Iowa

History

Design

The Iowa-class battleships were designed in 1938 when the Navy proposed a new class of battleships that were to develop on the lessons learned from the development and construction of the North Carolina-class and South Dakota-class of battleships. Of exceptional concern were the Kongo-class battleships that are able to use speed to harass convoys and outgun fast aircraft carrier escorts, as well as the refusal of Japan to disclose details regarding the construction of the Yamato-class battleships. Wishing to have an apt and equal response, the construction of the Iowa-class was approved. These factors culminated in the US, Britain, and France invoking the "Escalator Clause" of the second naval treaty, which permitted 16 inch guns and 45,000 long tons standard displacement.

With the emergence of aircraft carriers and the need to protect them from surface threats, the concept of “fast battleships” came into prominence; ships designed with the speed and the endurance to keep pace with carrier groups and serve as a major deterrent to surface attack. To fulfill this role, the design called for a top speed of 33 knots from 8 boilers connected to 4 turbines; each turbine to a propeller shaft. This layout produced a total of 230,000 shaft horsepower. Furthermore, the ship had a greater waterline length-to-beam ratio, making the ship longer than its predecessors, as well as notably faster.

The main armament of the Iowa class — while using rifles of the same diameter of 406mm as preceding ships — were longer than the rifles on the South Dakota-class (increased from 45 calibers to 50 calibers) and therefore have the distinction of being the largest rifles mounted on any US warship to date. This increase in rifle length resulted in greater distance for expanding gases in the chamber to propel the projectile, which equated to higher muzzle velocity, greater range, and greater armor-penetration capabilities than preceding rifles. Furthermore, the Iowa-class had a comprehensive suite of secondary and anti-aircraft guns due to the design emphasis of increased protection against air attacks; the armament systems were supplemented with state-of-the-art radar-based fire control systems (Iowa had Mark 8 Fire Control Radar sets fixed upon Mark 38 Fire directors).

The Iowa-class battleships had the characteristic “all-or-nothing” armor scheme seen in preceding American battleships, with the thickest armor around the citadel between Turrets A and Turret C. The outer hull plate was 38mm Special Treatment Steel (STS) and the side armor of 307mm was angled at 19-degrees inwards in order to confer greater armor thickness for little additional weight; this was especially advantageous against shells at longer range. The armor scheme of the Iowa-class was largely the same as the preceding South Dakota-class, which offered protection from 406mm/45 rifles firing 1,016 kg Mark 5 shells from ranges between 16,000 - 27,000 meters.

From the onset, Iowa was designed to fulfill the role of a fleet flagship; therefore, the conning tower was more enlarged than those of her sisters, to accommodate an admiral on board. Iowa was, therefore, the ideal choice when selecting which ship should ferry President Franklin D. Roosevelt to the Tehran Conference of 1943.

USS Iowa was the lead ship of the Iowa-class battleships. Ordered at the Brooklyn Navy Yard in New York City, she was laid down on 27 June 1940, launched on 27 August 1942, and commissioned into service on 22 February 1943.

Service

The Iowa-class battleships were a class of fast battleships ordered by the United States Navy in 1939 and 1940 to escort the Fast Carrier Task Forces that would operate in the Pacific Theater of World War II. Four were completed; two more were laid down but canceled at war's end and scrapped. Like other third-generation American battleships, the Iowa class followed the design pattern set forth in the preceding North Carolina-class and South Dakota-class battleships, which emphasized speed and the secondary and anti-aircraft batteries.

Historical Inaccuracies

• The Measure 32/22D permanent camouflage was worn by Missouri. Iowa's camouflage was Measure 32/1B.
• Three 20 mm Oerlikon cannons fitted to 'B' turret are missing.

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  USS Iowa (BB-61) fires a full broadside on 15 August 1984 during a firepower demonstration after her recommissioning.