U-505's fourth patrol sent her to the northern coast of South America. She left Lorient on 4 October and sank the British vessel Ocean Justice off the coast of Venezuela on 7 November. On 10 November near Trinidad, U-505 was surprised on the surface by a Lockheed Hudson maritime patrol aircraft from No. 53 Squadron, Royal Air Force, which made a low-level attack, landing a 250 lb (110 kg) bomb directly on the deck from just above water level. The explosion killed one watch officer and wounded another in the conning tower. It also tore the anti-aircraft gun off its mounting and severely damaged the ship's pressure hull. The aircraft was hit by fragmentation from the bomb's explosion and crashed into the ocean near U-505, killing RAAF pilot Flight Sergeant Ronald Sillcock and his entire crew. With the pumps inoperative and water flooding the engine room in several places, Kptlt. Zschech ordered the crew to abandon ship, but the technical staff (led by Chief Petty Officer Otto Fricke) insisted on trying to save her. The vessel was made water-tight after almost two weeks of repair work. After sending the wounded watch officer to the supply submarine ("milk cow") U-462, U-505 limped back to Lorient on reduced power, earning the distinction of being the "most heavily damaged U-boat to successfully return to port".