U-47 (German Submarine) Early in World War II, the British Navy was dealt a humiliating blow by an intrepid and resourceful German U-boat commander who slipped into the anchorage at Scapa Flow and sank the battleship Royal Oak on October 13, 1939. Through the narrow Kirk Sound, in which the British had sunk block-ships as an anti-submarine measure, Gunther Prien, skipper of the U-47, steered his craft fully surfaced. Once inside Scapa Flow, he sent a salvo of torpedoes into the Royal Oak, sinking her within sight of British shore batteries. Undetected, the U-47 slipped back to sea, completing one of the most daring submarine patrols in sea warfare.
