The Nevada class comprised two dreadnought battleships— and —built for the United States Navy in the 1910s. They were significant developments in battleship design, being the first in the world to adopt "all or nothing" armor, a major step forward in armor protection because it emphasized protection optimized for long-range engagements before the Battle of Jutland demonstrated the need for such a layout. They also introduced three-gun turrets and oil-fired water-tube boilers to the US fleet. The two Nevadas were the progenitors of the standard-type battleship, a group that included the next four classes of broadly similar battleships that were intended to be tactically homogeneous.
Nevada and Oklahoma deployed to Ireland in 1918 to escort convoys during World War I but saw no action. After the war, they were transferred to the Pacific Fleet, where they spent most of the 1920s and 1930s. During this period, they conducted extensive training operations and made several long-distance cruises, including to Australia and New Zealand in 1925 and Oklahomas voyage to Europe in 1936. Both vessels were extensively modernized between 1927 and 1930, having their armament improved, protection scheme strengthened, and new boilers installed. They were moored in Battleship Row in Pearl Harbor when the Japanese attacked on 7 December 1941; Oklahoma was sunk in the attack while Nevada was able to get underway before being forced to ground herself to avoid sinking in deeper water.
Only Nevada was salvageable, and she was repaired and modernized by mid-1943 when she joined the Aleutian Islands campaign. She then supported the Normandy landings in June 1944 and Operation Dragoon in August before returning to the Pacific in time for the Battle of Iwo Jima in February 1945, followed by the Battle of Okinawa from March to June. Worn out by the end of the war, she was allocated to Operation Crossroads in late 1945 for use in the nuclear weapons tests in mid-1946. She survived both of the Crossroads blasts and was ultimately sunk with conventional weapons off Hawaii in 1948. Oklahoma, meanwhile, was raised over the course of 1943, partially dismantled in 1944, and sold to ship breakers in 1946. While under tow to San Francisco in May 1947, she became separated from the vessel towing her and foundered.
Development
The design of the Nevada class took place in the context of strong political opposition to the continual growth (and thus increases in cost) of battleship building that had accelerated with the development of the dreadnought type. In the early 1900s, the Navy had settled on a program of two new battleships per year, a plan approved by President Theodore Roosevelt, but beginning in 1904, Congress began to reject the Navy's requests, frequently authorizing only one ship per year, and at times, no new vessels. William Howard Taft, Roosevelt's successor, attempted to pressure Congress to build more ships, but had little success, though he did secure a pair of ships for Fiscal Year 1912, which would become the Nevada class. Woodrow Wilson, who was elected in 1912, opposed what he saw as excessive naval spending and his Secretary of the Navy, Josephus Daniels, blocked proposals from the General Board for larger, more powerful ships as part of an effort to return to two vessels per year. The resulting stabilization of designs produced the standard-type battleship, of which the two Nevadas were the first.
Initial design
The General Board was not satisfied with the adoption of 5 and 6 twin-gun turrets in earlier dreadnoughts and so requested the next ship be equipped with three-gun turrets. Three-gun turrets would provide a main battery of twelve guns, two more than the preceding , but with four turrets instead of five. Design work on the ships that would be authorized for FY1912 had begun in 1910, with the first sketch prepared by the Bureau of Construction and Repair (C&R) in May that was based on the preceding New Yorks. The aft superfiring No. 4 turret was removed, the amidships No. 3 turret was moved up to superfire over what had been No. 5 turret in an arrangement similar to contemporary British battlecruisers. It was a complicated arrangement that required an ammunition magazine to separate the engine and boiler rooms; the naval historian Norman Friedman suggests it may have been adopted to reduce the concentration of weight aft, which would have put greater stress on the hull and thus required significant strengthening of the hull structure. The ship would also carry four torpedo tubes and a secondary battery of seventeen guns, while belt armor was to be thick.
By this time, the Navy had come to the conclusion that naval engagements would be fought at very long range, and primarily with armor-piercing shells (AP) instead of high-explosive shells, since the latter would be defeated by even medium armor, and at long range, there was no ability to aim specifically at unarmored portions of ships. And because AP shells would easily perforate medium armor plate, only the thickest possible protection should be carried. Another important development that resulted from the assumption of long battle ranges was the adoption of thick deck armor. This was necessitated by the trajectory of the projectiles; as range increased significantly, the angle of impact increased, and thus shells would tend to strike the horizontal deck, not the heavily armored sides, an effect known as plunging fire. The result was the "all or nothing" principle of armor protection, which reserved armor protection only for the ship's vitals, including magazines, propulsion machinery spaces, and command spaces. The arrangement was made watertight to create an armored raft that contained enough reserve buoyancy to keep the ship afloat even if the unarmored ends were completely flooded. The Nevada design was the first of any navy to introduce the concept.
In June, the Board sent a set of requirements to C&R that incorporated the twelve-gun battery already projected, a minimum speed of , and an armor layout based on the "all or nothing" concept. The engineers at C&R noted that the armor deck would considerably strengthen the hull, but pointed out that the 11-inch belt of the original design would be wholly insufficient to defeat the latest main guns in foreign navies. The Board suggested the addition of a splinter bulkhead behind the belt, which would contain shell fragments. In late 1910, before a final design was accepted, the Navy had to submit estimates for FY1912 to be voted on by Congress in 1911; they used figures based on the New Yorks, which were accepted by Congress, and in turn limited the size of the new ships to a displacement of around ; this was too low for C&R's existing proposals, necessitating a redesign. By this time, the first generation of American dreadnoughts had begun to enter service, so experiences operating them could be incorporated into the redesign.
Redesign and approval
The first major change was the arrangement of the aft pair of turrets. The amidships magazine of the battleship had difficulty remaining cool, as it was adjacent to the boiler room and the steam lines for the propulsion system ran alongside it. Since the thicker deck increased hull strength, the initial arrangement proposed for Nevada could be abandoned in favor of a closely spaced superfiring pair. This shortened the length of hull that required armor protection, and thus reduced displacement. Experience with Delawares propulsion system—which mixed coal and oil fired boilers—provided the next improvement: boilers that were exclusively oil fired. These would confer a number of advantages, including the ability to refuel at sea, a significant reduction in boiler room crews, greater fuel efficiency, and more compact boiler rooms, among others. Again, the smaller boiler rooms shortened the length of armor necessary to protect the vitals. C&R was not convinced, since coal bunkers had been used to reinforce the side armor, but the Board approved the change in November 1910. Even by that time, the engineers at C&R continued to lobby for their original design based on the New York class, but the Board refused to entertain the proposal. Next, the Board decided to return to steam turbines rather than triple-expansion engines, as they believed the greater efficiency of fuel oil would allow the notoriously voracious turbines to achieve the long cruising radius necessary for operations in the Pacific Ocean.
C&R submitted its next proposal on 13 February 1911; it generally aligned with the Board's ideas for the armor layout, but it retained some medium armor to protect the secondary guns and it incorporated triple-expansion machinery (though they noted that the engine rooms could accommodate Curtis turbines). The Board rejected it, leading the designers to remove the medium armor, producing a series of studies with speeds of , , and 21 knots and main batteries that ranged from eight to twelve guns. During this period, on 4 March, Congress authorized a pair of ships, designated BB-36 and BB-37 for FY1912. With the ships now authorized, the Board selected one of the ten-gun, 20.5-knot variations on 30 March, which had a belt that was increased to 14 in but included a series of tapers at the top and bottom edge to save weight. The Bureau of Ordnance pointed out that the belt could not be manufactured in a single strake with the tapers, so a joint between upper and lower strakes—a design weakness the engineers had been attempting to avoid—would have to be used. The problem was resolved in July, when C&R proposed removing the 1.5-inch splinter bulkhead in favor of increasing the belt to and incorporating only one taper at the lower edge.
The next issue to address was the triple turret that was the linchpin of the design, since the weight savings made the heavier belt possible and it corrected design defects present in the earlier 5- and 6-turret classes. The US Navy had never built a three-gun turret, and there were concerns that a single hit could disable all three guns, and that three holes in the turret face would weaken the armor too much. C&R suggested conducting firing trials with the old battleship , but nothing came of the proposal. Daniels approved the finalized Nevada design on 31 March, without a completed turret design, which was a significant gamble because the turret design might not have been successful. An experimental turret was completed in August 1912, proving the concept, though it required some modifications to reduce shell interference. Since the finalized design adopted a ten-gun battery, only two of the four turrets would be triple mounts, one forward and one aft, with twin-gun turrets superfiring over them.
With the design nearly finalized, the Board began to circulate it with fleet officers for comment; Captain John Hood, who was soon to become a member of the Board, criticized the placement of the secondary battery, as experience with the early dreadnoughts had shown casemate batteries to be completely unusable in all but the calmest seas. The Board pointed out that the increasing range of torpedoes meant that the standard 5-inch /51 caliber guns could not effectively engage destroyers before they launched their weapons, so retaining the weapons at all might not be worthwhile. But there were no suitable alternative, so the Board decided to keep the 5-inch guns as they were. This proved to be the correct decision, as the development of fire-control systems improved the guns' ability to hit at longer ranges.
Design General characteristics and machinery