World War II: HMS Venturer Sinks U-864

HMS Venturer. Public Domain


The engagement between HMS Venturer and U-864 took place during World War II.


Lt. Jimmy Launders and HMS Venturer sank U-864 on February 9, 1945.

Ships & Commanders:


  • Lieutenant Jimmy Launders
  • HMS Venturer (V-Class Submarine)
  • 37 men


  • Korvettenkapitän Ralf-Reimar Wolfram
  • U-864 (Type IX U-boat)
  • 73 men

Battle Summary:

In late 1944, U-864 was dispatched from Germany under the command of Korvettenkapitän Ralf-Reimar Wolfram to take part in Operation Caesar. This mission called for the submarine to transport advanced technology, such as Me-262 jet fighter parts and V-2 missile guidance systems, to Japan for use against American forces. Also on board was 65 tons of mercury which was needed for the production of detonators. While passing through the Kiel Canal, U-864 grounded damaging its hull. To address this issue, Wolfram sailed north to the U-boat pens at Bergen, Norway.

On January 12, 1945, while U-864 was undergoing repairs, the pens were attacked by British bombers further delaying the submarine's departure. With repairs complete, Wolfram finally sailed in early February. In Britain, code breakers at Bletchley Park were alerted to U-864's mission and location through Enigma radio intercepts. To prevent the German boat from completing its mission, the Admiralty diverted the fast attack submarine, HMS Venturer to search for U-864 in the area of Fedje, Norway. Commanded by rising star Lieutenant James Launders, HMS Venturer had recently departed its base at Lerwick.

On February 6, Wolfram passed Fedje the area however issues soon began to arise with one of U-864's engines. Despite the repairs at Bergen, one of the engines began to misfire, greatly increasing the noise the submarine produced. Radioing Bergen that they would be returning to port, Wolfram was told that an escort would be waiting for them at Hellisoy on the 10th. Arriving in the Fedje area, Launders made a calculated decision to turn off Venturer's ASDIC (an advanced sonar) system. While use of the ASDIC would make locating U-864 easier, it risked giving away Venturer's position.

Relying solely on Venturer's hydrophone, Launders began searching the waters around Fedje. On February 9, Venturer's hydrophone operator detected an unidentified noise that sounded like a diesel engine. After tracking the sound, Venturer approached and raised its periscope. Surveying the horizon, Launders spotted another periscope. Lowering Venturer's, Launders correctly guessed that the other periscope belonged to his quarry. Slowly following U-864, Launders planned to attack the German u-boat when it surfaced.

As Venturer stalked U-864 it became clear that it had been detected as the German began following an evasive zigzag course. After pursuing Wolfram for three hours, and with Bergen approaching, Launders decided that he needed to act. Anticipating U-864's course, Launders and his men computed a firing solution in three dimensions. While this type of calculation had been practiced in theory, it had never been attempted at sea in combat conditions. With this work done, Launders fired all four of Venturer's torpedoes, at varying depths, with 17.5 seconds between each.

After firing the last torpedo, Venturer dove quickly to prevent any counterattack. Hearing the torpedoes approach, Wolfram ordered U-864 to dive deeper and turn to avoid them. While U-864 successfully evaded the first three, the fourth torpedo struck the submarine, sinking it with all hands.


The loss of U-864 cost the Kriegsmarine the U-boat's entire 73-man crew as well as the vessel. For his actions off Fedje, Launders was awarded a bar for his Distinguished Service Order. HMS Venturer's fight with U-864 is the only known, publicly acknowledged battle where one submerged submarine sank another.

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Your Citation
Hickman, Kennedy. "World War II: HMS Venturer Sinks U-864." ThoughtCo, Aug. 26, 2020, Hickman, Kennedy. (2020, August 26). World War II: HMS Venturer Sinks U-864. Retrieved from Hickman, Kennedy. "World War II: HMS Venturer Sinks U-864." ThoughtCo. (accessed May 28, 2023).