High Quality Content by WIKIPEDIA articles! The Nimitz-class supercarriers are a class of ten nuclear-powered aircraft carriers in service with the United States Navy. With an overall length of 1,092 ft (333 m) and full-load displacements of over 100,000 long tons, they are the largest capital ships in the world. Instead of the gas turbines or diesel-electric systems used for propulsion on many modern warships, the carriers use two A4W pressurized water reactors which drive four propeller shafts and can produce a maximum speed of over 30 knots (56 km/h) and maximum power of around 260,000 shp (190 MW). As a result of the use of nuclear power, the ships are capable of operating for over 20 years without refueling and are predicted to have a service life of over 50 years. They are categorized as nuclear-powered aircraft carriers and are numbered with consecutive hull numbers between CVN-68 and CVN-77.