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Frontispiece
BOMBS AT BIKINI
The Official Report of Operation Crossroads
Prepared under the Direction of the
Commander of Joint Task Force One
hy
W. A. Shurcliff
Historian of Joint Task Force One
1947
Wm. H. Wise & Co., Inc.
New York
Woods HoIg Ocsanographic institution
ARCHIVE COLLECTIOM
Copyright, 1947
Wm. H. Wise & Co., Inc.
WISE books are trademarked
Look for the WISE old bird !
Printed in the United States of America
Pre fa
ce
Tests A and B of Operation Crossroads, perhaps
the most elaborate scientific tests ever conducted, are
described in this official report with no attempt to
prove or disprove anything. Its sole purpose is to
present facts on the origin, planning, and execution
of the joint enterprise.
The word joint needs emphasis. The Tests were
neither Navy tests nor Army tests; this Report is
neither a Navy report nor an Army report, and it has
not been submitted to Army or Navy for approval.
The Tests and the Report are the work of Joint Task
Force One, an agency created by the Joint (Army and
Navy) Chiefs of Staff and responsible only to them.
The Report does not attempt to duplicate the capable
reporting of the many experienced reporters who wit-
nessed the Tests. Through the press the general charac-
ter of the Operation is known to hundreds of millions
of persons here and abroad. The world knows that the
first explosion was an atomic bomb detonation in the
air on July 1, 1946, sinking 5 ships, and that the second
explosion was an atomic bomb detonation underwater
on July 25, 1946, sinking 9 ships.
But there is a wealth of information, much of it
technical, which has not reached the public. Time was
required to ferret out the significant facts; patience
was required to piece them together ; ingenuity was re-
quired to present the material without jeopardizing se-
nt
curity. For reasons of security a few results have been
omitted. These few are mainly technical correlations,
as between exact distance and damage, or exact dis-
tance and pressure. Good public relations and the duty
of the Services to the public demand that the fullest
account possible be made available.
The facts included should help the public form
sound conclusions and participate in the planning of
national and international policies. Bulk release of
energy from the nucleus is new on the earth ; its por-
tent is unlimited. But if it — and we — are to survive,
it must be controlled. And adequate control cannot be
achieved unless the people know the facts.
The present official account was written by the same
group which prepared the over-all top-secret report
recently transmitted by Vice Admiral W. H. P. Blandy,
Commander of Joint Task Force One, to the Joint
Chiefs of Staff.
To the many persons who helped in the prepara-
tion of this Report, I extend my thanks. I am partic-
ularly indebted to Mr. David Z. Beckler, Deputy His-
torian, and Mrs. Virginia Shapley, Editor.
W. A. Shurcliff,
Historian, Joint Task Force One
February 7, 1947
IV
TABLE OF CONTENTS
Page
List of Plates vii
Foreword by Vice Admiral W. H. P. Blandy, U.S.N ix
Chapter 1. Why Operation Crossroads! 1
2. Early Problems 16
3. Plans and Planners 27
4. Technical Offensive 46
5. Scientific Offensive 57
6. Bikini Overture 89
7. Test A. : Explosion in Air 104
8. Test B. : Underwater Explosion 145
Appendix 1. Organization Charts 173
2. List of Principal Participating Officials 176
3. Joint Crossroads Committee 181
4. The Evaluation Board 182
5. The President 's Evaluation Commission 183
6. United Nations Observers 184
7. Congressional Observers 185
8. Support Vessels 186
9. Target Vessels, Test A 190
10. Preliminary Statement by the Evaluation
Board on Test A 192
11. Preliminary Statement by the Evaluation
Board on Test B 195
12. Preliminary Statement by the Evaluation
Commission on Test A 200
13. Preliminary Statement by the Evaluation
Commission on Test B 202
14. Test C (Cancelled) 205
15. Chronology of Atomic Bomb Detonations 207
Index 209
PICTURE CREDITS
All photographs are Joint Task Force One photographs ex-
cept as follows :
Fritz Goro, Life Magazine : Plate 4 lower, plate 5 upper, plate 8,
plate 15 upper, plate 15 lower, plate 16, plate 24 lower, plate 32
upper.
Acme: Plate 17.
VI
LIST OF PLATES
Frontispiece View of Test B
Plate 1. Air Moek-up
Press Conference
Plate 2 Model of Bikini Lajsoon
Fleet Assembled in Bikini Lagoon
Plate 3 Photographic Towers
Native Outrigger Canoes
Plate 4 Carrier Plane Take-off
Materiel Prepared for Exposure
Plate 5 Naturalist at Work
Sonobuoys Being Assembled
Plate 6 Airplane Wing Spotted on Deck
Plate 7 Telemetering Instruments
Robot Boat
Plate 8 Animals Prepared for Exposure
Plate 9 Crushed Tin Can Gages
Underwater Camera Equipment
Plate 10 Testing Plane Engine for Radioactivity
Plate 11 Camera Equipment in Airplane
Plate 12 Foil Pressure Gage
Pendulum-type Inclinometer
Plate 13 Taking Water Sample
Plate 14 Pyramidal Orientometer
Cockpit of Drone Plane
Plate 15 Turtle Pressure Gage
Plate 16 Automatic Radioactivity Recorder
Plate 17 Submerging the APOGON
Plate 18 Test A— First Seconds
Plate 19 Test A Panorama
Plate 20 Test A— Fully Developed Mushroom
VII
Plate 21 Damage to the INDEPENDENCE
Plate 22 Damage to the SKATE
Plate 23 Damage to Airplane
Damage to NEVADA
Plate 24 Removing Radioactive Filter
Testing Goat for Radioactivity
Plate 25 Test B— Cinderella Ship
Test B— Early Phase
Plate 26 Test B— Bird's Eye View
Test B— Early Phase
Plate 27 Test B— Panorama
Plate 28 Test B— The Enveloping Cloud
Plate 29 Waves Breaking on Beach
Effect of Waves on Bikini Island
Plate 30 The SARATOGA Sinking
Decontaminating the NEW YORK
Plate 31 A Radioactive Fish
Underwater Damage
Plate 32 Chart of Bomb Burst
Bomb Burst over New York
VIII
Foreword
Operation Crossroads was directed by the United
States for purposes of national defense ; but its lesson
has world-wide significance. The atomic bomb is defi-
nitely not ^'just another weapon"; its destructive
power dwarfs all previous weapons. Observers at
Bikini saw the bomb sink great steel warships and,
with its penetrating nuclear radiations, reach into
ships' interiors to kill test animals. The explosions in
air and underwater were very different spectacles, but
their end results mean the same : death and destruction
on an enormous scale.
Only after the military implications of atomic en-
ergy have been grasped by the people of the world will
the way be clear for working out effective international
control. Throughout its ten-month tenure. Joint Task
Force One attempted to give the world an intimate
knowledge of the purposes, execution, and consequences
of the Tests. The present volume not only summarizes
much of the information already given out, but pre-
sents much material not previously disclosed. This
volume, together with the recently published Pictorial
Record, forms the final, and perhaps the most informa-
tive release on the Operation.
Vice Admiral W. H. P. Blandy, U.S.N. ,
Commander, Joint Task Force Ofie
IX
1
WHY OPERATION CROSSROADS?
The gray-green dawn of July 25, 1946, en-
veloped Bikini Atoll. The target fleet lay still, with
'^Yoke" flags flying to signify all personnel had been
evacuated. Like moving shadows the support vessels
slowly filed out of the Lagoon. Last to leave was the
flagship MT. McKINLEY. The Lagoon was deserted.
Just over the eastern horizon puffs of cumulus
clouds appeared, heralding perfect weather for the
flnal atomic test at Bikini. As the time for the ex-
plosion approached, men paced the decks, adjusted
their binoculars, studied the deserted target fleet to
fix in their minds the steel pattern soon to be shattered.
Clearly visible was the doomed SARATOGA, floating
majestically as she had throughout the war ; among the
forest of masts could be seen the tall thin mast of
LSM-60, the ship from which the bomb was suspended.
Closer — fatally close — lay the mighty ARKANSAS.
Men stared fascinated as the relentless count began.
In a few seconds the awful explosion would come. Not
few : Two ! One !
I
BOMBS AT BIKINI
The results are history. Ships were crushed, and
sank; two million tons of water and spray buried
scores of ships.
Even more deeply buried — lost in the drama of the
moment — were the underlying problems, the guiding
motive. Why plan an Operation Crossroads'? Why
send 42,000 men, 242 ships, 156 airplanes, 4 television
transmitters, 750 cameras, 5000 pressure gages, 25,000
radiation recorders, 204 goats, 200 pigs, 5000 rats and
why transport Numbers 4 and 5 of the atomic bomb
family thousands of miles across land and sea for two
brief moments of majestic destruction?
The general answer is, of course, well known: It
was imperative to find how to improve our Navy.
As long as we have a Navy — and we will have one
as long as the possibility of war remains — we want to
have one of highest possible quality. We want ships
which are tough, even when threatened by atomic
bombs; we want to keep the ships afloat, propellers
turning, guns firing; we want to protect the crews so
that, if fighting is necessary, they can fight well today
and return home unharmed tomorrow.
Underlying this general requirement is a long list
of specific questions. If" the list seems long, it is be-
cause of the unequalled importance of the atomic bomb.
This new bomb is no mere creator of dazzling light and
peach-colored clouds; it shakes the very foundations
of military strategy. The questions are many ; they are
highly technical and eminently practical. They are not
WHY OPERATION CROSSROADS?
easily separated and cataloged. Years may be required
to answer them, but answers must be found.
Naval architects, for example, were asking: When
naval ships are caught by atomic bombs bursting in air
what are the ships' "weakest links ?" What parts fail ?
Where should added strength be provided? Do we
need heavier side plating, or merely stronger joints'?
Which stands up best to the terrific stresses imposed
by atomic bombs: riveted seams or welded seams?
Does the ship's framework stand up? How about the
decks, superstructures, and masts ? What happens in-
side the ship, as to boilers and turbines? How about
radio and radar? Are the guns damaged? Do fuel
supplies escape and burst into flame? Is ammunition
setoff?
Important questions were asked about the ship's
crew. Ship designers wondered how the crew would
make out, whether men working below decks would
escape unharmed, whether the blast wave or thermal
radiation ("flash") or radioactivity would be most in-
jurious. Most of all, they needed to know how to pro-
tect the men. Medical men wanted information as to
how injuries can be diagnosed fastest and what medical
treatments are best.
Naval tacticians were asking even more basic ques-
tions. How far must a ship be from an atomic bomb
to survive? To prevent more than one ship in a fleet
from being sunk by one bomb, how far apart must the
ships be spaced? And if a bomb is about to explode.
BOMBS AT BIKINI
what avoiding action should the ship take? Should
topside men remain at stations, or should most of them
rush below for protection ? How about harbors ? Are
ships particularly vulnerable there *? How far apart
should they be anchored to prevent one bomb from
causing a large-scale ''Pearl Harbor"?
Scientists and engineers were on the spot, too. They
couldn't answer their own questions, and they were
equalty unable to answer the majority of the questions
asked by ship designers. Just what does an atomic
detonation consist of? What fraction of the tremen-
dous energy release goes into the pressure wave ? What
fractions go into thermal radiation, gamma radiation
and neutron radiation ? Major question marks on pres-
sure were : How great is the pressure ? How fast does
the pressure wave spread ? At any one spot, how long
does the high pressure last and what is the impulse
exerted? How strong is the suction which instantty
follows the pressure? Questions as to the inevitable
and deadly gamma radiation were : At what range is
it fatal? Are men behind steel walls protected? How
thick must the walls be? When does the radiation
sickness begin? Can the men continue to man their
battle stations even after they have received fatal doses
of the invisible radiation?
The effects of an underwater explosion were even
more difficult to predict. Nobody knew how many mil-
lions of tons of water would be thrown into the air,
how many miles this water would be thrown, what the
WHY OPERATION CROSSROADS?
shape of the water cloud would be, how big the water
''crater" would be, or at what ranges ships might be
broken or capsized by the first giant solitary wave ex-
pected to tower 100 ft. high from trough to crest.
Complete unknowns were such matters as: What
percentage of the lethal fission products from the
underwater explosion would remain trapped in the
water? How badly would these insidious products
contaminate the target ships ? Would they seep inside
the ships ? How long would their deadly effect linger ?
What could be done to wash them awa}^? Would an
entire harbor be seriously affected?
If we could get answers to all these questions, then
we could dare tackle the really big questions : Which is
more serious, the explosion in air or the explosion
underwater? What loss of military efficiency or gen-
eral crippling of an actual fieet will result from an
atomic bomb explosion? What new naval tactics are
required? How should our shipbuilding program be
modified? Are heavier ships now less valuable and
lighter ships more valuable, or vice versa? Should we
cut down our largest naval bases and make more of
smaller size ? In short, what must be done for our Navy
to be of maximum use in the next ten or twenty years
of the Nucleonics Age ?
Some persons urged calling off the tests. They
pointed to the high cost, expected to be many millions
of dollars. They condemned sacrificing seaworthy ships.
They feared tidal waves and chain-reactions in sea
BOMBS AT BIKINI
water. They thought cracks might be made in the
earth's crust, allowing sea water to rush into the white-
hot interior and form catastrophic quantities of steam.
They feared antagonizing other countries. Some per-
sons suspected that the target ships would be spaced
too far apart, so that the tests would be ineffectual.
A few technical men said that the tests were un-
necessary. They said that the atomic bomb had already
been tested successfully at Alamogordo, New^ Mexico,
at Hiroshima, and at Nagasaki. They had been told
of the elaborate preparations made for the Alamogordo
Test, of observers and scientific instruments that moni-
tored the explosions over Japan. They knew of the
careful inspections later made of the ruined Japanese
cities and of the extensive studies of injuries suffered
by the Japanese people. Some technical men said, in ef-
fect : " If we assemble the data already available, make
additional small-scale tests required, call in our best
theoretical physicists, then merely by computation we
can arrive at the results we need; we don't need any
further atomic bomb tests."
Technical men closest to the practical problems
knew that no such makeshift would work. They knew
that the Alamogordo test, although entirely successful
as a demonstration, did not produce all the technical
and scientific data needed. To be sure, the story ob-
tained as to gamma radiation and neutron radiation
was a good one. On the other hand the optical radia-
tion data and pressure data were not as extensive as
WHY OPERATION CROSSROADS?
had been hoped; real gaps remained. And then, of
course, no ships were involved.
At Hiroshima and Nagasaki a few photographs and
pressure measurements were made of the explosions,
but almost nothing of value to physicists was learned.
Physicists wanted actual values of the following:
pressure, impulse, accelerations, shock-wave velocity,
ranges and intensities of gamma radiation, ranges and
intensities of neutron radiation, decrease of the
gamma radiation during the first few hours. And med-
ical men, arriving on the scene late, found it difficult
to tell w^hat the early symptoms of the injured persons
had been, and whether the injuries resulted primarily
from flash burn, gamma radiation, or from secondary
factors such as fires, and floods, lack of food, over-exer-
tion, and lack of medical attention.
Nor could model tests give the pl\ysicists their an-
swers. At least four serious obstacles stood in the
way. First, you can't make a model atomic bomb; you
have to use TNT. To imitate even a small ''model"
atomic bomb, you use an enormous pile of TNT, and
the pile is so enormous that the whole test is spoiled,
at least as far as close-in events are concerned.
Second, model making is not the simple matter it
may appear to hobby-shop artists; a model ship, for
example, has to be not only the same shape as the
actual ship, but the model's sides and decks must
be almost perfectly to scale also. This means that the
sides of a model transport ship, for example, must be
BOMBS AT BIKINI
paper-thin, and at the same time must have the same
flexibility, elasticity, and plastic flow as the steel plates
on the transport ship. Model beams must be of paper-
thin material also. Even the rivets must be closely imi-
tated. The upshot is, of course, that no such thing as a
really comparable model exists; the model will show
damage from the model explosive charge, but nobody
will know what the damage means in terms of damage
to real ships. Determining the vulnerability of compli-
cated equipment such as ships' boilers by means of
models would, of course, be almost impossible.
Third, no one — not even the scientists in the
Navy's Bureau of Ships or Bureau of Ordnance —
knew how to fully interpret model studies of water
waves, when the test to be imitated is the shallow-
underwater explosion of 20,000 tons of TNT, or its
modern equivalent, one atomic bomb. The crux of the
difficulty is: the weaves don't ''scale" as other phe-
nomena do. We can use a model fleet in a model lagoon,
and we will be rewarded by obtaining a very fine model
pressure wave. But the water waves will come out all
wrong ; they are much too high. They must be corrected
by some rather uncertain calculation.
Fourth, we cannot imitate in a model test the sud-
den release of fission products and the sudden emission
of neutrons.
Thus it appears to be a true paradox that to show
what the smallest of bodies — the atom — can do in
chain-reacting concert, we must use a testing ground
8
WHY OPERATION CROSSROADS?
many square miles in extent. In any smaller theatre,
the atom's power cannot be displayed.
But this can be said : Once the full scale tests have
been held, then the model makers and model testers
come into their own; only then can they prove which
types of models correspond to the real thing and which
do not; they can tell with assurance how their model
water waves are to be corrected to represent waves pro-
duced by the atomic bomb.
Am^one could have thought up the idea of testing
the atomic bomb against naval vessels. It is indeed
routine to test each new weapon in all major applica-
tions. The novelty of the proposed test of the atomic
bomb against naval vessels would lie in the unprece-
dented scale and world-wide importance of the tests.
These were the unique elements which challenged the
imagination of scientist, officer, and layman alike.
The Los Alamos Laboratory, the group which has
made all our atomic bombs, was probably the first
to give serious consideration to "testing" the bomb
against naval vessels. Even in 1944 Los Alamos scien-
tists were looking into the possibilities of eventually
atomic-bombing Japanese fleet concentrations. But
Japan's navy was already doomed, and her ships were
destined to avoid atomic destruction until July 1, 1946,
at Bikini.
Immediately following President Truman's epoch-
introducing statement of August 6, 1945, announcing
the atomic bombing of Hiroshima, naval men and lay-
BOMBS AT BIKINI
men began asking: ''What would such a bomb do to
a battleship ? Or an entire fleet ? ' '
Senator Brien McMahon (D., Conn.), soon to be-
come chairman of the Senate's Special Committee on
Atomic Energy, was quick to ask that the new bomb
be tested against naval vessels. In a speech of August
25, 1945, he said, ' ' In order to test the destructive pow-
ers of the atomic bomb against naval vessels, I would
like to see these Japanese naval ships taken to sea
and an atomic bomb dropped on them. The resulting
explosion should prove to us just how effective the
atomic bomb is when used against the giant naval ships.
I can think of no better use for these Jap ships. ' '
Lieutenant General B. M. Giles, in Tokyo head-
quarters, led off for the Army. On September 14,
1945, he proposed that at least two atomic bombs be
used in the destruction of the Japanese Fleet. The
proposal was radioed that same day by Major General
C. E. LeMay to Washington, D. C, w^here it was
weighed by Lieutenant General C. A. Spaatz and also
by General H. H. Arnold, Commanding General of the
Army Air Forces.
Only four days later. General Arnold put the mat-
ter up to the Joint Chiefs of Staff, the country's top
military group.* He asked that the routine destruction
of surviving Japanese vessels — recommended on Aug-
* The Joint Chiefs of Staff then consisted of: General H. H.
Arnold, General G. C. Marshall, Admiral E. J. King, and Admiral
W. D. Leahy.
WHY OPERATION CROSSROADS?
ust 28, 1945, by Admiral E. J. King, Commander-in-
Chief of the U. S. Fleet and Chief of Naval Operations
— be countermanded. He urged that a number of the
Japanese vessels be made available to the Army Air
Forces for use in tests involving atomic bombs and
other weapons.
The Navy's response, made by Admiral King on
October 16, 1945, called for broadening the proposal
by having the Joint Chiefs of Staff control the tests
and by having all pertinent groups of Army and Navy
participate. Admiral King recommended that one
bomb be detonated in the air and another in the water,
and he made the very significant suggestion that a few
of our own modern naval vessels be included in the
target array.
To get detailed planning underway. General Ar-
nold suggested on October 31, 1945, that the Joint
Statf Planners, a permanent working committee of the
Joint Chiefs of Staff, decide just what tests should be
made and what groups should make them. The sug-
gestion was accepted, and the Joint Staff Planners
were asked on November 10, 1945, to proceed.
Their first act (November 13, 1945) was to appoint
an '^ad hoc subcommittee" to make a complete and de-
tailed proposal. This Subcommittee, usually called the
"LeMay Subcommittee," had the following member-
ship — after three early changes :
Major General C. E. LeMay (Steering Member)
Brigadier General W. A. Borden
II
BOMBS AT BIKINI
Colonel C. H. Bonesteel
Captain G. W. Anderson,' Jr. (Navy)
Captain V. L. Pottle (Navy)
Commodore (now Rear Admiral) W. S. Parsons
The Snbcommittee met frequently during the next
six weeks, and thrashed out in full all the tests' prin-
cipal features. The most controversial issues were:
Who should command the prospective Joint Task
Force? Should the target vessels carry full loads of
fuel and ammunition?
Some of the Subcommittee members suggested
that the Commander be chosen from Army officers
having close familiarity with the Manhattan Project.
Other members pointed out that the majority of the
operation would involve principally the Navy: naval
target vessels, naval supporting vessels, naval construc-
tion of shore facilities, inspecting and appraising dam-
age to naval vessels. The final decision was made by
the Joint Chiefs of Staff who designated Vice Admiral
W. H. P. Blandy. Admiral Blandy, an ordnance
specialist though a naval line officer, had been Chief
of the Bureau of Ordnance from 1941 to 1943. He had
commanded large Army and Navy forces of multiple
types in Pacific amphibious operations in 1944 and
1945. Since November, 1945, he had been Deputy Chief
of Naval Operations, Special Weapons, particularly
charged with developing atomic energy devices and
guided missiles.
12
WHY OPERATION CROSSROADS?
Debate was long and vigorous on the question of
fuel and ammunition loads. Air Forces' representa-
tives initially proposed having nearly every target ship
carry full loads of fuel and ammunition, to show the
maximum damage the atomic bomb could do, includ-
ing secondary effects of fires and ammunition ex-
plosions. Others opposed this proposal, pointing out
that with the ships crowded abnormally close together,
release and ignition of oil or gasoline from a single
ship might set fire to all adjacent ships; the result-
ing damage might give an entirely false picture of
what would happen to ships in their normal spacing.
Such fires might destroy much of the really significant
damage and large numbers of important scientific in-
struments too. (The satisfactory compromise reached
is discussed in Chapter 7.)
The work of the LeMay Subcommittee culmi-
nated in a detailed plan submitted to the Joint Chiefs
of Staff and accepted by them (with a few minor
changes) on December 28, 1945.
Vice Admiral Blandy w^as soon ready with a de-
tailed administrative and technical plan of action. The
Joint Chiefs of Staff gave preliminary approval to the
plan almost at once, and then referred it to the White
House. The President studied it, and added ' ^ Approved
Jan. 10, 1946. (signed) Harry S. Truman."
The next day, January 11, the Joint Chiefs of Staff
designated Admiral Blandy Commander of Joint Task
Force One, and directed him as follows:
BOMBS AT BIKINI
1. By direction of the President, you are
designated commander of a task force under
the Joint Chiefs of Staif for the purpose of
conducting tests for the determination of the
effects of atomic explosives against naval ves-
sels in order to appraise the strategic implica-
tions of atomic bombs including the results
on naval design and tactics. You will organ-
ize a joint staff with adequate representation
of land, sea, and air forces. You will include
civilian scientists in your organization.
2. The general requirements of the test will be
to determine the effects of atomic explosives
against ships selected to give good representa-
tion of construction of modern naval and mer-
chant vessels suitably disposed to give a grada-
tion of damage from maximum to minimum.
It is desired to include in the tests both air
detonation and underwater detonation if the
latter is considered feasible. Tests should be
so arranged as to take advantage of oppor-
tunities to obtain the effects of atomic explo-
sives against ground and air targets and to
acquire scientific data of general value if this
is practicable.
3. You are authorized to deal directly with
agencies of the War and Navy Department
in all matters relating to the preparation for
the conduct of these tests; including direct
access to the Manhattan District. Usual serv-
vice lines will be available for administrative
and logistic support of forces assigned. . . .
14
WHY OPERATION CROSSROADS?
4. The Joint Chiefs of Staff will appoint as
a separate agency, directlj^ responsible to
them, an evaluation board (committee) for
the express purpose of evaluating the results
of the tests. This board will be available to you
for advice during the preparation of the tests.
Appropriate sections of your organization will
collaborate with this board as necessary, and
you will provide it with all necessary facilities
it may require to fulfill its functions.
5. You will prepare plans for the test in-
cluding selection of a suitable site which will
permit accomplishment of the test with ac-
ceptable risk and minimum hazard. Your
plans for the operation and final report will be
submitted to the Joint Chiefs of Staff' for
their approval.
For the Joint Chiefs of Staff:
/a/ A. J. McFarland
Brigadier General, U. S. A.
Secretary
Authority was now complete for holding the most
observed, most photographed, most talked-of scien-
tific test ever conducted.
15
2
EARLY PROBLEMS
Even before Joint Task Force One had been
created, major problems were being tackled by the
Army and Navy groups most interested.
Choice of site was one of the biggest problems. Any
number of relatively near-at-hand sites in the Atlantic,
the Caribbean, and the nearer parts of the Pacific satis-
fied many of the requirements, but none of these
satisfied all of the requirements. What was needed was :
A protected anchorage at least six miles in
diameter. (It must contain not only the enor-
mous target fleet but also the even larger sup-
porting fleet.)
A site which was uninhabited, or nearly so.
(All inhabitants would have to be evacuated.)
A location at least 300 miles distant from the
nearest city. (Radioactive materials released
in the air might menace persons scores of
miles to leeward.)
A location within 1000 miles of a B-29 base.
(The airburst bomb was to be delivered by a
B-29 bombing plane.)
16
EARLY PROBLEMS
Freedom from severe cold and violent storms.
Predictable winds directionally uniform at
all altitudes from sea-level to 60,000 feet.
( There must be no chance that the radioactive
materials carried high into the air could be
wafted back over the task force personnel by
a fluke counter-wind.)
Predictable water currents of great lateral
and vertical dispersion; fast currents avoid-
ing important fishing areas, steamer lanes,
inhabited shores. (Radioactive materials re-
leased in water must be dispersed reasonably
rapidly, and without harm to persons or to the
fishing industry. )
Control by the United States.
Bikini won out. Its 162 inhabitants could be trans-
ferred readily. The few^ coral heads obstructing the
anchorage could be eliminated by dynamiting.
Bikini's location is shown in Figures 1 and 2. It
is one of the 34 atolls making up the Marshall Islands
group. Discovered in 1526 by a Spanish sea captain,
the islands were rediscovered by the English Captains
Grilbert and Marshall in 1788. Germany annexed them
in 1885, and they were mandated to the Japanese after
World War I. In World War II they were occupied
by the Japanese.
Final choice of Bikini suffered one delay. Spokes-
men for the fishing industry feared the explosions
17
BOMBS AT BIKINI
D
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Q.
O
I O)
18
EARLY PROBLEMS
I I <« I
|. ^ to
CO
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CO
D)
c
o
a
CM
19
BOMBS AT BIKINI
might kill millions of fish, even at great range. They
feared also that whales or tmia fish might be abundant
in the area, and might be killed, crippling various fish-
ing activities in the Pacific. To evaluate any such dan-
gers, advice was sought from the Fish and Wildlife
Service of the U. S. Department of the Interior. The
answer was definite : Bikini is so far from the migra-
tory routes of whales at the time of year in question
that no appreciable danger to whales exists; and the
area is not critical for tuna fish or other fish of com-
mercial importance. In particular, it is not a spawn-
ing ground for west coast tuna.
A real dilemma complicated the choice of dates for
the atomic bomb tests. The reasons for holding the
tests soon seemed very urgent ; yet the need for delay
seemed equally real. On the urgent side, these facts
were clear: (1) The scientific resources of the Navy
and Army (and the Army's Los Alamos Laboratory in
particular) were declining from their wartime peaks;
every month that passed left fewer scientists avail-
able to accomplish the highly technical mission lying
ahead. (2) The supply of nontechnical service per-
sonnel, too, was diminishing; before long it would be
difficult or impossible to obtain officers, technicians, or
crews for the enormous fleet. (3) Civilian scientists
to be ''drafted" from universities were insistent on
returning to their universities by early September ; if
they were to be used, the tests would have to be held
in the spring. (4) Army and Navy budgets were ex-
20
EARLY PROBLEMS
pected to become continually smaller, and might easily
be incapable of standing the expense. (5) Target ves-
sels, particularly the obsolete vessels, could not be held
available indefinitely. (6) Military and naval planners
had to proceed with plans for future strategy and
construction; the fundamental technical data were
needed almost immediate^.
But technical and nontechnical men alike saw the
othe]' side. They saw that a suitable task force could
not be assembled overnight, that much paperwork
must be done before men could step forward to plan
and execute the operation capably. They realized that
readying the ships of the great target fleet would be
an enormous job; months would be required even if
many different shipyards cooperated in the work. They
knew that a multitude of scientific instruments of en-
tirely new types must be designed, built, tested, in-
stalled. They knew that careful rehearsals of all tech-
nical and operational phases would be required before
anything like full value could be got from the Tests.
After consulting all his deputies and advisers, Ad-
miral Blandy named May 15, 1946, as date for the first
Test, the explosion in air; the second Test, the ex-
plosion beneath the surface of the lagoon, w^as to occur
approximately six weeks later. The race against time
was started.
No one knows whether the race would have been
won or lost. For on March 22 a delay was ordered ; the
President directed that the Tests be postponed approxi-
21
BOMBS AT BIKINI
mately six weeks in order that Congressional observers
could complete their legislative work and yet see the
Tests. July 1, then, became the new target date.*
What was the best altitude for Test A, the explosion
in air? This question shuttled back and forth across
conference tables for months. Scientists at Los Alamos
and in Washington swapped arguments as to what alti-
tude would produce sinkings at the greatest radius
or what altitude would produce moderate damage at
greatest radius. Clearly a low altitude w^ould better
insure sinking the nearest ships; but a greater alti-
tude would permit the blast wave to reach out farther
and do at least moderate damage at greater radius.
While these scientists were matching formulas and
graphs in friendly tussle to arrive at the best choice
of altitude, they were also re-studying the results of
the Alamogordo, Hiroshima, and Nagasaki explosions.
* One of the most unexpected results of the postponement was
the opportunity it gave to the Task Force's Wave Motion Section
to take the measure of the great tsunami ("tidal wave") which
struck the Hawaiian Islands on April 1, 1946. When the postpone-
ment was announced, the wave motion experts were en route to
Bikini; accordingly, they were directed to go to Pearl Harbor to
await further instructions. They had no warning there of the ap-
proach of the tsunami, and did not get their 65 tons of wave meas-
uring equipment into action. But they went to work quickly in-
specting the inundated areas and piecing together all availahle
evidence. A full report on the tsunami was issued later, and some
of the information learned was put to use in perfecting plans for
measuring homh- produced waves at Bikini. Mr. N. J. Hotter, head
of the Section, was asked to assure the population hy radio that
710 such, danger threatened in the forthcoming atoynic homh ex-
plosion.
22
A mock-up of the air op-
eration planned for Test
A is studied by Vice Ad-
miral W. H. P. Blandy,
Commander of JTF-1 , and
Maj. General W. E. Kep-
ner, Deputy Task Force
Commander for Aviation
(both standing) and
Brig. General T. W.
Power (kneeling). The
Air Plan specified the po-
sitions and courses of all
Army and Navy planes,
manned and unmanned.
A Washington press conference question is answered by Rear Admiral
W. S. Parsons, Deputy Task Force Commander for Technical Direction.
Flanking Admiral Parsons are Rear Admiral T. A. Solberg, Director of
Ship Material, and Dr. R. A. Sawyer, Technical Director. On the table
is a model of Bikini Atoll.
Pla+e I
UPPER. Adm. Blandy (left) confers with the Joint Chiefs of Staff's
Evaluation Board. Left to right are Lt. Gen. L. H. Brereton, Dr. K. T.
Compton (Chairman), R. Adm. R. A. Ofstie, Vice Adm. J. H. Hoover,
Maj. Gen. T. F. Farrell, and the late Gen. J. W. Stillv^ell. LOWER.
Activity in Bikini Lagoon.
Plate 2
Steel towers were erected on several Islands fringing the lagoon to
house automatic cameras and other instruments. Cameras are installed
inside lead-walled vaults whose doors are arranged to close auto-
matically after the filming has been accomplished, thus protecting the
film from gamma radiation.
Native outrigger sail-
boats are of double-
ender type; they can beat
to windward without
coming about. Thanks to
their speed and stability,
they are used even for
hundred-mile trips across
open ocean, from atoll to
atoll. These boats, to-
gether with their native
owners, were evacuated
aboard LST 1 108 to Ron-
gerik, another of the
Marshall islands.
Plate 3
The two supporting car-
riers, SAIDOR and SHAN-
GRI-LA, were used for
launching Navy drone
and drone mother planes,
photographic planes, and
helicopters; also for
processing photographs.
Navy drones were landed
on Roi island. Only one
accident occurred in the
course of their operation.
The carriers bore small
forests of radio and radar
antennas.
On the only clear plat-
forms available — ships'
decks — nearly every kind
of Army material was
placed for exposure to
the A-Day explosion. This
exposure program, which
was directed by Colonel
J. D. Frederick of the
Army Ground Group, in-
cluded everything from
machine guns, flame
throwers, and radio sets
to clothing, canned
goods, medical supplies,
and skiis. Crated equip-
ment was secured to the
deck by means of steel
straps and bolts. The in-
formation gained filled
seven volumes.
Plate 4
Surrounded by collecting
bags, bottles, knapsacks,
and other paraphernalia
cherished by naturalists,
Dr. J. P. E. Morrison, As-
sistant Curator of Mol-
lusks at the U.S. National
Museum, examines a sea-
faring bird caught at Bi-
kini. Careful censuses
were made, both before
and after the explosions,
of principal types of ani-
mal and plant life.
Sonobuoys to be used in the two Tests are inspected before being
moored in assigned positions in the target area. The column mounted
above the buoyancy barrel carries a horizontal, eight-sided loop serv-
ing as artificial electrical ground. Above this may be seen the small
vertical antenna.
Plate 5
An experimental wing panel is mounted by the Army Ground Group
on the deck of a target ship, to find the vulnerability of such panels
to atomic bomb explosions. Visible along the deck are a tail fin, a
stabilizer, and a range-finder. All items are clearly labeled for post-
explosion identification.
Plate 6
This Navy-NDRC radio te-
lemeter receiving equip-
ment permits scientists
miles away to follow the
performance of un-
manned planes flying
through the explosion
area. Eighteen amplifier
channels decode and
magnify the information
radioed automatically
from the drone planes.
Permanent records are
provided by the oscillo-
graph, shown at the rear.
Radio-controlled drone boats were used to traverse the target area
after each test, take samples of lagoon water, and send back informa-
tion as to extent of radioactivity encountered. Smoke signal equipment
may be seen overhanging the stern. The boats were guided by trans-
mitters aboard the BEGOR.
Plate 7
Goats, pigs, guinea pigs, and rats were exposed on many ships in
Test A to show what effects would be produced by the shock wave,
visible radiation, thermal radiation, and nuclear radiations. The ani-
mals were given sufficient food and water to last ten days. Only pigs
and rats were used in Test B.
Plate 8
EARLY PROBLEMS
The outcome: occasional major changes of mind, and
new line-ups of those favoring greater or lesser alti-
tude.
Meanwhile the operational men were talking feasi-
hility. If it were much more convenient and accurate
to set off the bomb atop a cheap tower, then that would
be an argument for choosing an altitude you could
reach with such a tower. Some thought was given to
use of a tower, possibly on a headland if greater alti-
tude was desired. Little thought was given to placing
the bomb atop the mast of a battleship since this would
probably mean sure and almost meaningless loss of the
battleship, and in any case this would definitely limit
the altitude to about 100 feet. The feasibility of sus-
pending the bomb from a captive balloon was explored
and rejected, since officers familiar with the erratic
behavior of such balloons argued strongly against any
such plan.
Other forces also were at work to influence the
choice of altitude. Some persons pointed out that a
rather low altitude would make Test A rather similar
to Test B in which the bomb was to be detonated at or
just below the surface. Air Forces' spokesmen pointed
out that dropping the bomb from an airplane would
not only provide invaluable experience in precision
atomic bombing but would also remove all restrictions
on altitude of the explosion, permitting the bomb to
be dropped from an optimum altitude.
23
BOMBS AT BIKINI
After all groups had given their views in full, the
decision was made. It w^as based principally on the cri-
terion of producing serious damage at greatest pos-
sible range. While the exact altitude chosen is restricted
information, it may be said that the altitude was sev-
eral hundred feet.
For Test B, the underwater explosion, the problem
was debated even longer. Many pages would be re-
quired to trace the arguments and counter-arguments
for setting off the bomb a few feet above the surface,
exactly at the surface, a few feet below the surface, or
considerably below the surface.
Some of the most interesting arguments were these :
If the bomb were detonated just above the surface of
the water, energy transfer to the water would be poor,
most of the fission products would go upward in the
mushroom, and, in general, the test would differ very
little from Test A. Even if the bomb were detonated
at the surface or very slightly beneath the surface,
no reall}^ impressive underwater pressures would re-
sult, and again the test would not be far different from
Test A. In fact a detonation very slightly beneath the
surface of the w^ater might be especially ineffective;
neither the air pressure wave nor the water pressure
wave would be maximized, and it is possible that a
curtain of spray might be throA\ai up which would
actually screen off a large part of the pressure wave
in air and nearly all the thermal radiation, gamma
radiation, and neutron radiation.
24
EARLY PROBLEMS
The greater depth for Test B appealed to nearly
everyone except the engineers who would have the job
of placing the bomb at the specified depth and detonat-
ing it there. Atomic bombs are new; none had ever
been set off beneath the surface of the water. In at-
tempting such an unprecedented act, it would be neces-
sary to provide means of '' keeping in communication"
with the bomb at all times, not only to fire it (or, in an
emergency, to prevent its firing) but also to test it.
Unique security problems were presented too, since
for a short interval the bomb would be very close to
thousands of persons not authorized to see it.
So difficult was the decision as to the best depth of
the bomb, that for a long time two alternative plans
were carried forward side by side. Not until late in
the winter was the final decision made : that the bomb
was to be suspended at appreciable depth — beneath
an ''expendable" ship.
No one should think that these problems arose at
expected times in well-crystallized form. They appeared
unexpectedly; they had a habit of being almost inex-
tricably tied up with other unanswered questions.
Many of them arose even before the creation of Joint
Task Force One on January 11, 1946, before clear
lines of authority were established, before a firm direc-
tive had been issued as to the principal purposes of
the Tests. And the key persons concerned were usually
scattered across the country. A question raised by a
scientist at Los Alamos, New Mexico, might be sent by
25
BOMBS AT BIKINI
coded telegram to the Maiiliattaii Engineer District's
office in the New War Department Building, in Wash-
ington, D. C. ; here the question would be decoded —
perhaps in somewhat puzzling form — and forwarded,
say, to representatives of the Chief of Naval Opera-
tions in the Navy Building. Here a definite reply
might be delayed until a civilian adviser located at
Princeton, N. J., had been consulted. By the time the
Princeton expert had been brought to Washington,
some of the Washington men might have been called to
Roswell Field, New Mexico, where the B-29's were
being readied. By the time the answer was ready, the
spotlight of interest might have shifted ; a whole new
set of questions might have taken the center of the
stage.
Thanks to cooperative spirit, the telephone, the air-
plane, and high priorities, the problems were solved.
The way was cleared for detailed planning.
26
3
PLANS AND PLANNERS
Joint Task Force One began its ten-month
lease on life on January 11, 1946. It had no time for
leisurely growth. Administrators had to be appointed
immediately. Tentative plans had to be formulated at
once and approved within a few days.
The growing infant had full backing. The Secre-
taries of War and Navy immediately issued orders to
give the Operation full support. Officers, enlisted men,
scientists, and technicians, were made available as re-
quired. Laboratory facilities were granted freely.
Quarters were offered, as well as supply lines, funds,
and equipment. Nearly every Service bureau, branch,
and division shared in the effort. Thanks to highest
priorities, the Task Force grew rapidly and smoothly.
Meanwhile, Admiral Blandy was conjuring a name.
''Crossroads" seemed good, but it was a word already
in use in certain code work. The code people were con-
sulted, and agreed to surrender the name. So, on Jan-
uary 12, 1946, the Operation was christened "Opera-
tion Crossroads."
Admiral Blandy drafted the Task Force organiza-
tion, and quickly assembled a central staff. He chose
27
BOMBS AT BIKINI
experienced officers from Army and Navy for the top
command and staff positions ; the men were chosen for
their ability to act promptly and skillfully, without ex-
tensive instruction or deliberation.
Rear Admiral W. S. Parsons was chosen to direct
the technical and scientific work. He was given the
title of Deputy Task Force Commander for Technical
Direction. His responsibility extended to preparing
the ships, instruments, and test animals, detonating the
atomic bombs, and determining the results of the ex-
plosions. Although he played a central role in the
planning, even before the creation of the LeMay Sub-
committee of which he became a member, his designa-
tion as a Deputy Task Force Commander of Joint Task
Force One was not actually formalized until February
26, 1946.
Atomic bombs were not new to Admiral Parsons.
For over two years he had served at the Los Alamos
Laboratory, where he was head of the Ordnance Di-
vision. And he had flown in the Enola Gay on her his-
toric flight to Hiroshima; he not only supervised the
combat delivery of the Hiroshima bomb but personally
assembled the bomb after the takeoff. His familiarity
with the bombs and with Manhattan Project officials
made it logical that he should be principal intermediary
between Joint Task Force One and the head office of
the Manhattan Project. Admiral Parsons' large and
versatile technical organization is described in detail
in a later chapter.
28
PLANS AND PLANNERS
To direct the extensive air activities of the Opera-
tion, Major General W. E. Kepner of the Army Air
Forces was brought in. His broad experience included
service in the Marine Corps and Army Infantry in
World War I, participation in the development of the
use of lighter-than-air craft at Lakehurst, N. J., and
several important Army Air Forces commands in
World War II. As Deputy Task Force Commander
for Aviation, General Kepner 's responsibility extended
to Navy air operations as well as Army air operations.
It included planning, organizing, and directing the
operations. The many novel problems he faced are
described in a later chapter.
When it became clear that the Army Ground Forces
also had a stake in the Tests, a Ground Forces' Ad-
viser was designated: Major General A. C. McAuliffe.
His duty was to advise the Task Force Commander on
the planning, organizing, and execution of the Ground
Forces' program, including exposure of a wide variety
of Army equipment to the explosions.
To handle the enormous quantity of problems aris-
ing as to personnel, public relations, military security,
ship movements, communications, and supply, a Joint
Task Force operational and administrative staff was
assembled under Commodore J. A. Snackenberg, Chief
of Staff. Of his four principal assistants, two were
drawn from Army and two from Navy. They were :
Captain Robert Brodie, Jr. (Navy), Assistant Chief
of Staff for Personnel ; Brigadier General (now
29
BOMBS AT BIKINI
Colonel) T. J. Betts, Assistant Chief of Staff for In-
telligence; Captain C. H. Lyman (Navy), Assistant
Chief of Staff for Operations ; and Brigadier General
(now Colonel) D. H. Blakelock, Assistant Chief of
Staff for Logistics. To handle the innumerable prob-
lems which would inevitably arise in Washington,
D. C, after the Task Force had left for Bikini, a special
rear echelon group was created under the command of
Rear Admiral F. J. Lowry.
The relationship of positions of Commander, Dep-
uty Task Force Commanders, Chief of Staff, and
Assistant Chiefs of Staff is shown in Appendix I.
Before discussing the technical phases of the Oper-
ation, we shall describe the less glamorous but equally
important problems encountered by Commodore
Snackenberg and his assistants.
PERSONNEL PROBLEMS
Handling of personnel matters was a long and up-
hill struggle. Personnel had to be recruited just when
the majority of Service men were heading for the exit
from military life. The trend had to be combated. Pleas
were made to man}^^ officers and enlisted men on the
point of returning to civilian life; special TAD's
(orders for temporary additional duty) were drafted;
promises were made that the men would be released
30
PLANS AND PLANNERS
immediately on completion of the Operation. In the
Navy, which was to supply over 90 per cent of the
personnel, the Bureau of Naval Personnel put its
weight behind the drive. The Bureau of Ships, Bureau
of Ordnance, Bureau of Aeronautics, and several other
bureaus also dug deep for personnel. And the same
cooperation was given by the Army.
Mere numbers were not enough. It was specialists
that were particularly needed. Especially hard to find
were electricians, radio and radar men, oceanograph-
ers, bomb disposal experts, veterinarians, experts on
fish and blood.
Particularly acute was the dearth of radiological
safety men. During the re-entry stages after the ex-
plosions, many lives might depend on the availability
of men who could quickly and reliably detect danger-
ous concentrations of radioactive materials on target
ships, or in lagoon water. Such men, called monitors,
were also needed to clear the way for the speedy re-
moval of animals and apparatus from the exposed
ships. Similarly, they were vital to the quick saving
of target ships which might be on the verge of sinking.
Several hundred recruits were selected and trained,
but when the tests were postponed by the President,
many resigned. More were recruited; they were given
last-minute training before departing for Bikini and
while at sea. Over 225 monitors were actually available
in the crucial periods at Bikini; and although they
were spread thin and worked long hours, they per-
31
BOMBS AT BIKINI
formed their tasks excellently. They have the honor of
being charter members in a new branch of defense:
radiological safety.
The demand for photographers, too, far exceeded
the supply. First, the Services were combed; then
appeals were sent out to hundreds of ex-servicemen
who had been trained in military photography during
the war. Over one hundred responded.
But corralling the men was only a part of the prob-
lem. They had to be inoculated against diseases com-
mon in the Paci^fic Theatre. They had to be assigned
living and working space, fed, and transported. Rec-
reation areas had to be provided on Bikini Atoll and
elsewhere. Finally, problems as to their return, re-
placement, and release had to be faced.
Hiring of civilians was especially complicated also.
Special contracts and payroll procedures had to be im-
provised almost overnight. Some men were arbitrarily'
placed on the Los Alamos Laboratory payroll; others
were paid from funds in the .Office of the Secretary of
the Navy. Nearly every Service department concerned
with the handling of personnel groaned under the
load of unprecedented problems demanding immediate
answers.*
Despite their unending problems. Captain Robert
Brodie and his assistants worked along doggedly, and
each time a ship headed out for Bikini, an effective
* E.g. before the author could ohtain a civilian secretary, formal
authority had to he obtained from the Joint Chiefs of Staff.
32
PLANS AND PLANNERS
crew was aboard; each time a group of experts was
needed to solve some unexpected technical problem,
the experts were there.
INTELLIGENCE FUNCTIONS
Brigadier General T. J. Betts, Assistant Chief of
Stai¥ for Intelligence, had a positive and negative func-
tion. The negative job was maintaining military se-
curity. Never before had a nation fanfared its most
secret military weapon so closely before the eyes of
the world. Never before had an atomic bomb been det-
onated in front of the world press. Each man partici-
pating was checked for character and loyalty.* Special
pass cards were issued. Courier services were estab-
lished for sending secret messages between Bikini and
Washington, D. C. Photographs were developed only
by authorized Joint Task Force One persons, and no
photograph was released until it had been found to
satisfy the security rules laid down by the Joint Chiefs
of Staff.
These security rules seemed to most persons to be
reasonable. They permitted discussion of the objects
of the Tests, the approximate locations of all target
ships, the kinds and numbers of animals placed on the
ships, the method of delivering the bombs, the types
* Each woman, too. There were 37 women nurses at Bikini,
although few of the 41,963 men there ever caught glimpses of more
than a half dozen.
33
BOMBS AT BIKINI
of scientific information sought. And they permitted
inspecting many of the damaged ships before and after
the explosions, obtaining statistics on test animals
killed, and rough values of the ranges at which ships
were sunk or damaged. Approximate figures were
given out as to the amount of radioactivity produced,
and the degree to which crews would have suffered.
Not to be released were facts as to bomb design, exact
amount of energy released, exact position of the bomb
at the instant of detonation, exact positions of the
target vessels, correlations between damage and exact
values of range, pressure, etc. More than enough in-
formation was released to permit the world to see both
the character and magnitude of the havoc a single
atomic bomb can cause.
The most important of General Betts' positive func-
tions (see Appendix 2) was providing the public with
a stream of accurate information. To General Betts
and his Public Information Officer, Captain Fitzhugh
Lee (Navy), it sometimes appeared that the public
went out of its way to conjure distorted pictures of the
planning and expected results. Some groups were
prone to believe that the target ship array was sup-
posed to resemble a typical fleet at anchor, or a fleet
at sea. Some persons tried to build up the Operation
into an ''Air Forces versus Navy" struggle, in which
the goal was to see how many ships the Air Forces
could sink with one bomb. Others pictured the Tests
34
PLANS AND PLANNERS
as more-or-less rigged shows to ''prove" that the Navy
was not obsolete ; they hinted that the Navy feared most
of all, and for that reason w^as avoiding, the deep-
under-water explosion of an atomic bomb with its re-
sulting possibility of extensive damage to ships.
But perhaps the commonest distortion was as to
the great calamities which were to threaten. Massive
underwater landslides might be tripped off ; enormous
tidal waves might sweep across the Pacific and devas-
tate its shores; the very crust of the earth might be
parted, with unimaginable consequences. The chain
reaction in the bomb might spread to the water and the
whole ocean might explode. Conjecture had no limita-
tions except man's imagination.
The majority of the misconceptions were gradually
dislodged by the steady stream of facts issued to press
and radio by Captain Lee and his assistants. Within
the first few weeks after the creation of the Task
Force, Captain Lee had prepared and issued over fort}^
bulletins, which covered nearly every phase of the
Operation. Open news conferences were held too. Ad-
miral Blandy and his staff sat across the table from
dozens of the country's best correspondents and gave
spot answers to their searching questions concerning
the atomic tests.
Again and again they explained that the Tests were
not Navy tests but Joint tests, to be carried out at the
request of the Joint Chiefs of Staif and with the
35
BOMBS AT BIKINI
authorization of the President and Congress.* They re-
iterated that the Tests were not designed to prove or
disprove anything, but merely to find the facts. They
pointed to charts showing that the planned target
arrays bore no resemblance to fleets in harbor or at sea,
but were designed specifically to produce the optimum
amount of technical data. Continual effort was made
to deflate predictions of catastrophes.
The last key to good public relations was provided
when authorization was arranged for inviting press
and radio to send representatives to Bikini. The Joint
Chiefs of Staff recommended such a course on January
10, 1946, and the Secretaries of War and Navy gave
their endorsement on February 5 ; final approval came
from the White House on March 14. Actual attend-
ance was as follows :
Test A Test B
Representatives of U. S. press, radio,
pictorial services, magazines, etc. 114 75
Foreign press, one representative from
each nation having membership in UN
Atomic Energy Commission, plus two
representatives from Great Britain 10 8
* Even the task of keeping the public informed was made a
joint activity. On March 8, 1946, the Joint Chiefs of Staff requested
that individual Services cease expressing to the press their own
fragmentary news and asked that they channel all news releases
through the Task Force Commander's central puhlic relations
group.
36
PLANS AND PLANNERS
Selecting the individuals was not easy. Far more
persons applied than could be accommodated. It was
essential to work out some impartial scheme of issuing
the invitations. One view was : Invite individual per-
sons directly, by name. The opposite view was: Pick
the news agencies, and let them name their own repre-
sentatives. This latter view finally prevailed. Another
nice question facing Captain Lee was : Should he try
to select news agencies most experienced in reporting
scientific and military matters, or should the selection
be broadened to include all kinds of news agencies, re-
gardless of the bents of their experience "^ The latter
course was chosen. Without doubt the result was that
some representatives unskilled in technical and mili-
tary reporting made the trip ; but a redeeming advan-
tage was that accounts of the Tests appeared in nearly
every type of newspaper and magazine, including even
some of our most "feminine" magazines.
Through a specially-created committee, press and
radio agencies were enlisted in helping to make the
final choice of the agencies to be invited.
Captain Lee arranged for the majority of the press
and radio men to be transported to Bikini in the
APPALACHIAN, press headquarters ship, and for
others to go by air. To avoid repeated problems of pro-
tocol. Captain Lee arranged that preferences in living
quarters and various nonprofessional privileges were
to be granted according to age, the oldest correspon-
dents being most favored.
37
BOMBS AT BIKINI
To help those correspondents who were starting off
''cold," Captain Lee arranged, besides press confer-
ences, various orienting schemes. Lectures were ar-
ranged; motion picture films were prepared and
shown; press packets of pamphlets on subjects rang-
ing all the way from nuclear physics to the history
of the Central Pacific were prepared and distributed.
No effort was spared in making this the Z)es^-reported
as well as being the mos^-reported technical experiment
of all time.
Li the Nucleonics Age it is still true that a single
picture is worth a thousand words. Recognizing this,
General Betts asked Captain R. S. Quackenbush
(Navy) to plan an adequate nontechnical photograph}^
program, whereby the press men and the world at large
could see vicariously all that security would permit.
His enormous program is described in a later chapter,
in connection with technical photography.*
A sincere gesture of international goodwill was
made by inviting foreign observers to see the explo-
sions. The desire to invite foreign observers was ex-
pressed by the Services and by large sections of the
public even before the Task Force had been formally
created. The Joint Chiefs of Staff were considering
the matter as early as January 10, 1946. The State De-
* A selection of over 225 of the photographs taken hy Captain
Quackenhush's group is presented in "Operation Crossroads, Offi-
cial Pictorial Record," published hy William H. Wise & Co., Inc.,
New York, New York.
38
PLANS AND PLANNERS
partment went on record in favor of the proposition,
and, on March 14, President Truman approved the
plan.
The Secretary of State accordingly asked our am-
bassadors in the eleven foreign countries having mem-
bership in the United Nations Atomic Energy Com-
mission to invite those countries to choose their official
witnesses. The countries and their representatives are
listed in Appendix 6.
The twenty-one global representatives selected as-
sembled in Washington, D. C, and went b}^ special
train to Oakland, California. There they boarded the
PANAMINT, Bikini bound.
Besides these foreign observers and a few partici-
pating scientists from Great Britain, there were eight
additional observers from Great Britain, four from
Canada, and one from Australia. There were also a
few press representatives invited from foreign coun-
tries.
But Colonel H. B. Smith, Head of the Nonpartici-
pating Observers Section, had many other observers
to shepherd also. There were fourteen Congressional
observers (see Appendix 7), eighty-seven Army and
Navy observers, and twenty-two civilian scientist ob-
servers. Congressional observers were considerably
fewer than expected. The Joint Chiefs of Staff orig-
inally set a quota of sixty but the invitations were not
issued until late — after June 14, 1946, when Congress
gave final approval to the Tests.
39
BOMBS AT BIKINI
OPERATIONS PLANNING AND
DIRECTION
Nearly every movement of the Task Force's 242
ships and 156 airplanes was made, of course, by direc-
tion of the Task Force Commander; but it was the
responsibility of Captain C. H. Lyman (Nav,y), Assist-
ant Chief of Staff for Operations, to plan and coordi-
nate all such movements. Captain W. C. Winn (Navy)
assisted in the directing of movement of vessels. He
maintained records showing where each ship was, who
was in command, what its mission and destination
were. When additional ships were required, it w^as his
job to obtain them; when certain ships were no longer
needed, it was his job to see that they were reassigned.
Captain Lyman was assisted by Colonel W. D.
Graney in the planning and directing of air operations.
He was assisted by Captain K. M. Gentry (Navy) in
communication matters, including radio, television,
and transmission of radio-photographs ; a schedule of
348 individual radio frequencies was arranged, of
which 163 were assigned to command and administra-
tive groups, 107 to instrumentation groups, and 78 to
press and radio groups. In the crucial matter of an-
alyzing and predicting weather, Captain Lyman was
assisted by Colonel B. J. Holzman and Captain A. A.
Cumberledge (Navy), outstanding experts in aerology.
Perhaps the two most important observer groups
at Bikini were the Joint Chiefs of Staff's Evaluation
40
PLANS AND PLANNERS
Board and the President's Evaluation Commission.
The Evaluation Board, whose members are listed in
Appendix 4, was responsible directly to the Joint
Chiefs of Staff and was to make careful technical study
and comprehensive conclusions. The Evaluation Com-
mission, whose members are listed in Appendix 5,
reported directly to the President. It was not expected
to make any highly technical studies. Preliminary re-
ports by these bodies are included in this volume as
Appendices 10, 11, 12, and 13.
LOGISTICS FUNCTIONS
The supply, transportation, and maintenance of
men and materials was the responsibility of Brigadier
General (now Colonel) D. H. Blakelock, Assistant
Chief of Staff for Logistics. The breadth of his work
is indicated in Appendix 1. He was responsible for
transporting the Task Force's 42,000 men and provid-
ing them with military, technical, and personal equip-
ment. (Approximately 1300 persons were flown from
continental United States to Bikini and back ; approxi-
mately 440,000 pounds of freight were flown from con-
tinental United States to Pearl Harbor or to the Mar-
shall Islands.)
Keeping these four fast-working staff divisions
working without any crossing of purposes was no easy
matter. Frequent staff meetings proved helpful. Here,
flanking an enormous table set in the center of a car-
41
BOMBS AT BIKINI
peted and air-conditioned room, Admiral Blandy and
his deputies would confer for an hour or two. Problems
weve presented and comments were invited from all
present. In each instance Admiral Blandy or his Chief
of Staff would make a summary as to the agreed-on-
course and designate one man to take the necessary
action.*
Between formal meetings there were innumerable
informal meetings. Staff officials whether from Army
or Navy were given adjacent offices so that they could
* The author and other civilians present found these meetings
impressive, both in their democratic method of procedure and
the quick avaiJ^hility of facts. Almost never did an officer have to
consult notes, or ask to get the information later. Usually, he had the
answers at the tip of his tongue; and if he did not, he was flanked
hy one or two junior officers instantly ready to cite case and num-
ber. Again, since representatives of all Service groups were present,
almost no question was outside the scope of the meeting.
One mildly humorous case of failure to obtain straight-off a
useful answer Jias stuck in the author's memory: An urgent dis-
patch was sent off to the advance group at Bikini to find whether
the coral heads obstructing navigation m the Lagoon were being
removed successfully. But the actual form of the message was to
the effect: "Are you havijig any difficulty in removing the coral
heads?" The laconic reply came back: "Yes." Admiral Blandy 's
comment drew broad grins from all the conferees: "We don't
care whether he's having difficulty: of course he is. All of us
have our difficulties. Send another dispatch and ask if he is over-
coming his difficulties."
Clairvoyance was effectively used by Admiral Blandy in solv-
ing one problem — ■ a problem as to what to do with the unconsumed
beer which might remain on Bikini Atoll during the evacuation
for Test A. After other officers had proposed various solutionis,
Admiral Blandy spoke up: "There really isn't any problem; if
I kyiow anything about military men, there won't be any uncon-
sumed beer."
42
PLANS AND PLANNERS
exchange memos and drafts promptly. Telephone direc-
tories of Crossroads officials were issued every two
weeks, to keep pace with expanding forces and con-
stantly shifting quarters. Throughout the day, streams
of new personnel would crowd in, new desks and file
cabinets were wheeled in on creaking dollies; new-
comers, unable to find empty chairs would perch on
desk tops or sit on staircases In the midst of this
apparent confusion, the ubiquitous telephone men
worked with pliers and screwdrivers.
A mammoth Operation Plan was prepared — a plan
so vast and detailed as to suggest the Book of Fate
itself. The Plan ' contained several thousand large,
finely-printed pages* and served as a bible throughout
the Operation. Heart of the Plan was a set of twenty-
nine annexes, each a veritable encyclopedia on all plans
relating to a given phase of the Operation. The titles
of the Annexes are illuminating ; they are :
Movement Plan
Logistics Plan
Communication and Electronics Plan
Security Plan
Safety Plan
Air Plan
Instrumentation Plan
Bikini Evacuation Plan
Re-entry Plan
* It is a great tribute to the Government Printing Office that it
could print and deliver this enormous plan in the space of a very
few weeks.
43
BOMBS AT BIKINI
Plan of Operation on A-Day
Plan of Operation on B-Day
Photographic Plan
Salvage Plan
Army Ground Group Plan
Public Information Plan
Target Layout Test A
Target Layout Test B
Oceanographic Survey Plan
Harbor Information
Aerological Plan
Boat Pool Plan
Typhoon Plan
Ship Preparation Plan
Reboarding and Inspection Plan
Air-Sea Rescue Plan
Nonparticipating Observers Plan
Rongerik Evacuation Plan
Reports
Drone Boat Plan
Several of the annexes, which themselves contained
voluminous appendices and even appendices to appen-
dices, were many hundreds of pages in length, and con-
tained a wealth of charts, graphs, etc.* Civilians or
others who may have expected the Task Force to be
directed by a multitude of impromptu decisions made
in the field were impressed with the completeness with
which problems were anticipated and categorically
* The Operation Plan was so complete that the writer, who
studied it with some care, had throughout the Operation the im-
pression of attending a good Technicolor motion picture of a re-
cently-read hook.
44
PLANS AND PLANNERS
solved long in advance. Even the exposure times for
the ten thousand most important photographs were
worked out and clearly specified in the Operation Plan.
One obvious advantage of the detailed, long-in-
advance planning was that it left the Task Force Com-
mander and his assistants relatively free to solve the
few unpredictable problems that were bound to arise.
Principal unpredictable matters were : weather, num-
ber of damaged target vessels which would require
beaching, extent of radioactivity to be found on target
vessels. As we shall see later, weather forced postpone-
ment of the "Queen Day" rehearsal of Test A, and all
but forced postponement of the ''William Day" re-
hearsal of Test B. It caused a half -hour postponement
of Test A. The radioactivity remaining on target ves-
sels after Test B was much more intense than most
persons had anticipated; considerable delays in re-
boarding, inspecting, and report- writing resulted, and
the final disposal of the surviving vessels was greatly
complicated.
The planning was good. As later chapters show,
the Task Force assembled without incident and the
target vessels were moored in the positions decided on
weeks in advance ; both Tests came off on the intended
days; no one was injured by the explosions; and a
great mass of technical information was gathered. A
vast administrative machine had proved its power.
45
4
TECHNOLOGICAL OFFENSIVE
Crossroads was above all a technical oper-
ation. All planning was subservient to the primary
mission: collecting technical information.
Rear Admiral W. S. Parsons, as Deputy Task
Force Commander for Technical Direction, led the
technological offensive. As Assistant Chief of Naval
Operations, Special Weapons, he played a large part
in formulating Navy opinion as to how the Tests should
be arranged ; and, as ranking Navy member of the joint
LeMay Subcommittee, he helped draw up the formal
directive.
His biggest job was analyzing the technical require-
ments, breaking them into logical divisions, and setting
up the necessary technical administration. With the
assistance of Navy Captains Horacio Rivero and F. L.
Ashworth, he found that the required technical activi-
ties could be aranged under four distinct headings. To
handle these activities, he set up two technical adminis-
trative groups and two advisory positions.
The largest of the two technical administrative
groups was made responsible for the following: (1)
preparing the target vessels, exposing them to the two
46
TECHNOLOGICAL OFFENSIVE
explosions, determining the damage, and disposing of
them; (2) the same for a wide variety of Army and
Navy equipment, including airplanes; (3) exposing
goats, pigs, rats, guinea pigs, mice, determining injury,
studying the symptoms, and finding the best methods
of diagnosis and treatment ; (4) decontaminating those
ships made radioactive by the explosions. This group,
which ultimately involved more than 10,000 men, was
directed by Rear Admiral T. A. Solberg, w^ho assumed
the title of Director of Ship Material.
Perhaps the most publicized of the two groups was
that containing the 500 scientists responsible for meas-
uring pressure, light, nuclear radiations, w^ave height,
etc. In charge of this group was Dr. R. A. Sawyer,
Technical Director.
Captain G. M. Lyon (Navy, Medical Corps) was
named as Safety Adviser. His job was to prevent in-
jury to personnel, either from hazards of normal type
or from hazards (other than nuclear radiations) pe-
culiar to this Operation. This included hazards to per-
sons first reboarding the target vessels :
Mechanical hazards, including danger from
falling objects, slippery (oil-covered) sur-
faces, weakened ladders, decks, gratings,
and weakened tanks under pressure.
Drowning in flooded compartments.
Fires; escaping steam; hot surfaces.
Electrical shocks due to damaged wiring and
short circuits.
47
BOMBS AT BIKINI
Chemical hazards due to carbon monoxide,
carbon dioxide, nitrous gases, alcohol and
other vapors, ammonia, corrosive acids and
alkalies, creosol cleaning solutions.
Miscellaneous hazards, including contami-
nated drinking water and food, escaping
gases from chemical warfare munitions,
secondary explosions of ammunition or
acetylene.
Enumerating the hazards was simple, but to warn
the thousands of men involved and instruct them in
safe practice required much planning and thorough
training.* Captain Lyon's designation as Safety Ad-
viser was a logical one in view of his extensive war-
time experience in chemical warfare technology and
his close association with the Atomic Bomb Project.
Colonel S. L. Warren (Army Medical Corps) was
made Radiological Safety Adviser to Rear Admiral
Parsons and also to Admiral Blandy. His job was the
* Accidents were very few. No one was injured hy the explosion,
and no one was seriously injured even hy indirect effects such as
radioactivity . However, jive fatal accidents occurred. A Navy en-
listed man, R. L. Mangum, Seaman First Class, drowned on March
25, 1946. Captain J. E. Bishop (Army) was killed on June 24,
1946, as a residt of being struck hy the propeller of a B-29 which
was warming up on the airstrip at Kwajalein. A Navy enlisted
man, J . D. Moran, Radioman First Class, was accidentally electro-
cuted on July 4, 1946, on the albermarle. Lt. W. H. William
(Navy) was killed on July 9, 1946, in an airplane crash on Roi.
J. R. Reagan, Seaman First Class, died as a result of methyl alcohol
poisoning on July 24, 1946.
48
TECHNOLOGICAL OFFENSIVE
unusual one of advising as to dangers which would lurk
in the invisible radioactive materials scattered on
target vessels, in lagooji water and even in the atmos-
phere itself. Col. Warren brought with him years of
experience gained wliile he was Chief of the Medical
Section of the Manhattan Engineer District.
Preparing the target ships and support ships was
an enormous job. The job was far greater than might
be expected bv persons unfamiliar with the prob-
lems. Admiral Solberg was called upon to execute
quickly an enormous planning program and to or-
ganize the extensive cooperation to be obtained from
all major shipyards, from the Office of the Chief of
Naval Operations, from the Commander-in-Chief of
the Pacific Fleet and Pacific Ocean Areas, and from
nearly every Naval Bureau.
Perhaps the simplest part of the work was pre-
paring the support vessels, listed in Appendix 8. There
were 149 of these vessels, 36 of them being of consid-
erable size, i.e., over 10,000 tons.
Considerable remodeling was required on many of
the ships. On the flagship MT. McKINLEY, forty more
desks were installed and air conditioning was provided
in two wardrooms and three staff cabins; television
and radio teletype equipment was installed also. On
the press ship APPALACHIAN a broadcasting studio
was built and television and radio teletype facilities
were installed; additional accommodations were pro-
vided for officers and press representatives, and several
49
BOMBS AT BIKINI
wardrooms were air conditioned. Air conditioning
equipment was installed in certain parts of the PANA-
MINT and BLUE RIDCIE also.
ALBEMARLE and CUMBERLAND SOUND,
to be used principally by the Los Alamos group, were
converted into great floating laboratories equipped
with nearly every kind of machine tool and electrical
instrument. Special laboratories were installed in the
KENNETH WHITING, WHARTON, HAVEN and
AVERY ISLAND. BURLESON, the animal ship,
was remodeled into a great dirtless farm, a palatial
hotel for animals ; biophysics, radiobiology, pathology,
and hematology laboratories were installed also.
LSM-60, the central or Zeropoint ship for the sec-
ond test, was remodeled to permit lowering the bomb,
in its watertight caisson, through a central bottomless
well. Special photographic laboratories were built in
SAID OR and other ships participating in the enor-
mous photographic program.
These remodelings were completed rapidly. The ma-
jority of the work on support ships and target ships
was done in the Naval Shipyards at Philadelphia,
Bremerton, Mare Island, Hunters Point, Terminal Is-
land, and Pearl Harbor. The work was based on de-
tailed plans prepared by the Bureau of Ships.
Many kinds of policy problems had to be solved
before the shipyards could begin preparing the target
ships — listed in Appendix 9. One fundamental ques-
tion was : Should the ships be stripped of all equipment
50
TECHNOLOGICAL OFFENSIVE
of value, or should tliey be left fully equipped ? Econ-
omy-minded persons favored removing much of the
valuable equipment such as guns, rangefinders, radar
equipment ; but others pointed out that the equipment
must be left on the ships if the tests were to yield the
maximum information. The final decision was as fol-
lows : Items of historical interest and all items actually
needed for our active fleet, except for sample items,
should be removed; other equipment should be left
aboard.
How much repair work should be done was another
puzzle. For results to be fully significant, the target
ships should resemble normal, fighting ships; that is,
they should be in good shape. But a number of the
ships were in fact not in good shape. A few had serious
war wounds, patched only in makeshift manner; it
was clear that the old wounds might be re-opened with
misleading ease. Similar questions arose as to ships'
machinery, ordnance equipment, etc., which suffered
damage during the war. The decision was made that the
ships and their equipment should, wherever feasible,
be put in first class condition. The amount of repair
work entailed was very great; but had this work not
been done, it would have been almost impossible to tell
after each explosion what damage was really caused by
the explosion, and what damage should be attributed to
prior circumstances.
An unusual ''must" — not normally applicable to
manned ships — was making the ships almost perfectly
51
BOMBS AT BIKINI
watertight. A fact not fully realized by the public is
that the majority of warships — even warships which
have never seen battle — leak slightly. Particularly in
older ships, it is almost impossible to make all joints
perfectly tight. The slight continual in-fiow of water is
of no consequence ordinarily ; it is easily pumped out.
But in this Operation, where the ships might have to
remain for weeks without crews and without pumps
operating, such leaks might be very serious. There was
some danger that the captured Japanese ships
NAGATO and SAKAWA might actually sink from
this cause if they were left unattended for three or
four weeks.
Admiral Solberg's group gave much attention also
to internal watertightness, a subject which may appear
to laymen to be of little importance, but was actually of
great importance. Ships expect to take punishment in
battles, but place reliance on internal watertightnc ss to
keep them afloat and mobile. Ships are, in fact, honey-
combs of separate compartments.*
In battle, hatches between compartments are closed
securely. If a shell, bomb, or torpedo opens a hole be-
neath the waterline, water pours in; but if the ship's
watertight integrity is good, only the compartments
adjacent to the hole are flooded. Other compartments
* Exact numbers of watertight compartments in modern ships
are kept secret. But it is no secret that for a modern U. S. battleship,
for example, the number of such compartments is nearer 1000 than
100.
52
TECHNOLOGICAL OFFENSIVE
remain dry. Thus the ship can continue to cruise and
to fight.*
But it is very difficult to maintain internal water-
tight integrity in older ships. In the first place, the
older ships have far fewer compartments. Secondly,
such ships have usually undergone considerable repair
and remodeling, which means new holes cut through
partitions for pipes, wiring, etc. It is almost impos-
sible to seal these holes perfectly. Tests can be made,
using compressed air, to see how tight any given com-
partment is, and the leaks can be found; but the job
is a very big one.
Leaks between compartments would be especially
serious in the target ships at Bikini. A typical ship
might be left unmanned, with pumps shut off, for days
or weeks. Water pouring into a single compartment
might slowly spread throughout the ship and sink it.
This, of course, would give a very false impression as
to the effectiveness of the bomb ; even a skeleton crew
might have prevented the flooding.
Admiral Solberg's job, therefore, was to test water-
tight integrity and to improve it so that the ships
would have normal survival power, even when one or
* During the war there were several occasions when a ship not
only survived hut actually continued fighting after several holes
had been torn in her hull plating below the ivaterline; there were
even instances where ships were broken in halves, and yet one or
both halves were kept afloat. The so-called "unsinkability" of the
largest warships derives in fact more from effectiveness of com-
partmentation than from mere toughness of exterior.
53
BOMBS AT BIKINI
a few holes were made in the hull by the great explo-
sions. Thousands of compartments were air-tested;
innumerable holes were filled, and the stuffing boxes
re-stuffed.
Besides stripping the target ships of valuable ma-
terial and putting them in good physical shape, the con-
struction and installation of special mounts for scien-
tific instruments was called for. Displacement and ac-
celeration gages were to be mounted below decks, and
a great variety of gages and automatic recorders were
to be mounted topside. These mountings had to be
very heavy in many cases to withstand the severe shock
wave expected. Special stands or cages were installed
for the test animals. Special fastenings were prepared
for the wealth of army material to be exposed on the
upper decks. Much special electronics equipment was
readied.
Even before the target ships began heading out to
sea, bound for Pearl Harbor and then Bikini, the enor-
mous task of inspecting them was being planned. The
two great explosions might create a wealth of dam-
age ; but unless the damage were cataloged effectively,
much value would be lost.
Admiral Solberg's technical staff found that no ordi-
nary inspection procedures would do. The procedures
used during the war were studied* but were found not
* During the war a very thorough systetn of inspections had
heen worked out, for example, hy the Board of Inspection and
Survey, Forces Afloat.
54
TECHNOLOGICAL OFFENSIVE
to be adequate for the peculiar purposes of these Tests.
A whole new set of instructions was therefore worked
out and printed; it contained over 250 pages, and
showed exactly how each part of the ship and each piece
of equipment should be inspected. Equally important,
it proposed standard forms for reporting the inspec-
tion results. Without uniform reporting, it would be
almost impossible to add up the information to get
meaningful totals and comparisons. Two thousand
copies of these instructions and five thousand inspec-
tion notebooks were distributed.
There was no formal parade of ships to Bikini, and
little drama. Ships put out from east coast Navy
yards as early as March 4, 1946. By mid-March the
Panama Canal was making its contribution to the Op-
eration. Many of the ships had left the west coast ship-
yards by early March. Ships were drawn from remote
Pacific bases also, including Manila, Shanghai, Guam,
Okinawa, Saipan. The Japanese battleship NAGrATO
came from Yokosuka, Japan, and the cruiser
SAKAWA came from Otake, Japan. The German
cruiser PRINZ EUGEN had come from Germany, via
Boston, Philadelphia, and the Panama Canal.
The great size of the Task Force became apparent
at Pearl Harbor, where, in mid-May, over one hundred
of the ships were assembled. But Pearl Harbor, fa-
miliarly known as "Pearl" or "P.H.," was more than
an assembly point; its huge shipyard had taken on
the work of preparing a large number of the ships.
55
BOMBS AT BIKINI
Here also many of the target ships were loaded with
ammunition and fuel.
The migration of target ^hips towards Bikini was
nearly completed by June 1. The focus of interest began
to shift towards results.
56
5
SCIENTIFIC OFFENSIVE
Science 's broad scope was clearly evidenced
at Bikini. Boarding the ships and airplanes heading
for Bikini were nuclear physicists, chemists, mathema-
ticians, spectroscopists, roentgenologists, biophysicists,
biologists, veterinarians, hematologists, piscatologists,
oceanographers, geologists, seismologists, meteorolo-
gists. Their work attracted particular attention because
of its novelty. New kinds of phenomena were expected ;
new kinds of instruments had to be built. No one could
say whether the instruments would work properly,
whether they would successfully cope with the extremes
of pressure, radiation intensity, etc. The scientists were
working at the frontier of experimental science ; some
of them were working far beyond the known frontiers.
They were filled with curiosity as to what information
their instruments would capture from the uncontrolla-
ble fury of the explosions which had never been wit-
nessed by such a large body of scientists.
Dr. R. A. Sawyer, Technical Director, arrived at
Bikini on May 29, 1946. From his headquarters in the
KENNETH WHITING, he and his assistants coordi-
57
BOMBS AT BIKINI
nated the final scientific preparations. Principal assist-
ants were Dr. E. W. Thatcher, Captain F. L. Riddle
(Navy), Commander E. S. Grilfillan, Jr., Commander
A. W. McReynolds, Lieutenant Commander J. K.
Debenham, and Ensign H. M. Archer.
These men had little time for sunning on the upper
deck, or watching the evening movies. Dressed in short-
sleeved khaki shirts, abbreviated khaki trousers, -and
sneakers, they worked in their small, hot, humid quar-
ters from early morning until late at night. They had
to study final plans, iron out the few minor inconsis-
tencies, locate men to help out on lagging projects. They
had to inspect installations, prepare progress reports,
attend staff meetings on the MT. McKINLEY.
The Venice-like transportation system was an ob-
stacle. Each trip to inspect apparatus or attend a meet-
ing meant traveling to another ship. Such trips usually
took 10 or 20 minutes — if a launch was available.
There were, of course, hundreds of small boats in the
area, and all day they dotted the clear blue expanse of
the Lagoon, their wakes crossing and interlacing. But
the supply could not keep up with the demand. To make
optimum use of these boats, scientists and others
worked out boat pools, planned their work so that the
minimum number of trips would be required. But
throughout the Operation they were careful to culti-
vate the friendship of the boat dispatchers.
Dr. Sawyer had, of course, set up the necessary ad-
ministrative organization long before he left Wash-
58
SCIENTIFIC OFFENSIVE
ington, D. C. (See Appendix 1). Few final readjust-
ments were required at Bikini. In creating this or-
ganization, Dr. Sawyer made every attempt to make
use of existing research groups ; for by using a group
already staffed for a particular kind of research, re-
sults could be obtained rapidly, with few personnel
problems, little need for any extensive study, and
almost no outside supervision.
Although the administrative organization was de-
signed to achieve maximum speed with minimum out-
side supervision, it was not necessarily based on simple
scientific lines. For this reason. Dr. Sawyer arranged
coordinating groups to see that each scientific function
was adequately taken care of. The functions covered
included bomb operation, pressure and impulse, ocean-
ography, electromagnetic propagation and electronics,
radioactivity, optical radiation, nuclear radiation,
technical photography, and remote measurements of
various phenomena.*
Dr. Sawyer's organization included more than 550
scientists and engineers. The majority of them were
civilians lent by the Services or by civilian agencies,
foundations, and universities; many were Army and
Navy officers. During their cooperative activities,
civilian and Service personnel worked with little re-
* Remote measurements included (1) measuring tide data at
Midway, Wake, Kwajalein, and Eniwetok Islands, (2) recording
shock at these islands, and (3) tracing radioactivity in the Central
Pacific.
59
BOMBS AT BIKINI
gard to protocol ; they sweated side by side to get the
apparatus ready for recording the full measure of the
great explosions of A-Day and B-Day.
PRESSURE
Pressure was to be king on A-Day, when the bomb
was to explode several hundred feet in the air. It was
expected that giant waves or intense gamma radiation
might do the worst damage on B-Day, day of the under-
water explosion ; but few doubted that pressure would
wear the crown on A-Day.
Air pressure may not sound fearsome. We are —
literally — under pressure at all times. The air around
us is compressed by the mere weight of overlying air.
Every part of our bodies is subjected to a steady pres-
sure of 14 or 15 pounds per square inch. Yet we sleep
and breathe with ease.
But although it is true that steady pressures of
10 or 20 pounds per square inch go almost unnoticed,
it is equally true that sudden increases in pressure
(overpressure) can be remarkably effective. Fast, re-
current pressure changes as slight as one billionth of a
pound per square inch are easily detected by the ear ;
many a building can be toppled by a sudden, transient,
pressure increase of one pound per square inch. Tran-
sient overpressure crtished thousands of buildings at
Hiroshima ; it was to sink five ships on A-Day.
60
SCIENTIFIC OFFENSIVE
Pressure experts cannot talk long about over-
pressure without bringing in the Mach Stem, a scien-
tific anomaly which makes pressure waves doubly de-
structive to houses, ships, or other objects situated just
above a large immovable surface. Near the end of the
last century an Austrian scientist named Ernst Mach
was studying electrical sparks — using apparatus plen-
tifully coated with dust and soot. He noticed that
whenever a spark was produced, dust was scoured
away from a nearby, dust-covered surface. He noticed
also that the scoured area was curiously limited in its
extent.
The explanation is now well known. It is worth re-
cording here since it had such a great influence on the
planning and results of the A-Day explosion at Bikini.
When an explosion occurs just above the surface
of the ground (or say, just above the surface of a
lagoon), the spherical pressure wave spreads in all
directions. The part of the wave which strikes the
ground is reflected. If the intensity of the direct and
reflected waves is not too great, the waves go their sep-
arate and easily-predicted ways. But if the pressure
waves are very intense, then the whole situation
changes : the waves affect one another curiously. Near
the ground, in what has come to be called the Mach
Stem region, the reflected wave finds itself close on the
heels of the direct wave, in fact practically in the direct
wave. Now it is a fact that when one intense wave
travels more or less within another intense wave, it
61
BOMBS AT BIKINI
travels unusually fast. The result is that the reflected
wave tends to catch up with — and even coalesce with
— the direct wave. Actually the combined wave is no
longer spherical, but nearly cylindrical or stem-like.
All this happens, of course, only in the limited region
where the two waves are initially fairly close together
— i.e., near the ground.
The scientific result is that near the ground the
pressure is now far greater than could be produced by
the direct or reflected waves singly.
The tactical implications predicted for A-Day were
ominous. The experts knew that a large fraction of the
great armada of target vessels would find themselves
in the Mach Stem region; what had been a scientific
curiosity might mean destruction for many warships.
Interest on this subject thus rose to an especially high
pitch.
Mere interest, of course, was not enough. Pressure
gages were needed. Some of the simplest yet most
effective gages were those devised by Dr. W. G. Penney,
a British scientist. Back in 1945 when he was work-
ing at Los Alamos, he made the daring guess that the
humble tin can would prove to be one of the best "in-
struments" for measuring the terrific pressures pro-
duced by atomic bomb explosions. He soon showed his
guess to be correct. He demonstrated that whenever a
five-gallon gasoline can was partially crushed by a
sudden pressure wave, the degree of crushing depended
on the exact intensity of the pressure wave. For ex-
62
SCIENTIFIC OFFENSIVE
ample, an overpressure of only a few pounds per square
inch might reduce the can's vohime to 80 percent of
the original volume ; but a more extreme overpressure
might reduce the volume to 10 percent. Cans are cheap ;
hundreds may be used, and the average effect can be
measured with accuracy. (The decrease in the can's
volume could be measured simply by filling the can
with water, weighing it, and making a comparison
with the weight of a filled tmcriished can). Many other
instruments were equally ingenious.
Dr. Penney and his assistants, collectively known
as the Pressure Group (Cans and Drums), experi-
mented with other gages of equally crude sort.* They
were especially keen to hit upon gages good for meas-
uring very high pressures. One type developed con-
sisted of a sort of pan-pipes or harp, of small pipes
of graded lengths. When the pressure wave strikes,
the pipes are bent; long thin pipes bend most, and
short fat pipes least. With the help of laboratory ex-
* This Group included six subgroups, as follows:
Air Blast Subgroup, headed by Dr. C. W. Lampson
Underwater Subgroup, headed by Dr. A. B. Arons
Low Frequency Subgroup, headed by Dr. J. V. Atanasoff
Radiometry Subgroup, headed by Comdr. S. S. Ballard
Pressure-Time Subgroup, headed by Dr. J. E. Henderson
Service Subgroup, headed by CWO J. P. Orr.
Captain L. W. McKeehan (Navy) served as Adviser. Personnel
was drawn principally from the Navy's Bureau of Ordnance, the
Naval Research Laboratory, and the David Taylor Model Basin;
pressure experts were borrowed also from various U7iiversities,
notably the University of Washington in Washington State.
63
BOMBS AT BIKINI
periments and some mathematics, Dr. Penney learned
how to translate bends into pressure values.*
Dr. Penney 's group was not the only one striving
to extract knowledge from the pressure wave. The
problem was attacked on a very broad front by the
powerful Bureau of Ordnance Instrumentation Group.
This Group, led by Captain A. E. Uehlinger (Navy)
and under the technical direction of Dr. G. K. Hart-
mann, surveyed all known types of pressure gages.
But finding suitable gages was difficult ; there were
many hard-to-meet requirements. Some of these re-
quirements pervaded the other scientific fields, and
were thus of especial importance.
Most important was the requirement that the gages
leave permanent records of their response; there
would be no one on hand to watch them. Among the
various automatic recording schemes available were:
(1) ink-recorders, in which a small fountain pen writes
its crude but significant message automatically on a
sheet of paper mounted on a slowly-rotating disk or
drum; (2) scratch-recorders, in which a needle
scratches its message on a wax-coated disk or drum;
(3) magnetic recorders, in which variations in pressure
are converted into variations in degrees of magnet-
ization of a short segment of a slowly-moving steel
wire or tape; (4) optical recorders, in which pressure
* /?i his official tour of inspection of Hiroshima and Nagasaki,
Dr. Penney had found that the pressure waves there had left read-
able records in the form of bent fence posts, sign posts, etc.
64
SCIENTIFIC OFFENSIVE
variations cause a small beam of light to move across a
slowly-traveling strip of photographic film, to be de-
veloped and analyzed later; (5) telemeter-recording
systems, in which pressure values are actually broad-
cast by small, automatic, radio transmitters to wait-
ing recorders located in some convenient places several
miles away; (6) permanent-deformation gages, such
as the Penney cans, which undergo permanent de-
formations easy to interpret.
A second requirement was that the gages be really
rugged. Despite the need for using ingenious record-
ing systems, the gages and their mounts must survive
the terrific overpressure. It is pointless to use a pre-
cision gage which is promptly flattened or blown over-
board.* Hence delicacy was not a characteristic of
the instrument cases taken to Bikini ; on the contrary,
many of the designers enclosed their instruments' deli-
cate worki^ in cases built of 2-inch-thick steel which
could withstand the pressure.
In the third place, the gages must resist corrosion.
In the hot humid air, metal objects corroded unusually
rapidly. Aluminum apparatus was, of course, very
vulnerable to salt water. Thus corrosion-resistant
metals were used ordinarily for exposed working parts,
or waterproof coatings of paint or lacquer were ap-
plied.
* In the Alamogordo test of June 16, 1945, a number of instru-
meyxts failed to stand up to the U7iprece dented pressures. Some
were crushed, others were torn loose and thrown considerable dis-
tances.
65
BOMBS AT BIKINI
In the fourth place, the gages must be able to bide
their time. Even if the explosion were to be post-
poned slightly, the instruments must be ready at the
new H-Hour. Batteries must not run down; record-
ers must be ready. In many cases the problem was
solved by installing special starter-clocks; in other
cases ''black box" remote-controlled starting devices
were used. (These are discussed in Chapter 7.) In a
few instances, the instruments were started by the flash
of light emitted by the exploding bomb itself.
A difficulty peculiar to the measurement of the
pressure wave was designing instruments which would
operate fast enough to catch the pressure wave at
its instantaneous peak. For at any given point (say
on a target vessel only a few hundred yards from the
Zeropoint) the pressure would, of course, increase ex-
tremely suddenly — so much so that the pressure ex-
perts, when drawing sketches of the wave, usually pic-
tured the wave as having what they called a ''square
front." After its extremely rapid rise, the pressure
would, of course, decrease again nearly as rapidly;
then for a moment the pressure would actually fall to
less than normal, in what is called the suction phase.
Obviously a slow-acting gage would become confused
by the many sudden changes in pressure, and would
present only a sort of average value. Unfortunately,
average values would be of little use ; every effort was
made, therefore, to design fast-acting "mas!-let^.s"
gages.
66
SCIENTIFIC OFFENSIVE
Fortunately, the pressure experts under Dr. Hart-
mann had faced these problems back in the United
States months before. Even during the autumn of 1945
informal exploratory conferences were held among
scientists and engineers from the Naval Ordnance
Laboratory, the David Taylor Model Basin, and else-
where. The difficulties were discussed, constructive
suggestions were offered, criticized, revised, and slowly
elaborated into sound designs. Whiteprints were
rushed to the machine shops, finished instruments were
tested, taken apart, adjusted and re-assembled.
From many shops and laboratories, crates filled
with instruments were started on their way by rail
and air freight to the West Coast. The crates were
almost always heavy, and stamped SECRET in large
letters. Special shipping orders were prepared and
guards provided. In all, over 5000 pressure gages made
the journey, to snatch permanent meaning from tran-
sient chaos.
Even on the KENNETH WHITING, as she
steamed westward at 16 knots, the specially-installed
machine shop was busy with Ph.D's and technicians
working with lathes, drill presses, and the ever-needed
screwdriver.
But now, as A-Day approached, emphasis shifted
to installing the instruments. Let us look over the
kinds of pressure gages which were installed.
1. Can-Type Peak-Pressure Gage. This gage has
been described on a previous page. Hundreds were
67
BOMBS AT BIKINI
made ready. In the expectation that some would be
blown overboard, but might yet be rescued, many of
them were tied to floats. An identifying number was
marked on each can with a few crude strokes of a paint
brush dripping red paint.
2. Pipe-Type Peak-Pressure Gage. This gage also
had been described on a previous page. The gages were
bolted to the superstructures of the target vessels, par-
ticularly the innermost vessels.
3. Ball-Crusher Peak-Pressure Gage. This gage
was designed to measure very high pressures. It con-
sists of a strong hollow cylinder of metal, with a slid-
able steel rod mounted in the hollow. When the pressure
wave strikes, the rod is slid forcibly and strikes a
small copper ball, flattening it. The greater the pres-
sure, the harder the rod strikes and the flatter the ball
becomes. The degree of flattening is later measured,
and the pressure value calculated. Hmidreds of these
gages were made ready.
4. Ruptured Foil Peak-Pressure Gage. This gage
was designed for intermediate pressures. It is ex-
tremely simple. In one common form, it consists of a
sheet of aluminum foil sandwiched between two heav,y
metal plates. The plates have previously been drilled
to provide a graduated series of holes of different size.
When the pressure wave strikes, the tendency is for
the exposed areas of the aluminum foil to bulge or
even burst. Naturally, the larger exposed areas rup-
ture most easily, and the small ones least easily. It is
68
SCIENTIFIC OFFENSIVE
a simple matter, after an explosion has occurred, to
inspect the foil, pick out the smallest area which burst,
and thus compute the peak pressure. Hundreds of
these gages were used. Typically, they were bolted to
''Christmas trees,'' sturdy 9-ft.-high structures of
heavy steel pipes. The Christmas trees were ordinarily
welded to the upper decks of the target vessels.
5. Deformed Plate Peak-Pressure Gage. This gage
was used to measure fairly high pressure. It somewhat
resembles the ruptured foil gage in operating prin-
ciple, but employs a thicker foil or diaphragm, which
ordinarily deforms without actually rupturing. A va-
riety of designs were used to accommodate different
pressure ranges.
6. Indentation Peak-Pressure Gage. This gage also
was capable of measuring very high pressures. Pres-
sure is recorded in terms of indentation produced by
a small steel ball forced against a sheet of lead. The
greater the pressure, the deeper the indentation.
In addition, various gages of more conventional
type were used for measuring more moderate pres-
sures. Some of these were of the familiar aneroid-
barometer type. Others were of a liquid-trap type, in
which the pressure wave depresses the liquid in a tube
and causes some of the liquid to become trapped.
Most elaborate of the pressure gages were those de-
signed to trace the entire rise and fall of the pressure,
i.e., the whole life history of the pressure wave as it
swept past a given point. In some of these pressure-
69
BOMBS AT BIKINI
versus-time gages, pressure values are measured me-
chanically, by small pistons moving against springs.
In others, the principle of operation is electro-mechan-
ical. The pressure wave moves a piston whose motion
is opposed by a wire. The wire is thus strained to an
extent depending on the pressure, and the wire's elec-
trical resistance changes correspondingly. It is this
electrical change which is actually recorded and later
interpreted in terms of pressure.
The five thousand pressure gages were placed with
great care. The majority were placed topside on target
vessels. Many were placed in especially unencumbered
positions so that the pressure values recorded would
not be invalidated by confusing reflections of the pres-
sure wave. (Nearly every part of the ships' super-
structures acted as a crude pressure-wave reflector,
creating compound, hard-to-interpret, pressure situ-
ations.) Gages capable of recording very high pres-
sures were mounted on the ships nearest the Zeropoint ;
gages of lower range were used on ships farther out.
Gages designed to measure relatively low pressures
were placed inside turrets, control rooms, and living
quarters to show the pressures crews might experience.
Even airplanes scheduled to be aloft near the target
area were fitted with special gages.
Nobody expected all the gages to deliver valuable
data. A high ''disappointment rate" was anticipated.
Some of the gages might fail to start ; others might be
sunk with the ships they were on ; others might be dam-
70
Some of the five-gallon
cans which were exposed
by Dr. W. G. Penny's
Pressure Group at various
distances from the A-Day
explosion in air. Peak
pressures produced at
these distances were
computed from the de-
grees of crushing of the
cans. Some of the cans
were fastened to life-
preservers so that they
could be recovered if
blown overboard.
^^
mm ~'*^p|
1
""^A. "'^tm
-^^fcZ'"""""""
1
1^^-^^
■ -m
}
Wfr
L. A
■ VI
" . . ».-i
^
r
11
r
■1
m
ffl
jj
: K:
Dr. V. E. Brock (right) and Ensign Richard Cron, Navy diver, examine
a camera specially designed for use underwater, as in photographing
damaged portions of sunken ships. This work was made difficult after
Test B by the potential dangers from radioactivity in the water or in
the ships themselves.
Plate 9
A "hot" engine on a B-29 is tested by means of a Geiger counter
operated by Colonel R. L. Snider. The B-29's, which were part of Task
Group 1.5, were based at Kwajalein. They were used for dropping
the bomb used in Test A, photography, observation, and releasing
special air-pressure gages.
Plate 10
Besides normal-speed and high-speed motion picture cameras, many
mammoth still cameras were mounted in the photographic planes.
Eight photographers are needed to operate the cameras in this C-54.
The majority of the films were processed in an air-conditioned labora-
tory constructed at Kwajalein.
Motion picture cameras
installed in a C-54 photo-
graphic plane. The six
Eastman high-speed cam-
eras shown at the right
are aimed up and down,
right and left, by a single
control handle. They op-
erate one after another,
automatically, so as to
provide an uninterrupted
record of the entire
course of the explosion.
The resulting films were
superb.
4%r<
Plate
UPPER. Dr. C. W. Lamp-
son and Captain A. E.
Uehlinger inspect a rup-
tured-foil type gage for
recording peak pressure
in air. Ten aluminum foil
disks of different size are
visible. LOWER. Pendu-
lum type inclinometer for
automatically recording
angles of roll and pitch
of target ships. Records
consist of scratches on the
polished aluminum disks.
Plate 12
Members of Colonel S. L. Warren's Radioactivity Group sample the
lagoon water by means of a Nansen bottle. Amounts of radioactivity
in the water samples were determined with the aid of Geiger counters;
the resulting data were entered on a "contour" chart showing the
periphery of the "Geiger sour" area.
Plate 13
UPPER. Members of the BuOrd Instrumentation Group examine a deck-
mounted pyramidal orientometer, a device for showing the direction
from which the bomb's thermal radiation came. LOWER. Control
panel of one of the B-17 Flying Fortress drones.
Plate 14
Final inspection and as-
sembly of one of the
thirty "turtles" specially
designed by the BuOrd
Instrumentation Group
for recording pressure
produced on the lagoon
bottom by the huge
waves generated by the
B-Day underwater explo-
sion. Pressure elements
were of the Bourdon
type, being actuated by
water forced in by ex-
cessive external pressure.
Water entered through a
fine capillary serving as
a protective frequency
filter.
Ready to plant a turtle
on the bottom of the la-
goon. The turtle cases
were made of very heavy
steel to prevent their del-
icate contents from being
flattened by the ex-
tremely intense under-
water shock wave. For
ease of recovery the tur-
tles were attached to tar-
get vessels or special
buoys by means of slack
steel cables. However,
several of the turtles
placed near the center of
the underwater explosion
were never seen again.
Plate 15
In the Instrumentation Laboratory of the AG-76 AVERY ISLAND Mr.
A. H. Waite, Jr., of the Radioactivity Measurement Section, checks the
timing of an automatic pen-and-ink recorder. Such recorders were
used on support ships to make permanent records of data gathered
by automatic instruments on "hot" target ships. Several of the Geiger
counters on the target ships v/ere employed in such telemeter system;
readings were broadcast automatically to recorders on support ships
stationed several miles from Bikini Atoll. The permanent records ob-
tained were available for immediate use, or for more detailed analysis
at a later time. Such data were of especially great importance in
evaluating Test B, the underwater explosion.
Plate 16
SCIENTIFIC OFFENSIVE
aged by fires. Of course, the A-Day bomb might be
(and indeed was) detonated at an miexpected position,
which would mean that some gages would find them-
selves nearer the detonation than had been expected
while others would be unexpectedly far away; some
gages, accordingly, would give readings so large as to
be off-scale and others would read zero.
Other complications were that the target vessels, de-
spite their special moorings, were continually shifting
with the tide and wind. Pressure gages intended for
the exposed side of a target vessel might find them-
selves actually on the shielded side. Then there was
always the chance that the bomb itself would be ab-
normally weak and would produce only abnormally-
low pressures.
IMPULSE
To a physicist, impulse is no evanescent whim ; it is
a prosaic but useful measure of cumulative push. It
takes account of both the intensity of a push and
the duration of the push, and is thus a compound con-
cept. The intensity and the duration were both expected
to be very great in the Bikini explosions. Engineers
were undecided as to whether pressure, impulse, ve-
locity, or acceleration data would be most useful in ex-
plaining damage ; but all agreed that impulse was one
of the important quantities to be studied if explosions
71
BOMBS AT BIKINI
and explosion-produced damage were to be fully under-
stood.
Impulse can be computed directly from pressure-
versus-time data.* It can also be measured by special
gages which take account of intensity as well as dur-
ation of pressure. A number of such gages were con-
structed and placed at strategic locations on target ves-
sels. No detailed description of these gages is neces-
sary; many of them resemble some of the pressure
gages described on the previous pages, but contain
heavier, slower-moving pistons, better suited to taking
a long view of things.
SHOCK- WAVE VELOCITY
Shock-wave is the name given to a pressure wave
in its early, spectacular phase. To appreciate the spec-
tacular phase, one must recall the relatively unspectac-
ular behavior of most pressure waves. A typical pres-
sure wave, such as the sound wave produced by banging
a dishpan, leads a very dull life. It has no choice as to
the velocity of spreading. It always spreads at exactly
the same rate of roughly 1100 feet per second. This ap-
plies to faint sounds and moderately loud sounds, to
low-pitched sounds and high-pitched sounds. And such
* It is well known that at moderate and great distances from
an explosion, the overall impulse zV zero. That is, the initial push
is exactly balanced by the pull of the ensuing suction phase. Close
to the Zeropoint, however, the push always exceeds the pull, and
the overall impulse has a net value greater than zero.
11
SCIENTIFIC OFFENSIVE
a wave avoids suddenness: like an ocean swell, the
pressure increases gradually and then decreases grad-
ually.
But a shock wave has a personality of its own. In
the first place, its intensity is so great that it cannot
be content with spreading at the usual velocity — the
velocity of the fastest jet planes; it demands higher
velocity, equal to that of the fastest bullets. The more
intense the shock wave, the higher its velocity. Sec-
ondly, the pressure does not arrive at any given point
gradually, but all at once. A building, tree, or ship may
be enjoying an uneventful existence at one instant, but
an instant later it may be reeling under the full im-
pact by the pressure wave. There is absolutely no
warning. The destructive effect is diabolically maxi-
mized.*
The most energetic explosions produce the most in-
tense pressures and the most unusual Shockwaves. The
experts at Bikini therefore went to great lengths to
measure the A-Day shockwave. Spearheading the at-
tempts to measure shockwave velocity was a group of
high-speed cameras. Some of these, located atop special
towers on Amen Island, were operated automatically
and were capable of taking over 500 individual pictures
each second. By use of short exposure times, and, of
course, long focal length lenses. Captain R. S. Quacken-
* This suddenness, or vertical front phenomenon, is due to tlie
tendency of the hack part of the pressure wave to catch up with —
and, so to speak, ride on the shoidders of — the front part. The
result is of sledge-hammer severity.
73
BOMBS AT BIKINI
l)U8irs expert photographers hoped to produce the
world's finest portraits of mammoth shock waves.
Supplementing these cameras were other ingenious
devices. Various kinds of shockwave detectors were
placed at varying distances from the center of the
target area. Some of the detectors were located on the
target vessels; others floated on the water. Each de-
tector was capable of sensing the passage of the shoe]-:
w^ave and instantly dispatching a pre-arranged signal
to monitoring apparatus located a few miles away.
By such systems, shock-wave velocity could be deter-
mined much as the British air-raid wardens were able
to clock the rate of approach of a German airplane
heading for London. In the Bikini tests, however, th(^
velocities would be many times greater, and the signal-
ing had to be done without benefit of human hand.
OPTICAL RADIATION
The most spectacular result of Test A was to be the
terrific output of optical radiation, including visible,
ultraviolet, and infrared light. The intensity was ex-
pected to be greater than ever before produced on
earth — except, of course, b}^ the previously detonated
atomic bombs.
The character of the light was not expected to ])e
unusual. It has been known for many years that
any very hot body tends to emit visible, ultraviolet,
and infrared light. The atomic bomb, being extremely
74
SCIENTIFIC OFFENSIVE
hot during the process of Hying apart, thus conforms
with this rule.
Measuring the total emission of light of all kinds
was obviously desirable, since it would help to fix the
total amount of energy released in the explosion. Also,
it would help explain the flash burns to be produced on
test animals and equipment. Measurements were ar-
ranged by Commander S. S. Ballard and his colleagues
from the Naval Research Laboratory. This group,
called the Radiometry Subgroup of the Bureau of Ord-
nance Instrumentation Group, had laid its plans long
in advance. It had studied the optical radiation data
obtained in the previous year's test at Alamogordo; it
had estimated how greatly the absorption of Bikini at-
mosphere would differ from that of the dry atmosphere
of Alamogordo, and had then designed and build instru-
ments ideal for the job at hand. Principal reliance
was placed on bolometers and thermocouples, very
small devices which detect without discrimination light
rays of all kinds and directions. The received light pro-
duces small electrical changes, which are amplified and
ultimately cause small fountain pens to draw revealing
curves on long sheets of graph paper.
Of principal interest to the spectroscopists was the
spectral distribution, or the relative amounts of light
of short and long wavelengths.* These men wondered,
* In these optical studies the Naval Research Laboratory spec-
troscopists were assisted by spectroscopists from the Bureau of
Ships, the Army Air Forces, and various private institutions.
75
BOMBS AT BIKINI
for example, how the intensity of ultraviolet light
would compare with the intensity of visible light. Their
wonderings led to the preparation of a number of dif-
ferent instruments, each designed to answer a specific
question. Several broad spectral bands, for example,
were to be compared by means of photocells or electric
eyes. Each of these electric eyes was deliberately made
color-blind to all but a single color — by the use of
''rose-tinted glasses," or glasses of any other color de-
sired. Thus each photocell was made ready to report
the results in its own spectral zone. For more precise
discrimination between different parts of the spectrum,
spectrographs were used. These employed small prisms
and gratings to separate more cleanly the different
wavelengths ; results were recorded on strips of photo-
graphic film.
High-speed techniques also were brought in. Com-
mander Ballard knew that tremendous changes would
occur in the emission of optical radiation during the
first few instants after the detonation. The changes
Avould occur hundreds of times too fast for the human
eye to notice — even if the eye were not momentarily
blinded. To catch these rapid changes, photocells were
used. Their responses, free from any appreciable delay,
were to be translated by means of cathode ray oscillo-
graphs into the usual end-products dear to the heart of
scientists : accurate and permanent charts.
76
SCIENTIFIC OFFENSIVE
Size and rate of growth of the fireball came in for
much attention. The creation of the atomic bomb had
fascinated experts on thermodynamics who were ask-
ing themselves : When the explosion first occurs, which
gets oft' to the fastest start: the pressure wave? the
optical radiation ? the nuclear radiation ? or actual ma-
terials from the bomb ? Satisfactory answers were non-
existent. Everyone agreed that at the instant of det-
onation, the bomb, or at least what had been the bomb,
is extremely hot. Its temperature is perhaps of the
order of a million degrees Centigrade. And everyone
agreed that every bit of matter which has that temper-
ature cannot fail to emit enormous quantities of op-
tical radiation. (It is well known, for example, that
doubling tlie temperature of a hot body causes it to
emit sixteen times as much energy, so that the rate of
emission of energy from a body raised to a million de-
grees must be staggering indeed.) But a tremendous
complication at once sets in. The bulk of the energy is
of very short wavelength, a wavelength which the at-
mosphere refuses to transmit. Thus a curious kind of
leapfrog must be taking place: the short- wavelength
energy starts outw^ard, but before it has gone more than
a few feet, it is absorbed by the surrounding air. The
surrounding air, however, is so heated by having ab-
sorbed this energy that it becomes highly luminous
and itself radiates energy. This energy fares little
better than the previous generation and is in turn ab-
sorbed. So a sort of leapfrogging chain-reaction is set
77
BOMBS AT BIKINI
up, in \Yhich energy is l^eing constantly absorbed and
re-radiated. The velocity of light is well known; but
who knows the velocity of such a halting process ? The
process cannot be imitated successfully in the labora-
tory ; we have little to go on except estimates by ther-
mod\^iamics experts — and close study of Test A at
Bikini.
The rate of spreading of this optical radiation zone
(rate of growth of the fireball) was to be measured
principally by cameras. But no ordinary camera would
do. Two special types, the O 'Brien and the Bowen, were
obtained. Each of these had microsecond resolution;
that is, each could distinguish what happened from one
millionth of a second to the next millionth. Each was
set up several miles from the target area center ; each
was capable of charting the fireball 's development from
birth to old age, a total span of only one or two sec-
onds.
The lowly human eye was used also. In order to
escape temporarj^ blindness, it had to be protected by
dark goggles* or by the ingenious device called an
Icaroscope. It was realized in advance that goggles
could not be a perfect solution. Goggles satisfactory
for the instant of greatest brightness would, of course,
be too dark for the ensuing less-bright intervals. It
* Most of the 6000 users of the special goggles found them too
dark. This was due partly to the abnormally great extent to which
light was absorbed in traveling for mayiy miles just above the
surface of the water; also it ivas due partly to the desire of the
safety advisers to make doubly sure that no one would suffer any
78
SCIENTIFIC OFFENSIVE
would be necessary to throw aside the goggles durmg
this important transition stage.
A more versatile aid to the ''obsolete" human eye
was the Icaroscope. This device, invented during the
war by Prof. Brian O'Brien of the University of
Rochester, represents the first use of the optical analog
of the automatic volume control commonly used in
radio sets. In the Icaroscope, excess brilliance is elimi-
nated by means of an ingenious use of phosphorescence.
Phosphorescent images, not direct images, are viewed.
And whereas objects of intermediate brightness appear
little changed, over-brilliant objects are subdued to a
comfortable brightness. During the war the Icaro-
scope permitted effortless visual detection of airplanes
approaching directly ''out of the sun." At Bikini,
over fifty Icaroscopes were made ready for viewing the
almost-unviewable fireball. A few of the Icaroscopes
were scanned by motion-picture cameras instead of
eyes.
NUCLEAR RADIATIONS
Nuclear radiations, almost unknown to the public
prior to the obliteration of Hiroshima, are now well
known. Thus, gamma rays are true rays or waves;
they resemble X-rays, but can penetrate even a foot-
eye injury. The goggles actually transmitted only about 0.003 per-
cent of the light striking them; without doubt a transmission two
to ten times greater would have been better under the particular
conditions prevailing.
79
BOMBS AT BIKINI
thick steel wall. Beta rays are particles. Specificall.y
they are light-weight negatively-charged particles
called electrons; they can scarcely penetrate a sheet
of cardboard. Alpha rays are heavier particles and
carry positive charges; they too have little penetrat-
ing power. Neutrons are uncharged particles; be-
cause of their lack of charge they are slippery, hard
to stop. They can penetrate several feet of steel.
In preparing for A-Day, Colonel S. L. Warren and
other experts of the Radioactivity Group focused their
attention on a period of one minute. They knew that in
the A-Day Test, where the bomb was to be detonated
in the air, the great bulk of the materials producing
nuclear radiations would be carried upward by the
fireball and the mushroom. Only during the first
minute would the nuclear radiations be of outstanding
intensity.*
There was no mystery as to the source of the nuclear
radiation. It was known that the fission products
would be highly radioactive.! Fission product s, of
* It was expected that on B-Day, when the homb was set off
underwater, the materials emitting nuclear radiations would he
trapped in the water and would present a prolonged menace. Prep-
arations for this more complicated situation are discussed in a
later chapter.
t Fissionable materials themselves can, of course he injurious.
The Smyth Report states that among materials which are radio-
active or toxic are to he listed not only fission products but uranium
and plutonium themselves; uranium, aside from its radioactive
properties, is poisonous chemically, and plutonium is alpha-radio-
active.
80
SCIENTIFIC OFFENSIVE
course, is the blanket name given to the fragments
formed when atoms of uranium or phitonium are
split. The splitting, which occurs within a small frac-
tion of a second after the atom captures a neutron,
does not always give the same kinds of fragments. In
fact, more than 100 kinds have been identified.* Among
them are : nuclei of atoms of bromine, krypton, rubi-
dium, strontium, ytterbium, columbium, molybdenum,
antimony, telurium, iodine, xenon, cesium, barium,
lanthanum. As the bomb detonates, hilUo7is of hilUons
of such fragments are flung out.
To radiologists, the importance of these fission
products lies in their instability. The products are not
well-adjusted at the time of their birth, but go through
tumid tuous "nervous breakdowns"; their electrical
charge is poorly matched to their weight. Readjust-
ment usually takes the form of emitting gamma rays,
electrons, or neutrons.
The principal questions asked by radiologists were :
How rapidly do these readjustments come? How soon
are they finished? Which type of radiation predomi-
nates ? Of course, for any one kind of fission product
the answers may usually be obtainable in the labora-
tory; but the fission products are such a motley mix-
ture, such an ephemeral hodge-podge, that their cumu-
*A recent tabulation, presented in the Jouryial of the American
Chemical Society for Novemher 1946, lists 160 fission products
(including isotopes).
81
BOMBS AT BIKINI
lative effects are very difficult to predict. Studies have
been made, of course, of fission products produced in
the piles operating at Oak Ridge and elsewhere. But
those fission products are born of a different process ;
they result from fission produced by slow neutrons.
Only when an atomic bomb explodes can the fission
products of a fast neutron chain reaction be studied.
From the tactical point of view^ this question was
important: How far out does the gamma radiation
reach ? It was well know^i that gamma radiation is ab-
sorbed, by air; but definite answers were lacking as
to just how many hundreds of yards of air were needed
to protect exposed personnel. For neutrons, too, in-
formation on shielding by air was incomplete. With
respect to both gamma and neutron radiations, more
information was needed as to the protection afforded
by steel walls. It was recognized that persons located
below decks would be relatively protected, but the exact
extent to which such protection really would save lives
was not known.
Colonel Warren's group brought to Bikini more
than 20,000 devices for measuring nuclear radiations.
The commonest device used for measuring gamma ra-
diation consisted merely of a small piece of unexposed
photographic film wrapped so as to exclude all light.
This device, called a badge, does its job silently and
simply. When gamma rays strike the badge, they pene-
trate the wrapping and produce a slight change in the
photographic emulsion. When the badge's message is
82
SCIENTIFIC OFFENSIVE
to be read, the badge is placed in photographic develop-
ing solution, and the emulsion becomes darkened. The
degree of darkening indicates the total amount of
gamma radiation which struck the badge. Such badges
were among the simplest and most reliable of all gages
used at Bikini. Thousands were used for each of the
two explosions. They were placed at innumerable posi-
tions topside on target vessels, below decks, and in the
same compartments where test animals w^ere sta-
tioned.*
Geiger counters were to be used to find the intensity
of gamma radiation at any one moment. These count-
ers are especially useful because they produce their
answers at once — either by motion of a needle across
a dial, or by producing a machine-gun noise in head-
phones. The marvel of the Geiger counter is that it can
detect a single pJioton, or unit of gamma radiation.
Heart of the counter is a crude electron tube, contain-
ing a central wire and a small quantity of gas; the
wire is at critically high voltage, such that the slightest
disturbance — even the slight disturbance produced by
arrival of a single photon of gamma radiation — com-
pletely upsets the electrostatic regime and causes a
violent discharge of current. Equilibrium is restored
* Much operational use was made of such badges. They were
carried continuously by persons working in contaminated areas
where unsuspectedly large dosages of gamma radiation might be
acquired. By developing and analyzing the badges, reliable an-
swers could be found as to whether or not over-exposure had oc-
curred. Fortunately, the answers were always in the negative.
83
BOMBS AT BIKINI
almost instantly, and the counter is ready to detect the
next photon. Detecting and even counting these dis-
charges is simple enough. Many different varieties of
Geiger counters were prepared. Some were easily car-
ried in the hand, for making quick spot checks. Others
were equipped to operate for long periods of time with-
out attention, recording their experiences on gi'aph
paper or even radioing their findhigs to men and re-
cording instruments located a few miles away. A few
were equipped to operate underwater. Some were
mounted in drone boats, a few carried in planes.
Preparations were made for measuring alpha, beta,
and neutron radiations also. Various standard types of
instruments were used; far fewer were required than
for gamma radiation.
TEST ANIMALS
Noah would have felt at home on the BURLESON.
But he would have been surprised at the selection of
animals which Captain R. H. Draeger (Navy Medical
Corps) brought. There were 200 pigs, 60 guinea pigs,
204 goats, 5000 rats, and 200 mice.
There was nothing haphazard in this choice. The
animals selected must be capable of keeping in good
health despite weeks spent on shipboard. Tropical
weather must not wilt them. They must be amenable to
remaining for days in confined quarters and com-
pletely unattended. More important they must be of
84
SCIENTIFIC OFFENSIVE
types already carefully studied ; it would be necessary
to translate their reactions into reactions of men.
Pigs were particularly valuable since their skin and
short hair are comparable to man's. Goats were useful
because their weight is comparable to man's and the
quantity of their body fluid is sufficient for extensive
laboratory analysis. Rats, time-honored experimental
animals of radiology, were a logical choice since so
much is known about their response to radiation and
the correlation of their responses with man's.
Some of the goats taken along were selected for
their psychoneurotic tendencies. Psychologists thought
that the severe explosion phenomena might change
these tendencies.
The mice were chosen from special strains show^-
ing especially great likelihood of developing cancer,
or especially small likelihood. Here too it was hoped
that some interesting change would be produced, either
in these mice themselves or in their progeny.
No dogs were included. During the early planning
of the operation many letters were received from the
public urging that dogs be excluded.*
Surprising though it may seem, the main purpose
of placing test animals on the target vessels was not
to find what percentage of the ships' crews would be
injured or killed. That information could be obtained
without using test animals. It could be obtained by
* Over 50 jjercent of the letters of protest received from the
public condemned the use of animals. A smaller percentage ex-
85
BOMBS AT BIKINI
instruments and calculations. Pressure gages, for ex-
ample, would provide accurate knowledge of pressures
produced. And previous history, such as that of Lon-
doners exposed to German bombing attacks, had al-
ready shown clearly what pressures would do to men.
It was well known that sudden pressures of one hun-
dred pounds per square inch could kill a man outright.
It was known that pressures of only five pounds per
square inch could throw a man so vigorously, that if
his head struck a hard surface, he might be killed. For
gamma radiation the situation was similar. Gages
woul(J show the intensity of the radiation, and pre-
vious experience in laboratories would show how to
evaluate the data in terms of injury to men.
The real purposes of using test animals were these :
(1) to show the types of symptoms produced by the
explosions; (2) to provide experience in cataloging
injuries and detecting the onset of slowly-developing
injuries; (3) to provide experience in treating injur-
ies; and (4) to reveal any new^ kinds of effects. The
injuries of principal interest were, of course, those
caused by nuclear radiations. Such injuries were found
at Hiroshima and Nagasaki, but the significant facts
had often been lost in the welter of confusing circum-
stances such as fires, floods, starvation, exposure, lack
pressed fear of a widespread calamity. One writer was very grieved
that the A-Day program was to come on a Sunday, intended to be
a day of quiet and prayer; he expressed great relief when he was
informed that Sunday in U. S. A. was actually Monday at Bikini.
86
SCIENTIFIC OFFENSIVE
of medical care. Little success had been encountered in
trying to reconstruct the relationship between injury
and cause of injury. It was to fill such gaps that test
animals were taken to Bikini. However, the number
taken was kept to a minimum.
Captain Draeger and his Executive Officer, Captain
Shields Warren (Navy Medical Corps) were well sup-
ported in their work. Starting with an important plan-
ning conference held in early January 1946, at the
Naval Medical Research Institution at Bethesda, Md.,
full cooperation by many agencies was obtained. These
principal Arnw and Nav,y medical research agencies
helped: Arniy Chemical Warfare Service (including
the Biological Warfare Division), Army Medical
Corps, Navy Bureau of Medicine and Surgery, Naval
Medical Research IiLstitute. Also cooperating were the
National Institute of Health of the United States Pub-
lic Health Service, the United States Department of
Agriculture, the National Cancer Institute, the United
States Geological Survey, and various universities and
private research agencies.
The BURLESON began taking aboard animals at
the end of May 1946, in San Francisco. The special
accommodations provided for the animals were found
to be very satisfactory. The ship began its westward
trip on June 1; she started long after the other ves-
sels, and made a fast run. The object, of course, was to
have the animals in the best possible condition at the
time of the first Test.
87
BOMBS AT BIKINI
Two weeks before Test A, the BURLESON passed
through Enyu Channel and joined the 140-odd support
ships already anchored at the northeast corner of the
lagoon.
88
6
BIKINI OVERTURE
The SUMNER and the BOWDITCH were
among the first of the ships to reach Bikini. In late
January 1946, the Chief of Naval Operations arranged
for these ships to proceed to Bikini to make needed
surveys and oceanographic studies. SUMNER did the
bulk of the hydrographic surveying. Her work was es-
pecially urgent because the only available hydrographic
charts of Bikini were Japanese and were quite inade-
quate. SUMNER and assisting ships made some use of
acoustical bottom scanners, but principal reliance was
placed on wire-drag methods.
The survey was finished in April, and the data were
flown to the Navy's Hydrographic Office in Washing-
ton, D. C, where the new charts were printed. Figure
3 is a simplified chart showing the form of the 26-
island Atoll. The earlier names of the Atoll's 26 islands
were difficult to spell and would have been almost im-
possible to handle in dispatches. Accordingly a set of
simple code names was adopted by the Task Force.
The two groups of names are as follows :
Earlier Name Code Name
Airukiiji , Arji
Airukiraru Airy
89
BOMBS AT BIKINI
p
<
CO
90
Aomoen
Arriikan
Bigiren
Bikini
Bokoaetokutokii
Bokobyaadaa
Bokonejien
Bokonfuaakii
Bokororyiiru
Chieerete
Eniairo
Eniirikkii
Eninman
Enyu
lonchebi
Namu
Oiirukaen
Re ere
Rocliikarai
Romurikkii
Riikeji
Uorikku
Yomyaran
Yurochi
BIKINI OVERTURE
Amen
Aran
Biren
Bikini
Boku
Boby
Bone
Bokon
Boro
Cherry
Enar ,
Erik
Eman*
Enyu
Ion
Namu
Oruk
Reer
Rokar
Romuk
Ruji
LTku
Yoran
Yuro
BOWDITCH, which arrived at Bikini on Marcli
10, 1946, gave valuable assistance to the SUMNER.f
But BOWDITCH '8 main job was making ocean-
* This was later changed to "Prayer" to avoid confusion with
"Amen."
t The BOWDITCH was huilt in Copenhagen over 30 years
ago. She still retains her promenade deck, square portholes, and
broad staircases. She was easily recognized hy her trailing column
of black smoke.
9!
BOMBS AT BIKINI
ographic, biological, and geological .surveys of the
atoll. Aboard her were wave motion experts, icthvolo-
gists, botanists, zoologists, and geologists drawn from
the Woods Hole Oceanographic Institution, the Uni-
versity of California's Scripps Institution of Ocean-
ography, the Smithsonian Institution, the University of
Michigan, the U. S. Geological Survey, the U. S. De-
partment of the Interior's Fish and Wildlife Service,
and the Army and Navy. These men, led by Lieutenant
Commander C. A. Barnes of the U. S. Coast Guard,
were the first scientists to reach Bikini, and they were
among the last to leave. Their most urgent job was
studying the lagoon currents to find out what might
happen after the B-Day explosion, which would cer-
tainly disperse enormous quantities of radioactive ma-
terials in the water. Prompt re-entry into the target
area would depend largely on accurate knowledge of
these previously-uncharted currents.
The BOWDITCH'S scientists also took censuses of
populations of fishes, corals, and other animals, to per-
mit later evaluation of the effects of the bombs on ani-
mal life of the atoll. Fish were caught with hook, net,
and seine. In some instances, the fish were poisoned
with rotenone and picked up dead. To increase the sig-
nificance of the censuses, similar censuses were taken at
unaffected ''control" atolls, Rongerik and Rongelap,
125 miles upwind, and also at Eniwetok, 200 miles
downwind. Botanists made systematic surveys of plant
life, and geologists gave the atoll the most thorough
92
BIKINI OVERTURE
going-over ever accorded one of these billion ton piles
of skeletal remains.
The order to evacuate the natives came from the
Navy Military Government Officer in February, when
choice of Bikini as the test site became final. The
Bikinians, convinced that the Tests would be a contri-
bution to world peace, indicated their willingness to
evacuate.* Their decision was reached at a meeting of
the Atoll Council. Nine of the eleven alaps (family
heads) named Rongerik Atoll, 128 miles to the East, as
their first choice for resettlement. Lajrwe, Paramount
Chief of Rongerik, concurred in this proposal. The trip
was made on March 7, 1946, on LST 1108. Although
much effort was spent to establish the Bikinians com-
fortably on Rongerik, some dissatisfaction and nos-
talgia have been apparent. Whether they will remain
there is uncertain; radioactivity at Bikini renders
their return there unsafe at present.
Japanese mines had to be cleared from Bikini
Lagoon before the support and target fleets arrived.
Thirty-five mines had been located and removed dur-
* Juda, Magistrate of Bikini Atoll, commonly called King of
Bikini, witnessed one of the Tests, hut the other 161 inhabitants
obtained only second-hand accounts. He was flown back to Bikini
the day preceding B-Day, before final approval for such a visit
had been obtained from the Joint Chiefs of Staff. He was received
aboard the flagship MT. McKINLEY amid much embarrassment.
The situation was saved by a quick interchange of radiograms with
the office of the Joint Chiefs of Staff' in Washington, D. C. Word
came back to Bikini that the Task Force Commander might "use
his judgment" in the ^natter.
93
BOMBS AT BIKINI
ing September and October of 1945 by Task Unit
96.38.1 under the Commander of the Marshall-Gilberts
Area. Five more mines were removed during March
of 1946 by Commander, Minecraft Pacific, Task Unit
18.11.
Coral heads were another menace to navigation
inside the Lagoon. They consisted of great underwater
obstructions rising nearly 200 feet above the lagoon
floor. Many of them extended up to the level of the
lagoon surface. Composed of corals and also deposits
made by the calcerous algae, they were solid enough
to damage any ships which might collide with them.
Some were in positions to interfere with the mooring
of target vessels or to impede the submerging of the
target submarines. Accordingly, the tops of these coral
heads were removed by dynamiting. Over 100 tons of
dynamite were used.
Much construction work was required on Bikini
Atoll. Principal structures built were the following:
. 12 75-ft. steel towers for mounting cameras
and other technical equipment. (In view
of high winds prevailing, these towers
were constructed in horizontal position
and then hoisted into vertical position.)
5 25-ft. wood towers
12 20 ft. X 20 ft. steel huts
5 Seismograph huts
5 '^ Dead-man" moorings for Test C
6 Photography beacons, for aerial photog-
raphy fixes
94
BIKINI OVERTURE
■ 1 Club (20 ft. X 200 ft.) for officers and
civilians
1 Club (16 ft. X 300 ft.) for enlisted men
5 Concrete basketball courts
10 Volley ball courts
4 Softball diamonds
1 Trap-shooting range
1 Concrete athletic court (100 ft. x 100 ft.)
26 Dressing huts
1 Water distillation and distributing system
1 Shore patrol and dispensary building
3 Life-guard platforms
1 Seaplane landing ramp
2 Swim floats
7 Pontoon causeways
1 Air-coordination station
3 Construction battalion shops
1 Sonobuoy work shop
10 Wave-height measurement piles
14 Shallow-water moorings for evacuation
barges and other small craft
2 Radio beacons
5 25-man camps
1 Aerological station
This construction was done by the 53rd Naval Con-
struction Battalion. The first group of the Construc-
tion Battalion to arrive at Bikini was a survey party
which arrived on March 11. By March 20 the entire
Battalion had arrived.
To reduce the insect nuisance, Bikini and Enyu
Islands were sprayed every few weeks with DDT;
95
BOMBS AT BIKINI
Amen and Erik were sprayed once. These precautions
proved effective.
Preparing moorings was a large job. The mooring
positions had been specified several weeks in advance,
in Washington, D. C. ; plans called for mooring bows
and sterns of the central target ships to prevent exces-
sive shifting: with tide and wind.*
^fc)
FORCE ORGANIZATION
Technical and scientific preparations were nearly
complete as A-Day approached. But the success of that
day was to depend fully as much on the Force Organi-
zation as on the Staff and Technical Organization.
The Force Organization was responsible for oper-
ations. After policy questions had been decided by
the staff organization and after the technical require-
ments had been decided by the technical men, it be-
came the responsibility of the Force Organization to
execute the necessary action in the field.
The Force Organization which had been adopted
by Admiral Blandy was designed especially to meet
the unusual requirements of the Operation. Eight sep-
arate Task Groups were created.
*A typical mooring consisted of a buoy, a riser chain, a clump,
three 10-ton anchors, and three anchor chains. The clump was a
10-ton concrete block resting on the bottom of the lagoon. It was
attached to the anchors by means of 500-ft. chains. The riser chain
coymecting the buoy and the clump was made as short as feasible,
to limit the swing of the attached target vessel.
96
BIKINI OVERTURE
Task Group 1.1, the Technical Group, was com-
manded by Rear Admiral W. S. Parsons, who was also
Deputy Task Force Commander for Technical Direc-
tion. The group included seven large laboratory ships,
several radio-controlled drone boats, and LSM-60,
which was the ship from which the B-Day bomb was
to be suspended.
Task Group 1.2, the Target Vessel Group, was com-
manded by Rear Admiral F. G. Fahrion, who had also
served as Commander of the Advance Echelon and
Commander of all the Naval Task Groups until the
Task Force Commander's arrival at Pearl Harbor.
From his Task Group flagship FALL RIVER, Ad-
miral Fahrion directed all operations of the 93 target
vessels, including mooring them. (These vessels are
listed in Appendix 9.)
Task Group 1.3, the Transport Group, was com-
manded by Captain W. P. Davis (Navy), who was re-
sponsible for the press ship APPALACHIAN, the
observer ships BLUE RIDGE and PANAMINT, and
eleven other large transport ships which were to quar-
ter and mess the target ships' crews after those ships
had been evacuated.
Task Group 1.4, the Army Ground Group, was led
by Colonel J. D. Frederick. It was responsible for all
opei-ational activities by the Army Ground Group. In-
cluded were units drawn from the Signal Corps, Ord-
nance Department, Chemical Corps, Quartermaster
Corps, and Army Air Forces. Principal activity was
97
BOMBS AT BIKINI
exposing as many types of Army equipment as pos-
sible to the explosions and determining the damage
produced.
Task Group 1.5, the Army Air Group, was com-
manded by Brigadier General R. M. Ramey. It was
responsible for all operations by Army planes. Its Air
Transport Unit, comprising ten C-54's each capable
of carrjdng 54 persons, flew thousands of tons of Cross-
roads personnel and freight between Kwajalein and
the United States. Its Tactical Operations Unit, com-
prising 13 B-29's, flew the bomb-carrying plane used in
Test A and also flew weather and radiological recon-
naissance planes. Other units operated photographic
planes, scientific instrumentation planes, and radio,
press, and observer planes. The Drone Unit was unique
in aviation history; it successfully operated 6 B-17
Flying Fortresses as drones. With no one aboard, these
great planes were radio-guided through their pre-
scribed flights across the target area, a unique and im-
pressive feat.*
*A number of Army Air Forces officials believe that the drone-
plane program midertaken for Crossroads advanced the science
of drone-plane operations by a year or more. To be sure, a few
ivar iveary B-17's had been flown ivithout crews during the latter
part of the recent war, but they and their cargoes of explosives were
deliberately crash-landed. Also, a few B-17's had been landed by
remote control; but pilots were aboard, ready to take over control
in case of trouble. Operation Crossroads was the first operation in
which take-off, flight, and landing were accomplished with no one
aboard. The feat was an impressive one; many experts had thought
it could never be accomplished with planes of this size.
98
BIKINI OVERTURE
Their photographic and air-sampling missions were
accomplished withont accident to any of the participat-
ing Fortresses.*
Task Group 1.6, the Navy Air Group, was com-
manded by Rear Admiral C. A. F. Sprague. This group
added to aviation history by perfecting the radio-con-
trol of drone planes catapulted from an aircraft car-
rier.! Such planes were used for photography and for
collecting air samples. The Group also operated four
helicopters, fifteen PBM patrol planes, and several
TBM avengers for use in guiding drone boats. Activi-
ties were based principally on the carriers SHANGRI-
LA and SAIDOR.
Task Group 1.7, the Surface Patrol Group, was
commanded by Captain E. N. Parker (Navy). It was
to play an especially large part in the radiological
safety operations immediately following the under-
water explosion. Test B.
Task Group 1.8, commanded by Captain G. H.
Lyttle (Navy), was responsible for many services, in-
* Closest approach to an accident occurred just after the B-Day
explosion, when one of the B-17 drones, returning to its Eniwetok
base overran the runway and came to rest on the heach. The plane
had been flying directly above the Zeropoint when the explosion
occurred, and its brakes had been damaged. Fortunately, over-
running the runway did no damage of any significance.
t The drone planes, F6F Hellcats, were not landed on the carrier
but on an airfield at Roi, an island of Kwajalein Atoll. Shortly
before the A-Day explosion one of the drones went out of control
and crashed.
99
Woods Hole Oceanographic Institi^ion
BOMBS AT BIKINI
eluding repair, fueling, water, mail, provisions, recre-
ation, hospitalization, and evacuation.
Lines of organization were pleasantly invisible at
Bikini. Officers and enlisted men, scientists, and ob-
servers, became a part of the tropical scene.
Shrill pipes called the men early each morning.
Breakfasts were varied and substantial. Plans of the
day were posted. Climbing from their steel- walled liv-
ing quarters to the clean gray decks, the men gave first
attention to the weather. Fortunately, fair weather
and cooling breezes usually prevailed. Tuna and barra-
cuda could occasionally be seen circling the ship.
The clutter of small boats flanking each ship came
to life. .Coxswains and their crews climbed out along
booms extending over the water; they descended by
rope ladders into the yawning boats bobbing up and
down on the waves. They warmed up the engines, re-
ceived megaphoned orders from the officer-of-the-deck,
cast off, and then picked up their loads of scientists,
technicians, and inspectors.
By 9 :00 a.m. thousands of men had been deposited
on the target vessels. They installed apparatus, tested
it, and adjusted it. They put animals aboard, placed
them in their cages, filled their reservoirs of food and
water. They hoisted trucks, airplane sections, machine
guns and field artillery aboard and secured them to the
decks with steel cables running through eye-bolts.
Boxes of pyrotechnics, canned goods, and medical sup-
plies were taken aboard, made fast, and clearly labeled.
100
Woods Hole Oceanographic Institution
BIKINI OVERTURE
Meanwhile ships' engineers and their assistants were
shutting down machinery and getting ready to close all
watertight compartments. When the day of the test
should finally arrive.
Throughout this scene of apparent confusion pho-
tographers and inspectors made their way, intermin-
ably photographing everything of interest and taking
voluminous notes on ready-made forms. No reliance
was to be placed on memory. The aim in the tests was
not merely success or failure, but accurately-inscribed
data sheets by the ton which could be referred to with
confidence in the future.
Meanwhile force and staff conferences were being
held on the MT. McKINLEY and good progress was
reported.* Press conferences were held on the port deck
of the APPALACHIAN.!
Men lucky enough to receive liberty picked up their
swimming trunks, piled into LCVP's or whale boats
and made for Bikini beach a few miles to the north.
They spent the afternoons swimming, playing baseball,
* 7^ is not surprising that scientific and operational groups
occasionally found themselves on opposing sides of discussions. Tech-
nical men showed no embarrassment in proposing whatever changes
of plaris would permit gathering better data. But operations men,
anxious to avoid last-minute complications, favored standing pat.
Because the Operation was basically a technical one, the technical
men usually had their way.
t Dr. R. A. Sawyer, Technical Director, brought with him to
one of the press conferences Mr. R. S. Warner, Jr., Los Alamos
bomb expert. He introduced Mr. Warner as "the man who will tell
you almost anything about the bomb — except what you want to
know."
101
BOMBS AT BIKINI
drinking beer and soft drinks. In the evenings they
attended motion picture shows on deck.* Recreation
was made as pleasant as possible.
Rehearsals and weather dominated discussions dur-
ing the last few days before A-Day. Many informal re-
hearsals were carried out by the various groups sep-
arately, and there was one full-dress rehearsal. This
was held on Queen Day, June 24, and was completed
with success.
The importance of weather was far greater than
might be expected. Naturally, clear skies were desired
by observers and photographers. Good visibility even
from an altitude of five or six miles was needed by the
bombing plane; no mistake could be tolerated in its
identifying of the brightl.y-painted Zeropoint ship,
NEVADA. High winds might have interfered with
bombing accuracy and drone plane operation ; unsteady
winds might have permitted the radioactive materials
in the air to be swept back over the support ships. Even
though the winds might be steady at low altitudes, a
counter current at high altitudes might have been dis-
astrous to the support ships. But perhaps the most
stringent requirement was that good weather be pre-
dictable 24 hours in advance. Only on the basis of firm
advance prediction could the great A-Day program be
gotten underway.
* For the 42,000 men of the Task Force, daily requirements in-
cluded 70,000 candy bars, 40,000 ^founds of meat, 89,000 pounds of
vegetables, 4,000 pounds of coffee, 38,000 pounds of fruit.
02
BIKINI OVERTURE
Early in the morning of June 30 the weather ex-
perts made a prediction of fair weather and favorable
winds for the following day, which was to be A-Day.
The word was flashed to all ships and land stations,
and to the entire world. Scientists gave their instru-
ments a final tuning up, test animals were placed at
their proper locations, target vessels were closed and
the crews were taiken off.
By dusk the evacuation of the lagoon was well
underway. For hours the support ships had been filing
silently southward, out into the open sea. No longer
was the lagoon fiUed with twinkling lights and sputter-
ing small boats. The target vessels la}^ deserted, a dark
cluster in front of the thin dark line of abandoned
beaches. For several of the ships, the sun had set for
the last time.
03
7,
TEST A: EXPLOSION IN AIR
The Test-A bomb exploded at exactly 34
seconds after 9:00 a.m. on July 1, 1946, Bikini local
time, or approximately 5 :01 p.m. June 30, 1946, East-
ern Standard Time.
The bomb had left Kwajalein at 5:55 a.m., aboard
the B-29 Dave's Dream, Aircraft No. 44-27354. It had
been loaded on the previous day. At the originally
scheduled take-off time, 5.34 a.m., the bomber was
standing ready and waiting. But uncertain weather
caused a short delay; the go-ahead signal was not
radioed from the MT. McKINLEY until 5 :40. Three
minutes later the plane taxied towards the take-off
position at the western end of the runway. The take-
off itself was uneventful.*
Climbing slowly, the bombing plane held a north-
westerly course. It reached bombing altitude over
* Those who climhed aboard the plane were: Maj. W. P. Swan-
cutt, Airplane Commander; Brig. Gen. R. M. Ramey, Task
Group 1.5 Commander; Col. W. J. BlancJiard, Air Attack Com-
mander; Capt. W. C. Harrison, Jr. (Army), Co-Pilot; Maj. H. H.
Wood, Bombardier ; Col. J. R. Sutherland, Bomb Commander;
Ens. D. L. Anderson, Weaponeer; Mr. L. D. Smith, Weaponeer;
Capt. Paul Chenchar, Jr. (Army), Radar Observer; Maj. W. B.
Adams, Navigator; Lt. R. M. Glenn (Army), Flight Engineer;
Corp. R. M. Modlin, Scanner; Corp. H. B. Lyons, Scanner; Tech.
04
TEST A: EXPLOSION IN AIR
Wotho Atoll, and continued on until 8:03 a.m., when
it arrived over Bikini Atoll. Its first practice run
over the target was made to check wind velocity figures
received by radio from the aerological group.
The final practice run, a full-rehearsal run, began
at 8 :20 a.m. A radar beacon at Bikini was picked up
from a distance of 50 miles and was used to time the
approach and maintain the desired course of 45 de-
grees true. The Bomb Commander and his tw^o weapon-
eers made last minute adjustments to bomb and bomb-
sight. A flashing lamp on the NEVADA came into
view; NEVADA'S high-visibility paint was clearly
identified. The simulated practice drop was made at
8 :31 a.m.
The final run began at 8:50 a.m., from a distance
of more than 50 miles. Course and altitude were held
constant. Visibility was excellent. Within a few seconds
of 9 :00 a.m. the bomb was released and the bombardier
called "Bomb away, bomb away!"
Bomb bay doors were then closed, and the plane
made a 150 degree level turn to the left. It made a
shallow dive, losing 1000 feet altitude while increas-
ing speed of get-away.
Sgt. J. W. Cothran, Radio Operator. Major Swancutt's crew had
been chosen for the job after long training at the bombing ranges
at Alamogordo, N.M.; Albuquerque, N.M.; and over Erik Island
of Bikini Atoll. His crew was winner in a strenuous competition
among many other outstanding crews. His plane was yiamed after
Capt. David Semple, Army bombing expert and leading bombardier
in the early competition, who was killed in a B-29 crasli m Neiv
Mexico before the move to Kwajalein.
105
BOMBS AT BIKINI
During the first few seconds of the bomb's descent,
the bomb's course was almost parallel to that of the
plane itself, and its velocity too was essentially the
same (roughly 300 miles per hour). The downward
velocity of the bomb increased rapidly at this point.
The target, enjoying its last few seconds of normal
existence, was the most gigantic test target ever as-
sembled. Enclosing it was the deserted circle of islands
and reefs; beached on Bikini were: one LST, two
LCI's, four LOT'S, five LCM's, and 6 LCYP's a total
of eighteen landing craft. Anchored on the surface of
the lagoon were two great PB2Y-5E Coronado sea-
planes.
But the heart of the target area was the great fleet
of vessels clustering about the NEVADA.* Nearest
the NEVADA were the Japanese battleship NAGATO,
the Japanese cruiser SAKAWA, the carrier INDE-
PENDENCE, the cruiser PENSACOLA, the sub-
marine SKATE, the destroyer HUGHES, the con-
crete oil barge YO-160, and the small LCM-1. The full
list of target vessels is given in Appendix 9.
Just outside the Lagoon, 42,000 men lined the rails
of their ships and waited. Nearest support ships, ten
* Ships located very near the huU's-eye, and ships almost di-
rectly upwind from the hull's-eye, carried light loads of fuel (10
to 33 percent) to avoid fires which might spread and envelop the
very closely-spaced ships. The remainder of the ships carried large
fuel loads ranging from 50 to 95 percent of capacity. Ammunition
loads were arranged in general accord with this same scheme. The
loading as well as the spacing was approved hy the Joint Chiefs of
Staff.
106
TEST A: EXPLOSION IN AIR
to fifteen miles away were : APPLING, ARTEMIS,
AVERY ISLAND, BARTON, BEGOR, BURLE-
SON, CUMBERLAND SOUND, HAVEN, HEN-
RICO, LAFFEY, MT. McKINLEY, O'BRIEN,
WALKE, WHARTON, WHITING. Other ships
were fifteen to twenty-five miles away.
Waiting aloft were airplanes, manned and un-
manned. Nearest manned planes were Dave's Dream
and the F-13 photographic plane, Eggleston Eight.
Nearest drone planes were three Navy F6F drone
planes and one Army B-17 drone plane, all at twenty
miles. There were three more Army B-17 drone planes
at thirty miles.
The bomb never reached sea level. When still sev-
eral hundred feet in the air, its special fuze came into
action and set the uncontrolled nuclear chain reaction
in motion. Generation after generation of fast neu-
trons sprang to life, born out of the atoms undergoing
fission. Each generation was much larger than its
predecessor. The last few generations, born only a few
millionths of a second after their remote ancestors,
were prodigious. The number of neutrons at work ex-
ceeded the population of the earth.
An amount of matter no heavier than a dime was
annihilated. But the energy release was enormous,
being roughly 1,000,000,000,000,000,000,000 ergs. This
was equivalent to the detonation of approximately
20,000 tons of TNT, a weight too great to be carried
even by the world's largest fleets of giant bombers.
107
BOMBS AT BIKINI
This huge quantity of free energy could not be tol-
erated by the bomb case. The outrush of energy was so
violent that it would be inaccurate to say that the
bomb case cracked or even melted. It simply sprang
outwards in all directions as though it were a gas ; indi-
vidual atoms shot outward with speeds far exceeding
the velocity of sound. Each atom started its trip in-
stantaneously, and without regard to previous physical
condition. It was literall.y ''every atom for itself" in
the chaotic rush from the intolerable concentration of
energy.
Atoms were not alone in their outward flight. Neu-
trons, beta particles, and protons joined the rush.
Mingled with them were the highly radioactive fission
products.
Electromagnetic radiations, too, joined the surge.
Gamma rays of extremely great intensity started out-
ward with the velocity of light, and ultraviolet light,
visible light, and infrared light followed suit. These
wave-like radiations tended to outrace the atoms and
nuclear fragments.
It was the visible light which gave the observers
their first indication that the explosion had taken
I^lace. This light, accompanied by invisible ultraviolet
and infrared radiation, sped onward, and even at dis-
tances as great as the moon it would have been clearly
visible.
Let us slow down the events of the first few seconds
after the detonation and examine each phenomenon
08
TEST A: EXPLOSION IN AIR
closely in the light of all information now available and
releasable. What the eye took in was relatively incon-
seqnential, but the complete sto-ry revealed by the pha-
lanx of instruments is a tremendous one. To analyze it
fully will require hundreds or even thousands of man-
years of effort by army and navy engineers.
For simplicity, we shall use Zeropomt hereafter to
indicate the actual position of the bomb at the instant
of detonation (Mike Hour) ; projected Zeropoint re-
fers to the point on the Lagoon surface directly be-
neath the Zeropoint.
SHOCK- WAVE VELOCITY
From the detonating bomb the spherical shock wave
in air spread rapidly. High speed cameras clocked its
expansion. Very close to the bomb the shock wave ve-
locity was extremely great, undoubtedly more than
three miles per second, or 10,000 miles per hour. No
bullet or rocket has ever approached this speed.
Even by the end of the first tenth of a second the
shock wave had slowed considerably. Before one sec-
ond had passed, it struck the water and forced the
surface down several feet throughout a wide area. The
shock wave reflected from the surface of the water now
joined the direct wave ; the merged wave then expanded
at very high speed, whipping the surface of the water
into shimmering fury. Many of the air-borne cameras
109
BOMBS AT BIKINI
made excellent records of the line of demarcation be-
tween agitated water and water not yet swept. The
shock wave buffeted every ship of the target array and,
still traveling at velocity greater than that of sound,
continued its outward sweep.
After traveling three miles, the shock wave had lost
much of its original character. Its hammer-blow qual-
ity was less pronounced, and it took on the character
of a sudden violent gust of wind. The automatically-
operated motion picture cameras on Bikini showed the
palm trees shake vigorously as the invisible wave shot
past.
After roughly fifty seconds the wave reached the
support ships, located ten or more miles from the
Zeropoint. But at this distance it was no longer a shock
wave; it was a mere pressure wave. The wave front
was no longer ^'square"; the velocity had subsided to
that of sound, 1140 feet per second. This fully-tamed
wave produced in the ears of observers only a dull,
low-pitched thud.
The shock wave had quitted the lagoon; but thou-
sands of instruments bore witness to its passage, and
five ships were sinking.
PRESSURE
Within five seconds an excellent, indelible record
was obtained of peak pressure, the most important
property of the shock wave. The majority of the gages
TEST A: EXPLOSION IN AIR
had performed well. The simplest ones operated es-
pecially well during the entire performance of the in-
visible shock wave.
Hundreds of gages were recovered within 48 hours.
Recovering the gages from the GILLIAM was par-
ticularly dramatic. GILLIAM was the ship nearest
the Zeropoint; in fact she was the only ship within
1000 ft. of the projected Zeropoint. She took a terrific
beating, and sank almost immediately. Pressure ex-
perts were most anxious to find what the pressure had
been at this key location; they wanted to know just
what constituted a fatal blow. Divers were put to work
quickly. They were briefed carefully as to just what to
look for, or rather grope for. They went down, moving
about with great difficulty through the almost formless
wreckage. Twice they came up to the surface to report
failure, and twice they were briefed further and sent
down to try again. The third attempt succeeded. They
located the gages and brought them to the surface.
Beaming scientists carried the gages back to the labora-
tory ship KENNETH WHITING, cleansed them, and
then strove to interpret their messages. No one had
expected the bomb to explode close to GILLIAM; ac-
cordingly the gages placed aboard her were not of a
type intended for measuring very high pressures. Many
of them had gone far offscale. Careful study was
needed before the readings could be interpreted re-
liably.
Ill
BOMBS AT BIKINI
Pressure readings from all types of gages were now
compiled, and elaborate graphs prepared. To the grati-
fication of the experts, the graphs jibed closely with ex-
pectations. Both the height and shape of the plotted
curves agreed well with predictions made months be-
fore by scientists from the Los Alamos Laboratory and
from the Navy's Bureau of Ordnance. The accuracy,
too, was satisfying. Although individual values often
appeared out of line by 20 or 40 percent, when the read-
ings of all gages at a given range had been averaged, a
composite value of high accuracy resulted.
Many pressure values considerably greater than
100 pounds per square inch were successfully recorded.
They were obtained by gages located at or just above
the surface of the water some distance from the pro-
jected Zeropoint. Unfortunately, there was no gage
located exactly at the projected Zeropoint; but esti-
mates indicate that the pressure there was extremely
great — expressible in hundreds or thousands of pounds
per square inch. At greater distances, pressure values
were, of course, smaller; at ranges of 2000 to 3000
yards, for example, the pressure was well below ten
pounds per square inch. The radiosonde-type pressure
gages parachuted from planes at ranges of six or eight
miles performed well. Their radioed messages were re-
ceived, recorded, and analyzed. Their pressure values,
amounting to only a small fraction of a pound per
square inch, were in excellent agreement with one
another.
112
TEST A: EXPLOSION IN AIR
Pressures inside gun turrets and ship compartments
were small, seldom exceeding a few pounds per square
inch. The data obtained were sufficiently extensive to
form a firm basis foi- determining where crew members
would have been safe from the ]:)last, and where ad-
ditional protection would have been needed to insure
safety.
There were, of course, many failures among the
thousands of pressure gages used. Some of those which
were to be started by radio were started too late as a
result of a timing signal failure.* Others operated
badly as a result of imperfect adjustment of the gages
themselves or of ''black box" starting mechanisms.
Some gages found themselves unexpectedly close to the
Zeropoint and gave undecipherable off-scale readings;
others were unexpectedly far from the Zeropoint and
gave no response whatever. Many gages sank with
the five mortally- wounded ships they were mounted on ;
few of these gages were recovered. Some of the gages
were shielded by ships' superstructures and gave ab-
normally low readings; in some instances the inter-
* Arrangements had heen made to send out a master timing sig-
nal, which was to start a number of recording instruments an in-
stant before the explosion occurred. Actually, the sigyial was sent
out a number of seconds too late. This delay was caused partly by
imperfect receptiori of a preliminary radio signal and partly by
human error. Plans were such that nothing short of this coinci-
dence of ill luck could have thrown off the master signal. The great
majority of instriiments were not dependent on this signal, and the
multiplicity of instrurnents was such that all principal types of
information sought were achieved despite inoperativeness of indi-
vidual groups of instruments.
113
BOMBS AT BIKINI
ference produced abnormally high readmgs.* Oddly
enough, one of the most valual^le of all the pressure
results was that obtained from a specially-mounted beer
can, whose graceless collapse filled an otherwise serious
gap in the pressure story.
IMPULSE
The measurement of impulse, although less satis-
factory than the measurement of pressure, was entirely
adequate. Despite the timing signal failure mentioned
previously, a number of good records of pressure-ver-
sus-time were obtained. From these, by the usual
method of integrating, physicists computed the impulse
values. As expected, the net impulse was practically nil
except extremely close to the Zeropoint. At greater
ranges the impulse delivered by the positive pressure
phase was almost exactly counterbalanced by the nega-
tive phase, which started one-half to one second later.
But even though the net impulse was practically nil
at most of the target vessels, the net effect was far
from nil. It was, of course, the impulse during the posi-
tive phase which was responsible for the majority of
^Although the homh detonated at approximately the planned
altitude, its plan-view position was 1500 to 2000 ft. to the ivest of
the intended hull's-eye ship NEVADA. How this discrepancy oc-
curred has been the subject of long study; but no answer has bee^i
found. Incontrovertible evidence is available to disprove each of the
dozen different hypotheses which may be advanced as explanation.
No discrepancy of anything like this magnitude occurred in the
long series of practice drops made.
114
TEST A: EXPLOSION IN AIR
the havoc wrought. Many masts, for example, were
bent by this positive phase; and they certainly were
not straightened out again by the ensuing negative
(suction) phase. Impulse values — and ship damage
— were particularly great because both the pressure
and the duration of the positive phase are exceptionally
great in atomic bomb explosions. Destruction was far
greater than would have resulted from high pressure
alone, or long duration alone. The bomb reaped double
havoc.
CONDENSATION CLOUD
The shock wave was not visible to the naked eye;
but the progress of the ensuing suction was apparent
enough. Racing closely on the heels of the fast-spread-
ing shock wave, the suction wave had the form of a thin
shell of rarefied air. Because this air was rarefied and
thus cooled, the water molecules present condensed in
myriad tiny droplets, millions of them in each cubic
inch.
The result was the formation of a large zone of fog,
called the condensation cloud. Some persons referred
to it as the "Wilson Cloud," in honor of C. T. R. "Wil-
son, who fifty years ago pioneered the study of fog and
rain, and made thousands of experiments in which fogs
were produced by sudden expansion of saturated vapor.
From a distance, the condensation cloud at first re-
sembled a white hemisphere, dazzlingly bright, resting
on the surface of the water. The hemisphere grew rap-
15
BOMBS AT BIKINI
idly, of course, in accordance with the velocity of the
suction wave. Thus its diameter increased initially at
the rate of several thousand miles per hour ; later, the
increase proceeded at the more modest rate of about
780 miles per hour, the velocity of sound.
But this great hemisphere lasted only a few sec-
onds. Its interior was rapidly burnt out by the trillion-
watt fireball located at the center. Upward growth of
the cloud was limited principally by too-low humidity
in the upper strata of air ; lateral growth was limited
by the gradual dying off of the suction wave. The
myriad droplets were evaporating fast. Within five sec-
onds the cloud had become a great horizontal ring two
miles in diameter, resting on the water and enclosing
the fireball. In another five seconds the ring had dis-
integrated; only patches of cloud remained.
THE FIREBALL AND OPTICAL
RADIATION
The fireball, unlike the condensation cloud, was
no mere spectacle. It dealt serious injury to ships and
test animals. Beginning its existence in the very proc-
ess of distintegration of the bomb, it was of indescrib-
able brightness during the first two seconds. Then, for
about three seconds, it was obscured by the condensation
cloud. At about five to eight seconds after Mike Hour
it came back into view again. It grew, swept rapidly
upward, and by ten to twenty seconds after Mike Hour
116
TEST A: EXPLOSION IN AIR
the fireball had lost itself in the rapidly rising mush-
room cloud.
The fireball's real punch occurred within the first
half second. In this brief interval an appreciable frac-
tion of the total energy released by the bomb sped out-
ward at the velocity of 186,000 miles per second. It was
in this interval that fiash burns were produced on
target equipment and animals.
The initial output of optical radiation was hundreds
of trillions of watts, greater than the aggregate power
output of all the electric light bulbs ever manufactured
by man.
In the first few tenths of a second the fireball grew
very rapidly. As it grew, each square inch of its sur-
face became less brilliant, but there were, of course,
more square inches in its surface. Accordingly, the
total output of light decreased according to a somewhat
complicated formula. Aerial photographs, analyzed
with the help of densitometers, were particularly valu-
able in following the detailed course of this split-second
life-history.
Photometrists found that the greatest surface tem-
perature of the fireball was well above 100,000 degrees
Fahrenheit. Interior temperatures were far higher.
To observers 10 miles away, the illumination pro-
duced per square inch of fireball area was several times
that of the sun at noon. The fireball produced a bluer
light than the sun, which again indicates the fireball's
greater intensity.
17
BOMBS AT BIKINI
Although the fireball itself was rich in ultraviolet
light, including light of the ''vacuum ultraviolet" re-
gion, much of this light was cut off from observers by
the intervening atmosphere. Practically no light of
wavelengths less than 3000 Angstrom units was de-
tected near sea level at ranges of twenty miles. Much
infrared light was detected, although here again ab-
sorption by the atmosphere was severe. The water vapor
content of the atmosphere was of course great, and such
vapor is well known for its reluctance to transmit
infrared light.
THE MUSHROOM
The mushroom, now the common sjaiibol of the
atomic age, was far more spectacular than any still
photograph can suggest. Its height and statuesque
beauty were impressive ; but even more impressive was
the speed of its writhing upward surge.
The speed of its ascent is understandable enough.
When the bomb exploded, Avhite hot gases instantly
spread and filled a region about one-third of a mile in
diameter. But these gases were ver}^ thin ; their aggre-
gate weight was extremely slight — about the same, in
fact, as the weight of a hydrogen-filled balloon of equal
diameter. Now a hydrogen-filled balloon of this fan-
tastic size would have enough lift to raise tJwusands of
tons. Such, then, was the magnitude of the buoyant
force urging the fireball upward.
18
Crew of the submarine rescue vessel WIDGEON watch the test sub-
merging of the submarine APOGON. The submerging operation was
difficult; never before had there been occasion to submerge a sub-
marine without crew aboard. The method used was to fill part of the
ballast tanks with water, then suspend heavy weights from the bow
and stern by cables of carefully chosen length. These weights over-
came the submarine's residual buoyancy and drew her down to the
desired depth. She could be surfaced again by pumping air back into
her ballast tanks.
Plate 17
UPPER. Test A, the explosion in air; 9:00 a.m. on July 1, 1946. The
hemispherical condensation cloud, lit by the white-hot fireball at the
center, outshines the tropical sun. LOWER. The fireball starts its swift
ascent into the stratosphere.
Plate 18
Plat© 19
The mushroom growing out of the Test A explosion in air has now
reached an altitude of five miles. Veiling the mushroom top is the ice
cap, or scarf cloud, believed to be composed of myriad tiny ice crystals.
The mushroom itself is a mixture of vapor, smoke, soot, and rqdioactiv?
fission products.
Pht§ 20
The light carrier INDEPENDENCE, located between 1000 feet and V2
mile from the projected Zeropoint, shows severe damage. Her 600
foot flight deck is broken in several places. Part of the deck planking
has burned. Her four stacks have been demolished, and her antenna
masts are bent or broken.
INDEPENDENCE'S port
quarter, being nearest to
the Zeropoint, took the
worst beating; much of
the wreckage here was
unrecognizable. A fire
broke out on the hangar
deck, adding to the dam-
age already done by the
shock wave. Huge beams
of heavy gage steel had
been ripped loose. The
plating above the water-
line was damaged over a
considerable area.
Plate 2
A monitor from the Ra-
dioactivity Group uses a
Geiger counter to meas-
ure the radioactivity on
the SKATE. This subma-
rine, of modern heavy
construction, v^as located
v/ithin 1/2 mile of the Test
A Zeropoint. Being fully
surfaced, she took ter-
rific punishment. Most of
her superstructure was
stripped off, exposing a
large area of her pres-
sure hull.
General view of damage produced on the submarine SKATE in Test A.
Her conning tower fairwater was badly smashed, and her bridge also.
Periscope and radar shears were bent. Inside her pressure hull, how-
ever, damage was not severe; within three days she made a successful
surface run under her own power.
Plate 22
Battered almost beyond
recognition is this Navy
seaplane which had been
placed on the stern of the
battleship NEVADA, lo-
cated 1500 to 2000 feet
from the Test A actual
Zeropoint. Besides pro-
ducing mechanical dam-
age, the explosion caused
fires in combustible ma-
terials at distances as
great as one or two
miles. Various other ma-
terials were melted or
scorched. Army quarter-
master stores proved to
be especially vulnerable.
The NEVADA, bull's-eye
battleship, escaped v/ith
moderate damage. The
bomb, instead of deto-
nating directly above her,
detonated 1500 to 2000
reet away. NEVADA'S
Iwo topmasts failed, and
the starboard yardarm
also. Her weather deck
was dished moderately.
Some stanchions and
bulkheads were distorted.
However, her hull was
practically undamaged,
and her interior was little
disturbed. The deck-
loaded gear suffered
severely.
Plate 23
,fiiii*>rf'1i^ mtfft^^
UPPER. Insidious almost be-
yond belief, the great mush-
room cloud conjured in Test A
harbored radioactive fission
products equivalent to hun-
dreds of tons of radium.
Manned planes v/ere kept
miles away, but drone planes
v/ere guided directly through
the cloud, sampling its content
v^ith the aid of filters mounted
in boxes attached to the under-
sides of the planes' wings. Re-
moving the filters was done
with great care. LOWER. A
radioactivity check is made on
a goat exposed to the Test A
explosion.
Plate 24
TESTA: EXPLOSION IN AIR
The fireball rose initially at a rate of more than one
hundred miles per hour. Within twenty seconds it
transformed itself into the fireless head of the mush-
room, now one mile high. Two minutes later the mush-
room's altitude was five miles; five minutes later it
was seven miles, one mile higher than Mt. Everest.
As the mushroom head rose at express-train speed,
it sucked air in beneath it. Scooped up in this turbulent
trailing festoon, called the stem, were soot from the
stacks of the nearer target vessels, smoke from the
flash-burned decks and equipment, and water vapor.*
The mushroom head broadened as it rose; event-
ually it attained a width of nearly two miles. The air
rising in the mushroom head became cooler as it rose
and expanded; air pushed upw^ard just above the
mushroom head was cooled also. This cooling resulted,
of course, in condensation. A remarkable phenomenon
occurred: a thin white cap or scarf cloud appeared
lying just above the mushroom top and cleanly sep-
arated from it. It is probable, although not certain,
that this consisted not of water droplets but of very
* The mushroom contained also various unusual gases created hy
the bomb's ionizing radiations. These radiations were partially ab-
sorbed by the nitrogen and oxygen molecules of the air and the
result was: nitrogen molecules were broken up into individual
nitrogen atoms; and the oxygen molecules were broken into indi-
vidual oxygen atoms. When the unmated nitrogen and oxygen atoms
collided, they immediately joined to form molecules containing
oxygen and nitrogen together. Such molecules have an apricot
color, and traces of this color were clearly visible in the A-Day
mushroom.
19
BOMBS AT BIKINI
small ice crystals. Sucli an ice-cap, never before pro-
duced by man, can only form when the meteorological
conditions are exactly right.
The mushroom did no damage, but it was far more
fearsome than its soft white form could suggest. In it
were shrouded the bomb 's deadly fission products ; for
in such a ''self -cleansing" explosion as this, nearly all
the bomb products remain in the air and are carried
aloft in the mushroom. The amount of radioactive
fission products infesting the cloud was small in terms
of weight. But its potency was impressive, being tem-
porarily equivalent to hundreds of tons of radium.
(The world's total supply of concentrated radium
amounts to only a few pounds.) If an aviator had flown
through the mushroom and inhaled its air, he would
probably have died as a result. If an aviator's plane
had failed and he had been forced to jump, his para-
chute w^ould have been of little avail if it carried him
into this cloud.
The mushroom's menace was a lingering one. Its
fission products settled out very slowly, endangering
everything lying in its path. The menace became the
more insidious when, about one hour after the explo-
sion, the cloud lost its characteristic shape and became
visually indistinguishable from other clouds in the
area.
Airmen continued to track it for many hours in
B-29 planes carrying Geiger counters ; they found that
the affected air region followed the course predicted
20
TEST A: EXPLOSION IN AIR
by the aerologists, and that only deserted ocean areas
received the continuous and invisible fall-out of radio-
active materials.
Fortunately, the contaminated region healed itself
relatively promptly. The fission products themselves
lost a large fraction of their potency in a matter of
hours, and lateral and vertical mixing with unaffected
air proceeded rapidly. Within a short period the ma-
terials were dispersed throughout thousands of cubic
miles of air. The materials were now so extremely dilute
as to be harmless. Nevertheless, various scientific
groups in America and in Europe are reported in the
newspapers as having detected slight changes in the
radioactivity in the atmosphere some days after the
explosion. There is no doubt that, like the ashes thrown
into the air in the explosion of the Krakatao many years
ago, the fission products circled the globe for many
months.
NUCLEAR RADIATION
Gamma radiation dominated the repertory of nu-
clear radiations. Alpha particles, beta particles, and
neutrons were, of course, produced in abundance, but
being light particles they were rather effectively
blocked or slowed by collision with atoms in the air.
Many of them failed to penetrate more than ten or a
hundred feet of air; few of them reached beyond the
innermost target vessels. And even on these vessels
their effects were of questionable importance in view
21
BOMBS AT BIKINI
of the great damage caused by the shock wave, heat
flash, and gamma radiation.
The gamma radiation's maximum power was dis-
played in the periods of a few seconds. Geiger count-
ers on target vessels demonstrated that an enormous
burst of gamma radiation was produced during the
instant when the bomb was detonating; additional
gamma radiation came from the fission products in the
fireball. But after the mushroom had borne its poison-
ous pall to high altitude the gamma radiation at sea
level was very weak indeed.
The total amount of gamma radiation reaching the
target vessels was large. In many instances the photo-
graphic film gages showed aggregate dosages of the
order of hundreds or thousands of roentgens.* The
total output of gamma radiation was so great that if
by some feat of magic it could have been distributed
uniformly among several million persons it would have
eventually killed or seriously injured all of them. Of
course, in any practical situation the number of per-
sons affected would be very much smaller.
The gamma radiation was of many wavelengths,
covering an appreciable spectral band. The typical
* The roentgen is a unit of cumulative intensity of ionizing
nuclear radiation. Radiation which is sufficiently intense and pro-
longed to produce a hillion ion pairs in a single cubic centimeter
of air represents approximately one roentgen. One tenth of a
roentgen was adopted hy Joint Task Force One as the maxijnum
safe dosage per day. Fifty or 100 roentgens per day can he seri-
ously harmful to man, and a few hundreds roentgens may prove
fatal.
122
TEST A: EXPLOSION IN AIR
wavelength was roughly one ten-billionth of a centi-
meter; 25,000,000,000 such waves would be required
to cover one inch. The energies of the individual gamma
ray photons, being in exact inverse proportion to the
wavelength, were tremendous. A typical photon had
an energy of about one million electron volts. The high
energy of these photons meant that they had great
penetrating power — greater than that of typical X-
rays. In practical terms this meant that no ordinary
screen of steel, lead, or other material known to man
could successfully block off the radiation. Very heavy
steel walls, several inches thick, would reduce the in-
tensity by an appreciable factor and foot-thick steel
walls would reduce the intensity to a fraction of the
original value. But in the face of such extremely in-
tense radiation as that which struck the target ships,
even a fraction of the initial intensity might do serious
and lasting harm.
To compute the total potential effectiveness of nu-
clear radiations on ships' crews has not proved to be
easy. To be fully meaningful, such computations must
take into account many factors. The most obvious of
these factors is the distance of the ship from the Zero-
lioint. All radiations are, of course, less intense at
greater distances and are therefore less effective there.
But the situation is complicated; the decrease in in-
tensity of some kinds of radiation is much more pro-
nounced than for others. Even fast and slow neutrons
show unlike deference to distance. Gamma rays too
123
BOMBS AT BIKINI
are not of uniform behavior. For each distance of in-
terest, it is necessary to compute separately each radia-
tion's effectiveness, and then to combine the results
to obtain a measure of the total effectiveness. Another
important factor is the altitude of the Zeropoint. Ob-
viously, if the bomb detonates almost at the surface
of the ocean, the radiation will probably enter the ship
through the side, and persons well below the waterline
may be almost perfectly protected by the intervening-
water. But if the bomb detonates directly overhead,
the thickness of the decks will be of principal impor-
tance. The type of ship, too, makes a difference. Thick-
walled battleships must be expected to give far greater
protection than thin-walled destroyers. The distribu-
tion of the men throughout the ship must be considered
too. Persons far below decks may escape relatively
lightly even when persons exposed topside receive fatal
doses. In a later section the attempt is made to state
the over-all effect of nuclear radiation on ships' per-
sonnel.
No one knows what psychic catastrophe the gamma
radiation might wreak on the doomed crews. The ra-
diation can claim these remorseless attributes : it is
invisible, so that no one can see it coming; ordinarj^
walls do not stop it, so that ''no hiding place down
here" applies all too fully; medical science knows of
no way to save severely exposed persons; and the ra-
diation produces no immediately apparent effect, so
that overly apprehensive persons entirely out of range
124
TESTA: EXPLOSION IN AIR
may be convinced death is at hand. This last factor is
probably more important than it logically should be
since persons almost always overestimate the closeness
of explosions. Explosions a considerable distance away
may somid next door.
DAMAGE TO SHIPS
The fact that five ships were sunk by the A-Day
explosion is of little absolute importance. The num-
ber might have been considerably greater or less, de-
pending on exactly where the bomb exploded and on
the exact disposition of the ships.
Damage to ships should be evaluated in the light
of their locations. Rough indication of the locations
with respect to the bulls-eye ship NEVADA is pro-
vided by Figure 4. Approximately twenty of the target
ships were located within the central area of one square
mile. Many of the other ships were spaced along
radiating lines or spokes. These lines were curved
slightly, so that the inner ships could not shield their
outer neighbors.
The majority of the ships carried considerable loads
of fuel and ammunition. Thus secondary effects, such
as fires and ammunition explosions, were evaluated
as well as the primary effects. Ships in the upwind
sector, however, carried only very small loads of fuel.
These loads were kept small so that, in the event that
the fuel caught fire and spilled out onto the Lagoon
125
BOMBS AT BIKINI
Fig. 4. Test A Target Array.
126
TEST A: EXPLOSION IN AIR
surface, it could not envelop scores of other ships, con-
suming them and their important cargoes of test ani-
mals and instruments. Such danger was heightened,
of course, by the abnormally close spacing of the ships.
What struck the ships first? Undoubtedly it was
the thermal radiation and the gamma radiation. These
struck the ships within the first thousandth of a second.
The thermal radiation lasted only a few seconds, ceas-
ing with the extinction of the fireball. The gamma radi-
ation was greatly reduced in intensity as soon as the
mushroom got underway in its climb to the strato-
sphere. The thermal radiation produced serious effects
on exposed test animals and on various kinds of ship
equipment, but it produced very little serious damage
to ships' hulls and superstructures. Gamma radiation
likewise had relatively little effect on ship structures.
The shock wave did the damage. The impulse it
delivered, with its extraordinarily high peak pressures
and its long-lasting positive pressure phase, was irre-
sistible on the nearest ships. It bent masts, depressed
decks, crumpled stacks, unseated cranes, dished side
plating. It twisted and broke the flight deck of the
nearer aircraft carrier and ripped nearly all the super-
structure off a surfaced submarine nearby.
Detailed surveys of damage had to wait until the
mammoth re-entry maneuver had been accomplished.
Drone planes were first to make close approach to
the target center. Only eight minutes after Mike Hour
a B-17 drone entered the mushroom at 24,000 feet. A
27
BOMBS AT BIKINI
few minutes later three other B-17's swung across at
altitudes of 30,000, 18,000 and 13,000 feet. Three F6F
drones made transits at 20,000, 15,000 and 10,000 feet.
The planes collected air samples and returned to base ;
their samples were sent to Kwajalein for radiological
analysis.
Four TBM planes were launched from SAIDOR a
few minutes after Mike Hour. They obtained valuable
photographs of sinking ships, but their main job was
to assist the controlling of drone boats soon to be
launched. No manned planes flew directly over the
Zeropoint until four hours after Mike Hour.
The LVCP drone boats started towards the target
array forty-four minutes after Mike Hour. Their
progress was controlled by radio signals sent from
BEGOR, which lay just outside the long Bikini-Enyu
reef. The leading LCVP reached the target center in
one hour, and picked up water samples. Two hours
later these samples had been put aboard the destroyer
MO ALE, which was soon speeding to Kwajalein where
the samples were to be analyzed.
Manned boats first re-entered the Lagoon two hours
after Mike Hour. First to enter were the six PGM's
of the radiological safety party. A little later, twenty
LCPL's entered also. These boats cautiously threaded
their way throughout the target area, using their
Geiger counters to detect any unsafe areas. Few such
''hot" or "Geiger sour" areas were found by this
patrol party.
128
TEST A: EXPLOSION IN AIR
The salvage vessels now entered the lagoon and went
to work to put out fires on several of the target ships.
At 2 :30 p.m. the Task Force Commander announced
over his radio circuits that the lagoon w^as safe for
entrance by all vessels. Ships of the Technical Group
entered almost at once. The flagship MT. McKINLEY
entered a few minutes later, and the other ships fol-
lowed.
By sundown, eighteen of the target ships had l)een
reboarded by special boarding teams, although regular
ships' teams were not put aboard until later. Many
animals were recovered and transferred to BURLE-
SON; a number of scientific instruments were recov-
ered also.
In the following few days the remaining animals
and instruments were recovered. While these were
being studied, diving and salvage operations were
rushed. An unsuccessful attempt was made to beach
the Japanese cruiser SAKAWA, which was afire for
24 hours. Soon after she was taken in tow, she keeled
over to port and sank by the stern. The aircraft carrier
INDEPENDENCE and the concrete oil barge YO-
160, both badly damaged, were moved to more appro-
priate berths. The submarine SKATE was beached in
shallow water off Enyu Island.
Inspection teams now swarmed over the ships, ex-
amining every damaged item. The special data forms,
printed long in advance, proved their worth. They in-
sured orderly and thorough inspection, and the re-
129
BOMBS AT BIKINI
cording of results in a consistently uniform manner.*
Six days after A-Day the staff of the Director of
Ship Material completed an 85-page provisional re-
port on damage to ships and animals. Within thirty
days this group had completed an interim report of
2000 pages. Five months later it had finished a monu-
mental report of 150 volumes. The full story is now
available as to the damage wrought in the five seconds
after the detonation on A-Day.
The GrILLIAM, closest of all the target ships, and
only ship located within 1000 ft. of the projected Zero-
point sank within one minute. She was a merchant-
type attack transport and was 446 feet long. Divers
later found that her superstructure was smashed al-
most beyond recognition, and her hull also was utterly
wrecked. She proved beyond the slightest doubt that
a ship of this type could not hope to stand up against
the atomic bomb at close range.
The ANDERSON, a 338-foot destroyer located be-
tween 1000 ft. and one-half mile, sank within eight
minutes. Pictures taken from a PBM photographic
* The difficulty of this job is hard to appreciate. On a single
ship such as the INDEPENDENCE, for example, there were liter-
ally thousands of compartments, rooms, and installations to inspect.
Hundreds of the rooms showed severe damage, and hundreds more
showed light damage. On the flight and hangar decks, too, there
were enormous areas of wreckage. Merely classifying an area as
''wrecked" or "partially wrecked" would have been relatively
easy; hut to describe the wreckage in detail, and in terms suitable
for later practical use by engineers, ordnance experts, commMnica-
tions men, medical men, fire control personnel, and naval archi-
tects, was truly a Herculean task.
30
TEST A: EXPLOSION IN AIR
plane show her visible through the smoke cloud one
minute after Mike Hour. Much of the upper part
of her superstructure was missing entirely. A fire
was burning amidships. A minute later the fire ap-
peared to be growing in intensity and to be spreading
aft along the port side. Still later, the fire amidships
increased markedly, and the entire central section of
the ship was in flames. She began to list ; within four
minutes of Mike Hour she was on her beam ends. A
cloud intervened for a few seconds, after which she
was found to have rolled still further on her port side.
Her fires now appeared extinguished, but she was
settling fast. By six minutes after Mike Hour only a
small portion of her bottom was visible, and in another
two minutes she was gone.
Divers later found her resting on her side in about
200 feet of water. They made an extensive survey of
her smashed superstructure and confirmed that much
of it was missing or unrecognizable. Her deck was in
very bad condition, and her shell plating also.
The CARLISLE, an attack transport much like
the GILLIAM, sank within forty minutes. She too
was within one-half mile of the projected Zeropoint.
Divers found her lying nearly upright, with about five
degrees list to port. Her condition was generally sim-
ilar to that of the ANDERSON.
The LAMSON, a 344-foot destroyer, located within
one-half mile of the projected Zeropoint, sank within
eight hours. Early photographs showed her listing to
131
BOMBS AT BIKINI
starboard with bridge structure badly smashed. Guns
were visible, but the mast and other light structures
were missing. Observers airborne in PBM Charlie
found the ship lying over on her starboard side about
forty-five minutes after Mike Hour ; her bridge struc-
ture was underwater and the port side of her bottom
was above the surface. Later she floated bottom up for
a short while, and then sank. Divers reported her
condition as being much like that of the ANDERSON.
The Japanese light cruiser SAKAWA, located
within one-half mile of the projected Zeropoint, sank
in mid-morning on the day after the explosion. A
severe fire burned in her stern for nearly twenty-four
hours. She showed severe structural damage topside.
Her hull too suffered major damage; her stern was
breached in several places. Water entered steadil^y, and
her draft increased seriously. Despite difficult radio-
logical conditions prevailing, the attempt was made
to tow her to a nearby beach. But by this time her stern
was awash and her stability had been reduced to the
vanishing point. Soon after being taken in tow she
keeled over to port at an angle of 85 degrees and sank
by the stern.
Sinkings made headlines, but it was the surviving
ships which provided the largest amount of precise in-
formation. The light carrier INDEPENDENCE, lo-
cated between 1000 ft. and one-half mile from the
projected Zeropoint, showed perhaps the most strik-
ing damage. Her 600-foot long flight deck was broken
132
TEST A: EXPLOSION IN AIR
in several places and badly buckled. The port corner
of the flight deck was blown oft'. Part of the deck
planking was burned away. All four stacks were de-
molished, the flight deck crane was knocked over, and
both airplane elevator platforms were blown overboard.
Antenna masts were bent or broken. A fire broke out
on the hangar deck, adding to the wreckage already
produced by the shock wave. Huge vertical beams of
heavy gage steel had been ripped loose; in some
instances they w^ere left hanging in grotesque array.
Her plating above the waterline was damaged over a
considerable area, and holes were blown in the sides
enclosing the hangar deck. Huge wrinkles disfigured
her starboard side. Her interior showed extensive
damage also. Her port quarter, being nearest to the
Zeropoint, took the worst beating ; much of the wreck-
age here was unrecognizable.
The submarine SKATE, over 300 feet long and of
modern heavy construction, was located within one-
half mile of the projected Zeropoint. She was on the
surface, and as a result lost nearly all her superstruc-
ture. The conning tower f airwater and the bridge were
badly damaged; the same was true of the weather
deck along most of her length. The periscope and radar
shears were bent to starboard. Aft of the conning tower
most of the decking, the majority of the free-fiooding
superstructure, and many pipes and fittings were bent,
smashed, or even blown over the side. The bridge struc-
ture was folded together upon itself in front of the
133
BOMBS AT BIKINI
conning tower. Nearl}^ half of the superstructure for-
ward was wrecked. The side lights were shattered and
the stern light was missing. The after windlass was in-
operable. Inside the pressure hull, however, damage
was not severe ; within three days she made a success-
ful surface run under her own power. Submerging
would have been unsafe, and was not attempted.
The ARKANSAS, oldest battleship of the United
States Fleet, was one of the three major combatant
ships within one-half mile of the Zeropoint. She suf-
fered heavy damage. When the lagoon was first re-
entered, she was still sending up clouds of smoke from
smouldering fires on her decks. But the shock wave
did the most damage. Stacks, masts, and mast support-
ing structures suffered, as well as pipe rails, bulwarks,
stowage spaces. Much dishing occurred. Mam" doors,
stanchions, and bulkheads were ])adly damaged. AR-
KANSAS was defuiitely put out of action and would
have required extensive repairs at a principal naval
base.
The NEVADA, bull's-eye battleship, escaped with
moderate damage. The bomb, instead of detonating di-
rectly above her, detonated 1500 to 2000 feet away.
Both topmasts failed, and the starboard yardarm
also. The weather deck was dished moderately. Some
stanchions and bulkheads were distorted. Painted sur-
faces on exposed parts of the superstructure were
blackened. However, her hull was practically undam-
aged, and her interior was little disturbed.
134
TEST A: EXPLOSION IN AIR
The CRITTENDEN, another 426-foot merchant-
type attack transport, received heavy damage of the
same general type described in the previous paragraph.
Other ships badly mauled were : the cruisers SALT
LAKE CITY and PENSACOLA, and the destroyers
HUGHES and RHIND. The concrete oil barge YO-
160 suffered lesser damage, and significant damage was
suffered by the aircraft carrier SARATOGA, the de-
stroyer TALBOT, the concrete drydock ARI)C-13, the
merchant-type attack transport DAWSON, and LST-
52. Among the other ships suffering negligible to mod-
erate damage were the ])attleships NEW YORK and
PENNSYLVANIA.
WHAT IS DAMAGE?
How was the wealth of ship-damage data to be
summarized ? This question puzzled Admiral Parsons '
technical experts from the outset. Various schemes
were proposed for synthesizing the almost endless
stream of data into simple generalizations. It would
be convenient to be able to say: '^ Ships are sunk at
ranges as great as X yards, badly damaged out to Y
yards, and slightly damaged out to Z yards." But it
was recognized from the outset that no such simple
rules could be expected. Each type of ship has a dif-
ferent vulnerability; and even within a single type of
ship, newer ships may not be of the same vulnerability
as older ships. Ship aspect, too, must be important. A
135
BOMBS AT BIKINI
ship caught broadside might be capsized where a bow-
on ship might remain upright.
Almost endless complications arise when a definition
of damage is sought. In the midst of a battle, the im-
portant damage is that which prevents the ship from
fighting with full effectiveness. Here damage means
loss of fighting efficiency. Mere loss of a rudder or
failure of the radar sets may be regarded by combat
crews as disastrous damage.
When the crippled ship limps into port, damage
means something quite different. It is expressed in
weeks to get the ship hack into action. Thus shipyard
engineers classify any damage as light if repairs can
be completed in a few days.
Foremen rate damage in terms of man-hours to re-
pair the ship ; accountants express damage in terms of
dollars.
From the scientific point of view, damage is a meas-
ure of how many parts are injured, and how elaborate
the injuries are. Of no concern here is the matter of
importance of the parts, or the time needed to repair
them. Some persons may be interested principally in
damage to ship's machinery or electronic equipment;
other persons may regard damage to guns and hull as
especially vital.
A nice question is whether radioactivity on the
target ships represents damage to the ships or injury
to the crews. The ships are contaminated, but it is the
crews which suffer.
36
TEST A: EXPLOSION IN AIR
Now the loss of fighting efficiency concept of dam-
age is certainly of very great importance. But it is
hard to define exactly. Failure of main turrets might
constitute serious loss of fighting efficiency in action
against surface ships, but it would have no bearing on
fighting enemy planes. Loss of radar is almost fatal in
a battle fought on a cloudy night, but it is far less
serious in a battle fought in brilliant sunshine. Loss
of speed may be only of minor importance on some
operations, and fatal in others. Another difficulty is
duration of loss of fighting efficiency. How can we
compare permanent loss of speed or fire-power with
loss which can be repaired in an hour or two by the
ship 's crew ? We can answer this only if we know how
long the battle is to last.
The solution adopted was to use several of these
damage concepts in parallel. Rough definitions were
drawn up, and the individual data were sorted out
accordingly. Totals were compiled, and the conclusions
came into view.
Some major conclusions are these:
, 1. The majority of lighter warships located
within a critical radius somewhat less than
one-half mile away may be expected to be
sunk by an atomic bombing attack such as
that executed on A-Da}^
2. Heavy warships located within one-half
mile may survive, but their superstruc-
tures will be badly damaged and the ships
will be put out of action ; extensive repairs
37
BOMBS AT BIKINI
at a principal naval base will be required.
Ships more than three-fourths of a mile
away may suffer damage, but the damage
will be relatively light in typical cases.
Among the most badly damaged ships,
damage to superstructures was very se-
vere; hulls escaped relatively lightly.
Damage extends to nearly all kinds of me-
chanical and electrical equipment.
DAMAGE TO SPECIAL TEST
EQUIPMENT
Ships' decks, the only platforms in the neighbor-
hood of the Zeropoint, had been generously covered
with special test equipment of nearly every imaginable
kind. Colonel J. D. Frederick's DSM Army Cround
Group had exposed equipment lent by all principal
branches of the Army, including the Air Forces, Engi-
neer Corps, Signal Corps, Ordnance Department,
Chemical Corps, and Quartermaster Corps. Much
Navy equipment was exposed also, principally by the
DSM Ordnance Group under Captain E. B. Mott, the
DSM Aeronautics Group under Captain T. C. Lonn-
quest, the DSM Electronics Group under Captain C. L.
Engelman, and the relatively small DSM Supplies and
Accounts Group. So extensive was the equipment that
seven volumes of several hundred pages each were re-
quired to summarize the results obtained.
38
TEST A: EXPLOSION IN AIR
Some of the heavier items exposed were tanks,
weapon carriers, trucks, amphibious clucks (or
DUKWs), tractors, airplanes. Lighter items included
guns, mortars, rocket launchers, rifles, torpedoes, mines,
depth charges, bombs, fuzes, grenades, rockets, flares,
telescopes, periscopes, infrared snooperscopes, alti-
meters, fire extinguishers, water distillation equip-
ment, odographs, knives, watches, telephones, switches,
gas maslvs, flasks, samples of oil, grease, gasoline. Lists
of clothing and supplies samples are almost endless;
they included canned apples, apricots, tomato juice,
string beans, creamed corn, bacon, turkey, butter. For
exposure inside ships' refrigerators, pork loins, hams,
sausage, beef, and frozen fish were taken along. There
were jackets, trousers, parkas, undershirts, drawers,
socks, boots, helmets, DDT, soap, and even skis.
Valuable results, impossible to summarize ade-
quately, were obtained. Combustible materials had a
tendency to catch fire, presumably due to the thermal
radiation. This occurred even at distances of one or two
miles from the Zeropoint. Of course, many of these
fires could have been brought under control quickly by
ships' crews, if there had been crews aboard.
As expected, thermal radiation showed a great pref-
erence for black surfaces. In many instances black-
jjainted objects, and even black writing, was burned
although nearby white surfaces were almost untouched.
Some objects melted. Rubber objects located near the
Zeropoint were scorched or burnt.
39
BOMBS AT BIKINI
Light metal surfaces, such as exteriors of trucks
and aircraft structures, were frequently demolished.
Bombs and torpedoes exploded in a number of in-
stances, but probably not as a direct result of the atomic
bomb explosion. Secondary causes, such as fires, were
presumably responsible.
Army quartermaster stores and other miscellaneous
equipment exposed showed greater vulnerability, ordi-
narily, than normal naval deck gear.
INJURY TO ANIMALS
The test animals which had been placed on the
twenty-two target vessels by Captain Draeger's DSM
Naval Medical Research Section were removed as soon
as possible after the detonation. Some of the animals
were removed on the afternoon of A-Day ; others were
removed on the two following days. They were brought
to the BURLESON, where injured animals were given
good medical care and all animals were examined
thoroughly.*
In all, about 35 percent of the animals used in Test
A had been killed as of late September, 1946. Ten per-
cent died from air blast, 15 percent from radioactivity,
and 10 percent were killed for study.
* Goats are imperturhahle animals. A goat aboard the NI-
AGARA was photographed hy a close-up automatic motion picture
camera just as the shock wave struck. The pictures give a clear view
of the goat, and show him ^nunching his hay without interruption
as the shock wave struck and debris flew all about.
40
TEST A: EXPLOSION IN AIR
Air blast, as expected, was particularly injurious
to the exposed animals. Principal symptoms of air
blast injury were contusions and lung hemorrhages.
Damage to animal's eyes was negligible.*
Flash burns produced by the thermal radiation did
considerable damage to animals situated in a direct line-
of-sight from the detonation. Fur, of course, provided
important protection. The protection afforded by anti-
flash creams and clothing was evaluated successfully;
knowledge is now adequate for giving personnel maxi-
mum feasible protection against burns.
Gamma radiation results developed more slowly.
Animals receiving only slight doses often appeared en-
tirely normal at first. Later some developed hemor-
rhagic patches ; a few showed partial loss of hair and
very few developed testicular atrophy. The more heav-
ily-exposed animals exhibited hyper-irritability, mus-
cular weakness, diarrhea, and increased rate of respira-
tion. Some of these were moribund, with exaggeration
of symptoms, bloody diarrhea, and inability to stand.
These symptoms appeared to have caused the animals
no intense pain.
Just how does gamma radiation deal its blow '? This
was one of the questions uppermost in the minds of
Captain R. H. Draeger and Captain Shields Warren
as they studied the animals taken off the target ships.
* This is in accord with experience at Hiroshima and Naga-
saki, where blindness was caused hy dust and smoke, rather than
hy the brilliance of the light.
14!
BOMBS AT BIKINI
Their answer was soon forthcoming. By combining
what had been learned in Japan with the added infor-
mation garnered at Bikini, a fairly complete under-
standing w^as arrived at.
The answer was a triple one: gamma radiation
reduces the supply of new^ white blood corpuscles, it
reduces the supply of new red corpuscles, and it reduces
the supply of materials necessary to prevent excessive
bleeding.
The most important eifect is the reduction of the
supply of white blood corpuscles. A very severe dose
of gamma radiation completely destroys the bone
marrow's ability to produce white blood corpuscles;
no new white corpuscles are produced. This would per-
haps not be serious if the existing white corpuscles
could last indefinitely. But they do not : in the natural
course of events most of them disappear in about two
weeks. Their absence is serious since the body depends
on them to destroy infections. With no white blood
corpuscles, the body is easily overpowered by any of
the common infections threatening from within or
without.
Red blood corpuscles, too, are a product of bone
marrow. They too face extinction when a large dose
of gamma radiation aifects the bone marrow. Exist-
ing red blood corpuscles may carry on for a month or
more, but eventually there are few left ; the anemia is
serious.
42
TEST A: EXPLOSION IN AIR
The third important effect of severe exposure to
gamma radiation is reduction in the body's ability to
prevent excessive bleeding. The injured bone marrow
is no longer able to produce the so-called platelets which
normally circulate in the blood. Platelets are the
particles that produce the enzymes essential to blood
clotting. Without platelets, the supply of the enzyme
vanishes. Then, when bleeding starts anywhere in the
body, the blood is unable to form clots ; bleeding con-
tinues. Hemorrhagic patches may appear almost any-
where on the body's exterior or interior; such patches
may appear, for example, on the skin or on mucous
membranes. Severe hemorrhages may cause death.*
Useful correlations of injury and distance of the
animals from the Zeropoint were made. Additional
correlations were made between injury and intensity
of effect responsible. This latter correlation was made,
of course, taking full account of the exact degrees of
protection afforded the animals. Captain Draeger's
records show the exact location of each animal; and
by combining these data with the measured values of
peak pressure, thermal radiations, and gamma radia-
tion, very useful analyses result.
The effect of the gamma-ray dosage given the mice
will not be known for some time. These animals were
* Although exposure of the entire tody to a few hundred roent-
gens may he fatal, exposure of only a small part of the body may
produce relatively little injury. There is at least one laboratory
case on record in which a patient's brain was given an X-ray ex-
posure of 24,000 roentgens, and the patient survived.
43
BOMBS AT BIKINI
placed so as to receive non-lethal dosage, in order that
genetic effects, if any, might be followed over several
generations of progeny. Immediately after the test,
the mice were flown back to the National Cancer Insti-
tute. They were bred, and even by late September of
1946 a few litters had been born. These litters were
apparently normal; but it was still too soon to tell
whether cancer would develop.*
The results obtained on animals and the extensive
radiation and pressure data obtained form a firm basis
for estimating the ranges at which exposed and pro-
tected crew members would be seriously injured; the
symptoms of injury are far better understood, and ad-
vances in diagnosis and treatment have been made.
One general conclusion is that casualties caused
by the shock wave may be expected to be high for per-
sons in exposed positions within one half mile of the
projected Zeropoint. Thermal radiation also may be
expected to be very harmful to exposed personnel.
Within the area of extensive blast damage to ship
superstructures, nuclear radiation may well prove
fatal ; thin walls of steel cannot insure protection, and
even thick walls are an imperfect answer.
* Gamma radiation is prohahly capable of producing chromo-
some changes which can he transmitted to progeny. It is likely that
the great majority of such chromosome changes are sufficiently un-
favorable that no progeny would be born alive; early prenatal
death would be more likely. Whether or not any mutations with
power of survival will result from the animals exposed at Bikini
cannot be decided for some time; such mutations woidd not he
expected to show up for several generations.
144
8
. TEST B: UNDERWATER EXPLOSION
Test A was over. Sunken ships had been
marked with buoys. Inspections were complete. A
few repairs were made to damaged ships ; some wrecked
equipment was jettisoned.
Eight Congressmen and thirty-nine press and radio
representatives returned to the United States. The
press representatives had radioed 1,000,000 words
on Test A to their home agencies. The press ship
APl^ALACHIAN made an interim trip to Pearl Har-
bor; PANAMINT and BLUE RIDGE made trips to
Truk, Guam, and other islands; SHANGRI-LA re-
turned to Roi.
The wTather was good, and the 42,000 men of the
Task Force made excellent use of the recreation areas.*
* The most leavening event of the interval between the tests
was a practical joke -perpetrated hy two members of the Bureau
of Ordnance lyistrumentation Group at the expense of their scien-
tific colleagues. On the evening of A-Day, after the support shijjs
had re-entered the Lagoon, Dr. C. W. Wyckoff aiid his friends on
the KENNETH WHITING were leaning against the railing at
the fantail, staring idly across the dark water. They had got up
at 4:00 a.m., and they were pretty well exhausted; they were re-
lieved that the Test had gone off successfully, and that there was
said to be no dangerous radioactivity about. Suddenly Dr. Wyck-
off's frieyids pointed to the water beneath them. The water there
145
BOMBS AT BIKINI
The target fleet was rearranged somewhat. The cen-
tral ship was to be LSM-60 ; the bomb was to be sus-
pended some distance beneath her in a watertight steel
caisson. An especially tall antenna mast had been in-
stalled to permit line-of-sight transmission of the coded
radio signal which was to fire the bomb.
Nearest to the LSM-60, but well over five hundred
ft. away, were the aircraft carrier SARATOGrA and
the thirty-four year old battleship ARKANSAS. These
were both moored broadside to the bomb, to receive the
maximum impact. Nearby were the concrete oil barge
YO-160, the submarines PILOTFISH, SKIPJACK,
and APOGON, and the Japanese battleship NAGrATO.
In all there w^ere seventy-four target vessels fixed in
predetermined positions. Roughly forty ships and/or
small craft were located within one mile of the Zero-
point, and twenty of these were actually within one
half mile.
was distinctly luminous. They watched fascinated, then called more
colleagues. They exchanged anxious questions as to whether a
chance accumulation of radioactive materials might he the cause.
If so, gamma radiation might that very moment he penetrating their
bodies. They called Dr. J. E. Henderson, who arrived quickly bring-
ing, on sudden inspiration, a piece of radioactive glass picked up
months before at Alamogordo, Neiv Mexico. Borrowing a Geiger
counter, he quickly found that the mysterious glow was harmless
and certainly a hoax, but he told no one. Instead, he surreptitiously
placed the radioactive glass near the Geiger counter and allowed
his colleagues to come to the dread conclusion that the glow was
indeed highly radioactive. But before the alarm had reached too
high a pitch, he made a confession, and Dr. Wyckoff reeled in the
long black string by which his waterproof flashlight had been
suspended.
146
TEST B: UNDERWATER EXPLOSION
Six of the eight submarines used were placed in
submerged positions, since it appeared certain that the
bomb would deliver its greatest punch underwater.
Placing the submarines in submerged positions some
distance above the bottom was not easy. The Navy had
never before had occasion to attempt such a feat. Not
only must the submarines be fixed at the right depth
and in normal horizontal position, but the arrangement
must be secure enough to last for weeks if necessary ;
and the submarines were to be raised again after the
explosion. A method of submerging which was found
satisfactory was to flood certain ballast tanks and then
attach heavy weights to the submarine 's bow and stern
by means of long chains of carefully chosen length. The
weights overcame the submarine's residual positive
buoyancy and drew her down until the weights them-
selves rested on the bottom, leaving the submarine at
the desired depth. The submarine Could be surfaced
later by pumping air back into the flooded ballast tanks.
The entire operation was controlled from a salvage
ship. The illustration Plate XVII shows the submarine
APOGON in the process of submerging.
For the underwater explosion, elaborate prepara-
tions were made for measuring wave heights. Waves of
unprecedented height were expected, and a unique
opportunity was j^resented for studying generation and
propagation of giant waves.
Preparing the highly-specialized instruments was
the responsibility of Mr. N. J. Holter, head of the
147
BOMBS AT BIKINI
Wave Motion Section of the Oceanographic Group.*
Much reliance was placed on photography. Tower cam-
eras on Bikini, Amen, and Enyu Islands were synchro-
nized in a w^ave photography network controlled by
radio. Cameras on three photographic planes were
brought into the same network. Each camera was to
take a photograph every three seconds.
Television was used also. Two transmitters, operat-
ing in the 200 megacycle band, were placed in the Bikini
towers ; ten receivers were used, several of them being
mounted in PBM planes.
Many direct-reading wave-height gages were read-
ied. Thirty of these, called turtles, were laid directly
on the lagoon bottom. When a wave crest passed, the
hydrostatic pressure on the bottom increased. Water
was forced into the instrument through a fine capillary
tube, a Bourdon-type pressure element was actuated,
and a small pen drew a significant line on a slowly-
revolving chart. Use of the capillary tube frequenc}''
filter was essential; it prevented the apparatus from
being wrecked by the extremely intense underwater
shock wave, which reached the apparatus a few mo-
ments before the water waves themselves swept past.
The underwater shock wave came and went within a
* Lieutenant Commander F. G. Mo7-ris was officer in charge of
the Wave Measurement Section. Group leaders were Dr. W. K.
Lyon, Lieutenant C. Sklaw (Navy), Mr. H. W. Iversori, Prof. Alex-
ander Forbes, and Mr. A. C. Vine. Very important parts in this
work were played by Dean M. P. O'Brien, Mr. J. D. Isaacs, and
Lieutenant J. H. Chamblin.
48
TEST B: UNDERWATER EXPLOSION
few thousandths of a second, and failed to penetrate
the capillary tube appreciably; but the slow-moving
water wave had no trouble in exerting its effect through
this tube.* A number of bottom-mounted hydrophones
(inductiphones) were used also. These, too, measured
wave height in terms of excess pressure at the bottom
of the lagoon.
Some wave-height gages were mounted directly on
the target vessels. These gages, called portable record-
ing echo sounders, made continual records of distances
to the lagoon bottom. Thus as a ship rose and fell on
a great wave, its changing elevation was recorded. t
Some echo sounders were mounted on buoys, which rose
and fell more freely than the cumbersome ships.
A few of the buoys sent off their wave-height data
at once, by radio, to scientists in a PBM plane circling
10 or 15 miles away.
The last important date before B-Day w^as 19 July
1946, when the final rehearsal was held. It went
* These instruments, powered hy batteries, could only operate
for limited periods and therefore had to he started almost at the
last moment before the explosion. To make final adjustments on the
starting mechanisms a number of picked men were kept aboard cer-
tain of the target ships until a few hours before Mike Hour. These
men breathed a great deal easier when the small boats showed up
on schedule to take them out of the lagoon.
t The echo sounder's main coynponent is a7i imderwaier "trans-'
ducer," or combination transmitter and receiver of souyid waves
in water. The transducer gives out a sudden pulse of sound, listens
for the echo from the bottom, and measures the time interval before
the echo is received. An increase in time interval corresponds to
an increase in depth.
49
BOMBS AT BIKINI
through successfully. However, the weather was dis-
appointing and much of the aviation program had to
be cancelled; luckily a complete aviation rehearsal
had been held separately a few days before.
The weather prediction for July 25, 1946, which was
to be B-Day, was indecisive. Colonel B. J. Holzman
and Captain A. A. Cumberledge (Navy), in charge
of weather forecasting, studied and restudied the bulle-
tins being sent in continuall,y from weather reconnais-
sance planes, land stations, and surface vessels ; by bad
luck, a so-called tropical front lay almost exactly above
Bikini Lagoon. But the odds appeared good that the
front would move oif slowly in favorable manner, and
at 8 :50 a.m. on July 24, Admiral Blandy made the de-
cision to get the B-Day program underway.
Final inspections were made of target vessels, and
final attentions were given to test animals and scien-
tific instruments.
Then the evacuation began. The majority of the
support ships quit the Lagoon by the evening before
B-Day. The remainder left by 6 :20 a.m. on the morn-
ing of B-Day. Among the last persons to leave the
lagoon was a group consisting of Admiral Parsons,
Dr. M. Gr. Hollo way, Mr. R. S. Warner, Jr., and a few
others. This group made the final adjustments aboard
the bomb-carrying ship LSM-60, and quit her at 6:07
a.m. Just 148 minutes later, this ship ceased to exist.
Shortly before How Hour, Dr. M. Gr. Hollo way on
the CUMBERLAND SOUND periodically closed
150
TEST B: UNDERWATER EXPLOSION
switches which sent to LSM-60 the successive coded sig-
nals 'preliminary to the actual firing on the bomb. Dr.
E. W. Titterton counted off the final seconds ; through
loudspeakers the relentless toll was heard by the 42,000
men waiting outside the lagoon, and by radio listeners
throughout the world.
The bomb detonated at 59.7 seconds after 8 :34 a.m.
on July 25, 1946, Bikini Local Time. This corresponded
to roughly 4:35 p.m. on July 24, Eastern Standard
Time and 9 :35 p.m. on July 24, Greenwich Civil Time.
The bomb was located at Latitude 11° 35' 05" North,
and Longitude 165° 30' 30" East. Its position was well
below the surface of the lagoon.
Things happened so fast in the next five seconds
that few e.yewitnesses could afterwards recall the full
scope and sequence. of the phenomena. B}^ studying
slow^-motion films and analyzing the records caught by
the thousands of instruments, the scientists eventually
pieced together the full story.*
When the bomb detonated, it released almost ex-
actly the same amount of energy as had been released
in Test A, namely 1,000,000,000,000,000,000,000 ergs
(10-^ ergs), equivalent to a])out 20,000 tons of TNT.
* Without question one reason ivhy observers had so much
trouble in retaining a clear impression of the explosion phenomena
was the lack of appropriate words and concepts. The explosion
phenoynena abounded in absolutely unprecedented inventions in
solid geometry. No adequate vocabulary existed for these novel-
ties. The vocabulary bottleneck continued for months even among
the scientific groups; finally, after two months of verbal groping, a
conference was held and over thirty special terms, with carefully
BOMBS AT BIKINI
This energy was transmitted initially as thermal
radiation, gamma radiation, neutron radiation, other
nuclear radiations, and shock wave.
The thermal radiation was extremely intense dur-
ing the first small fraction of a second; photographs
taken from the air show the water brightly illuminated
from beneath the surface. The region in which the light
originated, called the underwater fireball or "gas
bubble," rose rapidly to the surface and, still within
the first small fraction of a second, burst through the
surface to spearhead the upward shoot of the water
column. Many observers failed to see any light at all,
but the photographs taken with the Eastman high-
speed cameras and the Fastax cameras show clearly
the presence of a brilliant area atop the column during
the first instant of its rise. The practical effect of the
thermal radiation was, of course, almost nil.
The neutron radiation was of little immediate con-
sequence. Nearly all of it was absorbed in the sea
water; almost none reached even the nearest target
vessels. A significant fraction of the neutrons was ab-
sorbed by the sodium in the water, thereby producing
radioactive sodium (Na^''). Neutrons were heavily ab-
sorbed also by hydrogen, chlorine, and other elements
found in sea water.
drawn definitions, were agreed on. Among these terms were the
following: dome, fillet, side jets, hright tracks, cauliflower cloud,
fallout, air shock disk, water shock disk, base surge, water mound,
uprush, after cloud. These terms are defined in later pages of this
chapter.
52
TEST B: UNDERWATER EXPLOSION
The initial burst of gamma radiation was almost en-
tirely absorbed in the sea water. But the continuing
gamma radiation, produced by the fission products was
of great importance, as we shall see in a later para-
graph.
The shock wave in water was probably the most se-
vere shock wave ever produced on earth. Water, being
almost incompressible, forms an almost ideal medium
for transmitting shock waves. The special miderwater
gages showed that the pressure very close to the bomb
must have been far greater than 10,000 pounds per
square inch. Even at ranges of one-fourth to one-half
mile the pressure was hundreds or even thousands of
pounds per square inch. At distances of two to three
miles the pressure was still intense.
Throughout most of its course the underwater shock
wave traveled at the speed of sound, which was roughly
3500 miles per hour, or about one mile per second. Very
close to the bomb the velocity was even greater.
The underwater shock wave spread throughout the
shallow lagoon as a rapidly expanding circle. Photo-
graphs taken from the air show this water shock disk
clearly. But it did not grow entirely uniform; a va-
riety of irregularities were observed. Coral heads on
the lagoon bottom in some instances impeded the
growth and in other instances reflected the shock wave
towards the surface of the water where it out-cropped
in peculiar pattern. The shock wave was reflected from
the underwater portions of the target vessels, and peak
53
BOMBS AT BIKINI
pressure values measured just behind ships were defi-
nitely lower than pressures at the near sides of the
ships. Ordinarily, the pressure values were not as great
close to the surface of the water as they were at greater
depth.
As the underwater shock wave struck the target
ships, it delivered terrific blows. A peak pressure of,
say, 1000 pounds per square inch produces a total force
of nearly a million tons on the underwater hull of a
large warship situated broadside.
The underwater shock wave spread not only out-
ward but also upward. In fact, it was the upward
sweep which produced the most unprecedented effect.
The upward sweep of the shock wave and fireball ' ' gas
bubble ' ' reached the surface of the lagoon within a few
hundredths of a second. As the gas bubble approached
the surface, it produced a swelling called the dome.
The dome was, of course, illuminated from within ; and
atop the dome rode the LSM-60. The dome now burst,
and the fireball and water column leaped upward from
the lagoon.
At about this instant, LSM-60 was blown to bits
and sprayed upward with the column. If the column
could be called a jet, LSM-60 's departure was about
the ultimate in jet assisted take-offs. If LSM-60 ever
sank, it was as a fine rain of steel fragments and dust.
No large fragment of her was ever found.
Observers could scarcely follow the lightning ascent
of the column. Its upward rise was initially at a rate
154
TEST B: UNDERWATER EXPLOSION
greater than a mile per second. Almost at once the
rate decreased sharply ; the growth was very slow after
the first five seconds. The altitude reached at the end of
fifteen seconds was about one mile; at the end of the
first minute, the altitude was about one and one-half
miles.
The rising mass of water passed rapidly from the
''hair-do" stage to the crowned funnel stage and finally
to the full cauliflower stage. Judging from photo-
graphs taken from drone planes flying directly above,
the cauliflower appeared to have a relativeh^ hollow
center. The diameter of the cauliflower sixty seconds
after Mike Hour was greater than one and one-half
miles. The diameter of the column or stem itself was
roughly 2000 ft.
Rising in the column were various fragments, pre-
sumably from LSM-60 but possibly from the lagoon
bottom. Several of the larger fragments left in their-
wake white condensation trails, called bright tracks.
A number of the fragments struck the surface of the
water roughly a mile away.
Great black blotches appeared in the side of the
column. One blotch was as large as a battleship. The
cause of these blotches is not known with certainty.
One theory is that they consisted of dust and soot
sucked up from the target vessels. The largest of the
big dark areas, which appeared near the location of
the ARKANSAS, may not have been a true blotch at
all ; perhaps it was a cavernous hole in the side of the
155
BOMBS AT BIKINI
column. In other words, it may have been a ^'shadow"
produced in the upward-sweeping water by the rela-
tively immovable ARKANSAS.
It is estimated that the column contained several
million tons of water. Early guesses were that ten
million tons were tossed up, but later computations
suggest that two million tons may be a more accurate
figure. This amount of water would fill a swimming
pool about twenty feet deep and nearly half a mile in
diameter.
But the column was far from being solid water;
actually it was about 99 percent air. A shell fired from
a large gun could probably have passed straight
through the column with little difficulty. Probably the
water was more or less concentrated in the outer part
of the column, with the center relatively empty. Some
scientists believe that if suitable lighting had been
provided inside the column, a person flying directly
above could have peered down as far as sea level, and
possibly even down to the very bottom of the lagoon
itself.
The column wall was not smooth, but was inlaid
with thousands of separate spikes, or column side jets,
each as large as a destroyer. As the cauliflower ap-
proached maturity, these side jets began to fall. More
and more their points turned downward to form a
white cascade thousands of feet high. This falling cur-
tain gathered speed, carrying with it thousands of tons
of air in the cylindrical plunge back into the lagoon.
156
TEST B: UNDERWATER EXPLOSION
SHOCK WAVES
While the column was spurting upward, two kinds
of shock waves were racing outward. The underwater
shock wave, described on a preceding page, traveled
fastest, and did the greatest damage. The shock wave
in air was less harmful, but was extremely interesting
in many respects. It had, for example, a dual origin.
In part it was created by the very rapid expansion of
the fireball and column in their first instant of escape
from the water. The shock wave created, shaped like
an egg standing on end, was so intense that it showed
up clearly in short-exposure pictures taken from the
towers on Bikini Island. The concentration of air in
the shock wave acted like a prism and, by optical re-
fraction, left a clear elliptical line on the photographic
films. The shock wave in air was born also from the
fillet, the circular region surrounding the column base.
In the fillet area, the water was so violently hammered
from below that the surface of the lagoon was pushed up
slightly. The energy within the water could not be con-
strained to stay there; part of the energy leapt into
the air to produce an air shock wave proceeding more
upward than outward.
The combination of the elliptical shock wave and
the upward shock wave produced a wave of remarkable
shape. Where the two effects joined, the shock wave
had a definite bend, such as occurs where the brim of
a hat joins the crown. The bend did not last long. As
57
BOMBS AT BIKINI
the shock wave expanded, it smoothed out the bend
and in short order assumed nearly hemispherical
shape.
Both the underwater shock wave and the air shock
wave left their circular marks on the surface of the
lagoon. The water shock disk expanded very rapidl,y;
the air shock disk expanded more slowly and showed up
more clearly in the photographs.
The shock wave reflection effects were remarkably
vigorous. Slow-motion pictures show the strange pat-
terns produced on the surface by the underwater reflec-
tion of the water shock wave. They show also the typical
effect produced when the air shock wave struck one of
the inner ships: the localized reflection created a new
spherical wave spurting out in many directions. Ac-
tually, it was not the secondary shock wave itself
which was photographed, but the secondary conden-
sation cloud which was pursuing the secondary shock
wave.
The primary condensation cloud Avas tremendous,
covering an area of roughly six square miles. It had
started forming within one second of Mike Hour; one
or two seconds later it had reached the "birthday cake
on a platter" stage. But it evaporated very rapidly.
Within eighteen seconds after Mike Hour it had the
form of a hollow ring, and almost immediately there-
after it broke up and disappeared. A small conden-
sation cap formed momentarily directly above the
cauliflower; it lasted only a few seconds.
158
TEST B: UNDERWATER EXPLOSION
BASE SURGE
The base surge was an awesome yet deceptive phe-
nomenon. It looked like a great wave of water. Ac-
tually it was a rolling mass of flufty spray, mist, and
air. It was not formed by the explosion proper, but
as an indirect after-effect. The millions of tons of
water thundering l)ack into the lagoon created an enor-
mous volume of spray and mist, which billowed out-
ward from the column base. The outward velocity of
this diffuse mass was initially more than fifty miles
per hour ; later it slowed to twenty-five miles per hour.
As the base surge spread out, it resembled a steadily
expanding and fattening doughnut. At first, its height
was about 300 ft. — a mere three times the height of a
battleship's mast; later it reached 1000 ft., and ulti-
mately towered to 2000 ft.
The base surge, for all its tenuousness, left a kiss
of death on the majority of the target vessels. The white
billows carried radioactive fission products equivalent
to many tons of radium. Gamma radiation issued in all
directions. The base surge did not merely pass hy the
ships; its radioactive mist settled on the deck, moist-
ened every bit of exposed metal, wood, and canvas.
Even after the moisture evaporated, radioactive resi-
dues remained. And always the deadly gamma radia-
tion continued; persons remaining within its reach
Avould have been doomed. The radius of action is es-
pecially great downwind, since the surge tends to drift
59
BOMBS AT BIKINI
in that direction. The base surge is the newest menace
wrung from within the atomic nucleus.
WATER WAVES
Water waves were another type of unleashed fury.
When the millions of tons of water were ripped from
the lagoon, an enormous cavity was produced, extend-
ing probably to the very bottom of the lagoon. Almost
immediately the surrounding water rushed madly to
fill the cavity; actually, it over-filled the cavity and
produced a great mound. The mound then sank slowly
to the normal level of the lagoon. This rapid dying off
of the central oscillation in the water probably consti-
tuted the first experimental verification of the compli-
cated mathematical theory (Cauchy-Poisson equation).
From the birth and death of the giant mound, the
water waves were formed — majestic waves higher
than had ever before been produced by man and per-
haps greater than Nature herself ever raised.* No one
knows how great the waves were near the Zeropoint,
or whether there actually was inside this cauldron
anything that could properly be called a wave. But
near the edge of the column, say 1000 ft. from the
Zeropoint, the waves were very real. Photographs
show that the highest wave was eighty to one hundred
ft. from trough to crest. The wave heights were in
* Possibly greater- waves were produced when, in 1883, the
island of Krakatao exploded.
160
TEST B: UNDERWATER EXPLOSION
almost perfect agreement with predictions made before
the tests. These predictions were based on small scale
experiments made by the Oceanographic Group at the
United States Naval Electronics Laboratory, San
Diego, California, and the Naval Mine Warfare Test
Station at Solomons Island, Maryland. The explosive
charges used in those experiments contained TNT and
weighed from one to 2000 pounds.
The first wave, the highest of all, contained several
million tons of water. It traveled with a speed of the
order of fifty miles per hour, which is just what the
wave experts had predicted.*
At the start of its outward travel, the first wave was
in unstable condition ; its crest tended to get ahead of
its base. The result was what oceanographers call a
spilling breaker. But as the wave moved along, its
height diminished and it lost its tendency to break.
The first wave soon found itself less high than the
second wave ; and a little later the third wave claimed
pre-eminence. This handing down of the honors from
one wave to the next was in full accord with the expecta-
tions of the oceanographers, who say that the gf^otip
velocity is less than the phase velocity.
* The prediction made hy Commander Roger Revelle and Dean
M. P. O'Brien was based on the known depth of the lagoon and
on the rough rule that in shallow water of specified depth all very
long waves have the same velocity. Knowing the depth, they could
compute the velocity. In really deep water, of course, the situation
is entirely different: a wave's velocity depends on its length, long
waves traveling faster than short ones.
161
BOMBS AT BIKINI
The waves multiplied as they progressed. Near the
column there were few of them, but as they approached
Bikini beach, they were a family of fifteen or twenty.
Each wave gathered height as it entered the shallow
water off Bikini, three and a half miles from the Zero-
point; it drew itself up into a short, steep, plunging
breaker. Maximum height of the breakers was fifteen
feet.
The uprush was not particularly severe. The water
rushed up over the beach top, in many areas, and
caused some flooding and erosion. Thousands of tons
of beach materials were moved. Several medium-sized
beach landing craft and small boats were damaged and
a few huts also. But no noteworthy damage resulted.*
The ^'backrush" from the first wave swept more
than 50,000 tons of beach sand into the lagoon.
The explosion produced much erosion of the lagoon
floor directly beneath the bomb. The amount of bottom
material wrenched free was of the order of a million
cubic yards. The main crater formed was not entirely
* Maximum water height on Bikini Island was measured hy two
kinds of height gages: tin-can gages and electrical-fuse gages. The
tin-can gage consists merely of a tall pole securely mounted ver-
tically and carrying a number of tin cans at various heights. Each
can is upright; it is open at the top and has a small awning to keep
out the rain. If a wave covers the ground to a depth of, say, four
feet, then all cans helow the four-foot level are filled with water.
In the electrical-fuse gage, the tin cans are replaced hy wires having
small gaps. When the water rises enough to immerse a gap, an elec-
trical current flows and a small electrical fuse is blown out. From.
inspectio7i of the assembly of fuses, maximum water height can be
deterynined easily.
162
TEST B: UNDERWATER EXPLOSION
smooth, but was found to contain several secondary
craters.*
The majorit.y of the materials torn out settled to
the bottom within a few hours, forming a thick struc-
tureless carpet. But thousands of tons of sediment re-
mained in suspension. Even after two weeks, the water
still carried a mineral load. Some bottom material had
been thrown high into the air ; some of it fell onto the
decks of target vessels.
A large number of fish were killed in the corner of
the lagoon where the explosion occurred. Elsewhere in
the lagoon the fish survived, and outside the atoll the
fish were practically unaffected either by the explosion
or the subsequent radiological effects.!
* The depth of the bottom crater was computed from very ac-
curate sou7idings made before and after the explosion. The soimd-
ings were made by members of the Oceanographic Group operating
from, the hydrographic survey ship BOWDITCH. An ingenious
but unsuccessfid attempt was made to measure the exact diameter
of bottom area laid bare by the explosion. Some days before the
explosion, the Group laid long steel cables on the bottom near the
Zeropoint, and to these cables they attached a large number of hol-
low steel cylinders containing unexposed photographic film. It was
expected that in those areas where the water was swept clear, gamma
radiation from the underwater fireball would reach the cylinders
and affect the film. Unfortunately, the explosion was so violent that
none of the cylinders were ever seen again.
t Over 40,000 atoll fish were caught. Several new types were
found. Professional fishermen recruited from the west coast fishing
industry caught many tons of tuna and other deep sea fish (pelagic
fish). Unfortunately, 98 percent of these latter were lost when
YP-636 went aground thirty miles south of San Francisco in Sep-
tember, 1946.
163
BOMBS AT BIKINI
A strong earth shock was recorded by seismographs
located on Amen, eight miles from the Zeropoint.
DAMAGE TO SHIPS
The B-Day Bomb sank nine ships and seriously
damaged many others.
LSM-60, situated directly above the bomb, disin-
tegrated instantly. A few of the flying fragments were
photographed by tower motion picture cameras ; a very
few fragments fell on other vessels and were later
picked up by boarding personnel.
The 26,000 ton battleship ARKANSAS sank almost
at once, while still obscured by spray and steam. She
was the closest of the target vessels and was located
well over 500 feet from the Zeropoint. She suffered
severe damage to her hull. In sinking, she carried with
her the dubious honor of being the first battleship to
be sunk by an atomic bomb, and the first battleship to
be sunk by a bomb which never touched her.
The aircraft carrier SARATOGA sank by the stern
seven and a half hours after Mike Hour. She was the
next-to-closest of the target ships and was located over
500 ft. from the Zeropoint. Although she was de-
signed over 20 years ago and, before she sank, was the
oldest United States aircraft carrier afioat, she was
extremely strongly built. In fact her hull had been
designed originally as that of a battle cruiser, and in-
cluded . hundreds of watertight compartments. She
weighed 33,000 tons. By three hours after Mike Hour,
64
TEST B: UNDERWATER EXPLOSION
her stern was clearly low in the water and she had
begun to list slightly to starboard. By five hours after
Mike Hour her freeboard had decreased further, and
observers indulged in some betting as to whether she
would sink, and when. Admiral Blandy ordered tugs
to attempt to secure lines to her if practicable and tow
her to Enyu Island for beaching. But this proved to be
impossible. The ship herself and the water surround-
ing her were too "hot" to permit safe approach. She
sank slowly. Her stern was awash at 3:59 p.m. By
4 :09 p.m. her deck was completely awash and air could
be seen blowing from her. The last bit of her super-
structure sank forever beneath the surface of the la-
goon at 4:16 p.m. Analysis of photographs of ''Old
Sara" shows that all moored airplanes and materials
on her deck had been swept overboard; much of her
superstructure had been demolished; her distinctive
stack had crashed to the flight deck and her below-the-
waterline hull had taken a serious beating.
The ex- Japanese battleship NAGrATO sank during
the night, four and a half days after Mike Hour. Only
a few hours after Mike Hour she took on a list of about
5 degrees. This list increased so slowly that many ob-
servers expected her to survive. When her characteris-
tic silhouette failed to show itself on the morning of
July 30, surprise was general. No one had seen her
sink. Undoubtedly openings had been made in her hull.
Three of the submarines sank. They were the
PILOTFISH, SKIPJACK, and APOGON. All of
165
BOMBS AT BIKINI
these were in submerged position when the explosion
occurred. Air bubbles and fuel oil escaped from the
APOGON as she went down.
YO-160, a concrete oil barge, was seen in photo-
graphs taken immediately after the explosion, but she
sank quickly. LCT-1114, a 120-ft. landing craft, cap-
sized and was later sunk.
Besides sunken ships, there were many seriously
damaged ships to bear witness to the power of the
underwater explosion. Serious damage was done to
the battleships NEW YORK and NEVADA, the
cruiser PENSACOLA, the destroyers HUGHES and
M AYR ANT, the APA's FALLON and GASCON-
ADE, and LST 133. The HUGHES was soon found to
be in sinking condition, and the FALLON listed
badly. Both of these ships were therefore taken in tow
and beached.
Damage w^as caused principally by the underwater
shock wave, which tended to crush ships' hulls and
seriously jar internal machinery. The pressure wave
in air w^as severe also, but was responsible ordinarily
only for less serious damage to superstructures. The
towering waves of water shared in the production of
damage. It also tended to move some of the ships
bodity, outward from the Zeropoint.
INJURY TO ANIMALS
Because the target ships were so radioactive. Cap-
tain Draeger's men were for several days unable to
66
UPPER. Last resting place of the Test B bomb was a sturdy steel caisson
slung at predetermined depth beneath LSM-60. At exactly 8:35 a.m.
on July 25, 1946, bomb, caisson, and ship ceased to exist. LOWER.
A shimmering hemisphere, the condensation cloud, springs into being,
shrouding the target area.
Pla+e 25
This photograph was
taken by on automatic
camera mounted in a
drone plane flying di-
rectly above the Zero-
point at the instant of
detonation, a remarkable
achievement in drone
control. The cauliflower
is funnel-shaped at this
stage; within its jagged
rim is a condensation
cloud nearly a mile in
diameter, which evapo-
rated a few seconds later.
In this oblique view the condensation cloud, still in an early stage, is
expanding on the heels of the air shock wave at over 700 miles per
hour. A large ship appears as a tiny black speck in the air shock disk,
the white area marking the outward sweep of the shock wave across
the surface of the water.
Plate 26
-^iar^fAfi«''^»iiiM8Wig|iiiiMiB»aMB»
UPPER. The Test B column, containing two million tons of water, rises
in wroth. It towers above the ex-Japanese battleship NAGATO and
a large floating drydock. LOWER. Seconds later the great column
thunders back into the lagoon, unleashing the billowing base surge,
500-ft.-high wall of spray and mist.
Plate 27
This photograph, perhaps the most awesome of all, shows the cauli-
flower aftercloud looming darkly overhead, the mile-high column now
fast collapsing, and the base surge plunging towards the NAGATO
(left) and NEVADA (right). Fission products equivalent to hundreds
of tons of radium infest the area.
Plate 28
"^v
f.-
f^V
\ ^t
/f'lV
^^*^'****^ :tKk¥^
UPPER. Drawing itself up to a height of 15 feet, the first wave pro-
duced by the underwater explosion pounds Bikini beach. Note the
height-of-water marker pole. LOWER. Backrush from the waves carried
50,000 tons of beach sand into the lagoon. Note erosion visible at
right, and the sand-filled boat.
Plate 29
The aircraft carrier SARA-
TOGA is sinking by the
stern, seven hours after
the Test B explosion. She
was more than 500 feet
from the Zeropoint, yet
her below-the- waterline
hull took a bad beating;
much of her superstruc-
ture including her stacks
had been demolished,
and all moored airplanes
and materials on deck
had been swept over-
board.
A Navy fireboat washes down the deck of the battleship NEW YORK
after Test B. This procedure was followed for many of the target ships
prior to sending inspection parties aboard, since great quantities of
radioactive water had been thrown onto the decks. A few of the
ships remained "hot" for months.
Plate 30
A number of fish caught after Test B were found to be radioactive.
By placing them overnight on photographic films, radioautographs
v/ere obtained, as of the surgeon fish shov/n here. Radioautographs
v/ere obtained of "hot" algae also. Biological procosce: have, of
course, no effect on radioactivity.
The fourteen ships sunk
in the operation carried
down with them much
valuable information,
such OS instrument rec-
ords and various types of
damage to ship struc-
tures. Divers and under-
water cameras made
good a large part of the
informational gap. Here
is an underwater photo-
graph of superstructure
wreckage, including a
damaged pressure gage.
Plate 31
UPPER. Dr. G. K.
Green, of the Army
Ground Group, studies
a telemetered chart
mode by on Esterline
Angus recorder on AG
76 AVERY ISLAND.
LOWER. Composite
photograph roughly
comparing the Test B
cauliflower cloud with
New York skyscrapers.
An exact comparison
would be even more
extreme. The cauli-
flower cloud, nearly
two miles in diameter,
would overshadow a
considerable portion
of Manhattan. It re-
quires little study to
appreciate catas-
trophic destruction.
Plate 32
TEST B: UNDERWATER EXPLOSION
approach the ships on which the test animals were lo-
cated. Fortunately this situation had been allowed
for in advance : the animals had been given sufficient
food and water to last for at least ten days. In fact
all surviving animals had small supi^lies of food re-
maining at the time the ships were reboarded.
The animals were found to have suffered very little
from shock, and of course, none from heat or light.
But radioactivity took a heavy toll. Some of the
animals had died from radioactivity even before the
ships were reboarded. Many others died later. All the
pigs died as a result of exposure to nuclear radiations.
Many rats died from the same cause, but a number were
still alive in late September, 1946.
As before, exposure to gamma radiation ])roduced
a variety of symptoms, including general apathy, weak-
ness, and tendency to develop secondary infections.
But it should be remembered that radiation sickness
is essentiall,y painless ; and in the case of animals, vic-
tims have no mental anguish such as would presumably
assail human beings. The animal languishes and either
recovers or dies a painless death. Suffering among the
animals as a whole was negligible. By studying them
we have gained knowledge as to what dangers might
confront men and what steps would minimize the
injury.
The degree of radioactive poisoning of water and
ships was impressive. The total amount of radioactive
materials released was initially equivalent to hundreds
67
BOMBS AT BIKINI
of tons of radium. Some of the radioactive material
drifted off in the cauliflower cloud; but much re-
mained in the lagoon area. The base surge, in its pre-
cipitant flight outward from the column, carried radio-
active materials. It drenched the target vessels and left
them radioactively poisoned.
Over 90 percent of the target vessel array fell vic-
tim to radioactivity. The extent of radiological hazard
went beyond what had been expected.
Without question, ships' crews would have been
seriously affected over a wide area. Had the target
array been manned, casualties and both physical
and psychological injury would have been very
great. Rescue and attention to casualties would have
been difficult and dangerous. "Within 2000 yards of the
explosion center, ships would probably have been in-
operative and a lapse of weeks might well have ensued
before relatively undamaged ships could again have
been used in combat.
TERMINATION
It was several days before the majority of the target
vessels could be reboarded. Not until ten days after
B-Day was it feasible to reboard all the vessels. The
radioactivity of the ships was more severe than had
been expected.
The lagoon itself was re-entered a few hours after
the explosion. The first boats to approach the target
68
TEST B: UNDERWATER EXPLOSION
array were the unmanned drone boats, controlled by
radio signals sent from support ships located well out
of danger. These boats threaded their way through
the array of ''hot" ships, taking w^ater samples and
recording just how intense the radioactivity was in
each area. Manned boats skirted the region cautiously,
keeping outside of the really ''hot" zones.
Master charts were prepared on the support ships
showing danger areas. A "red line" was drawn show-
ing where the radioactivity exceeded one roentgen per
day, and was thus unsafe. A "blue line" indicated
where the activity was less than 0.1 roentgen, and was
safe. As the lagoon currents slowly spread, shifting
the contaminated water area, new charts were prepared
and word sent to all ships.*
All animals had been taken off the target ships by
five days after B-Day; some of the scientific instru-
ments could not be approached with safety for weeks
afterwards.
* Re-entry of the target area would have been greatly slowed if
previous studies of lagoon currents had not teen made. Commander
Roger Revellers Oceanographic Group, besides making model
studies, had spent weeks finding just where the lagoon currents
went, and how fast. With dye markers, floating poles, and other
equipment his group tracked not only the surface currents but also
the counter -currents flowing along the lagoon bottom. They found
where the bottom water welled up, and where the surface water de-
scended. They found how the current changed with wind and
tide. Thanks to this information, they could assure the Task Force
Commander that advance scouts would not suddenly find them-
selves trapped by radioactive water welling up behind them un-
expectedly.
69
BOMBS AT BIKINI
Decontamination measures were initiated promptly
by Admiral T. A. Solberg. A number of different
methods were used in this newest of problems : remov-
ing radioactive materials from ships' decks, sides,
superstructures. Streams of water were played on the
ships; special chemicals were applied; strenuous
scrubbing was tried. The success of these methods
varied widely.
Despite all efforts, radioactive contamination con-
tinued to be a major problem for many weeks. Some
of the ships, veritable radioactive stoves, were towed
to Kwajalein. Some contaminated ships were later
towed to Pearl Harbor and continental United States
to permit more convenient study of decontamination
methods and also to permit training personnel in radio-
logical safety and decontamination processes.*
Even some of the support ships found that their
salt water lines and evaporators became contaminated
* In late August of 1946, Captain G. M. Lyon, Safety Adviser,
was requested l)y the Task Force Commander to set up a Radio-
logical Safety School to train officers in all phases of radiological
safety. Commander D. L. Kauffman was placed in charge of the
School. First classes began on Septemher 9, 1946, and the stii-
dents included roughly 100 officers from Army Air Forces, Army
Ground Forces, Navy, Marine Corps, and the United States Public
Health Service. The training program, included a four-weeks aca-
demic course in Washington, D. C, followed by three months of
practical instruction in the field. The faculty of the school included
initially: Lt. Col. A. Roth of the Army Ground Forces, Lt. Col.
J. M. Talbot, of the Army Air Forces, Comdr. E. G. Williams, of
the United States Public Health Service, Dr. G. Dessauer of the
University of Rochester, Dr. R. J. Stephenson of Wooster College,
and Dr. M. L. Pool of Ohio State University.
170
TEST B: UNDERWATER EXPLOSION
by the radioactive lagoon water. Being well clear of
the lagoon at the time of the explosion did not prevent
these ships later feeling the effects of the bomb.
A number of the support ships, on reaching the west
coast of the United States, were found to be still af-
fected by radioactive materials, and were held in tem-
porary quarantine. Strenuous processes of cleaning
and decontamination were arranged. Special methods
of cleaning the sides and bottoms of the ships were
worked out; oxygen rebreathing apparatus was sup-
plied to the men doing the work; elaborate checking
procedures were established.
Fortunately, no hazard existed to personnel not
actively engaged in the operation, repair, or cleaning
of the contaminated portions of the ships. This meant
that there was no danger to anyone from having these
ships in harbors and at ordinary docking facilities.
By observing relatively simple safety precautions, per-
sonnel working on these ships did so with no danger
to themselves.
The homeward voyage of the support vessels from
Bikini got underway in early August. Few support
ships remained in the atoll after mid- September. The
scientists gathered again in their laboratories in con-
tinental United States, analyzed their instruments'
records and wrote their detailed reports. Then the
overall reports were compiled. For the first time the
full story of what happened at Bikini began to un-
fold. Now, armed with facts instead of guesses, engi-
171
BOMBS AT BIKINI
neers and strategists could proceed with their plan-
ning for a national defense geared to the Nucleonics
Age.
The Joint Task Force was dissolved on November
1, 1946, by the Joint Chiefs of Staff. Final activities
were carried on thereafter by a Joint Crossroads Com-
mittee, of which Rear Admiral W. S. Parsons was
made Chairman. It is the task of this Committee to
see that all possible information is gleaned from the
Operation. Years may elapse before the books may be
closed and the Operation allowed to settle itself into
its niche in History.
72
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175
Appendix 2
List of Principal Participating Officials
Vice Admiral W. H. P. Blandy, Commander of Joint Task
Force One, was assisted by a staff including two Deputy Task
Force Commanders and a Ground Forces Adviser.
Rear Admiral W. S. Parsons, Deputy Task Force Commander
for Technical Direction, was assisted by a technical staff includ-
ing the following:
Four special assistants :
Dr. John von Neumann, Scientific Adviser
Capt. F. L. Ashworth (Navy) Assistant for Aviation
Capt. Horacio Rivero (Navy) Assistant for Special
Dr. W. A. Shurcliff, Historian
Two technical administrators:
Dr. R. A. Sawyer, Technical Director
Rear Admiral T. A. Solberg, Director of Ship Material
Two technical advisers :
Capt. G. M. Lyon (Navy), Safety Adviser
Col. S. L. Warren, Radiological Safety Adviser
Major General W. E. Kepner, Deputy Task Force Commander
for Aviation, was assisted by Army and Navy officials including
the following :
Brig. Gen. T. S. Power, Assistant Deputy Task Force Com-
mander for Aviation
Capt. H. D. Riley (Navy), Assistant for Naval Aviation
Major General A. C. McAuliffe, Ground Forces Adviser, was
assisted by Col. J. D. Frederick and others.
CHIEF OF STAFF
Commodore J. A. Snackenberg, Chief of Staff of Joint Task
Force One, was assisted by four assistant chiefs of staff for person-
nel, intelligence, operations, and logistics.
Captain Robert Brodie, Jr. (Navy), Assistant Chief of Staff
for Personnel, was assisted by Comdr. C. A. Powell, Lt. Comdr.
H. B. Williams, Lt. M. S. Ochstein (Navy), Lt. (jg) John J. Bab-
inski (Navy), and Lt. A. J. Meyer (Navy).
Brigadier General T. J. Betts, Assistant Chief of Staff for
Intelligence, was assisted by a staff including the following:
76
Captain Fitzhugh Lee (Navy), Head of the Public Infor-
mation Section
Captain R. S. Quackenbush (Navy), Head of the Non-
Technical Photography Section
Colonel H. B. Smith, Head of the Nonparticipating Ob-
servers Section
Commander Charles Randall, Head of the Security Section
Captain C. H. Lyman, Assistant Chief of Staff for Operations,
was assisted by a staff including the following :
Capt. W. C. "Winn (Navy), Head of the Ship Operation
Section
Col. W. D. Ganey, Head of the Air Operation Section
Capt. K. M. Gentry (Navy), Head of the Communications
and Electronics Section
Col. B. J. Holzman, Head of the Aerology Section (Working
closely with him was Capt. A. A. Cumberledge (Navy) )
Capt. A. B. Leggett (Navy), Head of the History and
Analytical Section
Brigadier General D. H. Blakelock, Assistant Chief of Staff
for Logistics, was assisted by a staff including the following:
Capt. M. A. Norcross (Navy), Head of the Executive
Section
Comdr. M. H. Gatchell, Head of the Navy Supplies Section
Col. F. W. Ott, Head of the Army Supplies Section
Col. A. D. Higgins, Head of the Transportation Section
Comdr. J. J. Fee, Head of the Force Maintenance Section
Capt. W. E. Walsh (Navy), Head of the Force Medical
Section
Comdr. K. C. Lovell, Head of the Construction Section
TECHNICAL DIRECTOR
Dr. R. A. Sawyer, Technical Director, was assisted by a large
technical staff including six immediate assistants, and ten adminis-
trators. The six immediate assistants were :
Dr. E. W. Thatcher, Deputy Technical Director
Capt. F. L. Riddle (Navy)
Comdr. E. S. Gilfillan
Comdr. A. W. McReynolds
Lt. Comdr. J. K. Debenham
Lt. (jg) J. A. Young
Ens. H. M. Archer
177
The ten administrators were as follows :
Dr. W. 6. Penney, head of the Pressure Group (Cans and
Drums).
Comdr. Roger Revelle, Head of the Oeeanographic Group. As-
sisting him in the direction of the oeeanographic survey work were
Lt. Comdr. C. A. Barnes and also Lt. Comdr. J. R. Lyman, Lt.
Comdr. M. C. Sargent, Capt. M. A. Traylor (Army), assisting in
the direction of wave measurement work were Lt. Comdr. F. G.
Morris and also Mr. N. J. Holter, Comdr. Beauregard Perkins, Jr.
Comdr. C. H. Gerlach, head of the BuShips Instrumentation
Group. Principal assistants were Comdr. R. M. Langer, Lt. Comdr.
L. S. Beedle, Lt. Comdr. F. J. Dellamano and also Mr. E. E. John-
son, Dr. G. E. Hudson, Dr. Irwin Vigness, Mr. P. J. Walsh, Mr.
H. E. Jensen, Mr. C. F. Kasanda, Mr. F. J Friel.
Capt. C. L. Engelman (Navy), head of the Electronics Grouj).
Principal assistants were Dr. T. D. Hanscome, Comdr. J. L. Miller,
Comdr. J. E. Rice, Comdr. J. G. Houpis, Dr. D. G. Fink, Comdr.
F. X. Foster, Lt. Comdr. R. L. Reaser, Lt. Lawrence Bershad
(Navy).
Col. S. L. Warren, head of the Radioactivity Group. Principal
assistants were Col. A. A. deLorimier, Capt. R. J. Buettner (Navy),
Comdr. D. L. Kauffman, Dr. Herbert Scoville, Jr., Dr. Joseph
Hamilton, Dr. Kenneth Scott, Dr. Gerhard Dessauer, Dr. Lauren
Donaldson, Mr. Donald Collins.
Capt. A. E. Uehlinger (Navy), head of the BuOrd Instrumenta-
tion Group. Assisting him were Dr. G. K. Hartmann, Capt. L. W.
McKeehan (Navy), Lt. Comdr. F. L. Yeo, Dr. C. W. Lampson, Dr.
A. B. Arons, Dr. J. V. Atanasoff, Comdr. S. S. Ballard, Dr. J. E.
Henderson, CWO J. P. Orr.
Dr. M. G. Holloway, head of the Los Alamos Group. Assisting
him were Mr. R. S. Warner, Jr., Dr. N. N. Nereson, Dr. G. A.
Linenberger, Dr. William Rubinson, Dr. J. L. Tuck, Dr. B. Brixner,
Dr. J. Wieboldt, Dr. J. Wiesner, Dr. H. Weiss, Dr. J. Hirshfelder.
Comdr. George Vaux, head of the Remote Measurements Group.
Capt. R. S. Quackenbush (Navy), head of the Technical Photo-
graph Group. Principal assistants were Comdr. J. H. McElroy,
Col. P. T. Cullen, Comdr. K. S. Shaftan, Dr. Brian O'Brien, Lt.
F. Terzo (Navy), Dr. B. Brixner.
Col. D. F. Henry, head of the AAF Electronics Group.
178
DIRECTOR OF SHIP MATERIAL
Rear Admiral T. A. Solberg, Director of Ship Material, was
assisted by a large staff including six special assistants and six
group administrators. His six principal special assistants were as
follows :
Capt. L. A. Kniskern (Navy)
Capt. F. W. Slaven (Navy)
Capt. F. X. Forest (Navy)
Comdr. E. H. Batcheller
Lt. Comdr. L. H. Roddis, Jr.
Lt. Comdr. L. R. Crlostcn
His six group administrators were as follows :
Col. J. D. Frederick, head of the DSM Army Group. Principal
assistants were Col. J. S. Weber, Lt. Col. S. B. Smith, Capt. C. H.
Wollenberg (Army), Lt. Col. S. F. Musselman, Capt. H. C. Adams
(Army), Col. L. P. Jordan, Maj. E. K. Walters.
Capt. T. C. Lonnquest (Navy), head of the DSM Aeronautics
Group. Principal assistants were Capt. J. E. Dodson (Navy),
Comdr. J. K. Leydon, Maj. J. W. Morrison, Comdr. J. R. Reedy,
Lt. E. V. Sizer (Navy), Lt. Comdr. G. V. Schliestett, Lt. Comdr.
W. A. Hopkins, Lt. J. A. Torrey (Navy).
Capt. L. A. Kniskern (Navy) was originally head of the DSIM
BuShips Group; later Capt. F. X. Forest (Navy) was made head
of the Group. Principal assistants were Capt. F. W. Slaven (Navv),
Capt. R. C. Bell (Navy), Comdr. C. L. Gaasterland, Lt. (jg) J.'F.
DiStefano, Comdr. J. W. Roe, Capt. W. S. Maxwell (Navy), Capt.
P. S. Creasor (Navy).
Capt. E. B. Mott (Navy) was head of the DSM Ordnance Group.
Principal assistants were Comdr. A. A. Freedman, Capt. C. S.
Piggott (Navy), Comdr. Edgar O'Neill, Comdr. F. W. Russe,
Comdr. H. C. Dudley, Lt. Comdr. H. B. Taylor, Lt. Comdr. H. M.
Tatum, Lt. Comdr. T. W. Johnson
Capt. G. M. Lyon (Navy) was head of the DSM Medical Group.
Principal assistants were Capt. Oscar Schneider (Navy), Comdr.
Marshall Cohen, Lt. Harry Browdy (Navy), Lt. (jg) A. L. Rogers,
Lt. G. W. Morrison, Jr. (Navy), Lt. Comdr. J. J. McCoy; also Capt.
R. H. Draeger (Navy), Capt. Shields Warren (Navy), Comdr. R. H.
Lee, Comdr. J. L. Tullis, Lt. Comdr. R. E. Smith, Lt. Maynard
Eicher (Navy), Capt. F. R. Lang (Navy), CPhM C. E. Wagner.
Capt. C. L. Engelman, head of the DSM Electronics Group.
(See also electronics personnel listed under Technical Director's
staff).
79
TASK GROUP COMMANDERS
The eight task group commanders were as follows :
E. Adm. W. S. Parsons, Technical Group, T.Gr. 1.1
R. Adm. F. G. Fahrion, Target Vessel Group, T.G. 1.2
Capt. W. P. Davis (Navy), Transport Group, T.G. 1.3
Col. J. D. Frederick, Army Ground Group, T.G. 1.4
Brig. Gen. R. M. Ramey, Army Air Group, T.G. 1.5
R. Adm. C. A. F. Sprague, Navy Air Group, T.G. 1.6
Capt. E. N. Parker (Navy), Surface Patrol Group, T.G. 1.7
Capt. G. H. Lyttle (Navy), Service Group, T.G. 1.8
REAR ECHELON
Principal Rear Echelon officials included:
Rear Adm. F. J. Lowrey, Commander of Rear Echelon
Capt. H. R. Carson (Navy), Chief of Staff
Col. G. W. Trichel, Ground Force Adviser
Col. R. C. Wilson, Commander for Aviation
Comdr. D. Klein, Commander for Technical Direction
Lt. Comdr. D. M. Rubel, Asst. Chief of Staff for Personnel
Comdr. K. Daly, Asst. Chief of Staff for Intelligence
Lt. Comdr. P. J. Kidding, Asst. Chief of Staff for Operation
Maj. W. H. Lollar, Asst. Chief of Staff for Logistics
Appendix 3
Joint Crossroads Committee
The Joint Crossroads Committee was created by the Joint Chiefs
of Staff on November 1, 1946, to succeed Joint Task Force One,
which went out of existence on that day.
The membership of the Committee was as follows :
Rear Admiral W. S. Parsons, Chairman
Brigadier General T. S. Power, Army Air Forces Member
Colonel C. H. M. Roberts, Army Ground Forces Member
Rear Admiral T. A. Solberg, Navy Member
Captain H. R. Carson (Navy), Executive Secretary
Supporting officials were as follows:
Captain F. L. Ashworth (Navy), Technical Assistant
Captain A. J. Bibee (Marine Corps), Photographic Files
Dr. E. S. Gilfillan, Technical Director
Major J. B. Gulley, Security
Commander D. L. Kauffman, Radiological Safety Instruction
Captain G. M. Lyon (Navy), Safety Consultant
Captain L. A. O'Brien (Army), Army Personnel
Captain Horacio Rivero (Navy), Technical Assistant
Lieutenant Commander J. D. Roche, Documentary Film
Dr. H. P. Scoville, Jr., Radiological Safety Reports
Dr. W. A. Shurcliff, Historian
Captain F. I. Winant, Jr. (Navy), Technical Assistant
Captain G. E. Zawasky (Marine Corps), Communications
181
Appendix 4
The Evaluation Board
The Evaluation Board was created by the Joint Chiefs of Staff,
its functions were (1) to be available for advising the Commander
oL' Joint Task Force One in his planning of the tests, and (2) to
prepare and present to the Joint Chiefs of Staff an evaluation of
tlie results of the tests.
The complete membership of the Board, as announced on March
28, 1946. was as follows:
Dr. K. T. Compton, President of the Massachusetts Institute
of Technology (Chairman)
Mr. Bradley Dewey, President of the American Chemic:;!
Society (Vice Chairman)
Mr. T. F. Farrell, New York State Department of Public
Works, formerly Major General in the Manhattan Engi-
neer District
General J. W. Stilwell. Commanding General, Sixth Army
Area
Lieutenant General L. H. Brereton, on Special Duty in the
Office of the Secretary of War
Vice Admiral J. H. Hoover, a member of the Navy General
Board
Rear Admiral R. A. Ofstie, Senior Navy Member of the
U. S. Strategic Bombing Survey
After General Stilwell's death, Lt. General A. C. Wedemeyer,
Commanding General of the 2nd Army, was made a succeeding
member.
The Board made careful study of the Operation Plan, and
witnessed both tests. It observed Test A from an airplane located
twenty miles from the Zeropoint. Four members witnessed Test B
from an airplane eight miles from the Zeropoint, while the other
three members w^ere stationed on the hospital ship HAVEN, eleven
miles from the Zeropoint. Detailed inspections were made of the
target ships, and the technical reports were carefully studied.
The Board's final report, not yet completed, is expected to
include conclusions on strategic, tactical, and technical matters
pertinent to national defense. Preliminary reports, issued immed-
iatelv after each test, are presented in this volume as Appendices
10 aiid 11.
182
Appendix 5
The President's Evaluation Commission
An Evaluation Commission was created by the President and
given the function of (1) cooperating with the Secretaries of War
and Navy in the conduct of the Tests, and (2) undertaking a study
of the tests and submitting to the President a report of its obser-
vations, findings, conclusions, and recommendations.
The finally established membership, announced on March 30,
1946, Avas as follows :
Senator C. A. Hatch, New Mexico (Chairman)
Senator Leverett Saltonstall, Massachusetts
Representative W. C. Andrews, New York
Representative Chet Holifield, California
. Dr. K. T. Compton, President of the Massachusetts
Institute of Technology
Dr. E. U. Condon, Director of the National Bureau
of Standards
Mr. Bradley Dewey, President of the American Chemical
Society
Mr. W. S. Newell, President of the Bath Iron Works
Corporation
Mr. Fred Searls, Jr., special assistant to the Secretary
of State
Members witnessed the tests from airplanes and surface vessels.
Brief reports, included here as Appendices 12 and 13, were
made after each test.
183
Appendix 6
United Nations Observers
Each country having membership in the United Nations Atomic
Energy Commission was invited to choose two observers. The ob-
servers actually attending were as follows :
Australia
Brazil :
Canada :
China :
France :
Egypt :
Commander S. H. K. Spurgeon, R.A.N.
Major Orlando Rangel (Army)
Captain Alvaro Alberto de Motta y Silva
(Navy)
Air Vice Marshal E. W. Stedman
Major General R. M. Luton (Retired)
Chung- Yao Chao, Director of the Department
of Physics, National Central University
Major General Fisher Hou, Military Attache,
Washington, D. C.
Captain de Fregate Pierre Balande, General
Staff (Navy)
Mr. Bertrand Goldsehmidt
Colonel Hassen Ragab, Military Attache,
Washington, D. C.
Lieutenant Colonel Abdel-Gaffar Osman, Chief
Inspector of Explosives (Army)
Great Britain: Flight Lieutenant F. Beswick, M.P., R.A.F.
Commander A. H. P. Noble, M.P., R.N.
Mexico : Mr. Juan Loyo Gonzalez
Dr. Nabor Carillo
Netherlands : Captain G. B. Salm, Head of Naval Intelligence
Major H. Bruining, Ministry of Supply
Poland : Mr. Stefan Pienkowski, President, University
of Warsaw
Mr. Anrzej Soltan, Head of Physics Depart-
ment, University of Lodz
U.S.S.R. : Dr. A. M. Mescheryakov, Head, Physics Depart-
ment, University of Leningrad
Mr. S. P. Alexandrov
84
Appendix 7
Congressional Observers
Immediately following the June 14, 1946, passage by Congress
of House Joint Resolution 307 authorizing use of 33 United States
combatant vessels as target vessels, invitations were extended to a
number of Congressmen to witness the tests.
Thirteen Congressmen witnessed Test A and seven witnessed
Test B. They were as follows:
Se7iators
Cordon, Guy, Oregon
Hatch, C. A., New Mexico
Hickenlooper, B. B., Iowa
Saltonstall, Leverett, Massachusetts
Representatives
Anderson, J. Z., California
Andrews, W. G., New York
Bates, G. J., 'Massachusetts
Bradley, M. J., Pennsylvania
Engel, A. J., Michigan
Gillespie, Dean M., Colorado
Holifield, Chet, California
Izac, E. v., California •
Norrell, W. F., Arkansas
Rooney, J. -T., New York
85
Appendix 8
Support Vessels
Ship
Commanding Officer
(a) Force Flagship (carrying Vice Admiral
W. H. P. Blaiidy, Task Force Commander)
MT. Mckinley (agc-7)
Capt. W. N. Gamet
(b) Target Vessel Control Group (part of Task
Group 1.2, commanded by Rear Admiral F. G.
Fahrion)
FALL RIVER (flagship) (CA-131)
Capt. D. S. Crawford
(c) Technical Group (Task Group 1.1, commanded
by Rear Admiral W. S. Parsons)
ALBEMARLE (AV-5)
KENNETH WHITING (AV-14)
CUMBERLAND SOUND (AV-17)
WHARTON (AP-7)
AVERY ISLAND (AG-76)
BURLESON (APA-67)
HAVEN (APH-112)
BEGOR (APD-127)
LCT-1359
LSM-60
Capt. E. H. Echelmeyer, Jr.
Capt. A. R. Truslow, Jr.
Capt. H. R. Horney
Capt. V. F. Gordinier
Comdr. D. E. Pugli
Capt. C. L. Carpenter
Capt. A. C. Thorington
Lt. Comdr. R. K. Margetts
Cjmdr. H. A. Owens
(■d) Transport Group (Task Group 1.3, commanded
by Captain W. P. Davis (Navy))
GEORGE CLYMER (APA-27)
BAYFIELD (APA-33)
HENRICO (APA-45)
APPLING (APA-58)
ROCKBRIDGE (APA-228)
ROCKINGHAM (APA-229)
ROCKWALL (APA-230)
SAINT CROIX (APA-231)
BOTTINEAU (APA-235)
BEXAR (APA-237)
ARTEMIS (AKA-21)
ROLETTE (AKA-99)
OTTAWA (AKA-101)
APPALACHIAN (AGC-1)
BLUE RIDGE (AGC-2)
PANAMINT (AGC-13)
LST-817
LST-881
Capt. M. M. Bradley
Capt. J. C. Landstreet
Capt. J. B. Williams
Capt. H. W. Howe
Capt. W. H. Truesdell
Capt. G. P. Enright
Capt. C. H. Walker
Capt. C. E. Carroll
Capt. H. B. Edgar
Capt. C. C. Ray
Comdr. M. E. "Selby
Capt. M. Durski
Comdr. A. K. Ehle
Capt. J. B. Renn
Capt. C. R. Criddle
Capt. W. B. Ammon
Lt. (jg) J .A. Scott
Lt. (jg) J. M, Scott
86
Ship
CV-38 SHANGRI-LA
CVE-117 SAIDOR
AVP-49 ORCA
DD-834 TURNER
DD-835 C P CECIL
DD-882 FURSE
DD-883 N K PERRY
DD-368 FLUSSER
DD-692 A. M. SUMNER
DD-693 MOALE
DD-694 INGRAHAM
DD-722 BARTON
DD-723 WALKE
DD-724 LAFFEY
DD-725 O'BRIEN
DD-770 LOWRY
DD-781 R. K. HUNTINGTON
(g) Service Gr
by Captain
DIXIE (AD-14)
COASTERS HARBOR (AG-74)
CHICKASKIA (AO-54)
SEVERN (A0-(W)-61)
ENOREE (AO-69)
TOMBIGEE (AOG-(W)-ll)
POLLUX (AKS-4)
HESPERIA (AKS-13)
AJAX (AR-6)
PHAON (ARB-3)
TELAMON (ARB-3)
CEBU (ARG-6)
CREON (ARL-11)
SPHINX (ARL-24)
FULTON (AS-11)
SIOUX (ATF-75)
CHOWANOC (ATF-100)
LIMESTONE (IX-158)
ARD-29
ATA-124
ATA-187
LST-388
LST-861
YC-1009
Commanding Officer
(e) Navy Air Group (Task Group 1.6, commanded
by Rear Admiral C. A. F. Sprague)
Capt. W. D. Cogswell
Capt. T. U. Sissons
Comdr. J. D. Sliea
Comdr. E. B. Rittenhouse
Comdr. W. Outerson
Comdr. C. J. Heath
Comdr. N. E. Smith
(f) Surface Patrol Group (Task Group 1.7, com-
manded by Captain E. N. Parker (Navy) )
Lt. Comdr. W. R. Laird
Comdr. J. W. Howard
Comdr. R. P. Walker
Comdr. F. A. Brock
Comdr, H. P. Mclntire
Comdr. T. F. McGillis
Comdr. O. D. Waters, Jr.
Comdr. H. E. Day
Comdr. E. S. Miller
Comdr. M. Thompson
oup (Task Group 1.8, commanded
G. H. Lyttle (Navy))
Capt. J. C. Goodnough
Comdr. A. C. Harshman
Capt. W\ M. Searles
Capt. M. H. McCoy
Comdr. W. C. Cross
Lt. J. R. Davidson
Comdr. D. A. Crandall
Comdr. H. B. MacLeod
Capt. J. R. Clark
Lt. W. F. Horstkamp
Lt. F. B. Schwenneker
Comdr. D. B. Candler
Lt. Comdr. H. T. Smith
Lt. (jg) H. G. Salisburv
Capt. A. R. St. Angelo
Lt. W. H. Moore
Lt. Comdr. F. C. Ziesenhenne
Ens. J. H. Richter
Lt. J. B. Warner
Lt. (jg) F. H. La Pierre
Lt. E. B. Terrio
Lt. (jg) P. H. Sullivan
Lt. J. T. Gordon
187
Ship
YF-385
YF-733
YF-734
YF-735
YF-752
YF-753
YF-754
YF-990
YF-991
YF-992
MUNSEE (ATF-107)
WENATCHEE (ATF-118)
WILDCAT (AW-2)
QUARTZ (IX-150)
YO-132
YO-199
YOG-63
YOG-70
YW-92
Commanding Officer
(h)
PALMYRA (ARST-3)
PRESERVER (ARS-8)
CURRENT (ARS-22)
DELIVER (ARS-23)
CLAMP (ARS-33)
CONSERVER (ARS-39)
RECLAIMER (ARS-42)
CHICKASAW (ATF-83)
ACHOMAWI (ATF-148)
WIDGEON (ASR-1)
COUCAL (ASR-8)
GYPSY (ARSD-1)
MENDER (ARSD-2)
ETLAH (AN-79)
SUNCOCK (AN-80)
ONEOTA (AN-85)
SKAKAMAXON (AN-86)
ATA-180
ATA-185
ATA-192
ATR-40
ATR-87
LST-1184
LCT-1420
(i)
SAN MARCOS (LSD-25)
GUNSTON HALL (LSD-5)
Lt. J. Buday
Lt. T. P. Pierce
Comdr. R. N. Newton
Lt. (jg) R. K. Ritzett
Salvage Unit (Task Unit 1.2.7, commanded by
Captain B. E. Manseau (Navy))
Lt. Comdr. R. H. Drazell
Lt. C. B. Hiner
Lt. H. F. Gindling
Lt. F. F. Sharp
Lt. Comdr. S. D. Frey
Lt. Comdr. C. H. Rooklidge
Lt. J. S. Lees
Lt. Comdr. F. H. Matthews
Lt. C. H. McCuUar
Lt. A. F. Hamby
Lt. J. E. Reid
Lt. Comdr. C. S. Horner
Lt. Comdr. A. V. Swarthout
Lt. L. E. Marsh
Lt. L. G. Hickle
Lt. (jg) J. B. Birtch
Lt. (jg) M. F. Root
Lt. E. R. Weaver
Lt. R. B. Leonnig
Lt. (jg) A. Morris
Lt. A. J. Roberts
Lt. R. E. Ward
Despatch Boat and Boat Pool Unit (Task Unit
1.8.3, commanded by Comdr. J. G. Blanche)
Comdr. J. G. Blanche
Lt. Comdr. W. H. Barchmann
188
SMiy
PRESQUE ISLE (AJ'B-44)
PGM-23
PGM-24
PGM-25
PGM-29
PGM-31
PGM-32
LCI-977
LCI-1062
LCI-1067
LCI-1091
LCT-1116
LCT-1130
LCT-1132
LCT-1155
LCT-1268
LCT-1341
LCT-1361
LCT-1377
LCT-1415
LCT-1461
Commanding Officer
Lt. B. F. Caver
Lt. (jg) E. A. Clark
Lt. (jg) J. W. Ferrill
Lt. (jg) J. T. Moss
Lt. (jg) N. C. Thomas
Lt. (jg) J. L. DeBlock
Lt. (jg) G. A. Oberle
Lt. (jg) H. P. Cohn
Ens. H. W. Phipps
Ens. E. R. Nutter
Lt. L. r. Koch
Lt. L. F. Koch
Lt. (jg) J. D. Simmons
Lt. (jg) P. M. Mitchell
Ens. J. T. Jans
BOUNTIFUL (AH-n)
BENEVOLENCE (AJI-13)
(j) Medical Unit (Task Unit 1.8.4, commanded by
Captain E. P. Creehan (Navy))
Capt. D. M. Maekey
Capt. E. P. Creehan
(k) Survey Unit (Task Unit 1.8.5, commanded by
Captain C. B. Schiano (Navy))
BOWDITCH (AGS-4)
JOHN BLISH (AGS-10)
JAMES M. GILLISS (AOS-IS)
YP-636
YMS-354
YMS-358
YMS-413
YMS-463
Capt. C. B. Schiano
Lt. F. A. Wodke
Lt. E. E. Simms
Lt. C. D. Bailey
Ens. E. J. Litty
Ens. C. M. Clancy
Ens. V. P. Finos
Ens. R. H. Zisette
LST-S71
LST-!)S9
(1) Evacuation Unit (Task Unit 1.8.7, commanded
by Lieutenant G. H. Gromer (Navy))
Ens. M. B. Fletcher
Lt. G. 11. Gromer
89
Appendix 9
Target Vessels, Test A
(Note: all target vessels were under the general com-
mand of Rear Admiral F. G. Fahrion, commander of
Task Group 1.2)
Ship Commanding Officer
(a) Battleships and Cruisers (Task Unit 1.2.
commanded by Captain W. Deweese)
ARKANSAS, Br.:];!
NEW YORK, BB-34
NEVADA, BB-nO
PENNSYI.VANIA, BB-38
PENSACOLA, CA 24
SALT LAKE CITY, C \-25
NAGATO, Japanese BB
SAKAWA, Japanese CL
PRTNZ EUGEN, TX-300
Capt. W. Deweese
Capt. L. H. Bibby
Capt. C. C. Aden
Capt. C. H. Bushnell
Capt. D. J. Ramsey
Capt. J. Conner
Capt. W. J. Whipple
CaiJt. H. L. Stone
Capt. A. II. Graubart
(b) Aircraft Carriers (Task Unit 1.2.2, commande(
by Captain N. M. Kindell)
SARATOGA, CV-.T
INDEPENDENCE, CVL-22
Capt. O. S. MacMahan
Capt. N. M. Kindell
(c) Destroyers (Task Unit 1.2.3,
Comdr. L. W. Sedgwick)
commanded ])v
LAMSON, DD-367
CONYNGHAM, DD-371
MUGFORD, DD-380
TALBOT, DD-390
MAYRANT, DD-402
EHIND, DD-404
STACK, DD-406
WILSON, DD-408
HUGHES, DD-410
ANDERSON, DD-411
MUSTIN, DD-413
WAINWRIGHT, DD-419
SKIPJACK, SS-184
SEARAVEN, SS-196
TUNA, SS-203
SKATE, SS-305
APOGON, SS-308
Lt. Comdr. H. H. Ellison
Lt. Comdr. F. W. Bampton
Comdr. M. Harvev
Lt. Comdr. B. W.'Spore
Comdr. M. H. Buaas
Lt. Comdr. D. M. Sharer
Comdr. E. A. Shuman
Lt. Comdr. R. H. Pauli
Comdr. D. S. Bill, Jr.
Lt. Comdr. J. J. McMullen
Lt. Comdr. J. C. Mathews
Comdr. L. W. Sedgwick
(d) Submarines (Task Unit 1.2.4, commanded bv
Comdr. R. A. Waugh)
Lt. Comdr. F. J. Coulter
Lt. Comdr. R. C. Smallwood, J i-.
Lt. Comdr. G. Jacobsen
Lt. Comdr. E. P. Huey
Lt. Comdr. J. W. Johnson
190
Ship
DENTUDA, SS-335
PARCHE, SS-384
PILOTFISH, SS-386
EST 52
EST 220
EST 545
EST 661
ECI 327
ECI 329
ECI 332
ECI 549
ECT 745
ECT 816
ECT 818
ECT 874
ECT 1013
ECT 1078
ECT 1112
ECT 1113
ECM 1
GIEEIAM, APA-57
BANNER, APA-60
BARROW, APA-61
BEADEN, APA-63
BRACKEN, APA-64
BRISCOE, APA-65
BRUEE, APA-66
BUTTE, APA-68
CAREISEE, APA-69
CARTERET, APA, 70
CATRON, APA-71
CORTLAND, APA-75
CRITTENDEN, APA, 77
DAWSON, APA-79
FAEEON, APA-81
FIEMORE, APA-83
GASCONADE, APA-85
GENEVA, APA-86
NIAGARA, AP-87
YO-160
V0G-S3
ARDC-13
Commanding Officer
Comdr. R. A. Waugh
Lt. Comdr. H. G. Reaves
Et. Comdr. R. B. Eaning
(e) Landing Craft (Task Unit 1.2.5)
Et. (jg) C. E. Boggs
Et. (jg) J. O. Marzluff
Et. (jg) S. E. Voiler
Et. W. F. Marlow
Ens. R. P. Eemke
Ens. R. C. Hayes
Ens. W. F. Zartman
Et. (jg) W. F. Fergusen
(f) Merchant-Type Ships (Task Unit 1.2.6, com-
manded by Capt. W. H. Standley, Jr.)
Capt. D. F. Williamson
Comdr. W. E. Kitch
Comdr. J. E. Kendall
Capt. E. S. Mewhinney
Comdr. C. S. Eee
Capt. W^. S. Rodimon
Et. Comdr. A. B. Taylor
Capt. A. R. Montgomery
Comdr. E. T. Goyette
Et. Com. J. E. Hunter
Capt. E. B. Ellis
Comdr. J. E. Haines
Capt. P. C. Crosley
Capt. D. D. Humphreys
Comdr. W. W. Sackett
Capt. E. E. Divoll
Capt. A. S. Carter
Capt. P. J. Neimo
Capt. W. H. Standley, Jr.
(g) Concrete Drydocks and Barges
19
Appendix 10
Preliminary Statement by the Evaluation Board
on
Test A
The following preliminary statement on Test A was prepared
by the Joint Chiefs of Staff's Evaluation Board immediately fol-
lowing Test A. The statement was released by the White House
on July 11, 1946.
The members of the Board inspected target ships the day before
the test, witnessed the explosion from an airplane twenty miles dis-
tant, and then approached to within nine miles for a brief view.
On the following day, as soon as safety clearance had been received,
the members flew to Bikini and began their examination of ship
damage. Many photographs had been studied, and military and
scientific specialists interviewed in an attempt to obtain an over-all
understanding of test results prior to the compilation of all the
data.
From its previous study of the plans for the test, and from its
observations in the Bikini Area, the Board considers that the test
was well conceived and well executed by the services in close co-
operation with a large civilian staff. It is satisfied in that the con-
ditions of the test were well-chosen and that the highest skill and
ingenuity have been used to obtain a maximum amount of data
in an unbiased, scientific manner. It believes that the commander,
staff, and personnel of Task Force One deserve high commendation
for their excellent performance and their notable cooperative spirit.
Effective precautions appear to have been taken to safeguard
personnel against radioactivity and associated dangers.
The Board's present information is that the bomb exploded with
an intensity which approached the best of the three previous bombs,
over a point 1500 to 2000 feet westerly of the assigned target, and
at approximately the planned altitude.
The target array in no sense represented an actual naval dis-
position but was designed to obtain the maximum data from a single
explosion. The most important eff'ects produced by the bomb are
the following:
a. A destroyer and two transports sank prom])t]y and another
destroyer capsized. It later sank, and the Japanese cruiser
192
SAKAWA sank the following day. The superstructure of the sub-
marine SKATE was so badly damaged as to make it unsafe to
submerge the vessel. The light carrier INDEPENDENCE was
badly wrecked by the explosion, gutted by fire, and further dam-
aged" by internal explosions of low order, including those of tor-
pedoes. All the above vessels were within one-half mile of the
explosion point.
J). Numerous fires were started on other ships, including one
on a ship two miles distant, which was apparently due to some
unusual circumstance since the other fires were much closer. Here
it should be remembered that the target ship decks carried a great
variety of test material not ordinarily exposed on the decks of naval
vessels.
c. The only major combatant ships within one-half mile of the
explosion point were the battleships NEVADA and ARKANSAS
and the heavy cruiser PENSACOLA. The blast struck these from
the after quarter. Apparently little damage was done to their hulls
or their main turrets but their superstructures were badly wrecked.
These ships were unquestionably put out of action and would, along
with many others within three-fourths of a mile, have required
extensive repairs at a principal naval base.
d. Other ships on the target array suffered damage in varying
degree, depending on position and type of ship, but there was
relatively little damage at distances greater than three-fourths of
a mile.
e. The primary material effects noted were due to blast, buck-
ling of decks and bulkheads, and destruction or deformation of
lightly constructed exposed objects, including stacks, masts, and
antennae. Secondary effects were due to fire, and it is noteworthy
that Army Quartermaster stores and miscellaneous equipment
placed on the decks for the test proved more vulnerable than nor-
mal naval deck gear. It should be pointed out that since the targets
carried no personnel the fires were uncontrolled and undoubtedly
there was more damage than there would have been under battle
conditions. Singularly, although considerable amounts of explosive
ordnance were exposed on decks and in gun turrets, there is no
indication on ships which remained afloat that any of this ma-
terial was exploded by direct action of the atomic bomb. Fire-
fighting ships entered the target area as soon as they could obtain
radiological security permission and subdued a number of fires.
The speed and efficiency with which these ships acted preserved for
later examination a great deal of evidence of bomb action which
might otherwise have been lost.
193
/. Examination of the flashburn effects produced by the initial
radiation from the explosion indicates that casualties would have
been high among exposed personnel. However, it is the opinion
of the Board that persons sheltered within the hull of a ship or
even on deck in the shadow of radiation from the bomb would not
have been immediately incapacitated by burns alone, whatever have
been the subsequent radiological effects.
g. Within the area of extensive blast damage to ship super-
structures there is evidence that personnel within the ships would
have been exposed to a lethal dosage of radiological effects.
Personnel casualties due to blast would no doubt have been
high for those in exposed positions on vessels within one-half
mile of the target center. Beyond this, any discussion of the blast
effect upon personnel will have to await the detailed reports of the
medical specialists.
In general no significant unexpected phenomena occurred,
although the test was designed to cope with considerable variation
from predictions. There was no large water wave formed. The radio-
active residue dissipated in the manner expected. No damage oc-
curred on Bikini Island, about three miles from the explosion
center.
From what it has seen and from what it has ascertained from
data now available, the Board is able to make certain general
observations :
a. The atomic bomb dropped at Bikini damaged more ships
than have ever before been damaged by a single explosion.
5. The test has provided adequate data of a sort necessary
for the redesign of naval vessels to minimize damage to superstruc-
tures and deck personnel from this type of bomb. Because of the
nature of the first test (air blast) little information has been ob-
tained on hull effects. Damage to ships' hulls will be studied spe-
cifically in the second test when a bomb will be exploded under
water.
c. A vast amount of data which will prove invaluable through-
out scientific and engineering fields has been made available by this
test. Once more the importance of large-scale research has been
dramatically demonstrated. There can be no question that the effort
and expense involved in this test has been amply justified both by
the information secured and by greatly narrowing the range of
speculation and argument. Moreover, it is clear to the Board that
only by further large-scale research and development can tlie
United States retain its present position of scientific leadership.
This must be done in the interests of national safety.
194
The board desires to say that it has had the fullest cooperation
of the task force commander, and that every opportunity has been
afforded it in carrying out its mission. The members of the Board
have had access to all data thus far accumulated and have had
every facility for personally inspecting the results of the test.
Appendix 1 1
Preliminary Statement by the Evaluation Board
on
Test B
The following preliminary statement on Test B was prepared
by the Joint Chiefs of Staff's Evaluation Board immediately fol-
lowing Test B. The statement was released by the White House
on August 2, 1946.
SECTION I
Supplement to Preliminary Report on Test "A"
In general, the observations on ship damage presented by this
board in its first report were confirmed by engineering surveys.
The location of the bomb burst, accurately determined from photo-
graphs, was such that only one ship was within 1,000 feet of the
surface point over which the bomb exploded. There were about
20 ships within half a mile, all of which were badly damaged, many
being put out of action and five sunk. It required up to 12 days to
repair all of those ships left afloat sufficiently so that they could
have steamed under their own power to a major base for repair.
It is now possible to make some estimate of the radiological in-
juries which crews would have suffered had they been aboard Test
"A" target vessels. Measurements of radiation intensity and a
study of animals exposed in ships show that the initial flash of
principal lethal radiations, which are gamma-rays and neutrons,
would have killed almost all personnel normally stationed aboard
the ships centered around the air burst and many others at greater
distances. Personnel protected by steel, water, or other dense ma-
terials would have been relatively safe in the outlying target vessels.
The effects of radiation exposure would not have incapacitated
all victims immediately, even some of the most severely affected
195
might have remained at their stations several hours. Thus it is pos-
sible that initial efforts at damage control might have kept ships
operating, but it is clear that vessels within a mile of an atomic
bomb air burst would eventually become inoperative due to crew
casualties.
SECTION II
Observations on Test "B"
The Board divided into two groups for the observation of Test
"B." Four members, after surveying the target array from the
air, witnessed the explosion from an airplane eight miles away at
an altitude of 7,500 feet. The other three members inspected the
target array from a small boat the day before the test and observed
the bomb's explosion from the deck of the USS HAVEN, 11 miles
at sea to the east of the burst.
The Board reassembled on the HAVEN on July 26, and the
members have since examined photographs, data on radioactivity,
and reports of other phenomena, and have inspected some of the
target vessels. They have also consulted with members of the Task
Force technical staff.
As scheduled, at 0835 Bikini time on July 25, a bomb was
detonated well below the surface of the lagoon. This bomb was
suspended from LSM-60, near the center of the target array. The
explosion was of predicted violence, and is estimated to have
been at least as destructive as 20,000 tons of TNT.
To a degree which the Board finds remarkable, the visible phe-
nomena of explosion followed the predictions made by civilian and
service phenomenologists attached to Joint Task Force One. At
the moment of the explosion, a dome, which showed the light of
incandescent material within, rose upon the surface of the lagoon.
The blast was followed by an opaque cloud which rapidly enveloped
about half of the target array. The cloud vanished in about two
seconds to reveal, as predicted, a column of ascending water. From
some of the photographs it appears that this column lifted the
26,000-ton battleship ARKANSAS for a brief interval before the
vessel plunged to the bottom of the lagoon. Confirmation of this
occurrence must await the analysis of high-speed photographs
which are not yet available.
The diameter of the column of water was about 2,200 feet, and
it rose to a height of about 5,500 feet. Spray rose to a much
greater height. The column contained roughly ten million tons of
96
water. For several minutes after the column reached maximum
height, water fell back, forming an expanding cloud of spray which
engulfed about half of the target array. Surrounding the base of
the column was a wall of foaming water several hundred feet high.
Waves outside the water column, about 1,000 feet from the
center of explosion, were 80 to 100 feet in height. These waves rap-
idly diminished in size as they proceeded outward, the highest
wave reaching the beach of Bikini Island being seven feet. Waves
did not pass over the island, and no material damage occurred
there. Measurements of the underwater shock wave are not yet
available. There were no seismic phenomena of significant magni-
tude.
The explosion produced intense radioactivity in the waters of
the lagoon. Radioactivity immediately after the burst is esti-
mated to have been the equivalent of many hundred tons of
radium. A few minutes exposure to this intense radiation at its
peak would, within a brief interval, have incapacitated human
beings and have resulted in their death within days or weeks.
Great quantities of radioactive water descended upon the ships
from the column or were thro\\ai over them by waves. This highly
lethal radioactive water constituted such a hazard that after foui-
days it was still unsafe for inspection parties, operating within a
well-established safety margin, to spend any useful length of time
at the center of the target area or to board ships anchored there.
As in Test "A," the array of target ships for Test "B" did not
represent a normal anchorage but was designed instead to obtain
the maximum data from a single explosion. Of the 84 ships and
small craft in the array, 40 were anchored within one mile and 20
within about one-half mile. Two major ships were sunk, the battle-
shijj ARKANSAS immediately and the heavy-hulled aircraft car-
rier SARATOGA after 71/0 hours. A landing ship, a landing craft,
and an oiler also sank immediately. The destroyer HUGHES, in
sinking condition, and the transport FALCON, badly listing, were
later beached. The submerged submarine APOGON was sent to the
bottom emitting air bubbles and fuel oil, and one to three other
submerged submarines are believed 16 have sunk. Five days after
the burst, the badly damaged Japanese battleship NAGATO sank.
It was found impossible immediately to assess damage to hulls,
power plants and machinery of the target ships because of radio-
active contamination. Full appraisal of damage will have to
await detailed survey by engineer teams. External observation
from a safe distance would indicate that a few additional ships
near the target center may have suffered some hull damage. There
97
was no obvious damage to ships more than one-half mile from the
burst.
SECTION III
Observations and Conclusions, Both Tests
The operations of Joint Task Force One in conducting the tests
have set a pattern for close, effective cooperation of the Armed
Services and civilian scientists in the planning and execution of
this highly technical operation. Moreover, the tests have provided
valuable training of personnel in joint operations requiring great
precision and coordination of effort.
It is impossible to evaluate an atomic burst in terms of con-
ventional explosives. As to detonation and blast effects, where the
largest bomb of the past was effective within a radius of a few
hundred feet, the atomic bomb's effectiveness can be measured in
thousands of feet. However, the radiological effects have no parallel
in conventional weapons. It is necessary that a conventional bomb
score a direct hit or a near miss of not more than a few feet to cause
significant damage to a battleship. At Bikini the second bomb,
bursting under water, sank a battleship immediately at a dis-
tance of well over 500 feet. It damaged an aircraft carrier so that
it sank in a few hours, while another battleship sank after five days.
The first bomb, bursting in air, did great harm to the superstruc-
tures of major ships within a half-mile radius, but did only minor
damage to their hulls. No ship within a mile of either burst could
have escaped without some damage to itself and serious injury to
a large number of its crew.
Although lethal results might have been more or less equivalent,
the radiological phenomena accompanying the two bursts were
markedly different. In the case of the air-burst bomb, it seems cer-
tain that unprotected personnel within one mile would have suf-
fered high casualties by intense neutron and gamma radiation as
well as by blast and heat. Those surviving immediate effects would
not have been menaced by radioactivity persisting after the burst.
In the case of the underwater explosion, the air-burst wave
was far less intense and there was no heat wave of significance.
Moreover, because of the absorption of neutrons and gamma rays
by water, the lethal quality of the first flash of radiation was not
of high order. But the second bomb threw large masses of highly
radioactive water onto the decks and into the hulls of vessels. These
contaminated ships became radioactive stoves, and would have
98
burned all living things aboard them with invisible and painless but
deadly radiation.
It is too soon to attempt an analysis of all of the implications
of the Bikini tests. But it is not too soon to point to the necessity
for immediate and intensive research into several unique problems
posed by the atomic bomb. The poisoning of large volumes of water
presents such a ])roblem. Study must be given to procedures for
protecting not only ships' crews but also the populations of cities
against such radiological effects as were demonstrated in Bikini
lagoon.
Observations during the two tests have established the general
types and range of effectiveness of air and shallow underwater
atomic-bomb bursts on naval vessels, army materiel, including a
wide variety of Quartermaster stores, and personnel. From these
observations and from instrumental data it will now be possible
to outline such changes, not only in military and naval design but
also in strategy and tactics, as future events may indicate.
National security dictates the adoption of a policy of instant
readiness to defend ourselves vigorously against any threat of
atomic weapon attack at any time and adherence to this policy
until it is certain that there can never be an atomic war. One en-
during princii)le of war has not been altered ])y the advent of the
atomic weapon. Offensive strength will remain the best defenses.
Therefore, so long as atomic bombs could conceivably be used against
this country, the Board urges the continued production of atomic
material and research and development in all fields related to
atomic warfare.
199
Appendix 12
Preliminary Statement by the Evaluation
Commission on
Test A
The following preliminary statement on Test A was prepared
by the President's Evaluation Commission immediately following
Test A. The statement was released by the White House on July
11, 1946.
Dear Mr. President:
Your Evaluation Commission, divided between positions at sea
and in the air, witnessed the First Bikini Test, at 33 seconds after
9 :00 A.M., local time on July 1st, and has since completed a sur-
vey of the damage. The Second Test, wherein the bomb will be
exploded under water, will in some respects be of even greater
interest, for it will have no precedent.
The report of your Commission required by its directives of
May 18th must await the assembling of considerable data deriving
from instrumental and photographic measurements and analysis
of tission product samples. However, we believe that it lies within
the scope of your directive and may be of possible assistance to
you, to submit, now, the following brief observations made from
the layman's point of view, but with such accuracy as is presently
available :
1. The organization and execution of the operation was mag-
nificently handled and has commanded our continuous admiration.
The bomb was dropped under favorable weather conditions about
30 seconds after the time set. The greatest credit is due Admiral
Blandy and the officers and enlisted personnel of both services
who, with scientists and other civilians, have served and are serv-
ing under him with a display of team work that must be seen to
be fully appreciated.
2. Their conservatively safe distance from the burst led many
observers to entertain an initial opinion that the bomb employed
was somewhat under par. It is now, however, safe to state that
the energy was of the same order of magnitude as in the case of
previous atomic detonations, between the highest and lowest of this
bomb's three predecessors.
200
3. The accuracy of the drop was such that the explosion oc-
curred within the area included within the allowance for the prob-
able error of the elevation of drop, and detonation was probably
within 100 feet of the chosen altitude. Nevertheless, the explosion
actually occurred several hundred yards west of a point directly
above the target ship NEVADA and therefore entirely west of the
closely spaced array of capital ships.
4. There were 90 targets anchored in the lagoon when the bomb
exploded. These were not in battle formation but were placed in
positions to give the largest amount of desired technical information
with especially close concentration around the center target point.
Those ships anchored a mile or more from the point of drop largely
escaped injury. Those within a mile were sunk or suffered damage
varying with the distance from the point of detonation and with
the type of ship construction. On explosion, a destroyer and two
transports sank promptly. A second destroyer and the Japanese
cruiser SAKAWA sank within twenty-seven hours. The light car-
rier INDEPENDENCE was gutted with fire and resultant explo-
sions. The submarine SKATE was heavily damaged and later
towed away. All of these were near the point of explosion. The
other ships, including the only two capital ships which were within
one-half mile of the detonation, received damage that would re-
quire more or less complete overhaul and in most cases repair
at major bases before they could again be used in combat. A
study of this damage will point the way to changes in design which
should minimize damage from blast and heat. Beyond these ships
there was extensive damage to superstructure, radar, and fire con-
trol. Had the ships within the damage area been manned, casualties
and psychological injuries would have required a large percentage
of replacements. Until the readings of complex instruments and
the future life history of animals within the ships have been de- ,
termined no accurate appraisal of potential damage to humans
within the ships can be made.
5. No wave or blast damage could be noticed on Bikini Island,
which is approximately three miles from the point of detonation.
6. We are of the unanimous opinion that the first test amply
justified the expenditure required to conduct it and that the second
test is equally desirable and necessary. You made a wise decision
when you approved the plans for these tests and they have been
carried out with extraordinary skill, diligence and ingenuity. The
test just completed has again proven that the atomic bomb is a
weapon of terrific power when used on land or sea.
201
Appendix 13
Preliminary Statement by the Evaluation
Commissionon on
Test B
The following preliminary statement on Test B was prepared
by the President's Evaluation Commission immediately following
Test B. The statement was released by the White House on August
2, 1946.
Dear Mr. President :
Your acknowledgment on July 7th of our preliminary report
on the tirst test at Bikini was much appreciated.
The second test was conducted in the same area, July 25, local
time, and on the same target ships less those sunk in the first test.
The bomb was exploded under a moderate depth of water at 8 :30,
a.m., local time, on schedule. Weather conditions were perfect. Seven
members of your committee witnessed the results from the USS
HAVEN stationed 11 miles from the point where the bomb ex-
ploded. There was no requirement of dark glasses for this test, and
the target ships were readily visible to the naked eye and easily
distinguishable with the aid of binoculars.
Our previous report endeavored to express our appreciation
of the cooperation, assistance and unfailing courtesy extended by
Admiral Blandy and by the officers and enlisted men and civilian
scientific personnel of Joint Task Force One. Throughout, this
attitude of interest and diligence has remained at the same high
level, and the effect of longer observation of operations and better
acquaintance with officers and men has been to convince us that
you and the people of the United States can place the utmost re-
liance on the fairness, thoroughness and real effort for the maximum
of honest information which has characterized these tests. This
disposition has expedited and lightened our task in complying
with your directive. These tests have consistently adhered to the
stated purpose of the mission : ' ' Primarily to determine the effects
of the atomic bomb on naval vessels in order to gain information
of value to the national defense."
In the interval between tests the target ships were redeployed
in respect to the point chosen for the second explosion so as to fur-
202
nish maximum scientific and technical information from expected
results.
When the bomb exploded, the battleship ARKANSAS, nearest
to the center of impact, and three other smaller ships sank at once.
The aircraft carrier SARATOGA, also placed close by, sank 71/0
hours later. As soon as radioactivity lessened sufficiently to permit
safe operations, the destroyer HUGHES and the attack transport
FALLON were beached to prevent their possible sinking. Of the
eight submarines involved, six were submerged. Several of these
appear to be injured and one at least has gone to the bottom. The
two on the surface are not noticeably injured. All but a few of the
target ships were drenched with radioactive sea water, and all
within the zone of evident damage are still unsafe to board. It
is estimated that the radioactivity dispersed in the water was the
equivalent to that from many hundred tons of radium.
We believe that interesting distinctions between the general
results of the two explosions can even now be drawn without
the risk of serious error. Both explosions sank several ships.
From the limited observations we have thus far been able to make,
the ships remaining afloat within the damage area appear to have
been more seriously damaged by the aerial explosion than by the
submarine explosion. The damage to ships in the first test might
have been far greater if the bomb had exploded directly over the
target ship, the NEVADA.
In the first test much of the personnel within the ships would
have received fatal doses of neutrons and gamma rays from the
first deadly flash. On the other hand, the deadly effects of persistent
radioactivity would have been much more severe in the second
test. Had the target array been manned, it seems clear that casual-
ties and both physical and psychological injury to personnel would
have been very great. Rescue and attention to casualties would be
difficult and dangerous. Within 2000 yards of explosion, ships would
probably have been inoperative and a lapse of weeks might well
ensue before relatively undamaged ships could again be used in
combat.
The second bomb caused a deluge of water loaded with deadly
radioactive elements over an area that embraced 90 per cent of the
target array. Such results might be as disastrous to the fleet as
results of the first test, although in part for different reasons.
An enemy possessed of two or more bombs might well so dispose
them as to create simultaneously the deadly features of both tests.
Such tactics might effectively dispose of a fleet for many months ;
for example, consider a Pearl Harbor attack on these lines.
203
The results of both tests are already under study by the Bureau
of Ships and will undoubtedly point the way to changes in ships'
size, design and structure, both above and below the water line.
Such changes can offer increased immunity to flash and blast effect,
but protection from catastrophe by deadly gamma and neutron
radiations lies rather in wide spacing of task forces and decentral-
ization of navy yards, repair and loading facilities, of ships within
ports, and amongst all available harbors. We are convinced distance
is the best defense.
As was demonstrated by the terrible havoc wrought at Hiro-
shima and Nagasaki, the Bikini tests strongly indicate that future
wars employing atomic bombs may well destroy nations and change
present standards of civilization. To us who have witnessed the
devastating effects of these tests, it is evident that if there is to be
any security or safety in the world, war must be eliminated as a
means of settling differences among nations.
204
Appendix 14
Test C (Cancelled)
Prior to its cancellation by the President, the proposed "Test
C" was the center of much discussion. In this test an atomic bomb
was to be exploded at great depth beneath the surface of the
water.
Persons favoring holding such a test believed that it would
produce an underwater shockwave of almost incredible violence.
Ships might be crushed at ranges not equaled by explosions in air
or by shallow-underwater explosions. Involving an entirely new
kind of explosion, the test might till a large gap in physicists' under-
standing of explosion phenomena. Would a great "gas bubble,"
hundreds of yards in diameter, break through the surface? Or
would the surface remain unbroken? Would great waves be pro-
duced? Some cynics, believing that this type of test would pro-
duce the most damage, thought the Navy would try to avoid it.
To many persons it was clear that this test would be less im-
portant than the other two. On the technical side it was obvious
that little or no thermal radiation would reach the surface. Neutron
and gamma radiations also would be almost completely muffled by
the intervening layer of water. The tactical considerations were
even more pertinent. Nearly all harbors are shallow ; most coastal
waters are shallow. Thus a deep underwater explosion could never
be used in these important regions. It would be applicable only
in the open ocean, and here, of course, a fleet could be dispersed as
widely as necessary so that only one or two ships could be sunk
by one atomic bomb.
Nevertheless, plans were made to hold Test C, and a considerable
amount of preparatory work was done. Studies were made as to
how to position the target ships accurately. Anchoring being im-
practical in very deep water, thought was given to "streaming"
the ships. They could be fastened to a small island by means of
long cables, and then allowed to take up more or less fixed positions
determined by the direction of the ocean currents and by the
lengths of the cables. Or perhaps the ships could be powered and
underway, steered by radio. Work was started also on methods of
lowering the bomb to the desired depth, holding it in the desired
position despite the ocean currents, and firing it. It was expected
that the test would be held near Bikini Atoll, and construction
crews went to work preparing necessary installations there.
205
But the success of the first two tests, together with the increas-
ing shortage of military personnel and available civilian scientists,
caused reconsideration of the desirability of holding this third
test. And on September 7, 1946, President Truman, acting with
the advice of the Joint Chiefs of Staff, postponed the test indefi-
nitely. His statement was as follows :
"In view of the successful completion of the first
two atomic bomb tests of Operation Crossroads and
the information derived therefrom, the Joint Chiefs
of Staff have concluded that the third explosion, Test
C, should not be conducted in the near future. . . .
"The additional information of value expected to
result from Test C is such that the Joint Chiefs of
Staff do not feel that completion of the test in the near
future is justified."
206
Appendix 15
Chronology of Atomic Bomb Detonations
Five atomic bombs liave been detonated to date. The times and
places of tlieir detonation are as follows :
Bomb
No.
Place
Alamogordo, N. M.
Time
MWT : July 16, 1945, at 5 :30 a.m.
EWT : July 16, 1945, at 7 :30 a.m.
GOT : July 16, 1945, at 11 :30 a.m.
Local Time : Aug. 6, 1945, at 8 :15 a.m.
EWT : Aug. 5, 1945, at 7 :15 p.m.
GOT : Aug. 5, 1945, at 11 :15 p.m.
Local Time: Aug. 9, 1945, at 10:58
a.m.
EWT : Aug. 8, 1945, at 9 :58 p.m.
GOT : Aug. 9, 1945, at 1 :58 a.m.
Local Time: July 1, 1946, at 34
seconds after 9 :00 a.m.
EST: June 30, 1946, at 34 seconds
after 5 :00 p.m.
GOT : June 30, 1946, at 34 seconds
after 10 :00 p.m.
Bikini (underwater) Local Time: July 25, 1946, at 59.7
seconds after 8 :34 a.m.
EST: July 24, 1946, at 59.7 seconds
after 4.34 p.m.
GCT : July 24, 1946, at 59.7 seconds
after 9 :34 p.m.
2 Hiroshima, Japan
3 Nagasaki, Japan
4 Bikini (in air)
207
INDEX TO SUBJECTS
A-Day, 23, 104
A-Day, miss, 71, 114
Aerology, see Meteorology
Aircraft, 98, 127
Alamogordo, 6
Alpha particles, see Radiation, alpha
Ammunition, 13, 125
Animals, 50, 84, 129, 140, 166
Army, see War Department
Army Air Forces, 97
B-Day, 1, 150
Ball-of-Fire, see Fireball
Base Surge, 159
Beta particles, see Radiation, beta
Bikini Atoll
choice of, 17
damage to, 163
map of, 18, 19, 89
Bombs, chronology, 207
Burst, see Detonation
Cameras, 78, 148, 152
Cauliflower, 156
Chief of Staff, 29
Chronology, see Bombs, chronology of
Cloud, condensation, 115
Column, 155
Commander Joint Task Force One, 12
Congress
observers from, 39, 186
Contamination, 159, 166
Correlation of damage and cause of
damage, 127
Crater, 160
Crews, injury to, see Personnel
Damage
terms for expressing, 130
to materiel, 127, 138
to ships, 125, 130-135, 164-166
Data, see Oceanography, Pressure,
Radiation, etc.
David Taylor Model Basin, 67
Decontamination, 169
Deputy Task Force Commander for
Aviation, 29
Deputy Task Force Commander for
Technical Direction, 28, 97
Detonation
Test A, 108
Test B, 151
Director of Ship Material, 47
Dogs, 85
Dome, 154
Drone boats, 128, 168
Drone planes, see Aircraft
Energy release, 152
Equipment, see Material
Errors, see A-Day Miss, Timing Signal
Failure
Evaluation Board
creation, 15, 182
membership, 182
preliminary reports, 193, 196
Evaluation Commission
creation, 40, 184
membership, 184
preliminary reports, 199, 202
Explosion, see Detonation
Fall-out, 152
Fillet, 157
Fireball, 116
Fires, 129
Fish, 92, 163
Fish and Wildlife Service, see Interior
Department
Fission products, 81, 108, 120
Force Organization, 96
Fuel loads, 13
Gages, 62-71, 111, 148, 162
Gamma radiation, see Radiation,
gamma
Genetic effects, see Mice
Geological survey, 87
Goats, 84, 140
Ground Forces Adviser, 29
Guinea pigs, 84
Heat, see Radiation, thermal
Hiroshima, 6, 28
How hour
Test A, 104
Test B, 151
Hulls, 131, 132
209
Illumination, see Eadiation, optical
Immobilization, see Damage
Impulse, 71, 114
Infrared radiation, see Radiation,
optical ; Radiation, thermal
Injury, see Damage, Animals, Goats,
etc.
Intelligence, 33
Interior Department, 20
Joint Chiefs of StaflE, 11, 33
Joint Crossroads Committee, 181
Joint Staff Planners, 11
Joint Task Force One
creation, 13, 25
directive, 14-15
dissolution, 172
organization, 96, 173
LeMay Subcommittee, 11, 28
Lethal radius, see Damage
Light, see Radiation, optical
Logistics, 41
Los Alamos Laboratory, 9
Mach Stem, 61
Manhattan Engineer District, 12, 28
see also Los Alamos Laboratory
Maps
Bikini Atoll, 89
Marshall Islands, 19
Pacific Ocean, 18
Target layout for Test A, 126
Marine life, see Fish
Marshall Islands
history, 17
map, 19
Material
damage to, 139
exposure of, 138-140
Meteorology, 102, 150
Mice, 84, 143
Mike hour
Test A, 109
Test B, 151
Mushroom, 118
Nagasaki, 6
Navy Department, 8, 14
Nuclear radiation, see Radiation,
nuclear
Objects of tests, 14
Observers
Congressional, 39, 186
Evaluation Board, 40, 182
Evaluation Commission, 41, 184
United Nations, 39, 185
others, 36
Oceanography, 22, 161, 169
Operation Crossroads, code name of,
27,
Operation plan, 43
Optical radiation, see Radiation,
optical
Pacific Ocean
map, 18
Personnel
injury to, 48
recruiting of, 30
Photography, 32, 50, 74
see also Cameras
Pigs, 84
Planning, 40
Plume, see Mushroom, Column
Plutonium, 81
President, 13
President's Evaluation Commission,
see Evaluation Commission
Press, 36
Pressure
in air, 60, 110, 111
in water, 153
Public relations, 34
Purpose, see Object of tests
Queen day, see Rehearsals
Radiation
alpha, 80, 121
beta, 80, 108, 121
gamma, 80, 83, 121, 127, 141, 153
neutron, 108, 121, 152
nuclear, 80, 82, 121
optical, 74, 108, 116
thermal, 127, 152
Radio, 40
Radioactivity, 45, 167
Radiological safety, 31, 124, 128, 141,
168, 170
Radiological Safety Adviser, 170
Radiological Safety School, 170
Rats, 84
Rehearsals
for Test A, 45, 102, 105
for Test B, 45, 150
210
Remote measurements, 59
Reports, see Evaluation Board,
Evaluation Commission
Safety Adviser, 47
Security, 33
Ship design, 3
Sliip parts, see Damage
Ships, see Vessels
Shockwave
in air, 72, 109, 127, 144, 157
in water, 109, 153, 157
Site, see Bikini Atoll
Sodium, 153
Sound, 110
Steel, 144
Target array
Test A, 106, 126
Test B, 146
Task Groups, see Force organization
Technical Director, 47, 57
Temperature, 117
Termination of operation, 171
Test A, 23, 104
Test B, 24, 145, 151
Test C, 205
Thermal radiation, see Radiation,
thermal
Timing signal failure, 113
Trinity, see Alamogordo
Ultraviolet radiation, see Radiation,
optical
United Nations observers, 39, 185
Uranium, 81
Vessels
anchoring, 96, 147
authorization to use, 14
decontamination, 169
German, 55
inspection, 55
Japanese, 52, 55, 132, 165
preparation, 46, 50, 147
watertightness, 52
see also Damage, Ship design
Visible radiation, see Radiation,
optical
War Department, 14, 97
see also Army Air Forces, Man-
hattan Engineer District
Water
currents in, 169
radioactivity in, 170
see also Shockwave, Waves
Waves, 22, 147, 160
Weather, see Meteorology
William day, see Rehearsals
Winds, see Meteorology
Zeropoint
definitions, 66
locations, 109, 143
INDEX TO PERSONS
Adams, Major W. B'., 104
Anderson, Captain G. W., Jr., 12
Anderson, Ensign D. L., 104
Archer, Ensign H. M., 58
Arnold, General H. H., 10, 11
Arons, Dr. A. B., 63
Ashworth, Captain F. L., 46
Atanasoff, Dr. J. V., 63
Ballard, Commander S. S., 63, 75, 76
Barnes, Lieutenant Commander C. A.,
92
Betts, Brigadier General T. J., 30, 33,
34, 38
Bishop, Captain J. E., 48
Blakelock, Brigadier General D. H.,
30,41
Blanchard, Colonel W. J., 104
Blandy, Vice Admiral W. H. P., 12, 13,
21, 27, 35, 42, 48, 96, 150, 165
Bonesteel, Colonel C. H., 12
Borden, Brigadier General W. A., 11
Brodie, Captain Robert, Jr., 29, 32
Chamblin, Lieutenant J. H., 148
Chenchar, Captain Paul, Jr., 104
Cothran, Sergeant J. W., 105
Cumberledge, Captain A. A., 40, 150
Davis, Captain W. P., 97
Debenham, Lieutenant Commander
J. K., 58
Dessauer, Dr. G., 170
Draeger, Captain R. H., 84, 87, 140,
141, 143, 166 ■
211
Engelman, Captain C. L., 138
Fahrion, Rear Admiral F. G., 97
Forbes, Professor Alexander, 148
Frederick, Colonel J. D., 97, 138
Ganey, Colonel W. D., 40
Gentry, Captain K. M., 40
Gilbert, Captain, 17
Giles, Lieutenant General B. M., 10
Giltillan, Commander E. S., 58
Glenn, Lieutenant R. M., 104
Harrison, Captain W. C, Jr., 104
Hartmann, Dr. G. K., 64, 67
Henderson, Dr. J. E., 63, 146
Holloway, Dr. M. G., 150, 151
Holter, N. J., 22, 147
Holzman, Colonel B. J., 40, 150
Isaacs, J. D., 148
Iverson, H. W., 148
Juda, 93
KautFman, C )mmander D. L., 170
Kepner, Major General W. E., 29
King, Admiral E. J., 10, 11
Lampson, Dr. C. W., 63
Leahy, Admiral W. D., 10
Lee, Captain Fitzhugh, 34, 35, 37, 38
LeMay, Major General C. E., 10, 11
Lonnquest, Captain T. C, 138
Lowry, Rear Admiral F. J., 30
Lyman, Captain C. H., 30, 40
Lyon, Captain G. M., 47, 48, 170
Lyon, Dr. W. K., 148
Lyons, Corporal H. B., 104
Lyttle, Captain G. H., 99
McAuliffe, Major General A. C, 29
McFarland, Brigadier General A. J.,
15
Mach, Ernst, 61
McKeehan, Captain L. W., 63
McMahon, Senator Brien, 10
McReynolds, Commander A. W., 58
Manguni, Seaman First Class R. L., 48
Marshall, Captain, 17
Marshall, General G. C, 10
Modlin, Corporal R. M., 104
Moran, Radioman First Class J. D., 48
Morris, Lieutenant Commander F. G.,
148
■3
Mott, Captain E. B., 138
O'Brien, Dean M. P., 148, 161
O 'Brien, Professor Brian, 79
Orr, Chief Warrant Officer J. P., 63
Parker, Captain E. N., 99
Parsons, Rear Admiral W. S., 12, 28,
46, 48, 97, 135, 150, 172
Penney, Dr. W. G., 62, 63, 64
Pool, Dr. M. L., 170
Pottle, Captain V. L., 12
Quackenbush, Captain R. S., 38, 74
Ramey, Brigadier General R. M., 98,
104
Reagan, Seaman First Class J. R., 48
Revelle, Commander Roger, 161, 169
Riddle, Captain F. L., 58
Rivero, Captain Horacio, 46
Roth, Lieutenant Colonel A., 170
Sawyer, Dr. R. A., 47, 57, 58, 59, 101
Semple, Captain David, 105
Sklaw, Lieutenant C, 148
Smith, Colonel H. B., 39
Smith, L. D., 104
Snackenberg, Commodore J. A., 29, 30
Solberg, Rear Admiral T. A., 47, 49,
52, 54, 169
Spaatz, Lieutenant General C. A., 10
Sprague, Rear Admiral C. A. P., 99
Stephenson, Dr. R. J., 170
Sutherland, Colonel J. R., 104
Swancutt, Major W. P., 104, 105
Talbot, Lieutenant Colonel J. M., 170
Thatcher, Dr. E. W., 58
Titterton, Dr. E. W., 151
Truman, President Harry S., 9, 13, 31,
36,39
Uehlinger, Captain A. E., 64
Vine, A. C, 148
Warner, R. S., Jr., 101, 150
Warren, Captain Shields, 87, 141
Warren, Colonel S. L., 48, 49, 80, 82
William, Lieutenant W. H., 48
Williams, Commander E. G., 170
Wilson, C. T. R., 115
Wood, Major H. H., 104
Wyckoff, Dr. C. W., 145, 146
212
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