The Iowa class was a class of six fast battleships ordered by the United States Navy in 1939 and 1940. They were initially intended to intercept fast capital ships such as the Japanese Kongō class and also serve as the "fast wing" in a traditional battle line alongside slower battleships. The Iowa class was designed to meet the Second London Naval Treaty's "escalator clause" limit of 45,000-long-ton (45,700 t) standard displacement. Beginning in August 1942, four vessels, Iowa, New Jersey, Missouri, and Wisconsin, were completed; two more, Illinois and Kentucky, were laid down but canceled in 1945 and 1958, respectively, before completion, and both hulls were scrapped in 1958–1959.
USS Iowa (BB-61) fires a full broadside on 15 August 1984 during a firepower demonstration after her recommissioning
USS Iowa in World War II configuration and wearing Measure 32 Design 1B camouflage pattern, c. 1944.
USS Iowa fires a full broadside of nine 16-inch and six 5-inch guns during a gunnery exercise
16"/50 gun projectile with six propellant bags (display) aboard USS Iowa (BB-61)
A fast battleship was a battleship which in concept emphasised speed without undue compromise of either armor or armament. Most of the early World War I-era dreadnought battleships were typically built with low design speeds, so the term "fast battleship" is applied to a design which is considerably faster. The extra speed of a fast battleship was normally required to allow the vessel to carry out additional roles besides taking part in the line of battle, such as escorting aircraft carriers.
HMS Queen Elizabeth, the first "fast battleship" of the Dreadnought era, in 1918
French battleship Dunkerque
USS Missouri, among the last "fast battleships", would serve until 1992
Figure 1. Concept that maneuverability and armament were more important than speed. A slower ship with larger guns could render a speedier ship's advantage moot.