commissioned as Pontiac (AF-20), 12 May 1942. Following conversion and shakedown, Pontiac, assigned to Service Force, Atlantic, departed Norfolk, Virginia, 15 June 1942 on her first Argentia run. On 15 July she completed that run at Boston, Massachusetts, whence she continued to carry supplies to the Maritime Provinces and Newfoundland through 1943. Between late January and May 1944 she conducted sugar runs between Norfolk and Trinidad, Guantánamo Bay and San Juan, then returned to Boston to resume runs to Argentia and, in June, to Iceland. She completed a quick run to Bermuda in early August, then returned to the Boston-Argentia route before undertaking her last Caribbean run from New York 7 September. On 25 September she arrived at Norfolk from San Juan, made a trip to Bermuda and on 16 November returned to Boston to resume carrying stores to Nova Scotia and Newfoundland. For the next two months she alternated voyages to Argentia with runs to Bermuda and on 29 January 1945 departed Boston for her last run to Canada. On 30 January 1945 in heavy seas off Halifax the ship's hull was damaged by a loose paravane. She began taking water in her forward compartments and sank off McNabs Island in of water. The tug , out of Halifax, took her in tow and subsequently beached the vessel on Maughers Beach, McNabs Island at coordinates . Raised on 17 February, she was towed to Halifax for temporary repairs. The Navy's Bureau of Ships noted in a review that the cargo space lacked bulkheads with only a half-height one between number one and two cargo hatches and none aft between the engine room bulkhead and afterpeak. The near loss — and actual total constructive loss — of the ship due to damage from relatively small holes in the hull confirmed estimation that the ship would sink in event of any uncontrolled flooding either forward or aft. On 14 March she arrived at Norfolk, where she decommissioned 20 May 1945. The Navy had removed deck machinery, stripped main and auxiliary engines of usable parts and removed items such as the laundry. To decrease draft and improve stability the topside areas had been stripped of movable items. Pontiac was returned to the Maritime Commission on the 21st and was struck from the Navy List 2 June 1945. For compensation, $1,374,255.86 were paid to her former Danish owner on 12 July 1945. The