Seawise Giant, later Happy Giant, Jahre Viking, Knock Nevis, Oppama, and Mont, was a ULCC supertanker that was the longest ship ever, built by Sumitomo Heavy Industries in Yokosuka, Kanagawa, Japan. It possessed the greatest deadweight tonnage ever recorded. Fully loaded, its displacement was 657,019 tonnes. The heaviest ship of any kind, and with a laden draft of 24.6 m (81 ft), it was incapable of navigating the English Channel, the Suez Canal or the Panama Canal.