The largest ship ever built is the Knock Nevis, a supertanker 458 meters (1504 ft) in length and 69 m (226 ft) in width. Its dry weight is 564,763 tonnes, 647,955 tonnes when fully loaded with oil. Built between 1979 and 1981 in Oppama shipyard in Japan, this ship is larger and heavier than the Empire State Building on its side. For over a decade it has been the world's largest ship by a significant margin, although its current function is only as an FSO (floating storage and offloading unit).
When fully loaded, the Knock Nevis' structure reaches 24.6 m (81 feet) underwater, so deep that it cannot navigate the English channel, much less the Panama and Suez canals. This also prevents it from docking at many of the world's major ports.
The Knock Nevis is more than twice than tonnage of the 2nd largest ship in the world, which weighs in at only 170,974 tons. At one point there were seven other ships with a tonnage over 500,000, but they have since all been scrapped. Knock Nevis is more than twice the size of typical oil tankers, such as the ill-fated Exxon Valdez.
Prior names the ship has borne include the Happy Giant, Seawise Giant, and Jahre Viking. Although initially built for a Greek customer, the ship was rejected due to vibration problems stemming from faulty gear design. Thus the ship was sold to Chinese interests and had its length extended, at which point it became the largest ship ever built.
The ship's typical route was to deliver oil to the USA from the Middle East, although Knock Nevis was used as a floating storage and offloading unit during the Iran-Iraq war, when it was damaged by a fighter jet. The ship was repaired at great expense in Singapore, and sold to a Norweigan company. After going through a series of renamings, the ship was eventually stationed at the Qatar Al Shaheen oil field, located in the Persian Gulf, for good, as a storage platform.
Despite its massive size, when the Knock Nevis was in operation, it was maintained by a crew of just 40.