For much of the Cold War the U.S. Navy lived under the threat of nuclear attack at sea. Indeed, the specter of warships torn asunder by nuclear explosions obsessed naval planners and weapon developers in the early days of the development of naval nuclear weapons. Those visions were very real: In July 1946, a massive flotilla of combatants and amphibious ships were subjected to the power of atomic bombs at Bikini atoll. Two atomic bombs—one an air burst and one a shallow underwater burst—were detonated to evaluate the power of the atom against warships and military equipment.1
By 30 June 1946—ten months after the end of World War II—there were nine nuclear components and assemblies for the Fat Man (plutonium) atomic bombs of the kind that had been tested at Alamogordo, New Mexico, and dropped on Nagasaki. (Materials were more difficult to produce for the uranium bomb—dubbed Little Boy—that was dropped at Hiroshima.)
The Fat Man bomb, now designated Mk 3, had an explosive force equivalent to more than 20,000 tons of TNT, referred to as a yield of 20 kilotons. In conventional bombs, this was equal to the payloads of 2,000 four-engine B-29 Superfortress bombers.
The 1946 atomic bomb tests at Bikini were given the code name Operation Crossroads. Originally intended to determine the effects of atomic bombs on naval ships, the program rapidly expanded to include numerous scientific and military tests supported by the Manhattan Project, which had developed the atomic bomb, and the military services. In addition, representatives of Congress, the United Nations (including the Soviet Union), and the press were invited to observe the tests.
The massive organization needed to set up the target array and run the tests was designated Joint Task Force 1. Under the command of Vice Admiral W. H. P. Blandy, JTF-1 numbered 42,000 men and women, both military and civilian, some 200 ships, and 156 aircraft.2
A flotilla of U.S. Navy ships and surrendered German and Japanese warships were employed as targets, their decks loaded with military vehicles, aircraft, ordnance, and test animals, as well as instrumentation. The largest of the target ships were the carriers Saratoga (CV-3) and Independence (CVL-22) and the battleships Arkansas (BB-33), New York (BB-34), Nevada (BB-36), and Pennsylvania (BB-38), all veterans of World War II action. The Japanese dreadnought Nagato and light cruiser Sakawa and the German heavy cruiser Print Eugen represented the vanquished navies.
The other ships in the target fleet were 2 U.S. cruisers, 16 destroyers, 8 submarines, 4 tank landing ships, 36 landing craft, 23 attack transports, and 2 attack cargo ships—a total of 100 ships and large landing craft. There also were several service (yard) craft.
Almost as many Navy ships were deployed to the area to support the tests. These included 4 command ships, 1 large and 1 small aircraft carrier, 9 transports to accommodate the mass of observers and technical personnel, and 35 auxiliary ships, including several salvage ships and tugs that were to assist stricken target ships.
Most of the target ships were damaged or overaged and of little operational use. Still, in answer to critics of the tests. Joint Task Force I issued a press release showing that the 370,000 tons of usable scrap steel in those warships was worth less than $4 million, about half the cost of a new destroyer.
The ships were anchored during the tests to obtain the maximum data possible from the atomic explosions and in no sense represented an actual naval disposition. On their decks and the nearby Bikini atoll were several hundred unmanned cameras, 5,000 pressure gauges, 25,000 radiation recorders, 204 goats, 200 pigs, and 5,000 laboratory rats.
In the Able test on 1 July 1945, the B-29 Dave’s Dream dropped a Fat Man bomb that detonated at an altitude of 520 feet above the target ships. The Nevada was the aim point, the center of an array of 78 target ships in the first test. The bomb missed the aim point by 2,130 feet. The 50-year-old, unmanned Nevada was burnt and battered by the 23-kiloton blast but not sunk; five ships did go down as a result of the blast and many others were wrecked or damaged.
For test Baker, a Fat Man bomb was suspended 90 feet below the landing ship LSM-60. That bomb, of approximately 20 kilotons, was detonated on 25 July. A column of water nearly a half-mile across rose almost 6,000 feet into the air, tossing warships around like toys. Of the 75 moored target ships, nine were sunk and many more were damaged.
While some ships were sunk outright, others suffered lengthy, painful deaths from fires and flooding that went unchecked. Some might have been saved, but salvage crews could not go on board because of radioactivity. The heavily damaged Independence was retained for several years after Bikini as a radiation research ship.
A planned deep-water test, an underwater detonation 1,000 feet below the surface, was canceled, ostensibly because scientists and military officers felt that there were sufficient data on the effects of nuclear weapons. There are indications, however, that the third detonation—test Charlie—was called off because of the limited number of atomic weapons available and the short supply of fissionable material needed for additional bombs.3
Commenting on the two atomic tests, Vice Admiral Blandy wrote:
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 the air and underwater were very different spectacles, but their end results mean the same: death and destruction on an enormous scale.4
The Bikini tests demonstrated that ships were vulnerable to atomic attack, but also that ships could survive such attacks if dispersed. Studies of shipboard damage led to several protective features, such as rounded superstructures, enclosed “citadels,” and washdown features. Navy planners also studied formation tactics that could mitigate the effects of nuclear weapons.
The absence of a major Soviet surface fleet in the immediate post-World War II period alleviated the need for U.S. nuclear weapons for war at sea; however, the Navy soon advocated nuclear weapons that could be used against targets in the Soviet Union, delivered both by carrier-based aircraft and by guided missiles (Regulus, Triton, and Rigel).
The subsequent Soviet development of a modem surface fleet provided targets for U.S. nuclear weapons, but the U.S. Navy, with a relatively few, high-value aircraft carriers, would have been at a comparable disadvantage in a nuclear exchange at sea. Indeed, few U.S. antiship weapons were developed and relatively little tactical thought was given to this area of war at sea.
In the wake of the collapse of the Soviet Union, both the United States and Russia have removed virtually all nuclear antiship and antisubmarine weapons from their respective fleets. Probably few of the men handling those weapons when they were removed knew that two nuclear tests at Bikini atoll 50 years ago this month were the harbinger of those weapons.
1 A recent, comprehensive discussion of the Bikini tests and an assessment of the damage inflicted on the target ships in James P. Delgado, et al.. The Archaeology of the Atomic Bomb (Santa Fe, NM: National Park Service, 1991).
2 An ordnance specialist, Blandy had commanded major amphibious forces during the war in the Pacific; when the war ended he was Commander, Cruisers and Destroyers, Pacific Fleet.
3 Memorandum from Secretary of the Navy James V. Forrestal to President Harry Truman, 30 August 1946, in “NSC Atomic Test—Misc.” folder. Box 201* Harry S Truman Library.
4 W. A. Shurcliff, Bombs at Bikini (New York: William H. Wise, 1947), p. ix. This was the official report of Joint Task Force 1.