USS Iowa (BB-4) - Superior Design

Superior Design

The second half of the 19th century saw radical changes in shipbuilding design. Wood-built sailing ships with cannons were replaced by steam-powered warships armored with steel. There was great interest in new shipbuilding techniques and a search for stronger metal alloys, and discussion of new designs, centerboards, ventilating techniques, with active participation between private builders and naval designers.

The Congress of the United States authorized a 9,000 long tons (9,100 t) warship on 19 July 1892. Specifically, it was for a 'seagoing coastline battleship', to fill the Navy's desire for a ship that could sail and fight effectively in open waters; the preceding Indiana class— authorized by Congress as 'coast-defense battleships'— had many problems with endurance and speed.

Iowa had a unique design and did not belong to a specific ship class. She represented an upgrade from the Indianas. Iowa's keel was built by William Cramp and Sons of Philadelphia, Pennsylvania on 5 August 1893, who also built the coal-powered, 11,000 ihp (8,200 kW) vertical reciprocating steam engines. It had twin above-board 14 in (360 mm) torpedo tubes. She carried 1,795 short tons (1,628 t) of coal. Iowa was based on the earlier Indiana-class with similar armament layout and four 12 in (300 mm) guns in twin turrets fore and aft, supplemented by four twin 8 in (200 mm) turrets. There was extensive testing of new armor plating; at one point, Iowa was fired on in testing to assess the strength of its steel shell. Like Indiana, Iowa was made using "Harveyized steel".

Several design modifications made Iowa a far more powerful warship than its predecessors. The diameter of the main four largest guns was 12 in (300 mm) and were hydraulically powered. The vessel had a larger margin of freeboard and a longer hull and forecastle, which resulted in a more stable and seaworthy ship. Further, the raised height made the gunnery area drier and further reduced the risk of malfunctions due to wet weather. By utilizing the Harvey process, Iowa's armor was thinner but stronger than the nickel-steel used in the Indianas. Compared to British warships, Iowa had excellent speed (18 kn (21 mph; 33 km/h)) but was 3,500 long tons (3,600 t) lighter.