Decommissioning
Underway for the West Coast on 7 October 1946, Tuna arrived at the Mare Island Naval Shipyard a week later where she moored with the 19th Fleet. Scheduled for decommissioning on 11 December 1946, she was retained as a radiological laboratory unit and subjected to numerous radiological and structural studies while remaining at Mare Island. No preservation work was undertaken on the ship, and she was decommissioned on 11 December 1946. On 20 September 1948, fleet ocean tug Tekesta (ATF-93) towed Tuna from Mare Island for the submarine's "last patrol." On 24 September 1948, Tuna was sunk in 1,160 fathoms (7,000 ft; 2,120 m) of water off the West Coast and struck from the Naval Vessel Register on 21 October 1948.
Read more about this topic: USS Tuna (SS-203)