USS Deimos (AK-78) was a Crater-class cargo ship in the service of United States Navy in World War II. It was the first ship of the Navy to have borne the name Deimos, after one of the moons of Mars.
Deimos was laid down 27 November 1942 as liberty ship SS Chief Ouray (MCE hull 513) by Permanente Metals Corporation, Richmond, California, under a Maritime Commission contract. Deimos was launched on 28 December 1942 and sponsored by Mrs. M. Moyer. Deimos was transferred to the Navy on 7 January 1943 and commissioned 23 January 1943, with Lieutenant Commander W. L. Sorenson, USNR, in command.
Deimos sailed from San Francisco 27 January 1943 with cargo for Espiritu Santo, New Hebrides, and Townsville, Australia. She arrived at Nouméa, New Caledonia, 23 May to load cargo which she delivered to Guadalcanal in June. Returning to her base, she was torpedoed on 23 June on the port side, aft. Efforts to save her failed. She was finally abandoned and sunk by gunfire from O’Bannon (DD-450) at 11°26′S 162°01′E / 11.433°S 162.017°E / -11.433; 162.017Coordinates: 11°26′S 162°01′E / 11.433°S 162.017°E / -11.433; 162.017.
Deimos received one battle star for World War II service.