British Sailors in Submarines 51 Feet Long Slipped Under the Nets Around the 40,000-Ton Battleship Tirpitz and Left Charges on the Seabed Beneath Her. The Blast Lifted the Ship Out of the Water and Put Her Out of the War for About 6 Months.

On September 22, 1943, four British sailors in an X-class midget submarine slipped into Norway’s Kaafjord fjord and planted explosive charges beneath the German battleship Tirpitz, a 40,000-ton warship defended by torpedo nets, anti-submarine measures, and heavy anti-aircraft guns. Tirpitz’s geography and minefields were designed to insulate it from the British Royal Navy, but the underground attack didn’t sink the battleship. Instead, the blast lifted the ship out of action for months, delaying its threat to Allied Arctic shipping lanes. With the Royal Navy keeping at least two battleships, a fleet carrier, and escorts ready to deter any deployment, the episode shows how unconventional warfare forced Germany into constraints.