History of the USS Montana BB-67
The Montana-class battleships were planned as successors of the Iowa class for the United States Navy, to be slower but larger, better armored, and with superior firepower. Five were approved for construction during World War II, but changes in wartime building priorities resulted in their cancellation in favor of continuing production of Essex-class aircraft carriers and Iowa-class battleships before any Montana-class keels were laid.
Their intended armament would have been twelve 16-inch (406 mm) Mark 7 guns in four 3-gun turrets, up from the nine Mark 7 guns in three turrets used by the Iowa class. Unlike the three preceding classes of battleships, the Montana class was designed without any restrictions from treaty limitations. With an increased anti-aircraft capability and substantially thicker armor in all areas, the Montanas would have been the largest, best-protected, and most heavily armed US battleships ever. They also would have been the only class to rival the Empire of Japan's Yamato-class battleships in terms of displacement.
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 the 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 perceived value of the battleship. Consequently, the US Navy chose to cancel the Montana class in favor of more urgently needed aircraft carriers as well as amphibious and anti-submarine vessels.
Because the Iowas were far enough along in construction and urgently needed to operate alongside the new Essex-class aircraft carriers, their orders were retained, making them the last US Navy battleships to be commissioned.
Montana was planned to be the lead ship of the class. She was to be the third ship named in honor of the 41st state, and she was assigned to the Philadelphia Navy Yard. Both the earlier battleship, BB-51, and BB-67 were cancelled, so Montana is the only one of the (48 at the time) US states never to have had a battleship with a "BB" hull classification completed in its honor.
The Hope and Fate of Montana
As the political situation in Europe and Asia deteriorated in the prelude to World War II, Carl Vinson, the chairman of the House Committee on Naval Affairs, instituted the Vinson Naval Plan. It aimed to get the Navy into fighting shape after the cutbacks imposed by the Great Depression and the two London Naval Treaties of the 1930s. As part of the overall plan, Congress passed the Second Vinson Act in 1938, which was promptly signed by President Franklin D. Roosevelt and cleared the way for construction of the four South Dakota-class fast battleships and the first two Iowa-class fast battleships (hull numbers BB-61 and BB-62). Four additional battleships (with hull numbers BB-63, BB-64, BB-65, and BB-66) were approved for construction on 12 July 1940, with the last two intended to be the first ships of the Montana class.
The Navy had been considering large battleship design schemes since 1938 to counter the threat posed by potential battleships of the Imperial Japanese Navy, which had refused to sign the Second London Naval Treaty and furthermore refused to provide details about its Yamato-class battleships. Although the Navy knew little about the Yamato class, some rumors regarding the new Japanese battleships placed their main gun battery caliber at 18 inches (457 mm). The potential of naval treaty violations by the new Japanese battleships resulted in the remaining treaty powers, Britain, France, and the United States, invoking the tonnage "Escalator Clause" of the Second London Naval Treaty in June 1938, which raised the maximum standard displacement limit from 35,000 long tons (36,000 t) to 45,000 long tons (46,000 t).
The increased displacement limit allowed the Navy to begin evaluating 45,000-ton battleship designs, including "slow" 27-knot (50 km/h; 31 mph) schemes that increased firepower and protection over previous designs and also "fast" 33-knot (61 km/h; 38 mph) schemes. The "fast" design evolved into the Iowa class while the "slow" design, with main armament battery eventually settled on twelve 16-inch (406 mm) guns and evolution into a 60,500-ton design, was assigned the name Montana and cleared for construction by the United States Congress under the Two-Ocean Navy Act on 19 July 1940; funding for the new ships was approved in 1941. The five ships, the last battleships to be ordered by the Navy, were originally to be designated BB-65 through BB-69; however, BB-65 and BB-66 were subsequently re-ordered as Iowa-class ships, Illinois and Kentucky, in the Two Ocean Navy Act due to the urgent need for more warships, and the Montanas were redesignated BB-67 through BB-71.
Completion of the Montana class, and the last two Iowa-class battleships, was intended to give the US Navy a considerable advantage over any other nation, or probable combination of nations, with a total of 17 new battleships by the late 1940s. The Montanas also would have been the only American ships to rival Japan's massive Yamato and her sister Musashi in size and raw firepower
Realisation of a change in warfare
The Navy ordered the ships in May 1942, but the Montana class was placed on hold because the Iowa-class battleships and the Essex-class aircraft carriers were under construction in the shipyards intended to build the Montanas. Both the Iowa and Essex classes had been given higher priorities: the Iowas as they were far along enough in construction and urgently needed to operate alongside the Essex-class carriers and defend them with 5-inch, 40 mm, and 20 mm AA guns, and the Essexes because of their ability to launch aircraft to gain and maintain air supremacy over the islands in the Pacific and intercept warships of the Imperial Japanese Navy. The entire Montana class was suspended in June 1942 following the Battle of Midway, before any of their keels had been laid. In July 1943, the construction of the Montana class was finally cancelled after the Navy fully accepted the shift in naval warfare from surface engagements to air supremacy and from battleships to aircraft carriers. Work on the new locks for the Panama Canal also ceased in 1941, owing to a shortage of steel due to the changing strategic and material priorities.