Atomic Bomb, Baker, is Detonated Underwater
The second test, Shot "Baker," proved much more impressive.
Detonated ninety feet underwater on the morning of July 25, Baker produced a spectacular display as it wreaked havoc on a seventy–four–vessel fleet of empty ships and spewed thousands of tons of water into the air. As with Able, the test yielded explosions equivalent to 21,000 tons of TNT. Baker, as one historian notes, "helped restore respect for the power of the bomb."
Baker also created a major radiation problem. The test produced a radioactive mist that deposited active products on the target fleet in amounts far greater than had been predicted. As the Joint Chiefs of Staff evaluation board later noted, the contaminated ships "became radioactive stoves, and would have burned all living things aboard them with invisible and painless but deadly radiation." Decontamination presented a significant radiation hazard, and, as a result, over a period of several weeks personnel exposure levels began to climb.
History's fifth atomic explosion. A standard Fat Man type Mk 3A fission bomb was used in test. The bomb was encased in a watertight steel caisson, and suspended beneath landing ship LSM-60. The closest ship to surface zero was the USS Saratoga. Eight ships were sunk or capsized, eight more were severly damaged. Sunk vessels were the USS Saratoga, USS Arkansas, the Nagato, LSM-60 (obviously), the submarines USS Apogon and USS Pilotfish, the concrete dry dock ARDC-13, and the barge YO-160.
Serious radioactive contamination of the lagoon occurred, radiation exposure at the surface near the detonation point amounted to a lethal 730 R in the first 24 hours. Bikini Island, some three miles from surface zero could not be safely landed on until a week had passed.
The close of the Second World War ushered in the beginning of the atomic age. The United States was the only nation at the time to successfully develop and produce this devastating weapon, yet it knew very little about the bomb's potential or effects. This initiated an era of nuclear weapons testing that began in 1946 on the remote Pacific islands of Bikini Atoll.
Operation Crossroads was the name given to these naval atomic tests. These tests were designed to show the world that the United States had established nuclear deterrence as part of its defense policy. On July 1, 1946 "Able" and July 25, 1946 "Baker", the world's fourth and fifth nuclear detonations occurred. Now nearly half a century later, over twenty ships from the fleet of Operation Crossroads lie wrecked on the bottom of the lagoon at Bikini Atoll.
In Baker on July 25, the weapon was suspended beneath landing craft LSM-60 anchored in the midst of the target fleet. Baker was detonated 90 feet (27 m) underwater, halfway to the bottom in water 180 feet (54 m) deep. How/Mike Hour was 0835. No identifiable part of LSM-60 was ever found; it was presumably vaporized by the nuclear fireball. Ten ships were sunk, including the German heavy cruiser Prinz Eugen, which sank in December, five months after the test, because radioactivity prevented repairs to a leak in the hull.
Photographs of Baker are unique among nuclear detonation pictures. The blinding flash that usually obscures the target area took place underwater and was barely seen. The clear image of ships in the foreground and background gives a sense of scale. The large Wilson cloud and the vertical water column are distinctive Baker shot features, making the pictures easily identifiable. The most notable picture shows a mark where the 27,000 ton battleship Arkansas was.