USS Iowa BB-61

Third Generation Battleship

USS Wisconsin

SPECIFICATIONS

Displacement: 48,100 tons (standard), 57,340 tons (full load)

Dimensions: 887 ft 03 in length x 108 ft 2 in beam x 36 ft 2 in draft (full load)

Armament: 9x16in 50cal (3x3); 20x5in 38cal (10x2); 80x40mm (20x4); 49x20mm (49x1); 3 aircraft

Armor: Main belt 12-9in

Turrets 19.7-9.5in

Conning tower 17.5in

Machinery: 4-shaft General Electric turbines, 8 Babcock & Wilcox boilers, 212.000 shp=32.5kts

Oil Capacity: 7621 tons

Endurance: 15,000 nautical miles at l5 knots

Complement: 1921

General The four Iowas were the largest and fastest battleships completed for the US Navy during World War II; in principle they were South Dakotas lengthened for higher speed, the increased displacement being used also to pass from 45 to 50 cal l6 inch guns. In view of the past US preference for protection instead of high speed, 10,000 tons seems a very high price to pay for the jump from 27 to 33 knots. However, the motivation, which parallelled that for the original 30 knot North Carolina design, was the need for ships to form fast carrier task forces. US prewar strategists expected Japan to form such task forces out of her carriers and her large heavy cruisers, for attack upon US lines of communication to the Western Pacific prior to a decisive battle near the home islands; they felt that any fast carriers assigned to action against such task forces would have to be covered by heavy units capable, for example, of defeating the three Japanese Kongo class battlecruisers which might well be detached from the Japanese Battle Force as cover for the carriers - which indeed occurred in 1941.

Careers Design work began in 1938, after rumors of Japanese 46,000-ton battleships led the United States, Britain, and France to agree to invoke the Escalator Clause of the 1936 London Treaty, to raise the limit on displacement from 35,000 to 45,000 tons; in fact the Iowas as built exceeded the latter limit. The existence of three Kongos (the refit of the training ship Hiei was apparently unsuspected as late as 1940) set a lower limit of three Iowas, with a fourth as insurance against the unavailability of anyone of them, and similarly against requirements in the Atlantic. Indeed, in 1940 it was expected that battleship construction would soon revert to the more traditional heavy type, and the first studies of what would become the Montana were made under the designation 'BB65'. However, on 19 July 1940 Congress passed a very large emergency construction program, and the Secretary of the Navy decided that a large part of it would simply duplicate the latest classes already on order, as a means of saving time. Thus two more battleships, BB65 and BB66, were ordered as Iowas rather than as a new class.

Only four out of the six ships were ever completed, and they served in the Fast Carrier Task Force in the latter part of the war. Iowa was built with an enlarged conning tower; to balance its topweight, she was never fitted with a quadruple Bofor guns on No. 2 turret. Ironically, although she was thus designed as a Force Flagship, in fact her sisters also proved quite suitable for that role, New Jersey serving as Fifth Fleet flagship in 1945. Iowa's 20mm and 40mm outfit differed from her sister's: she carried 60 of each. Wartime modifications included some extensions to the bridgework and major additions of light anti-aircraft weapons; surely an unexpected dividend of the great length adopted for high speed was the ease with which light weapons could be added without interfering with the arcs of fire of l6 inch and 5 inch guns. In 1945, Iowa had l9 and her sisters 20 quadruple 40mm mounts. Their 20mm batteries varied: Iowa had 52 single mounts, New Jersey 41 single and 8 twin, Missouri 49 single, and Wisconsin 47 single and 2 twin. The extra mounts in Iowa were atop No 2 turret in place of the 40mm.