The crew braced for the second pattern of depth charges from the Japanese destroyer which could easily sink their submarine. But there weren’t any depth charges. Instead there was a completely different kind of noise. The last torpedo had hit hard and exploded with such force it practically tore the Japanese ship in half. The noise the crew heard was the Japanese destroyer breaking up.
This story, which is absolutely true, became legendary in the American submarine force in the Pacific during World War Two and set the standard for the aggressiveness the US Navy wanted in its submarine commanders.
[Sources: Execute Against Japan: The US Decision to Conduct Unrestricted Submarine Warfare by Lt. Joel Ira Holwitt, USN and Wahoo: The Patrols of America’s Most Famous World War II Submarine by Richard H. O’Kane (three stars).]