SEALAB II heating system used convection, radiant
and deck heaters. By maintaining the deck heaters at 1100F,
the radiant and convection heaters were seldom needed. Heating
the diver is much more difficult and methods are still in the
development stage. One method of providing heat to the diver's
suit is electrical heating, similar to an electric blanket.
The electrically heated wet suits evaluated on SEALAB II used
resistance wires imbedded between layers of foam rubber with
controls to regulate the amount of heat supplied, up to 350
watts. The suit is designed to operate from an AC or DC power
supply. The DC power pack is made of silver-zinc cells for
maximum power from minimum size. The cells are designed to
withstand pressure and operate in any position. Three hours
is the designed duration at full power.

On AC operation, a power cord is connected from the suit to a
12 volt AC source capable of supplying 350 watts. The obvious
disadvantage to this method is the limited range possible;
however, if a hookah breathing rig is being used there is no
problem, since the diver is limited to the range of his air
hoses, anyway.

Of equal importance to the diver, and offering some challenging
problems with much room for creative improvement is the breath-
ing apparatus. The present open circuit apparatus using mixed
gas only allows up to 30 minutes gas supply at 200 feet. The
semi-closed circuit mixed gas apparatus offers up to 70 minutes
at the same depth. As the operating depth increases and certainly
at 600 feet, the mixed gas apparatus in its present form will
be so inefficient as to be nearly useless. The swimmer at
these depths needs some new apparatus, perhaps a closed circuit
type with an oxygen sensor and regulator to replace only the
amount of oxygen used from the breathing mixture. Since the
oxygen percentage will be only about 1.5% at 600 feet, a precise
sensor and regulator is necessary. As an alternative, perhaps
some type of cryogenic SCUBA would be suitable. Should the
diver choose to remain close to his habitat, the hookah rig
should be adequate at any depth.

If the undersea atmosphere were air, communications from
habitat to surface or other habitat would be a relatively minor
problem. With Helium as the primary inert gas, however, the
intelligibility of communications is greatly diminished. The
only available equipment designed to eliminate this problem is
the Helium Speech Unscrambler which was used on both SEALAB
experiments. As a backup to ensure clear communications, an
electro-writer was provided. This device is basically a pen
and paper machine servoed to another identical machine.

For personnel in the Helium atmosphere adaptation to the effect
is rapid and no trouble is experienced after a day or two.
Some words are hard to understand but fortunately they are few.

213

Communications between divers or from diver to habitat present
even more problems. The major one is still Helium distortion
of speech since no available underwater communicators, at
least that I know of, have been designed for any breathing
medium but air.

Diver communications are complex for other reasons, also.
Articulation is nearly impossible with standard Navy SCUBA
because of the mouthpiece. The mouth-mask which has been
designed to solve this problem does not readily adapt itself
to the semi-closed circuit breathing apparatus. Because of
the normal back pressure of the Mark VI SCUBA, gas loss around
the edges of the mask is difficult to control.

If a wire-type intercom is used, the intelligibility is still
poor and care must be taken to prevent entanglement. Simple
audio amplifiers driving an electro-acoustic transducer and
transmitting unmodulated voice are limited in range. For
size, range and freedom from encumbrance, a communicator using
a modulated carrier with the entire package mounted on the
diver's hood is desirable. A voice-operated microphone mounted
in a suitable gas-tight mouth-mask would leave the diver's
hands free. A bone conduction unit could function as the ear-
phone, and certainly some means of eliminating the Helium
speech distortion should be an integral part of the circuitry.

Perhaps one of the most underrated and unusual problems is
that of logistics. How are supplies to be transferred from the
surface to the undersea dwelling efficiently without damage?
At present, this is being accomplished by a dumbwaiter system
consisting of pressure-proof containers for dry articles and
wire cages for articles already waterproof. If the undersea
habitat is a permanent type fixed beneath a pier or tower
structure, an elevator with a pressure lock on the surface
could be used to transfer large objects or personnel. Since
the habitat is sure to be expensive, storage space is costly
and must be efficiently used.

An area that could perhaps present some unique problems is the
power and lighting system. The power can either be produced
in the habitat or brought in from shore or surface. The on-
board power supply must be capable of delivering large amounts
of energy, in the forty to fifty kilowatt range, or more. If
the power is brought in by cable, the engineering involved is
straightforward. Where a long run of cable is involved, as on
SEALAB II, to minimize losses in the cable a high voltage is
necessary which can be transformed down to the useful voltage
levels at the habitat. Lighting falls into two categories,
interior and exterior. The problems involved are easy to
solve as far as the interior lighting is concerned. As an
example, in spite of the high ambient pressure, the interior
light bulbs do not have to be a special design. Ordinary rough
service bulbs up to 75 watts will withstand at least 200 psi.
These bulbs have a longer life in the Helium atmosphere because
they operate at a cooler temperature. The exterior lighting
is not so simple, however. Because of the high power levels
that these bulbs operate, 250 watts up to about 1000 watts,
their expected life is short. Changing bulbs is quite a problem
on some of these lights since a waterproof splice must be made.
This is time consuming, for the entire fixture must be brought
inside to make the splice. The need exists for a truly
versatile underwater light that is compact, inexpensive, portable
with a bulb life of at least 1000 hours and the capability of
wet bulb changing.

214

In conclusion, the problem areas mentioned certainly aren't the
only ones involved in engineering for undersea living. However,
they represent the ones I am most familiar with, as observed
on the SEALAB II experiment. Probably the two areas most
important are those of atmosphere control and communications.
The need exists for a completely automatic atmosphere control
with great reliability. And at the increasing depths planned
for future man in the sea ventures, where surface divers will
be useless, communications will play an even more vital role.

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C a, A ., ~ ~ ~ 21