The atomic bombs dropped on Japan in August 1045 provoked intense curiosity concerning the capability of the new weapons. Especially significant tor naval forces was what effect such explosions would have on ships. People working on the development of the bomb addressed this issue as early as 1944, when the idea of testing such a weapon against the Imperial Japanese Navy at Truk received serious consideration.1
The questions were many, and the answers could affect the entire future of naval forces. What damage would a capital ship incur from an atomic weapon that exploded over the ship—an airburst? What would happen when the weapon exploded under water—a subsurface burst? What damage would it inflict on ships' hulls? On armor and topside armament? On superstructure? On crew members?
Those planners thinking ahead toward future naval tactics were concerned that the defensive and offensive ship formations developed in World War 11 would no longer be effective, particularly in defense against atomic weapons delivered from the air. Others began worrying about how the bomb would affect the entire national strategy for the employment of armed forces. Surely, a new plan would be needed. Would it call for a great reduction in or maybe even elimination of naval combatant forces, concentrating instead on atomic bombs dropped by long-range bomber aircraft? Atomic weapons could determine whether or not we were going to have a Navy at all.
Do We Need a Navy?
The Navy was aware it would need to have a role in atomic warfare if it were to continue to be a major force in national defense. Naval aviators were seriously concerned, realizing that delivery of an atomic weapon weighing 10,000 pounds from existing carriers would be impossible. Some radical changes in carriers and delivery aircraft would have to be made. Planners realized early that some major force- level battles were on the horizon, and World War 11-vintage carrier aircraft could not meet the challenge.
Along with naval personnel, the scientists who had developed the bomb wanted to know more about what they had created. What was the nature of the damage that would occur/ How much equivalent yield in conventional explosives would they create, and what could he created in the future? Was a hydrogen bomb possible? Would fallout he harmful, and what would he the extent of the radiation? Answering these questions required tests.
The scientists and then-Army Major General Leslie Groves, leader of the Manhattan Project that developed the bomb, had pushed tor Kyoto as the initial target in Japan. Kyoto was on a relatively flat plain, a feature that would permit accurate measurements of the damage. Further, although Army Air Forces General Curtis LeMay’s B-29 bombers operating from Tinian Island were systematically destroying the major cities in Japan, they had not yet attacked Kyoto. If used as the first target for an atomic explosion, Kyoto would he an excellent “laboratory” for measuring damage and constructing mathematical tables for computing the effects of these new weapons.
Much pressure was applied for Kyoto’s selection as the first target, hut Secretary of War Henry Stimson ruled it out. Secretary Stimson had visited Kyoto before the war, and he knew it was a major cultural center, almost a shrine in itself. If the United States destroyed that city, any chance for reconciliation with the Japanese alter the war would he lost. Si) with President Harry S. Truman’s concurrence, Kyoto was vetoed as a target, and the scientists were forced to gain answers in other ways. Tests of the weapons under controlled conditions were high on their priority list.
The Army Weighs In
After the war, members of the Army Air Forces were also interested in answers. Many thought they now had the ultimate weapon for destroying ships a-, well a-- cities. They would he the dominant force in the U.S. defense establishment—maybe the only force—tor they had proved their ability to deliver the bomb on target. Some members of the armed forces expressed their views on the subject in frank and open terms. General Carl A. Spaatz, a great leader of the Army Air Forces during World War II, reflected the opinions of many in that branch when he said: “Why should we have a Navy at all? The Russians have little or no navy, the Japanese Navy has been sunk, the Germans never did have much of a navy. The only reason for us to have a Navy is because someone else has a navy and we certainly do not need to waste money on that.”2
In hearings held by the House of Representatives, General of the Army Omar Bradley let the Navy and the public know where he stood on the subject of the Navy, Marines, and carrier aviation. In his closing argument against a proposed new carrier for the Navy, he emphasized that the United States would carry the war to the enemy by means of strategic bombing and large-scale land operations; that the sea-going Navy was vulnerable to atomic attack; and that amphibious operations would be of questionable value in the future.3
However, even with all of the interest in the effect of the atomic bombs on the Navy, the Joint Chiefs of Staff strongly supported the need for a testing program that would cover the effects of the weapons on equipment from all services; the testing program would he “joint” in its design and implementation. Accordingly, the Chiefs recommended the creation of Joint Task Force One, and the president approved it on 10 January 1946. The mission was “to carry out the atomic bombing of a target array of naval ships.” More than 200 ships, 150 aircraft, and 42,000 men would be involved, including representatives from the Army, the Navy, and civilian scientists.4
It was ironic that, while the tests would provide many answers about the impact of these weapons on ships and possibly jeopardize the future of the Navy, several of the key players in the development and delivery of the two weapons on Japan were Navy officers. It was logical that they would play key roles in the testing of atomic weapons.
The Team
Soon after World War II, the Navy established a small atomic-energy staff in Washington. Vice Admiral W. H. P. “Spike” Blandy had been the head of the Bureau of Ordinance during the war. He was a postgraduate in ordnance engineering and the unofficial guru of the famed “gun club”—a collection of officers with special education in ordnance who did much to develop and improve the Navy’s ability to destroy targets. Blandy later became known as the “atomic admiral.” Captain (later Rear Admiral) William “Deak” Parsons was the most critical and significant member of the group. Fascinated since his days at the U.S. Naval Academy with the problem of hitting a target, he had devoted much of his early career to that aspect of the military profession, with a great deal of postgraduate training and experience in gunnery on board ships.
Captain Parsons was such an outstanding scientist that he was accepted by the elite of the world’s scientific community and became physicist J. Robert Oppenheimer’s deputy in the development of the bomb. His assigned role in the Manhattan Project was to engineer the delivery of the weapon on a target, but because of his background, he figured heavily in the bomb development process itself, receiving much credit for solving the problem of creating a bomb that could be detonated by implosion—the “Fat Man” bomb dropped on Nagasaki. Although not an aviator, he also played the key role as “weaponeer” in the crew of the Enola Gay as it delivered the “Little Boy” bomb on Hiroshima.
Parsons rapidly became the leading authority in the military on atomic affairs.5 His appreciation of the role of atomic energy in future military and civilian applications was remarkable. And his paper on the subject written in March 1946 is a classic indicator of how a good, educated mind can predict the future.6
Admiral Horacio “Rivets” Rivero was a commander at the time, with a reputation as being the most intelligent officer ever to graduate from the Naval Academy. Highly educated in technical matters, he had made his mark in the early days of World War II in the procurement and use of radar on Navy ships. Consequently, he became a member of the Navy atomic team after the war, coming on board to help Captain Parsons address some of the technical aspects of the program.
Commander Frederick “Dick” Ashworth was the naval aviator in the group, another ordnance postgraduate picked as backup to Parsons in the engineering aspects of getting the atomic bombs on target. He was the officer who selected Tinian as the launch site for the B-29 bomber force used to deliver the bombs on Japan and was the weaponeer in Bockscar, the B-29 that dropped the second bomb on Nagasaki. It was intended that Parsons and Ashworth would alternate as weaponeers if more bombs were to be delivered on more targets.
All of these officers represented the Navy’s atomic arsenal and assumed major roles in the Crossroads tests. Blandy was designated as commander of the task force established by the Joint Chiefs of Staff to conduct the tests. Parsons was in charge of the scientific aspects of the tests, and Rivero was assigned as the representative of the Joint Chiefs of Staff to ensure their objectives were met. Ashworth was involved with the assembly of the weapons at Kwajalein Atoll, their delivery to the target at Bikini, and subsequently with the assessment of the damage to the ships.
The Tests
One of the first jobs of the task force was to select a location for the tests. Because he had been designated to locate a suitable site in the Pacific for the launch of the atomic bomb attacks against Japan, it was logical that Ashworth be assigned the task of locating a suitable site for the tests. After much consideration, assisted by Rivero, Ashworth selected Bikini Atoll. His recommendation was accepted, and three tests were ordered. (The third, code- named Charlie, was scrapped after strong objections from Army leadership.)'
More than 20 ships were in the target group deployed in an artificial formation for naval operations in the atoll’s lagoon. They were all within 1,000 yards of the bull’s-eye ship, USS Nevada (BB-36). The group included eight submarines, some of them the most modem at the time.8 The special formation was designed to meet the Joint Chiefs of Staff requirement “of securing graded damage on all principal types of vessels, graded damage meaning damage ranging from negligible, as in the case of ships at a considerable distance from the explosion, to lethal, in the case of ships close in.”9
The first test, on 1 July 1946, was known as Test Able. The bomb was exploded in the air at low altitude above the targets, and it subjected everything in the vicinity to intense heat, blast, and radioactivity, which its mushroom cloud dissipated rapidly into the upper atmosphere. The scientists had wanted to explode the bomb from a tower or some hovering device placed directly over the bull’s-eye ship, but the Air Forces insisted on dropping the bomb from a B-29, using one of their best bomber crews for the task. For reasons never really explained, the bomb missed the Nevada by a wide margin, requiring considerable extrapolation of data to relate damage effects to the proper aim point. The error was an embarrassment to many, particularly the pilot, one of the finest officers who ever served his country.10
The second test, on 25 July, was known as Test Baker. An underwater shot, it channeled the bomb’s tremendous energy release in a different way. The huge pressure built up by the bomb was transmitted to the underwater portions of the neighboring ships. Ship hulls were forced inward on all sides at once. Furthermore, since the bomb was submerged in the lagoon, its radioactivity could not pass instantly into the upper atmosphere. Intense and lasting radioactivity permeated the lagoon's water. The ships, drenched by tons of water thrown up by the explosion, became similarly contaminated. The extent of such contamination proved a matter of great interest.11
The nature of the damage is evident in the photo report of the tests, showing damage to the 34-year-old battleship Arkansas (BB-33), the oldest ship in the target fleet. She was one of three major combatants within a half-mile of the explosion point of Test Able. Although her hull and turrets suffered little damage, her wrecked superstructure showed the hammer-like effect of the bomb. Amidships she was a shambles. When military personnel and scientists first re-entered the Bikini lagoon after Test Able, the Arkansas was still sending up clouds of smoke from smoldering fires on her decks. She was definitely put out of action and would have required extensive repairs. However, in Test Baker she was near the bomb detonation point, took brief but terrific punishment, and sank almost instantly.12
Lessons Learned
In a foreword to the photographic report of the tests, Admiral Blandy’s assessment was prophetic:
[T]hese photographs no more than hint at the tremendous amount of data obtained concerning the effect of the bombs upon ships and material. They necessarily slight the technical and scientific lessons learned at Bikini. They do, however, evidence an incontestable truth. The Atomic Age is here. It is no myth. Nor is the atomic bomb “just another weapon.” It is the most lethal destructive agent yet devised by man. Its energy release is staggering; its radioactivity is slow-killing poison.
The purpose of these tests was to determine the effect of the atom bomb against various types of naval vessels. With the information secure, we can improve our ship design, tactics, and strategy, to minimize our losses in the unfortunate event of war waged with atomic weapons. A reliable and continuously effective plan to avoid competition in atomic armaments is the best possible defense against surprise attacks. With such a plan, atomic energy can in time become the controlled slave of man’s peacetime pursuits. In the face of this new knowledge, these recently discovered truths concerning the atom, so suddenly thrust upon an already chaotic world, not only warfare but also civilization itself literally stands at the Crossroads. Hence the name of this operation.13
Blandy was pleading for an effective plan to keep the atom under control. Unfortunately, his appeal went unheeded, particularly by the Soviet Union. When he wrote those words, a total of five atomic weapons had been exploded: the Trinity Test of a Fat Man model in New Mexico, the two at Hiroshima and Nagasaki, and the two at Bikini. Blandy realized that the future use of atomic weapons for any purpose under any circumstances was a highly questionable action for any nation to take.
The Crossroads tests, with more than 42,000 participants and 10,000 instruments to measure results, provided a tremendous amount of data that gave analysts the means to answer many questions. The Army Air Forces learned that if it was going to sink a ship with an atomic bomb, it would have to be accurate or have a bomb with a much bigger yield than 20 kilotons, the approximate power of each of the tests. Such a blast could damage the superstructure of a ship, but unless the weapon exploded close aboard or beneath it, an armored ship would probably survive.
The Navy learned that it would have to greatly modify its tactics when employing ships in an atomic environment, that the ships would have to sail in dispersed formations. Although one or two in a formation might be sunk or at least put out of action by an atomic bomb, most would survive. To improve the chances of survival, some major design modifications in hull structure and armor protection would have to be incorporated.
Of major significance, however, was the lesson learned about radiation, both prompt, from the detonation, and residual. Commander Ashworth pointed out that the radiation levels exceeded expectations. Although several of the ships, such as the New York (BB-34), Arkansas, Pennsylvania (BB-38), and Saratoga (CV-3), were sunk, the task force was still left with quite a number of highly contaminated ships.14 Radiation problems were particularly significant in affecting the future design of protective measures required for ships that had any possibility of operating in a nuclear environment.
We learned that any atomic explosion, whether on a military or civilian target, was going to create a residual radiation hazard of immense proportions. For the Navy, that meant developing means of decontaminating ships subjected to atomic attacks. For all, it meant developing and learning protective measures to neutralize or eradicate the effects of exposure to both prompt as well as residual radiation. That meant such items as bomb shelters, protective clothing, and water washdown (decontamination) procedures. The Navy had to get organized to deal with the potential of atomic energy and the problems it would bring for the defense of naval forces.
Although Crossroads provided answers to many questions, it also created more questions, which meant more tests. The tests seemed to whet the appetite of scientists and engineers for exploration of the real parameters of what they had created. Naturally, the military became intrigued with the possibilities of atomic weapons. What could they do? What were their limitations? What dangers did they pose to friendly forces? How much bang? At what weight and size? And by what means of delivery? How many could be produced and at what rate? Most significant, what would the Soviet Union do to match U.S. capabilities? The stage was set for much more testing.
One crucial lesson that slowly evolved was that the lifeblood—the validity—of a nuclear weapons deterrent force was going to depend on testing the various components in the bombs and their delivery systems, as well as their explosive characteristics. With more nations attempting to attain the atomic capability, testing would become an increasingly significant part of the emerging international debate about this new aspect of a deterrent strategy.
Diving at the Crossroads
By James P. Delgado
In the aftermath of Operation Crossroads, Navy divers descended to the bottom of Bikini Lagoon in the summer of 1946 to retrieve test instruments and make observations. A year later, naval personnel including divers returned to Bikini as part of a scientific reassessment of the bomb’s effect on the lagoon and islands. After that, with the exception of the rare government diver, including famed oceanographer Willard Bascom, few descended into the milky blue depths of the lagoon to visit the lost ships of atomic bomb tests.
In 1989 and 1990, a joint U.S. Navy-Department of Energy- National Park Service exercise located and revisited many of the sunken ships in Bikini Lagoon. The results of that two-year project, published by the Park Service in 1991 as Archaeology of the Atomic Bomb, provided the background for a new initiative to open Bikini to dive tourism. Bikinians displaced by the nuclear tests have yet to permanently return home to their irradiated atoll. However, the Department of Energy maintains a scientific station there to assess the long-term effects of radiation and to stop the island’s plants—a staple of the Bikinian diet—from absorbing and concentrating fallout. At the site of the scientific station, the Bikinians have erected a world- class diving facility with air-conditioned quarters, technical dive support, and a dive boat, Bravo (named for the 1953 hydrogen bomb tests at Bikini).
The key attraction is the veteran aircraft carrier USS Saratoga (CV- 3), which lies in 180 feet of water. The Baker blast of 25 July 1946 sent Saratoga to the bottom after atomic tidal waves lifted and smashed into the moored carrier, toppling her stack and collapsing part of the flight deck. The deck, littered with the fallen stack and test instruments, has opened in spots, allowing access into interior compartments. Skilled divers penetrate the interior regularly, visiting the hangar deck, crew' quarters, mess decks, and machinery spaces. Aircraft on the hangar deck, placed there for the tests, remain in place, wings folded and cockpits open. They include two Helldivers that provide one of the most dramatic images of the sunken carrier.
The other popular dive destination at Bikini is the Japanese battleship Nagato. Capsized, this veteran of the 1920s—and onetime flagship of the Kengo Kantai (Combined Fleet)—is a massive structure. Beneath the overturned hull, Nagato's 16-inch guns remain seated in their turrets. The once-towering superstructure, with the bridge, rests to starboard, twisted away from the hull when the battleship capsized and sank in the evening hours after the Baker test.
Close to Nagato and Saratoga is the venerable old battlewagon USS Arkansas (BB-33). Caught by the up-surging blast of the underwater Baker detonation, Arkansas’ crushed and capsized hull lies exactly where she sank less than a minute after the explosion. Hammered down into the seabed by the weight of falling water and blast-excavated coral and sand, the battered Arkansas is still recognizable. The starboard hull is intact, and divers have penetrated the aircastle to examine the 5- inch/25-caliber antiaircraft guns and unbroken light bulbs amazingly unscathed by the force of the Baker bomb.
Other popular dives sites include the submarines USS Pilotfish (SS- 386) and USS Apogon (SS-308), both moored submerged off the lagoon floor and sunk on 25 July 1946. Divers have penetrated Apogon to find the torpedo tubes still painted with wartime depictions of her kills. The destroyers USS Anderson (DD- 411) and USS Lamson (DD-367) also lie on the floor of the lagoon, both sunk by the Able detonation of 1 July 1946. Anderson lies on her side, depth charges tumbled from the racks at the stern, her bridge gaping open and her forward gun twisted aft by the force of the atomic blast that swept over her decks and sent her, on fire, to the bottom.
The attack transports USS Carlisle (APA-69) and USS Gilliam (APA-57) are less frequently dived, as is the Japanese cruiser Sakawa. Mangled by the Able blast, all three ships are mute evidence of the destructive force of the atomic bomb. Gilliam, softened by the heat of the detonation, is warped and deformed, with hatchways drooping surreally like a Salvador Dali painting. Off to one side, a bulldozer placed on Gilliam’s deck for the tests lies upright, stripped of much of its structure and its thick steel blade twisted into an “S” shape.
The gently sloping sides of the Baker crater, ground zero on 25 July 1946, are practically untraceable except by sonar. However, other evidence of Crossroads resting in the silt of Bikini Lagoon includes landing craft, a concrete-hulled fleet oiler, and an advanced concrete repair drydock.
Vessels exposed to the blasts hut not sunk were dispersed to various locales for decontamination and eventual scuttling. Out of more than 200 ships at Bikini 60 years ago, the only other Crossroads wreck accessible to divers is the former German cruiser Prinz Eugen, which capsized and sank at Kwajalein Atoll after the tests. Lying off the shores of Enubuj Island, her stern rises out of the sea, while her bow sits in 130 feet of water. Ironically, the dive tender used during and after the Crossroads tests, USS Clamp (ARS- 33), now rests at anchor with the Maritime Administration reserve fleet in Suisun Bay, California. She apparently is the last Crossroads veteran left afloat.
1. Office of the Historian, Joint Task Force One, Operations Crossroads: The Official Pictorial Record (New York: Wm. H. Wise, 1946), 8.
2. Demetrious Caraley, The Politics of Military Unification (New York: Columbia University Press, 1966), 100.
3. Information Planning Associates, Cold War Navy (Falls Church, VA., 1976), chapter 1. A report prepared for the chief of information, Department of the Navy, 4-20.
4. Operations Crossroads, 8.
5. Al Christman, Target Hiroshima: Deak Parsons and the Creation of the Atomic Bomb (Annapolis: Naval Institute Press, 1998).
6. Christman, Target Hiroshima, 213.
7. VADM Frederick Ashworth, USN, Oral History, on file with the U.S. Naval Institute, Annapolis, MD.
8. Operations Crossroads, 9, 105, 106.
9. Operations Crossroads, 118.
10. During 1960-62, the pilot, then-Colonel Woody Swancutt, and the author were part of the team targeting 3,500 nuclear weapons against the Soviet Union, the first Single Integrated Operation Plan (SIOP). They became good friends.
11. Operations Crossroads, 8.
12. Operations Crossroads, 161.
13. Operations Crossroads, 6.
14. Ashworth, Oral History.