South Dakota-class battleship (1939)

Alabama in Casco Bay, Maine, circa December 1942
Class overview
Name	South Dakota class
Builders	New York Shipbuilding Corporation Newport News Shipbuilding Bethlehem Steel Corporation Norfolk Naval Shipyard
Operators	United States Navy
Preceded by	North Carolina class
Succeeded by	Iowa class
Built	1939–1942
In commission	1942–1947
Completed	4
Retired	4
Scrapped	2
Preserved	2
General characteristics
Type	Fast battleship
Displacement	35,412 long tons (35,980 t) (standard) 44,519 long tons (45,233 t) (1942 full load)
Length	666 ft (203 m) (waterline) 680 ft (207 m) (o/a)
Beam	108 ft 2 in (33 m)
Draft	36 ft 2 in (11 m)
Installed power	8 × water-tube boilers 130,000 shp (97,000 kW)
Propulsion	4 × screws; 4 × geared steam turbines
Speed	27.5 knots (50.9 km/h; 31.6 mph)
Range	15,000 nmi (28,000 km; 17,000 mi) at 15 knots (28 km/h; 17 mph)
Complement	1,793–2,634
Sensors and processing systems	SC radar SK radar SR radar (South Dakota, Indiana and Alabama)
Armament	3 × triple 16 in (406 mm) guns 16 or 20 × 5 in (127 mm) DP guns 76 × 40 mm (1.6 in) AA guns 67 × single 20 mm (0.8 in) AA guns
Armor	Belt 12.2 in (310 mm) Bulkheads 11.3 in (287 mm) Barbettes: 11.3–17.3 in (287–439 mm) Turrets: 18 in (457 mm) Conning tower 16 in (406 mm) Decks 1.5 in (38 mm), 5.75–6.05 in (146–154 mm), 0.63–1 in (16–25 mm)
Aircraft carried	2 × OS2U Kingfisher floatplanes
Aviation facilities	1 × aircraft catapult

The South Dakota class was a group of four fast battleships built by the United States Navy. They were the second class of battleships to be named after the 40th state; the first were designed in the 1920s and canceled under the terms of the Washington Naval Treaty. Four ships comprised the class: South Dakota, Indiana, Massachusetts, and Alabama. They were designed to the same treaty standard displacement limit of 35,000 long tons (35,600 t) as the preceding North Carolina class and had the same main battery of nine 16"/45 caliber Mark 6 guns in three-gun turrets, but were more compact and better protected. The ships can be visually distinguished from the earlier vessels by their single funnel, compared to twin funnels in the North Carolinas.

Construction began shortly before World War II, with Fiscal Year (FY) 1939 appropriations. Commissioning through the summer of 1942, the four ships served in both the Atlantic, ready to intercept possible German capital ship sorties, and the Pacific, in carrier groups and shore bombardments. All four ships were retired shortly after World War II; South Dakota and Indiana were scrapped in the 1960s, Massachusetts and Alabama were retained as museum ships.