German submarine U-505

U-505 is a German Type IXC submarine built for Germany's Kriegsmarine during World War II. She was captured by the United States Navy on 4 June 1944 and survives as a museum ship in Chicago.

In her unlucky career, she had the distinction of being the "most heavily damaged U-boat to successfully return to port" in World War II, suffering six botched patrols, and becoming the only submarine in which a commanding officer killed himself in combat conditions. On 4 June 1944, she was captured by United States Navy Task Group 22.3 (TG 22.3), one of six U-boats that were captured at sea by Allied forces during the war. All but one of U-505's crew were rescued by the Navy task group. The submarine was towed to Bermuda in secret, and her crew was interned in an American prisoner-of-war camp, where they were kept in isolation. The Navy classified the capture as top secret and went to great lengths to prevent the Germans from discovering it.

In 1954, U-505 was donated to the Museum of Science and Industry in Chicago, Illinois. She is now one of four German World War II U-boats that survive as museum ships, and one of just two Type IXCs still in existence, along with U-534.