Montana-class battleship

A 1944 model of a Montana-class battleship
Class overview
Name:	Montana-class battleship
Builders:	New York Naval Shipyard Philadelphia Naval Shipyard Norfolk Naval Shipyard
Operators:	United States Navy
Preceded by:	Iowa class
Succeeded by:	N/A, last battleship class authorized
Planned:	5
Completed:	0
Cancelled:	5 Montana Ohio Maine New Hampshire Louisiana
General characteristics
Displacement:	65,000 long tons (66,040 t) (standard); 70,965 long tons (72,104 t) (full load)
Length:	921 ft 3 in (280.80 m) oa 890 ft 0 in (271.27 m) pp
Beam:	121 ft 2 in (36.93 m)
Draft:	36 ft 1 in (11.00 m)
Propulsion:	8 × Babcock & Wilcox 2-drum express type boilers powering 4 sets of Westinghouse geared steam turbines 4 × 43,000 hp (32 MW) – 172,000 shp (128 MW) total power
Speed:	28 kn (32 mph; 52 km/h) maximum
Range:	15,000 nmi (17,000 mi; 28,000 km) at 15 kn (17 mph; 28 km/h)
Complement:	Standard: 2,355 Flagship: 2,789
Armament:	12 × 16-inch (406 mm)/50 cal Mark 7 guns 20 × 5-inch (127 mm)/54 cal Mark 16 guns 10–40 × Bofors 40 mm anti-aircraft guns 56 × Oerlikon 20 mm anti-aircraft cannons
Armor:	Side belt: 16.1 inches (409 mm) tapering to 10.2 inches (259 mm) on 1-inch (25 mm) STS plate inclined 19° Lower side belt: 7.2 inches (183 mm) tapered to 1 inch (25 mm) inclined 10° Bulkheads: 18 inches (457 mm) forward, 15.25 inches (387 mm) aft Barbettes: 21.3 inches (541 mm), 18 inches (457 mm) (aft) Turrets: Face 22.5 inches (572 mm), Roof 9.15 inches (232 mm) Decks: main 0.75 inches (19 mm) + 1.5 inches (38 mm) second 5.8 inches (147 mm) + 1.25 inches (32 mm)
Aircraft carried:	3–4 × Vought OS2U Kingfisher/Curtiss SC Seahawk floatplanes
Aviation facilities:	2 × aft catapults for launch of seaplanes
Notes:	This was the last battleship class designed for the United States Navy; the class was cancelled before any of the ships' keels were laid.

The Montana-class battleships of the United States Navy were planned as successors to the Iowa class, being slower but larger, better armored, and having superior firepower. Five were approved for construction during World War II, but changes in wartime building priorities resulted in their cancellation in favor of the Essex-class aircraft carrier and Iowa class before any Montana-class keels were laid.

Intended armament would have been 12 16-inch (406 mm) Mark 7 guns in four 3-gun turrets, up from the Iowas' three 3-gun 16s. With an increased anti-aircraft capability and thicker armor belt, the Montana class would have been the largest, best-protected, and most heavily armed U.S. battleships ever, the only class to come close to rivaling the Empire of Japan's immense Yamato-class battleships.

Preliminary design work for the Montana class began before the US entry into World War II. The first two vessels were approved by Congress in 1939 following the passage of the Second Vinson Act. The Japanese attack on Pearl Harbor delayed construction of the Montana class. The success of carrier combat at the Battle of the Coral Sea and, to a greater extent, the Battle of Midway, diminished the value of the battleship. Consequently, the US Navy chose to cancel the Montana class in favor of more urgently needed aircraft carriers, amphibious and anti-submarine vessels.

Because the Iowas were fast enough to escort the new Essex-class aircraft carriers, their orders were retained, making them the last US Navy battleships to be commissioned.