South Carolina Class Battleship - Design

Design

In design and characteristics, South Carolina represented an evolution of the preceding Connecticut class, rather than a revolutionary "clean sheet" design such as HMS Dreadnought. This included a requirement that U.S. battleships have adequate coal storage for long operational ranges. While other navies built 18,000 ton ships, the 16,000 ton limitation imposed by Congress on earlier classes remained in force. (The disparity was actually much greater since American capital ships had to carry a greater amount of coal than their foreign contemporaries.) To meet this requirement, C&R removed one deck from a preferred design, limited the secondary armament to 3-inch (76 mm) guns and speed to 18.5 knots (34.3 km/h). They were also slower than foreign dreadnoughts.

The Congressional limitation on weight also forced C&R to adapt an all-centerline mounting of main armament. If the hexagonal arrangement of twelve 12-inch guns suggested by the NWC were adapted, this would mean a displacement of at least 21,100 tons, as the ship with such weaponry would have to be larger than the Connecticut class to accommodate this arrangement. If the number of guns were reduced to 10, displacement would be 18,300 tons. Moreover, the extra weight of the guns increased stress on the hull and the large holes cut into the decks for the barbettes for their turrets would affect hull strength adversely. C&R concluded that heavy wing turrets would be impractical and inadvisable for a 16,000-ton ship. Chief Constructor Washington L. Capps then came up with the idea of a superfiring centerline arrangement. In doing so, he broke ranks with many of his contemporaries, who believed a capital ship would be involved primarily in single-ship actions and be involved in a considerable amount of fire ahead and astern. Capps assumed the premise that an individual ship was merely part of a larger fleet, assumed that the primary objective of a battleship was to fire on the broadside. If that were the case, the wing turrets on the disengaged side of the ship would be wasted weight. If all guns were to fire on the broadsiede, they all had to be on the centerline. Superfiring then became essential to conserve weight and volume, especially on a ship of 16,000 tons. Capps was not sure about blast effects of end-on fire from superfiring guns, as this had not been tested adequately. However, this point was irrelevant if broadside fire, where there was no blast effect, was the goal. While it would seem the South Carolinas were weaker than Dreadnought from the number of main guns carried, their placement was more effective by allowing them to fire the same number of guns on the broadside as the British ship.

Because the superfiring arrangement used a great amount of space within each ship, Capps had to economize in other ways to stay within the tonnage limit. The officers' quarters were moved from their traditional place at the stern of the ship to amidships in the superstructure. The need to cut the ship down one deck created problems with volume. Machinery had to be built smaller than normal to fit in the space between the fore and aft magazines, both of which were larger than usual. Boiler rooms were moved inboard to make room for torpedo protection. The biggest drawback was in propulsion. There was no room for engines that could provide more power and even maintaining the same amount of power as previous battleships would be a challenge. Capps suggested cutting down the number of boilers by one-third to make room; it may have been at this point that he considered turbine propulsion, for which he would have needed the extra room. All the Bureau of Engineering could offer in response was more compact boiler rooms by eliminating centerline bulkheads. This was why the American ships fell behind Dreadnought in speed, with the South Carolinas' top speed at 18.5 knots compared to 22.4 knots for Dreadnought.

The South Carolinas were the first of 11 separate designs begun from 1906 to 1919, Some 29 battleships and 6 battle-cruisers would laid down during this period, though seven of the battleships and all six of the battle-cruisers would be cancelled. All except the Lexington class battlecruisers would be relatively slow speed designs and would range in weight from 16,000 to 42,000 tons. At this time no U.S. dreadnought class battleship had yet hit the water as all were either at some stage of building or in design. Virtually the entire U.S. Navy battle line was being designed by drawing on experience from pre-dreadnought designs or from observation of foreign battleship design.