During the Second World War, two American submarines were sunk by their own torpedoes. Each boat had fired a spread of torpedoes at an enemy ship and in both cases one of the torpedoes malfunctioned, ran in a circular pattern, and exploded when it hit the American submarine. The USS Tullibee was sunk in this way with only one survivor. The other submarine to be sunk by its own torpedo was the USS Tang (SS 306), one of the most famous US Navy submarines of World War Two, commanded by one of the greatest submariners in the US Navy, Richard O’Kane. Only he and eight crew members survived the explosion which occurred when the USS Tang was struck by its own torpedo.
[Sources: Iron Men and Tin Fish: The Race to Build a Better Torpedo During World War II by Anthony Newpower.]