Operation Crossroads
# Name Type Yards from surface zero
50 LSM-60 Amphibious 0
3 Arkansas Battleship 170
8 Pilotfish Submarine 363
10 Saratoga Aircraft carrier 450
12 YO-160 Yard oiler 520
7 Nagato Battleship 770
41 Skipjack Submarine 800
2 Apogon Submarine 850
11 ARDC-13 Drydock 1,150
Test Baker -- Baker target array
The array of target ships in Bikini lagoon for the Baker shot of Operation Crossroads . Half of the target ships were outside the area of this map . The ten red X 's mark the ten ships that sank . The table ( left ) contains the key to ship numbers . The black circle , with a radius of 1,000 yards ( 914 m ) from the point of detonation , outlines the area of serious ship damage . The blue circle , 330 yards ( 302 m ) radius , marks the rim of the shallow underwater crater created by the blast , as well as the outer circumference of the hollow water column which enveloped Arkansas . The submarines were submerged : Pilotfish , ship # 8 , to a keel depth of 56 feet ( 17 m ) , Apogon , ship # 2 , to a keel depth of 100 feet ( 30 m ) , and Skipjack , ship # 41 , to 150 feet ( 46 m ) .
Operation Crossroads was a pair of nuclear weapon tests conducted by the United States at Bikini Atoll in mid-1946. They were the first nuclear weapon tests since Trinity in July 1945, and the first detonations of nuclear devices since the atomic bombing of Nagasaki on August 9, 1945. The purpose of the tests was to investigate the effect of nuclear weapons on warships. The Crossroads tests were the first of many nuclear tests held in the Marshall Islands, and the first to be publicly announced beforehand and observed by an invited audience, including a large press corps. They were conducted by Joint Army/Navy Task Force One, headed by Vice Admiral William H. P. Blandy rather than by the Manhattan Project, which had developed nuclear weapons during World War II. A fleet of 95 target ships was assembled in Bikini Lagoon and hit with two detonations of Fat Man plutonium implosion-type nuclear weapons of the kind dropped on Nagasaki, each with a yield of 23 kilotons of TNT (96 TJ). The first test was Able. The bomb was named Gilda after Rita Hayworth's character in the 1946 film Gilda, and was dropped from the B-29 Superfortress Dave's Dream of the 509th Bombardment Group on July 1, 1946. It detonated 520 feet (158 m) above the target fleet and caused less than the expected amount of ship damage because it missed its aim point by 2,130 feet (649 m). The second test was Baker. The bomb was known as Helen of Bikini and was detonated 90 feet (27 m) underwater on July 25, 1946. Radioactive sea spray caused extensive contamination.