Early in 1937 the US Navy started work on the design of 45,000-ton battleships as a contingency against any Japanese refusal to continue the international treaty limits on displacement. In January 1938 emphasis switched from ships with heavy armament and protection but modest speed (12 406-mm/16-in guns, 27 knots) to fast designs, capable of 30 kts or more. The new 'Essex' class carriers were taking shape on the drawing board at this time, and there was a need to provide them with battleship escorts of similar performance.
The 'Iowa' class which resulted sacrificed gunpower (only nine 406-mm/ 16-in guns) and protection (310-mm/ 12.2-in belt armour) to permit the speed to be increased to 33 kts. Although intelligence sources suspected that the new Japanese battleships would have 457-mm (18-in) guns, it was hoped that the 'Iowa' class would not have to fight them as carrier aircraft would keep the Japanese giants outside gun-range. The 'Iowas' were primarily intended to keep heavy cruisers, rather than battleships, at bay, and as such they came close to the original concept of the battlecruiser, although never rated as such.
The Iowa (BB.61) was laid down in June 1940, launched in August 1942 and commissioned in February 1943, In August of that year she escorted convoys from Newfoundland and then took President Roosevelt to North Africa, before being sent to the Pacific to join the 5th Fleet. She took part in the Marshall Islands landing, and suffered slight damage from Japanese artillery. At Leyte she was part of Vice Admiral William Halsey's Fast Carrier Force, and took part in the Okinawa landing; in July 1945 she bombarded targets on Hokkaido and Honshu, and was part of the enormous force anchored in Tokyo Bay for the Japanese surrender.
The lowa was mothballed in 1949 but reactivated in 1951 for service in the Korean War. She carried out a large number of shore bombardments but was decommissioned once more in 1953, It was widely thought that she would be scrapped, but in 1981 she was towed to New Orleans to begin reactivation. In her new configuration she will carry a large number of Harpoon anti-ship missiles and Tomahawk cruise missiles to enable her to function as the main unit of a Surface Action Group (SAG). Her 406-mm (16-in) guns are to be retained to provide gunfire support.
SpecificationUSS Iowa (BB.61)
Displacement: 48,500 tons standard, 57,450 tons full load
Dimensions: length 270.43 m (887 ft 3 in) overall; beam 32,97 m (108 ft 2 in); draught 11.58 m (38 ft)
Machinery: 4-shaft geared steam turbines delivering 212,000 shp (158088kW)
Speed: 33 kts
Armour: belt 310 mm (12.2 in); decks 38-120 mm (1.5-4.7 in); turrets 457 mm (18 in)
Armament: nine 406-mm (16 in), 20 127-mm (5-in) DP, 60 40-mm AA and 60 20-mm AA guns
Aircraft: three Vought Kingfisher floatplanes
Complement: 1,921 officers and men