When the helicopter arrived near "Grayback"'s expected position, they could not locate the submarine. In 1958, "Grayback" conducted tests and shakedown along the West Coast. "Grayback" CO John Anderson Moore was awarded the Navy Cross after this mission. However, the destroyer evaded the torpedoes and dropped 19 depth charges on "Grayback". The fifth war patrol began as "Grayback" sailed from Australia on 7 December 1942. The Regulus missile program ended in 1964 and "Grayback" was withdrawn from active service. "Grayback" received eight battle stars for World War II service. "Grayback" continued on patrol, torpedoing and damaging several Japanese ships. The oiler "Nanpo Maru" was sunk by "Grayback" in the same attack. "Grayback" reported seeing "Grampus" in that same area 4 March. After an unsuccessful attack the following night had exhausted her torpedo supply, "Grayback" headed home. On 12 June, the remaining team members were transferred back to "Grayback". "Grayback" sent ashore two men, then submerged at dawn to avoid enemy aircraft. "Grayback" was originally commissioned in March 1958, the first submarine built to accommodate Regulus. Then, on 25 December, "Grayback" surfaced to sink four landing barges with her deck guns.