The Nimitz Class aircraft carriers are the largest warships ever built. All seven nuclear-powered Nimitz class carriers have been built by Newport News Shipbuilding in Virginia. The Nimitz air wing consists of 74-86 aircraft. Flight decks measure 333 x 77m and are equipped with four lifts, four steam-driven catapults and four arrestor wires. The carriers are capable of launching one aircraft every 20 seconds. They feature two General Electric pressurized water reactors driving four turbines of 260,000hp (194MW) and four shafts. There are four emergency diesels of 10,720hp (8MW). The first of class, USS Nimitz, was commissioned in 1975. The latest, USS Ronald Reagan CVN-76, was commissioned in July 2003.