The first South Dakota class was a class of six American battleships that were laid down in 1920 but never completed. They would have been the last dreadnoughts in the Naval Act of 1916 to be commissioned had the Washington Naval Treaty not caused their cancellation one-third of the way through their construction. They would have been the largest, most heavily armed and armored battleships in the U.S. Navy and, designed to achieve 23 knots (43 km/h), represented an attempt to abandon its 21-knot (39 km/h) standardized fleet speed and catch up with the increasing fleet speeds of its main rivals, the British Royal Navy and Imperial Japanese Navy. In this, size and secondary armament, they represented a break from the Standard-type battleship that had dominated American capital ship design for the prior five ship classes, while their use of standardized bridges, lattice masts and other features was a continuation of this practice and the increase in the number of main guns from the preceding Colorado class had long been standard U.S. naval policy. The main restriction to which they had to adhere was the ability to pass through the Panama Canal.
The South Dakotas were authorized 4 March 1917, but work was postponed so that the U.S. Navy could incorporate information gained from the Battle of Jutland, fought in 1916, in this class's final design. Construction started only in 1920. As the Washington Naval Treaty both restricted the total allowable battleship tonnage allowed the U.S. Navy, and limited individual ship size to 35,000 tons, construction was halted 8 February 1922. While the unfinished hulls (most over 30% completed) were scrapped in 1923.
The design characteristics of the South Dakotas closely followed those of the Tennessee and Colorado classes. The increase in the number of main guns was a continuation of U.S. Navy practice from the beginning of the dreadnought era. Like the Tennessees and Colorados, they would have been fitted with standard bridges and lattice masts. Although Norman Friedman describes the South Dakotas as the ultimate development of the series of U.S. battleships that began with the Nevada class, they were also a departure in size, speed and intermediate armament from the "Standard Type" that characterized the Nevada through Colorado classes. The main restriction imposed on them by the Navy was the ability to pass through the Panama Canal. This was a policy to which capital ship designs were to strictly adhere due to the savings in time when ships needed to travel from the Pacific Ocean to the Atlantic or vice versa.
USS South Dakota-Class Battleship
USS South Dakota (BB-49)
Displacement:
Standard: 41,400 long tons (42,100 t)
Design: 43,200 long tons (43,900 t)
Full: 47,000 long tons (47,800 t)
Length:
684 ft (208 m) overall
660 ft (200 m) waterline
Beam:106 ft (32 m)
Draft:33 ft (10 m) (design)
Installed power:
12 × boilers, 60,000 hp (45,000 kW)
Propulsion:
4 × Westinghouse steam turbine electric drives (BB−49–BB−52)
4 × propeller shafts
Speed: 23 knots (43 km/h)
Range: 8,000 nautical miles (15,000 km; 9,200 mi) at 10 knots (19 km/h; 12 mph)
Complement:137 officers, 1404 enlisted, 75 marines
Armament:
12 × 16"/50 caliber Mark 2 guns (4×3)
16 × 6"/53 caliber Mark 13 guns
4 × 3"/50 caliber guns (dual purpose)
2 × 21 inch (533 mm) submerged torpedo tubes
Armor:
Belt: 8–13.5 in (203–343 mm)
Barbettes: 4.5–13.5 in (114–343 mm)
Turret face: 18 in (457 mm)
Turret sides: 9–10 in (229–254 mm)
Turret top: 5 in (127 mm)
Turret rear 9 in (229 mm)
Conning tower: 8–16 in (203–406 mm)
Decks: 3.5–6 in (89–152 mm)
Bulkheads: 8–13.5 in (203–343 mm)Uptakes: 9–13.5 in (229–343 mm)
Secondary armament: none
USS South Dakota (1920) as Designed
![[ img ]](https://i.imgur.com/id5JLk3.png)
