Armament of the Iowa-class battleship

The Iowa-class battleships are the most heavily armed warships the United States Navy has ever put to sea, due to the continual development of their onboard weaponry. The first Iowa-class ship was laid down in June 1940; in their World War II configuration, each of the Iowa-class battleships had a main battery of 16-inch (406 mm) guns that could hit targets nearly 20 statute miles (32 km) away with a variety of artillery shells designed for anti-ship or bombardment work. The secondary battery of 5-inch (127 mm) guns could hit targets nearly 9 statute miles (14 km) away with solid projectiles or proximity fuzed shells, and was effective in an anti-aircraft role as well. Each of the four battleships carried a wide array of 20 mm and 40 mm anti-aircraft guns for defense against enemy aircraft.

When reactivated and modernized in the 1980s, each battleship retained the original battery of nine 16-inch (406 mm) guns, but the secondary battery on each battleship was reduced from ten twin-gun mounts and twenty guns to six twin-gun mounts with 12 guns to allow for the installation of two platforms for the Tomahawk missiles. Each battleship also received four Harpoon missile magazines, Phalanx anti-aircraft/anti-missile systems, and electronic warfare suites.