New Mexico-class battleship

Mississippi, c. 1918
Class overview
Name	New Mexico-class battleship
Builders	New York Naval Shipyard Newport News Shipbuilding New York Shipbuilding Corporation
Operators	United States
Preceded by	Pennsylvania class
Succeeded by	Tennessee class
Built	1915–1919
In commission	1917–1956
Completed	3
Retired	3
General characteristics
Type	Dreadnought battleship
Displacement	Normal: 32,000 long tons (32,514 t) Full load: 33,000 long tons (33,530 t)
Length	624 ft (190 m)
Beam	97 ft 5 in (29.7 m)
Draft	30 ft (9.1 m)
Installed power	9 × Babcock & Wilcox boilers 32,000 shp (24,000 kW)
Propulsion	4 × steam turbines 4 × screw propellers
Speed	21 kn (24 mph; 39 km/h)
Complement	1,081 officers and men
Armament	12 × 14 in (356 mm)/50 cal guns 14 × 5 in (127 mm)/51 cal guns 8 × 3 in (76 mm)/50 cal guns 2 × 21 in (533 mm) torpedo tubes
Armor	Belt: 8–13.5 in (203–343 mm) Turret face: 18 in (457 mm) Conning tower: 11.5 in (292 mm) Decks: 3.5 in (89 mm)

The New Mexico class was a class of three super-dreadnought battleships built for the United States Navy in the late 1910s. The class comprised three ships: New Mexico, the lead ship, Mississippi, and Idaho. Part of the standard series, they were in most respects copies of the Pennsylvania-class battleships that immediately preceded them, carrying over the same main battery arrangement of twelve 14-inch (356 mm) guns, but now increased to 50-caliber. They incorporated several other improvements, including a better arrangement of the secondary battery that increased its usability, a clipper bow that improved seakeeping, and an experimental turbo-electric propulsion system adopted on New Mexico. Like the other standard-type battleships, they had a top speed of 21 knots (39 km/h; 24 mph) that allowed the fleet to operate as a tactically homogeneous unit.

All three ships spent the bulk of their peacetime careers in the Pacific Fleet; throughout the 1920s and 1930s, they were involved in numerous Fleet Problems, which were large-scale training exercises that helped develop the doctrine later employed during the Pacific War. By 1941, the three ships were moved to the East Coast to join the Neutrality Patrols that protected American merchant ships from German U-boat attacks during the Battle of the Atlantic. Following the Japanese attack on Pearl Harbor in December, they were quickly transferred back to the Pacific, though they spent most of 1942 escorting convoys off the west coast of the United States. Beginning in mid-1943, they supported amphibious operations during the Aleutian Islands, Gilbert and Marshall Islands, and the Mariana and Palau Islands Campaigns. The Philippines Campaign followed in late 1944, though Mississippi was the only member of the class to participate in the early stages of the campaign, the other vessels being under refit at the time. There, she was present for the Battle of Surigao Strait on 24 October, the last battleship engagement in history.

Mississippi and New Mexico took part in the Invasion of Lingayen Gulf, part of the Philippines Campaign, in early 1945 and both were hit by kamikazes. As they were both under repair, only Idaho participated in the Battle of Iwo Jima, but all three ships were part of the bombardment force for the Battle of Okinawa, where all were damaged by kamikazes. They were present for the occupation of Japan in August and September, thereafter returning to the United States. New Mexico and Idaho were quickly decommissioned and sold for scrap, but Mississippi remained in service, having been converted into a gunnery testing and training ship. In this capacity, her crew experimented with anti-aircraft missiles in the mid-1950s before the ship was sold to ship breakers in 1956.