Once Saipan had been taken, the U.S. Navy wanted a base that would allow its ships to operate in the Pacific, near Japanese territory, without the need to constantly return to the U.S. for supplies and repairs. The coral atoll of Ulithi, a string of sparsely inhabited and remote islands around a lagoon located some 1,300 miles from mainland Japan, fitted the bill. Once a base had been established there, ships would not need to go back to the U.S. for 12 months or more.
During the early stages of the war, the Japanese themselves had occupied Ulithi and operated a meteorological station and a radio base from the islands. But they had then abandoned the atoll. And on September 23, 1944, U.S. troops took the islands without opposition. They were soon followed by a unit of navy construction workers. Those men were tasked with transforming the idyllic Pacific islands into a working naval base.