USS Prometheus (AR-3) was a repair ship that served the United States Navy during World War I and World War II. Named after Greek mythology figure Prometheus, she was originally laid down as a collier on 18 October 1907 at the Mare Island Navy Yard, Vallejo, California; launched on 5 December 1908; and commissioned 15 January 1910 as USS Ontario (Fleet Collier No. 2). Service history 1910–1924 Ontario served with a merchant complement until she decommissioned on 7 April 1913 to undergo conversion to a repair ship. After conversion, she recommissioned 23 December 1914 as USS Prometheus (Repair Ship No. 2). After a cruise to Alaskan waters in 1915, she was assigned to duty with the Atlantic Fleet, 16 May 1916 operating out of Norfolk, Virginia and bound for Bermuda, remaining there until 29 January 1918. While at Bermuda she was ordered to join the Naval forces at Brest, France to provide repair services, and she did a commendable job until she sailed on 16 January 1919 for New York City. Upon arrival at New York she was assigned to Battleship Force 1 for duty in conjunction with the upkeep of vessels engaged in overseas transportation of troops. She was classified as AR-3 on 17 July 1920. Prometheus sailed from New York on 1 September 1920 with orders to tow the , disabled at Cuba, to Philadelphia. For her performance in this assignment she was commended by the Commander-in-Chief, Atlantic Fleet. Prometheus made additional cruises to Cuba in 1921 and 1923 while operating with the Atlantic Fleet. Prometheus transferred to the west coast early in 1923, arriving at San Pedro, Los Angeles on 17 April. She operated along the Pacific coast as far north as Washington, until she decommissioned on 4 October 1924 at Bremerton. 1942–1946 Prometheus recommissioned on 15 May 1942 at the Bremerton Navy Yard and following shakedown, she sailed from San Francisco, California on 9 August for Pearl Harbor, Hawaii where she took in tow the drydock ARD–2 and proceeded to Noumea, New Caledonia. She rendered repair services from the largest warship, the , to the smallest amphibious craft, which were beginning to figure so prominently in the island-hopping campaign towards the Japanese home islands. Her only breaks, from a steady demand of hard work from her crew, came on infrequent trips to Sydney, Australia. Following the push westward across the Pacific, Prometheus moved in the Spring