The six battleships of the South Dakota class were slower but more heavily armed and armored contemporaries of the Lexington class battle cruisers. All were laid down in 1920 and 1921, only to be suspended under the terms of the Naval Limitations Treaty in February 1922 when they were between 11% and 38% completed. All six remained on the building ways until October-November 1923, when they were sold for scrapping.

Like the Lexington class, the South Dakota's were large ships, with a designed displacement nearly a third greater than their immediate predecessors. These were classic U.S. Navy battleships, well protected against gunfire and torpedoes, heavily armed, but relatively slow, intended to prevail in a big-gun slugging match with an enemy battleline. Their main battery represented a fifty-percent increase in number of guns (twelve versus eight), and these 16" guns were of a somewhat more powerful type than those fitted to previous U.S. battleships. After cancellation of their ships, some of these weapons were employed for seacoast defense. Armor and boilers from the South Dakota class were also recycled for use in modernizing older battleships.

The six South Dakota class battleships were being constructed at five locations:


South Dakota (BB-49). Fiscal year 1918 program. Keel laid at the New York Navy Yard in March 1920. Construction cancelled when the ship was 38.5% completed and she was broken up on the building ways.

Indiana (BB-50). Fiscal year 1918 program. Keel laid at the New York Navy Yard in November 1920. Construction cancelled and the ship scrapped on the building ways.

Montana (BB-51). Fiscal year 1918 program. Keel laid at the Mare Island Navy Yard, California, in September 1920. Construction cancelled and the ship was broken up on the building ways.

North Carolina (BB-52). Fiscal year 1919 program. Keel laid at Norfolk Navy Yard, Virginia, in January 1920. Construction cancelled and the ship was broken up on the building ways.

Iowa (BB-53). Fiscal year 1919 program. Keel laid at Newport News, Virginia, in May 1920. Construction cancelled and the ship was scrapped on the building ways.

Massachusetts (BB-54). Fiscal year 1919 program. Keel laid at Quincy, Massachusetts, in April 1921. Construction cancelled when the ship was about 11% completed and she was broken up on the building ways.


South Dakota class design characteristics:

Displacement: 43,200 tons

Dimensions: 684' (length overall); 106' (maximum beam)

Powerplant: 60,000 horsepower steam turbines with electric drive, producing a 23 knot maximum speed

Armament (Main Battery): Twelve 16"/50 guns in four triple turrets

Armament (Secondary Battery): Sixteen 6"/53 guns in single mountings (eight guns on each side of the ship)