In preparation for the first nuclear tests since Trinity, the Seabees entered the post-WWII era building infrastructure at Bikini Atoll in the South Pacific
The Second World War ended with the dawn of the nuclear age, and with it the demobilisation of the American military meant a decrease in US Navy Seabee manpower from its peak of more than 250,000 to approximately 20,000. Never theless, the Seabees were called upon to construct facilities of varied types across the globe, and maintain and upgrade existing ones.
Among the most prominent Seabee projects during the immediate post-war years was the construction of a weather station on the Kamchatka Peninsula near the Aleutian Islands. Kamchatka was actually territor y belonging to the Soviet Union, but the Seabees were authorised by the Soviet government to complete the project.
Other projects involved the construction and repair of harbour facilities in Chinese cities such as Shanghai and Tsingtao, and the building of airstrips, barracks, support facilities, electrical and telephone systems, bridges, roads and other infrastructure in the devastated cities of Japan, including Hiroshima, Nagasaki, Kure and Yokosuka. In mid-1946, Seabees were detailed to Antarctica for the first time, establishing research facilities and staging supplies and equipment during Operation High Jump.
Amid this high demand for skilled naval construction personnel, the Seabees were ordered to par ticipate in Operation Crossroads, in which the United States intended to conduct a series of nuclear weapons tests at Bikini Atoll, a remote location in the Marshall Islands of the South Pacific. The Seabees of the veteran 53rd Naval Construction Battalion, initially scheduled for deactivation on 1 March 1946, instead came ashore at Bikini Atoll on 13 March and set to work in advance of the main military and civilian contingent soon to arrive. The 1,000 Seabees served as stevedores unloading supplies and construction materials, and as experts in pontoon deployment, builders and planners. The entire atoll consists of 35 separate islets, and the Seabees completed some form of construction on nine of these.
Operation Crossroads was to be the first nuclear weapons detonations since Trinity in the New Mexico desert in July 1945 and the wartime dropping of the atomic bombs on Hiroshima and Nagasaki in August 1945.
The underwater ‘Baker’ nuclear weapon test at Bikini Atoll, 25 July 1946 Its aim was to provide data on the effects of nuclear weapons detonations on naval surface ships and accompanying equipment, sea life and the surrounding environment. A Joint Army/Navy Task Force organised the effort, and more than 90 vessels were positioned at varying distances across the lagoon and environs in preparation for the nuclear detonations, including obsolete warships and submarines of the US Navy, three former combat ships of the German and Japanese navies
