The third ship to be named Genesee by the Navy, AOG-8 was launched on 23 September 1943 by Cargill, Inc., Savage, Minnesota, sponsored by Mrs. Helen Rae Clark and commissioned on 27 May 1944.

After shakedown, Genesee loaded her first cargo of high octane aviation gasoline at Aruba, Netherlands West Indies, 14 July 1944 and entered Pearl Harbor 11 August.

She moored to the Yokohama Oil Docks 2 September 1945, the day of Japan's formal surrender ceremony on board battleship Missouri (BB-63).

Based at Pearl Harbor until the spring of 1960, Genesee cruised thence to Eniwetok, Guam, Subic Bay, Melbourne, Australia, Long Beach, California, and Yokosuka, Japan.

Her home port was changed to Subic Bay early in 1962 and, through June 1964, Genesee was occupied with demanding training exercises and cruises in the Philippine, Korean, Japanese, and Okinawan waters.

Late in October she left the war zone and steamed, via the Philippines and Japan to Pearl Harbor, where early in 1967 she prepared for future action.

She was transferred to Chile under terms of the Security Assistance Program, 25 June 1972, and renamed Beagle (AOG-54), serving mostly as an auxiliary submarine tender, based on the port of Valparaíso.