The Seawise Giant, a 420,000-dwt tanker owned by Universal Petroleum Carrier Inc., has been jumboized at the Tsu Shipyard of NKK (Nippon Kokan) in Japan. The huge ship gained 81 meters in length and 140,000 tons (metric) in deadweight to become, at 560,000 dwt, the world's largest tanker. She is classed by the American Bureau of Shipping.

Shin ichi Hirayama, president of NKK America Incorporated, said that the operation was carried out by cutting the tanker into two parts at about 120 meters from the stem, and adding a new midbody between them.

Her overall length went from 377 meters to 458.45 meters (1,237 to 1,504 feet) and her draft increased from 23.62 meters to 24.56 meters (77.5 to 80.6 feet). Beam and depth remained the same at 68.8 and 29.8 meters, respectively (225.7 and 97.8 feet).