Operation Crossroads

Operation Crossroads
Prior to July 1946 only three atomic bombs had been detonated. Bomb number one detonated in the New Mexico Desert in the "Trinity Test" on 16 July 1945. The second exploded over Hiroshima, on 5 August 1945 and was the first military use of atomic power. Four days later, on 9 August, the third flashed high over Nagasaki, which convinced the Japanese to surrender five days later, on 14 August 1945. Thus, the first three atomic detonations took place in a one month period and two of them were fired in anger and, thus, no data was collected regarding their performance. By early 1946 the scientific community was curious about the effects of the bomb against naval vessels. They also wanted to study different techniques to protect vessels against a nuclear attack and possibly change the design of future naval ships. On 10 January 1946, a presidential order created Task Force ONE, with an assigned mission to discover the answers to these questions. The commander was Vice Admiral W. H. P. Blandy who was responsible for 200 ships, 40,000 men and 150 aircraft. He would ultimately detonate two atomic bombs against a target fleet that consisted of obsolete American vessels and captured ships from Germany and Japan that the US received at the conclusion of WW2. The first detonation, called "Able" was dropped from a B-25 over the target fleet in the Bikini Atoll in the Marshall Islands. The purpose was to check the radioactive effects on test animals and blast effects against the surface ships in the target array. The second shot, "Baker" was detonated beneath the surface of the lagoon in the center of the target ship array. This test was designed to determine the hull damage caused by the hydraulic effect of the underwater nuclear detonation.
Test "Able" on 7/1/46 @ 0900
Crew of the USS Saidor (CVE-117) cover their eyes and prepare for the atomic blast on 7/1/46. National Archives #80G627519
The instant of detonation of test "Able" at approximately 0900 on 1 July 1946. National Archives #80G422349
This photo was taken from one of the automated camera towers on Bikini atoll just seconds after the detonation. Slightly to the left of the base of the mushroom is the USS Arkansas. National Archives #80G411587
High above Bikini atoll a clear shot of Able's characteristic mushroom cloud. During this test a Battleship, Aircraft Carrier and 8 other ships were sent to the bottom. National Archives #80G411588 National Archives #80G411586 National Archives #80G478060
Aerial shot of the instant of detonation of test Able. National Archives #80G478061
Typical set-up for animals on board the target ships. During "Able", 176 goats, 146 pigs, 109 mice, 57 guinea pigs, and 3,030 white rats were used on 22 different target ships. They were placed in positions where crewmembers would normally occupy to check the effect of gamma radiation. During test "Baker", only 200 white rats and 20 pigs were used. National Archives #80G627486
USS Nevada (BB-36), a 30-year veteran of Navy service was the first of the USN's oil-burning super-dreadnaughts. The Nevada was the bull's-eye ship for Test Able and was painted orange-red to aid the bombardier, Major Harold H. Wood of the B-25 "Dave's Dream". He barely missed. The bomb struck a point 1500-2000 feet west of the ship. The Nevada was scorched from the waterline to the top of the mast. A great deal of damage was done to the superstructure. National Archives #80G627472
Crew of the USS Fall River (CA-131) watching the atomic blast. National Archives #80G627452
The USS Independence (CVL-22) after test Able. The carrier was badly damaged by the blast and gutted by fire. The fire caused some torpedoes on board to low-order detonate, which further damaged the light carrier. The bomb exploded approximately one half mile from the Independence. National Archives #80G627482 National Archives #80G627502
Two Japanese ships were used as targets. The light cruiser SAKAWA and the Battleship NAGATO, pictured here. The NAGATO was a 35,000-tom mainstay of the Japanese Imperial Navy and one of her two heaviest pre-war Battleships. Commissioned in 1919, she was modernized in 1936. National Archives #80G701811
Wreckage of the superstructure of the Japanese warship SAKAWA after the Atomic Explosion in July 1946. The ship suffered severe damage to the superstructure and breaches in her hull, which ultimately sank her in the lagoon. National Archives #80G628355
Operation Crossroads target, the USS New York (BB-34). The veteran Battleship was commissioned in 1914 and served in both WW1 and WW2. She participated in the North African Landings and saw action off Iwo Jima and Okinawa. Attacked by Japanese torpedoes, aircraft, bombs and artillery, she was only hit once. What the Japanese couldn't do, we did ourselves. National Archives #80G701808
The German cruiser Prinz Eugen was moved from European waters to Philadelphia, where her armament was stripped, and then on to the Pacific. Bottled up in Gdynia during the end of WW2, she was handed over to the British when the Germans surrendered. She made her trip to Philadelphia with a German crew which was replaced with an American Crew at Boston and Philadelphia. The Prinz Eugen was the pride of the German Navy. National Archives #80G627444 (top) National Archives #80G627445 National Archives #80G627446 National Archives #80G701810
The USS Skate (SS-305) after the detonation. The Skate was one of the ships close to the detonation, which thoroughly mangled her superstructure. The hull, however, did not rupture. National Archives #80G627489 In all, there were eight submarines used in the test: Searaven, Skipjack, Tuna, Dentuda, Skate, Pilotfish, Parche, and the Apogen. National Archives #80G627498
Test Baker on 7/25/46 @ 0835
Baker test as 10 million tons of water enter the atmosphere. The column is 2,200 feet in diameter and 6,000 feet high. The water was highly contaminated and caused a great deal of difficulty to the decontamination crews. National Archives #80G422351 National Archives #80G478062
High altitude view of the Baker test taken by a drone aircraft arriving perfectly on time. National Archives #80G422348
The crew of the USS Begor (APD-127) washing down one of the drone boats, used to remotely collect radioactivity data and water samples after the atomic detonations. Eight drones (actually converted LCVPs with electronic remote control mechanisms installed) were used in test Able and six in test Baker. The drones were painted yellow with black stripes for easy recognition by controlling aircraft. National Archives #80G627497
Saratoga (CV-3) going down at 1540 on 7/25/46 "Baker Day". National Archives #80G627507
Baker blast photographed from the USS McKinley (AGC-7) casually watching a nuclear detonation.... National Archives #80G627521 National Archives #80G627510
2 years later, the last casualty...
Operation Crossroads target, the USS Pennsylvania, was sank off Kwajalein Atoll on 3/4/48. The ship had been anchored off Bikini Atoll since "Baker" day, the second atomic detonation of Operation Crossroads, and the fifth atomic detonation in history. It was towed to deep water and the sea cocks opened and sunk. She was commissioned in 1916 and served in both wars and was once the flagship of the United States Fleet. The Pennsylvania was also damaged at Pearl Harbor on 7 December 1941 during the Japanese invasion. She sank only 30 minutes after the sea cocks were opened. National Archives #80G705027 (top) National Archives #80G705028