German submarine U-29 sank HMS Courageous in September 1939, the first aircraft carrier sunk by a submarine.
U-29 torpedoed Courageous on 17 September 1939 in the Western Approaches during the opening weeks of World War II. The British carrier was operating with an escort group when U-29, commanded by Otto Schuhart, fired from a submerged position.
Courageous sank quickly, killing more than 500 people. The loss prompted the Royal Navy to withdraw its aircraft carriers from anti-submarine patrols in exposed waters, changing how carriers were employed early in the war.
This event is sometimes confused with later attacks on fleet carriers. Courageous was a prewar carrier converted from a battlecruiser design, not one of the purpose-built armored carriers introduced later. U-29 survived the attack but was eventually sunk in 1941 by British warships.