Hollywood might often showcase submarines hunting down and attacking other submarines in a variety of movies and TV shows, but it’s actually been a very rare event in history.

In fact, the only time a submarine has ever been known for successfully hunting down and destroying an enemy submarine while underwater was in February 1945, with the destruction of the U-864, a German Type IX U-boat off the coast of Norway by a Royal Navy sub.

Towards the end of the war in Europe, U-864 under the command of Ralf-Reimar Wolfram, was sent out on a secret transport mission as part of Operation Caesar to smuggle jet engine components and schematics, bottles of mercury for constructing explosives, advisors, and engineers to Japan undetected by Allied warships prowling around for U-boats.

U-boats
German U-boats outside a Norwegian submarine pen. (Wikimedia Commons)

The faltering German higher command had hoped that even if they were unsuccessful in their theater of war, the Japanese military could benefit from the advanced technology they sent over, continuing the war effort and eventually affording Germany a chance to get back in the fight.

In December 1944, the U-864 left its submarine pen in Kiel, Germany, for a trip to occupied Norway where it would be refitted with a new snorkel before departing on its mission. The problematic refit and damage sustained from accidentally running aground pushed its deployment back until January of the next year.

Unbeknownst to the German navy, Allied forces were already aware of Operation Caesar, having cracked the Enigma code which was used by the German military to encrypt its classified communications. As a response to Caesar, the Royal Air Force and Navy bombed a number of submarine pens in Norway, including one where U-864 was temporarily housed in for repairs.

Lt. Jimmy Launders
Lt. Jimmy Launders during the commissioning of the Venturer in Holy Loch, Scotland (Royal Navy)

The U-864 eventually deployed on Operation Caesar, slipping away undetected by nearby Allied warships. However, a monkey wrench was thrown into the covert mission’s gears when the Royal Navy – unwilling to take unnecessary chances – tasked the HMS Venturer to hunt down and kill the U-864 before it could make a dash for the open oceans.

Venturer was commanded by Lt. Jimmy Launders, a highly-respected and brilliantly-minded tactician. Within days of reaching the U-864’s last suspected position, Launders “spotted” his quarry, thanks to noises emanating from the German warship’s engines.