A battleship is a large, heavily armored warship with a main battery consisting of the largest calibre of guns. Battleships are larger, better armed, and better armored than cruisers and destroyers. A Battleship was a naval vessel of the first class carrying maximum armament and protection; both against gun fire and torpedo attack, and having good speed.
The modern battleship traces its ancestry to the 74-gun ship-of-the-line of the sailing era. It is also the product of a series of modifications of the heavy steel ships that formed the backbone of the so-called New Navy of the 1880s, when the steel industry was introduced in the United States. The mission of the battleship was to conduct sustained combat operations at sea worldwide; to operate as an element of a carrier battle group or amphibious group; and in areas of lesser threat, to be capable of surface-action group operations with appropriate antisubmarine and antiair warfare escort ships.
The four battleships of the Iowa class were modernized and recommissioned in the 1980s. All were decommissioned in the 1990s. In addition to their nine 406-mm (16-in) guns in three turrets, used primarily for shore bombardment, each carries twelve 127-mm (5-in) twin batteries for anti-aircraft protection, four Phalanx close-in weapons systems for defense against anti-ship missiles, and sixteen Tomahawk cruise missiles for surface warfare and land attack