In June 1944, American sailors did something they had not attempted in 129 years — they captured a German U-boat at sea. Led by Lieutenant Albert David and Captain Daniel Gallery, a small boarding party risked drowning inside a sinking submarine to seize its secrets. What they found inside helped shift the Battle of the Atlantic at a critical moment before D-Day.
When U-505 surfaced crippled in the Atlantic, U.S. Navy doctrine said to sink her immediately. Instead, eight men climbed aboard a vessel rigged to flood and explode. Inside were Enigma cipher machines, current codebooks, patrol charts, and advanced acoustic torpedoes.
The capture remained secret for nearly a year. Germany never learned its naval codes had been compromised. Convoys were rerouted. Countermeasures were developed. Supply lines stayed open as Allied armies landed in Normandy.
Today, U-505 survives in Chicago — the only enemy warship captured at sea by the United States Navy since 1815.
