battleship, large, armored warship equipped with the heaviest naval guns. The evolution of the battleship, from the ironclad warship of the mid-19th cent., received great impetus from the Civil War. By 1872 the French were building iron and steel warships, and in 1876 the British started construction of two all-steel war vessels. Developments continued to improve speed, fortification, accuracy of armament, and size. The H.M.S. Dreadnought, which was completed in 1906, was the first modern battleship and introduced the "all-big-gun" class of warship. It was armed with ten 12-in. (30.5-cm) guns and was powered by steam turbines, which developed a speed of 21 knots. The battleship became the major capital unit in modern navies, although there was only one fleet engagement of battleships in World War I and no fleet engagements in World War II. However, with the development of new aerial tactics, such as dive bombing, and the introduction (1941) of aircraft carriers as the major unit of a naval attack force, battleships became nearly obsolete. The fate of the battleship as a major weapon in modern warfare was sealed on Dec. 7, 1941, when Japanese carrier-borne aircraft attacked the U.S. navy's battleships at Pearl Harbor, sinking or badly damaging all eight. Shortly after the Korean War the last battleships of the British and American navies were decommissioned. The U.S. navy, during part of the Vietnam War, used one battleship, the New Jersey, for shore bombardment and antiaircraft defense. The four Iowa-class battleships were recommissioned in 1980s; all were again decommissioned by 1992.

Capital ship of the world's navies from circa 1860, when it began to replace the wooden-hulled ship of the line, until World War II, when it was superseded by the aircraft carrier. It combined large size, powerful guns, and heavy armour with fairly high speed and great cruising radius. The most powerful could hit targets at a range of more than 20 mi (30 km) and absorb heavy damage while remaining afloat and continuing to fight. It originated in early ironclad vessels with mixed sail and steam propulsion, such as the French armoured frigate Gloire (1859). In 1906 HMS Dreadnought revolutionized battleship design by introducing steam-turbine propulsion and an array of ten 12-in. (305-mm) guns. In World War II (1939–45) battleships were used mainly for specialized tasks such as bombarding enemy coastal defenses in amphibious warfare. After the Persian Gulf War (1990–91), the U.S. decommissioned its last two active battleships.

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