High Quality Content by WIKIPEDIA articles! Seawise Giant, later Happy Giant, Jahre Viking, and Knock Nevis, was a ULCC supertanker and the longest ship ever built, and possessed the greatest deadweight tonnage ever recorded. Fully laden, her displacement was 657,019 tonnes (646,642 long tons; 724,239 short tons), the heaviest ship of any kind, and with a draft of 24.6 m (81 ft), she was incapable of navigating the English Channel, the Suez Canal or the Panama Canal. Overall, she was generally considered the largest ship ever built, as well as the largest self-propelled, man made object ever built. She was last used as a floating storage and offloading unit (FSO) moored off the coast of Qatar in the Persian Gulf at the Al Shaheen Oil Field.