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The sinking of U-864 was a memorable episode of British derring-do. Once the British decrypted U-864's mission, they deployed the Venturer, commanded by 25-year-old Jimmy Launders, to destroy it. The Venturer located U-864 on the morning of Feb. 9, 1945, and waited for the German sub to surface and present an easier target, according to a BBC documentary on the sinking of U-864. The German sub's operators, however, realized they were being tailed, and began zig-zagging to get away.

Knowing he was outgunned — the Venturer had only four torpedoes and U-864 had 22 — Launders decided to launch all his torpedoes, in 17-second intervals, along what he predicted would be his adversary's path. Launders then dived to evade retaliation. Hearing the torpedoes coming, U-864 dived deeper and turned to avoid them; it managed to dodge the first three but steered into the path of the fourth. Seventy-three men were killed. It was the first instance of one submarine sinking another while both were submerged.