The T class was a large ambush predator designed to fire an exceptionally heavy bow salvo. During Operation Weserübung, Karlsruhe left Kristiansand with three Type 23 torpedo boats but still had to follow a predictable route out of the fjord. Truant waited near that exit and launched a full salvo as the cruiser approached. Karlsruhe took evasive action, yet one torpedo struck her starboard side amidships. Careful positioning let one submarine impose a serious cost on the German invasion force without scoring multiple hits.
Chapter · 28:02-30:43
HMS Truant ambushes Karlsruhe off Kristiansand
HMS Truant exploited Karlsruhe's predictable route out of Kristiansand, placing a T-class submarine where its heavy bow salvo could punish the German invasion of Norway.