Shangri La (CV 38) - Naval Cruise Book

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I ii Mushroom of radio-activity reached skyward to 40,000 feet. came to the Shangrz'-La after a tour of duty as Director of the Electronics Divi- sion, Bureau of Aeronautics. After winning his wings in Pensacola in l926, Captain Cogswell took a postgraduate course in radio at Harvard and served in various executive capacities on experimental radio control and radar projects. This training was particularly valuable in the advanced methods of radio control initiated in Operations Crossroads. . For the second test the Atomic Bomb was suspended in a caisson lowered into a well in the bottom of LSM 60. The mechanism was set to- explode upon the receipt of a predetermined radio signal but carried an intricate timing device which prevented premature or delayed explosion. As in the previous test, land- ing craft stood by Eniwetok and Rongerik to take off personnel if a shift of wind should threaten the atolls with radioactive particles. Shortly after dawn on July 25th, the Shalrzgrz'-La wheeled into the wind launch her drones for Test Baker. The explosion was set for slackwater, before the tide commenced to Hood. By firing at low water it was hoped to save Bikini from total inundation in the wall of radioactive water thrown up by- the under- Water explosion. Animals used in Test Baker consisted of two hundred white

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Man made sun released in Able-Day Bikini Test - photographed by drone a fraction of a second after blast destroyers, Lamson and Anderson, sank immediately while the Japanese cruiser Sakawa received mortal wounds, sinking the following day. The Skate's conning tower was wrecked, rupturing the submarine's watertight integrity so she could not be safely submerged. No ship outside the three-quarter mile perimeter suf- fered appreciable damage but the Evaluation Board, under Dr. Karl Compton, surmised lethal effects on personnel from radiation on ships within the half- mile circle. Bikini Atoll suffered no damage from the bomb blast and recreation activities were resumed ashore during the evaluation period between Able and Baker Day. While scientists swarmed aboard ships with Geiger counters checking their instru- ments before the next big blast, the Navy rearranged the target array to provide the maximum laboratory specimens in the next test, The job required a con- siderable amount of seamanship, as many ships had been forced out of position by the tremendous pressure wave of the initial explosion. While preparations were under way for Baker Day, the Shangri-La received her fourth commanding oflicer. On July 5th, 1946, Captain W. P. Cogswell relieved Captain Cruise in traditional ceremonies on the carrier's flight deck. The new commanding officer, a graduate of the Naval Academy class of 1918,

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Seconds after the Able-Day blasts, soot and smoke from target ships billows up while the under water pressure wave I black linej races toward the surrounding atoll. rats and twenty pigs, the latter appropriately placed in sick bay aboard the target ships. At 0830 on July 25, 1946, the tranquil waters of Bikini Lagoon erupted in an awe-inspiring column of smoke and steam, -blotting out the target array for several minutes as the terrific heat and power combined to force tons of radio- active water skyward. A wave of water fifty feet high rushed towards the sur- rounding beaches in a powerful but diminishing surge, causing a shallow water flood which quickly spilled back to seaward. Radio-controlled Geiger counters recorded intense radioactivity equivalent to many hundred tons of radium. PBM patrol planes appro-ached the lagoon from windward twenty minutes after the blast, sampling the air for radioactivity, while the Shangri-La drones followed to leeward in the atomic cloud, collecting samples of radioactive par- ticles for laboratory study. Piloted planes relieved the drones to follow the cloud until most of the dangerous radioactivity had been dissipated. Approximately twenty minutes elapsed before the target array was clearly visible to observation planes. When the steam and smoke had lifted, the battle- ship Arkansas was missing from the array. Pictures of the half-mile-wide co-lumn Q H , , -:1,,, ,-:,:, 1?11yr. .. ' . ,,., .,'. I v.,.,- r Q , W . . ,. I A , ,H - , V '- h - H I I M '- W W Ming-H - i MA- V MM- I v - g WV., 1 V '