 "Catocin" was launched as SS "Mary Whitridge" 23 January 1943 by Moore Dry Dock Co., Oakland, California, under a Maritime Commission contract; sponsored by Miss A. H. Morton; acquired by the Navy 31 August 1943; and commissioned as "Catoctin" the same day, Commander H. B. Olsen, USNR, in command.Between 14 September and 11 October 1943, "Catoctin" sailed from Long Beach, California, to Philadelphia, where she was decommissioned upon arrival.Converted to a combined operations and communications headquarters ship, "Catoctin" was recommissioned 24 January 1944, Commander Charles Owen Comp in command, and reported to Atlantic Fleet.