The Only Time a Submarine Destroyed Another Submarine Underwater

During World War I, Germany created havoc in the seas by unconventional means.

The German U-boats, or submarines, sent tons of Allied war material to the bottom of the ocean in such a practical approach that the US and its allies could not keep up with the production line of new supplies other nations desperately needed.

Eventually, the US, Great Britain, and other countries realized that the submarine, although slow and clunky at times, was a useful war asset.

During World War 2, the Kriegsmarine continued to make fair use of the U-boat fleet, conducting a naval blockade all over Europe that forced the Allies to be cautious at sea.

Nonetheless, since the original submarines were put afloat for the first time, there have only been two registered encounters of two of them clashing in a combat zone.

The first one occurred in World War I, when U-27 sank the British E3. The submarine was destroyed, but the crew was saved.

The second one had a more sinister ending in February 1945 when a U-boat carrying a secret cargo on its way to Japan was intercepted by British submarines dispatched to eliminate it.

When both submarines were in range of each other, a short battle followed underwater, with the vehicles fully submerged.

The skirmish jeopardized a secret mission whose objective was to help the Japanese Army with the latest German technologies to fight the Americans in the Pacific.

Aboard U-864, the Germans carried prototype weapon designs along with German and Japanese scientists and a significant quantity of liquid mercury for transport to Japan.

It was Operation Caesar, and it was the Reich's last attempt at trying to win the war against the Allied forces.