On September 9, 1943 USS Wahoo (SS-238) departed Pearl Harbor on her seventh patrol. She topped off with fuel at Midway and left September 13 heading for the dangerous mine-laden Sea of Japan. Shortly afterwards, USS Sawfish left Midway and also headed for this area.
Wahoo was to pass through Etorofu Strait, in Kurile Islands, and La Perouse Strait, between Hokkaido and Karafuto, and enter the Japan Sea. She was to head south and remain below 43° north. USS Sawfish was to follow Wahoo and patrol the area north of her. Though no transmission was received from Wahoo, either by any shore station or by Sawfish, she was reported missing on November 9, 1943.
On October 31, 2006, the U.S. Navy confirmed that the images provided by "Iskra" research team were of USS Wahoo (SS-238), the wreckage lying intact in about 213 ft (65 m) of water in the Soya Strait. It is now known that the submarine was sunk by a direct hit from an aerial bomb near the conning tower.
Wahoo was one of the Submarine Force's most valuable units during her six patrols, and her feats have become submarine legend. Wahoo was awarded the Presidential Unit Citation for her third patrol. Claiming to sink 27 ships, totaling 119,100 tons, and damaged two more, for an additional 24,900 tons, in the six patrols completed before her loss.
Lieutenant Commander Dudley Walker "Mush" Morton was considered one of the topnotch officers in the Submarine Force, and the loss of this ship was an irreparable blow to the Service.