Only ONCE in history has a submerged submarine sunk another submerged submarine.

IN World War II, the British submarine HMS Venture was ordered to intercept and destroy a German U-boat, U-864. U-864 was en route to Japan on a secret mission to deliver some new technology to them. Amazingly, the Venture almost didn’t find U-864 at all! On February 9, 1945, the German U-boat was going through some engine problems, so it was making some unusually loud noises. The crew of the Venture heard the noise, raised their periscope, and happened to see U-864’s periscope.

The British sub pursued the German one for hours. At the time, no one knew how to hit a submarine underwater with a torpedo, and the Venture’s commander had turned off the sonar to reduce their chances of being detected. The Germans were zigzagging underwater to avoid torpedoes. The Venture fired four torpedoes at different depths. Three of them missed, and the Germans dove deeper to dodge them. They ended up crashing right into the fourth one, they sunk, and everyone on board died.