The German submarine U-505 endured one of the most bizarre and brutal careers of any vessel to survive the Second World War. Commissioned in Hamburg in August 1941 as a long-range Type IXC U-boat, it sank four Allied ships in a single month off West Africa, then torpedoed a Colombian sailing vessel owned by a diplomat, handing Colombia the justification it needed to declare war on Germany. From there its luck collapsed: a British bomber dropped a 250-pound bomb directly on its deck near Trinidad, French Resistance dock workers in Lorient quietly sabotaged six consecutive patrols, and in October 1943, under a depth-charge attack near the Azores, Commander Peter Zschech took his own life in the control room while his first watch officer brought the boat home.

Drawing on declassified US Navy intelligence reports, captured German naval logs, and histories of French Resistance operations, this episode follows U-505 to its capture on June 4, 1944, by Captain Daniel Gallery’s Task Group 22.3, just two days before the D-Day landings. An eight-man boarding party from the USS Pillsbury leapt onto the circling, sinking submarine to close the scuttling valves and secure its charts and Enigma code books, and the carrier’s chief engineer turned the boat’s electric motors into generators to pump it dry for a 1,700-mile tow to Bermuda. Today U-505 sits in a climate-controlled bunker at Chicago’s Museum of Science and Industry, restored with parts supplied free of charge by its original German manufacturers.

• Why the Type IXC’s double hull and 15,000-mile surface range made it an ocean-crossing predator
• How French Resistance workers sabotaged U-505 with pinhole fuel leaks, weak welds, and miswired radar
• The only known case of a U-boat commander dying by suicide during an active combat attack
• Hedgehog mortars, a jammed rudder, and engines left running: how the abandoned boat kept circling
• Why Admiral Ernest King was furious at the capture and how 58 prisoners were hidden to protect the Enigma secret