South Dakota class battleships

The first South Dakota class of battleships was designed to provide the US Navy with larger fast battleships to counter rumoured Japanese fast battleships, but the entire class was cancelled under the terms of the Washington Naval Conference.

The General Board of the Navy had been asking for larger battleships since 1914. It finally got its way with the first South Dakota class. They were 60ft longer and 10,000 tons heavier than the previous Colorado class ships. Firepower was increased from eight 16in/45 guns up to twelve 16in/50 guns, with the number of guns increased by using triple instead of double turrets. Armour thickness remained the same as on the previous class. The biggest visual change would have been the trunked funnel - four smoke pipes emerged separated but merged just before their tops.

The design of the South Dakota class ships was frozen in the summer of 1918, but at the time all US capital ship construction was frozen in favour of anti-submarine warfare vessels and merchant ships. Some in the US navy were already looking at building faster 16in armed battleships, modelled partly on HMS Hood but with better armour, but the General Board believed that this would make their existing battleships obsolete and would thus be against their best interesting (assuming nobody else built such ships). Work on the South Dakota class ships began after the end of the First World War but all six ships were cancelled under the terms of the Washington Naval Conference before much progress had been made on any of them.

Of the six names allocated to this class North Carolina was used in the next class of battleships to be built (the North Carolina class), South Dakota, Indiana and Massachusetts were used in the second South Dakota class, and Iowa became the name-ship of the fast Iowa class battleships. Montana became the name-ship of the heavy Montana class of battleships, but these ships were never laid down.

Displacement (standard)


Top Speed



8,000nm at 10kts

Armour – belt


 - deck


 - turret faces

18in or 16in

 - turret sides


 - turret top


 - turret rear


 - barbettes


 - coning tower


 - coning tower top







Twelve 16in guns in four triple turrets
Sixteen 6in guns
Four 3in guns
Two 21in submerged beam torpedo tubes

Crew complement


Ships in Class

All cancelled 8 February 1922

USS South Dakota (BB 49)


USS Indiana (BB 50)


USS Montana (BB 51)


USS North Carolina (BB 52)


USS Iowa (BB 53)


USS Massachusetts (BB 54)


Books on the First World War | Subject Index: First World War

How to cite this article: Rickard, J (31 May 2012), Title,

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