Wyoming-class battleship

The Wyoming-class battleship was the fourth series of two dreadnought battleships built for the United States Navy. The class comprised two ships: USS Wyoming (BB-32) and USS Arkansas (BB-33). At the time of the design of this pair of dreadnoughts, not a single one of the previous designs had yet gone to sea. While somewhat larger than their predecessors they retained all the features that were common to American battleships to date, with centerline turrets, low freeboard, long service ranges, and very thick side armor. They were also the last U.S. capital ships armed with 12 inch (305 mm) guns; the battlecruisers which would follow in World War II were classified by the navy as "large cruisers", despite having 12" guns.

The two ships served during both World War I and World War II. In the First World War, both ships were assigned to the 6th Battle Squadron of the British Grand Fleet, and saw limited action in the North Sea from 1917 to 1918. Wyoming and Arkansas were both rebuilt in the mid-1920s, as was the case for all of the American battleships of the era. Due to the Washington Naval Treaty, Wyoming was reduced to a training ship after 1931, while Arkansas saw convoy escort duty during World War II. She also conducted shore bombardment in support of the invasion of Normandy, as well as in Southern France during Operation Dragoon, both of which were conducted in mid-1944. She was then transferred to the Pacific theater, where she bombarded Iwo Jima and Okinawa during the amphibious invasions of those islands. Both ships were struck from the Navy list after the end of the war; Wyoming was scrapped in 1947, while Arkansas was expended as a target during the Operation Crossroads nuclear weapon tests in 1946.

Design
The requirements for this class arose from the very general requirements of the 1908 Newport Conference. This design marked the end of the Board on Construction and the rise of the General Board in U.S. ship design. The class marked a significant growth over its predecessor—the —of some 20% in size.

The Wyoming class was the fourth class of 11 separate designs begun from 1906 to 1919; some 29 battleships and 6 battlecruisers would be laid down during this period, though seven of the battleships and all six of the battlecruisers would be cancelled due to the Washington Naval Treaty in the early 1920s. All except the would be 21 kn 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.

The Newport Conference established a general consensus among leaders that U.S. Navy ships should carry larger batteries in response to the increasing caliber of battleships in other countries, notably the BL 13.5 inch Mk V naval gun which had been introduced by the Royal Navy's Orion-class battleship. There was debate at the time as to whether the Florida-class battleships, laid down in 1909, should carry heavier armament than the 12 inch (305 mm) Mark 5 gun. On 26 August 1908, Secretary of the Navy Victor H. Metcalf authorized drawings for ships with eight or ten 14 inch (356 mm) guns and heavy armor, with the first ships anticipated for delivery in June 1911. President Theodore Roosevelt took personal interest in the design, favoring an eight-gun ship with a displacement of 24,000 t over a 10-gun ship with a displacement of 27,000 t. Ultimately, on 30 March 1909, U.S. Congress approved the construction of two "Design 601" battleships with six twin 12 inch (305 mm) turrets, which the General Board had selected over two 14 inch (356 mm) designs in 1909.

Main guns
The Wyomings were armed with twelve 12"/50 caliber Mark 7 guns (305 mm) in six twin turrets, all on the centerline and with the superfiring pattern repeated with the midship pair of turrets. The Mark 7 probably had a longer continuous active service life in the U.S. Navy than any other large caliber weapon; it would first go to sea aboard USS Wyoming in 1912 and remain in service until USS Arkansas was sunk during the Bikini tests in 1946.  This weapon was only slightly more powerful than the preceding 12"/45 Mark 5 (305 mm) gun. It fired an 870 lb armor piercing (AP) shell at a muzzle velocity of 2,900 ft/s and a rate of between two and three rounds per minute to a range of 24000 yd at a maximum elevation of 14.7 degrees.

As in the Delaware and Florida classes, the midships turrets in both this and the following s proved problematic; the turrets and magazines were both located near the boiler spaces with high pressure steam piping surrounding the magazines. This produced a marked temperature difference in the powder charges and contributed to excessive dispersions in the pattern of shell fall from the two classes. Attempts to cool the 12" midship magazines were only moderately successful. The General Board estimated that battle ranges for the main armament would be 8,000 to 8500 yd.

Secondary armament
Twenty-one 5 in /51 cal (127 mm) guns were fitted initially on Arkansas and Wyoming. Sixteen of these were mounted in individual casemates below the main deck. This limited their use as they became so wet at speed as to keep one-third of them useless. The others were mounted in open positions on the superstructure. These guns fired a 50 lb (22.7 kg) armor-piercing (AP) shell at a muzzle velocity of 3,150 ft/s (960 m/s) and a rate of 8 to 9 rounds per minute. The guns could depress to −10 degrees and elevate to 15 degrees. The guns were manually operated, and had a range of train of about 150 degrees. The ships were also initially fitted with two 21 inch (533 mm) torpedo tubes for the Bliss-Leavitt Mark 3 torpedo.

Armor suite
Fire control limitations also explain the lack of deck armor that continued onward in this design. The armor suite also displayed other signs of transition with a heavy belt, and mid-grade 6.5" casement armor for the secondary battery and internal partitions to limit damage. The entire horizontal armor scheme was designed to stop shells at very shallow angles of attack; the anticipated range of engagement meant that incoming fire would be at a relatively flat trajectory, and the danger of high-arcing plunging fire was considered minimal, given the poor performance of contemporary fire-control systems at extreme ranges. The idea being to cause the armor-piercing shells to burst on the thin deck armor and have the splinters of the shell caught on the even thinner 1" STS steel plate deck below the decapping armor above. This was a rational thought in the light of the known technology of the time. Unfortunately, better fire control systems could and would be installed with relative ease, while refitting armor on existing battleships would be very hard. The idea of plunging fire would not be addressed until the all or nothing scheme of the s two classes after the Wyoming class. The main armor belt remained at 11" tapering to 9" enough to protect against 12" naval guns of the period.

Engine design
Wyoming was the final battleship class in the United States to employ direct drive steam turbines without cruising turbines for power. In subsequent designs, geared cruising turbines (supplementing direct drive turbines), geared steam turbines, triple-expansion steam engines, and turbo-electric drive were all found to give better range for fuel expended.

Upgrades
In 1919, a refit reduced the secondary armament to 16 5 inch/51 caliber (127 mm) guns and added two 3 inch/50 caliber (76 mm) anti-aircraft (AA) guns. The 5 inch guns were reduced as the mounts near the ends of the ship were difficult to work in any kind of sea.

Modernization began in 1925, finishing in 1927. This included anti-torpedo blisters giving them broader beams and greater displacement, and also thicker deck armor. Four White-Forster oil-fired boilers replaced the 12 previous Babcock and Wilcox coal-fired boilers with no loss of power, resulting in only a single smoke stack. The masts were reduced to a single cage mast. Both ships were outfitted with newer gunfire controls. Some of the 5" secondary battery was moved to the superstructure. The 3" AA battery was increased to eight guns and the torpedo tubes were removed. An aircraft catapult and facilities for three floatplanes (typically the Curtiss SOC Seagull from 1935) were added.

Arkansas was primarily used for training cruises until World War II, during which she received a second modernization in 1942. The 5" secondary battery was reduced to six guns and the 3" AA battery was increased to 10 guns. The attack on Pearl Harbor had shown the need for significant light AA armament on all ships, so 36 40 mm Bofors guns in quadruple mounts were added, along with 26 20 mm Oerlikon guns in single mounts.

Due to the Washington Naval Treaty, Wyoming was partially disarmed in 1932 and used as a gunnery training ship for the rest of her career. During World War II, all her 12" guns were removed and additional 5" (127 mm) dual purpose guns (in several different mountings) and other guns were added, the ship becoming an urgently needed anti-aircraft training platform.

History
Despite the class name, Arkansas preceded Wyoming both in construction and commissioning, although both were commissioned during September 1912. As the class was fitted with coal-fired boilers, both Wyoming and Arkansas were able to operate with the British Grand Fleet in the then-oil-deprived North Sea during World War I. Before the war, they served in the Atlantic Fleet and afterwards in both the Atlantic and Pacific, with modernization following in 1925-27. Both ships served in both world wars, and like many older American ships were quickly retired at the end of the second. Wyoming marked the end of the class' nearly 35 years of service when decommissioned 1 August 1947 for scrapping. Arkansas had already been sunk during nuclear testing in the Pacific.

USS Wyoming

 * Designation: Battleship No. 32, BB-32, AG-17
 * Builder: William Cramp and Sons in Philadelphia
 * Laid down: 9 February 1910
 * Launched: 25 May 1911
 * Commissioned: 25 September 1912
 * Operations: World War I convoy escort in the North Sea, interwar and World War II gunnery trainer
 * Victories:
 * Fate: Decommissioned 1 August 1947 and scrapped



USS Arkansas

 * Designation: Battleship No. 33, BB-33
 * Builder: New York Shipbuilding Corporation in Camden, New Jersey
 * Laid down: 25 January 1910
 * Launched: 14 January 1911
 * Commissioned: 17 September 1912
 * Operations: Tampico Affair, Allied invasion of French north-west Africa, Normandy landings, invasion of southern France, Iwo Jima, Okinawa, Operation Magic Carpet
 * Victories:
 * Fate: Decommissioned 29 July 1946 and sunk at Bikini Atoll in nuclear tests