Montana-class battleship
The Montana class battleships of the United States Navy were proposed successors to the Iowa class, being slower, but larger, better armored, and carrying more guns. Five ships of the Montana class were approved for construction during World War II. However, changes in priority during the war resulted in cancellation of the design in favour of aircraft carriers before the first keel was laid.
History
In 1939, only three Iowa battleships were planned: BB-61, BB-62, and BB-63. BB-64, BB-65, and BB-66 were intended to be larger, slower ships mounting twelve 16-inch guns, which would soon be known as the Montana class. In late 1939, as the Navy decided that it needed more 33-knot (61 km/h) fast battleships, BB-64, BB-65, and BB-66 were laid down as Iowas as well, pushing the Montana to BB-67.
The Navy authorized five battleships of the Montana class under the 1940 "Two Ocean Navy" building program; funding for the new ships was approved in 1941. These ships, the last battleships to be ordered by the Navy, were to be designated BB-67 through BB-71.
The five ships were to be constructed at three navy yards:
- Montana (BB-67), to be built at the Philadelphia Navy Yard, Pennsylvania;
- Ohio (BB-68), to be built at the Philadelphia Navy Yard;
- Maine (BB-69), to be built at the New York Navy Yard, Brooklyn, New York;
- New Hampshire (BB-70), to be built at the New York Navy Yard; and
- Louisiana (BB-71), to be built at the Norfolk Navy Yard, Portsmouth, Virginia.
Completion of the Montana class, as well as the last two Iowa ships, would have given the late 1940s Navy a total of 17 new battleships, a considerable advantage over any other nation, or probable combination of nations. The Montanas also would have been the only American ships to come close to equaling Japan's massive Yamato in terms of sheer size and raw firepower. The US was the only nation to have the resources to build such behemoths, while other comparable designs like the H-class of Plan Z and Super Yamatos had little realistic chance of coming to fruition, given their countries' strained resources.
However, World War II's urgent requirements for more aircraft carriers, amphibious and anti-submarine vessels resulted in suspension of the Montanas in May 1942, before any of their keels had been laid. In July 1943, when it was clear that the battleship was no longer the dominant element of sea power, their construction was canceled, along with the final two members of the preceding Iowa class. Thus, the four battleships of the Iowa class were the final battleships actually built by the United States.
Interestingly, the cancellation of this battleship class meant that Montana became the only one of the lower 48 states never to have a large capital ship of any kind actually commissioned in its name.
Design
With an intended standard displacement of 60,500 tons, the proposed Montana class ships were nearly a third larger than the preceding Iowa class, and would have been the largest warships in the American fleet until the postwar Forrestal-class aircraft carriers, the first of the "supercarriers."
The Montanas were intended to carry twelve 16-inch (406 mm) Mark VII caliber guns, three more than their Iowa class sisters. Had Montana been completed, she would be one of the most powerful battleships to ever set sail. Only the Japanese Yamato class would have had stronger armor and heavier shells, though Montana had superior fire control and would have overtaken the Yamato as the battleship having heaviest broadside overall, at 32,400 pounds vs. 28,800 for Yamato.
Protection against underwater weapons and shellfire was also greatly enhanced; they would have been the only new World War II-era U.S. battleships to be adequately armored against guns of the same power as their own. The armor scheme of the preceding North Carolina class was only proof against 14-inch (356 mm) shells, while the South Dakota, and Iowa classes were designed only to resist their original complement of Mark V 2,240 lb (1,020 kg) shells, not the new "super-heavy" 2,700 lb (1,220 kg) APC (Armor Piercing, Capped) Mark VIII shells they actually used. The Montanas were the only US battleships designed to resist the Mark VIII.
To achieve these advances, the Montana class returned to the 28-knot (52 km/h) maximum speed of the North Carolina and South Dakota classes, rather than the 33 knots (61 km/h) of the very fast Iowas. Because of the lowered speed, they probably would have seen the same fate as the North Carolina and South Dakota class ships post-war: laid up for many years, then finally scrapped or handed over as museums.
The new ships, being significantly larger than the Iowa class, would have been too wide to pass through the existing Panama Canal locks. However, at the time the Montana class was authorized, work was already under way to construct a third, larger, set of locks on the canal; these new locks would have comfortably accommodated the Montanas, thus maintaining the U.S. Navy's ability to rapidly deploy its ships between the Atlantic and Pacific Oceans. The canal expansion was canceled at the end of the war, after the cancellation of the Montana class.
While the Montana class was never completed, her hull design served as a model for the aircraft carrier Midway.