163-686: 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
326-557: A broadside of all nine. The fire control was performed by the Mark 38 Gun Fire Control System (GFCS); the firing solutions were computed with the Mark 8 rangekeeper, an analog computer that automatically receives information from the director and Mark 8/13 fire control radar, stable vertical, ship pitometer log and gyrocompass, and anemometer. The GFCS uses remote power control ( RPC ) for automatic gun laying . The large-caliber guns were designed to fire two different conventional 16-inch shells:
489-459: A metacentric height of 8.2 feet (2.5 m). Their projected crew was to have amounted to 115 officers and 2,240 enlisted men; this grew to 189 officers and 2,789 enlisted men while serving as a flagship . The Montana design shares many characteristics with the previous classes of American fast battleships starting from the North Carolina class, such as a bulbous bow ,
652-481: A standard displacement of 60,500 long tons (61,500 t), with a designed trials displacement of 68,317 long tons (69,413 t). Full load displacement increased to 70,965 long tons (72,104 t), and emergency load grew further to 71,922 long tons (73,076 t). At their standard displacement, the ships would have had a draft of 35 ft (11 m), while at emergency load, the draft increased to 36 ft 10 in (11.23 m). The ships would have had
815-502: A triple bottom under the armored citadel , and twin skegs in which the inner shafts were housed. The Montana s ' overall construction would have made extensive use of welding for joining structural plates and homogeneous armor, which saved weight compared to traditional riveting . Like all of the US interwar designs, the Montana s would have had a flush main deck that was steeply flared at
978-502: A 1935 empirical formula for predicting a ship's maximum speed based on scale-model studies in flumes of various hull forms and propellers and a newly developed empirical theorem that related waterline length to maximum beam, the Navy drafted plans for a battleship class with a maximum beam of 108 ft 2 in (32.97 m) which, when multiplied by 7.96, produced a waterline length of 860 ft (262 m). The Navy also called for
1141-422: A 2,700 lb (1,200 kg) armor-piercing shells and 1,900 lb (860 kg) high capacity (HC) shells that carried a larger high-explosive bursting charge. The shells had muzzle velocities of 2,500 ft/s (760 m/s) and 2,690 ft/s (820 m/s), respectively. Firing AP shells at the maximum elevation of 45 degrees, the guns could reach targets out to 42,345 yd (38,720 m), while
1304-424: A bore length of 190 inches (4,800 mm), and a rifling length of 157.2 inches (3,990 mm). The gun could fire shells at about 2,500–2,600 ft/s (760–790 m/s); about 4,600 could be fired before the barrel needed to be replaced. Minimum and maximum elevations were −15 and 85 degrees, respectively. The guns' elevation could be raised or lowered at about 15 degrees per second. The mounts closest to
1467-522: A design in mid-January 1940 that largely met the General Board's requirements, but displacement was set at 51,500 long tons (52,300 t). An option to replace the standard 5-inch/38 secondaries with longer-barrel 5-inch/54 guns would add about 2,000 long tons (2,032 t) to the ships. During a meeting on 16 February 1940, the Board requested a new series of proposals. These included a modified version of
1630-408: A design labeled "BB 65A", which used South Dakota as a baseline, but increased the length to accommodate the fourth main battery turret. Displacement was already over the limit at 45,435 long tons (46,164 t), and the ship was only protected against the earlier 2,250 lb (1,020 kg) AP shell. The design staff estimated that more than 2,000 long tons (2,032 t) would be needed to protect
1793-399: A displacement greater than that of most battleships, its armor would have protected it only against the 8-inch (200 mm) weapons carried by heavy cruisers . Three improved plans – "A", "B", and "C" – were designed at the end of January. An increase in draft , vast additions to the armor, and the substitution of twelve 6-inch (152 mm) guns in the secondary battery were common among
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#17328590716751956-402: A high-tensile structural steel with armor properties comparable to Class B, was extensively used in the hull plating to increase protection. The citadel consisting of the magazines and engine rooms was protected by an STS outer hull plating 1.5 inches (38 mm) thick and a Class A armor belt 12.1 inches (307 mm) thick mounted on 0.875-inch (22.2 mm) STS backing plate; the armor belt
2119-447: A maximum range of 25,909 yd (23,691 m) against surface targets and a maximum ceiling of 51,600 ft (15,700 m) against aerial targets. The guns had a rate of fire of fifteen shots per minute. Each ship would have carried a light anti-aircraft armament of thirty-two 40 mm (1.6 in) Bofors guns and twenty 20 mm (0.79 in) Oerlikon guns . The Bofors guns were to be carried in eight quadruple mounts, while
2282-610: A maximum superheater outlet temperature of 850 °F (454 °C). The double-expansion engines consist of a high-pressure (HP) turbine and a low-pressure (LP) turbine. The steam is first passed through the HP turbine which turns at up to 2,100 rpm. The steam, largely depleted at this point, is then passed through a large conduit to the LP turbine. By the time it reaches the LP turbine, it has no more than 50 psi (340 kPa) of pressure left. The LP turbine increases efficiency and power by extracting
2445-488: A muzzle velocity of 2,740 to 2,770 ft/s (840 to 840 m/s). As designed, the Montana s used the "all or nothing" armor philosophy, with most of the armor concentrated on the citadel that includes the machinery spaces, armament, magazines, and command and control facilities. The belt armor would be 16.1 in (409 mm) Class A face-hardened Krupp cemented (K.C.) armor mounted on 1 in (25 mm) Special Treatment Steel (STS), inclined at 19 degrees. Below
2608-454: A nominal range of 15,000 nmi (27,800 km; 17,300 mi) at 15 kn (28 km/h; 17 mph). Two semi-balanced rudders were placed behind the two inboard screws. The inboard shafts were housed in skegs, which, while increasing hydrodynamic drag, substantially strengthened the stern structure. While less powerful than the 212,000 hp (158,000 kW) powerplant used by the Iowa s,
2771-570: A quadruple turret aft. The outbreak of World War II in September 1939 radically altered the constraints imposed on C&R. The remaining limits imposed by the Washington and London treaties were now removed entirely; the new ship would only be limited by logistical restrictions of existing naval infrastructure, most significantly the Panama Canal and available dry docks . The Navy had been pushing for
2934-411: A reasonable degree of success. However, this did not mean that it possessed inferior anti-air abilities. As proven during 1941 gunnery tests conducted aboard North Carolina the gun could consistently shoot down aircraft flying at 12,000–13,000 feet (2.3–2.5 mi; 3.7–4.0 km), twice the effective range of the earlier single-purpose 5-inch/25 caliber AA gun. As Japanese airplanes became faster,
3097-426: A reversion to the 27-knot standard-type battleship would occur with the next design. The primary consideration for this new class was the development of the super-heavy 2,700-pound (1,200 kg) armor-piercing shell that had been developed during the construction of the North Carolina class. Standard design practice stated that battleships should be immune to guns of their own calibers at expected battle ranges, but
3260-521: A shortage of steel due to the changing strategic and material priorities. The final contract design was issued in June 1942. Construction was authorized by the United States Congress and the projected date of completion was estimated to be somewhere between 1 July and 1 November 1945. In October 1942, work on the ships was again delayed by the order of some eighty destroyers, which were badly needed for
3423-516: A significant accuracy advantage over earlier ships with optical rangefinders; this was demonstrated off Truk Atoll on 16 February 1944, when the New Jersey engaged the Japanese destroyer Nowaki at a range of 35,700 yards (32.6 km; 17.6 nmi) and straddled her, setting the record for the longest-ranged straddle in history. In World War II, the electronic countermeasures (ECM) included
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#17328590716753586-426: A slight advantage over the 16-inch/50 caliber Mark 7 gun when hitting deck armor – a shell from a 45 cal gun would be slower, meaning that it would have a steeper trajectory as it descended. At 35,000 yards (20 mi; 32 km), a shell from a 45 cal would strike a ship at an angle of 45.2 degrees, as opposed to 36 degrees with the 50 cal. The Mark 7 had a greater maximum range over
3749-534: A small detachment of Marines aboard, the Marines would man one of the 5-inch gun mounts. At the time of their commissioning, all four of the Iowa -class battleships were equipped with 20 quad 40 mm mounts and 49 single 20 mm mounts. These guns were respectively augmented with the Mk ;14 range sight and Mk 51 fire control system to improve accuracy. The Oerlikon 20-millimeter (0.8 in) gun, one of
3912-438: A steam pressure of 565 psi (3,900 kPa) and a steam temperature of 850 °F (454 °C). The boilers supplied steam to four geared steam turbines , each driving one screw propeller . The boilers were vented through a pair of funnels placed on the centerline amidships . To meet the high electrical loads anticipated for the ships, the design was to have ten 1,250 kW ship service turbogenerators (SSTG), providing
4075-592: A third, wider set of locks for the Panama Canal since 1938, which was approved in 1940. Nevertheless, some limitations still existed; the length and height of the BB65 designs had to take into account one of the shipyards at which they were to be built: the New York Navy Yard slipways could not handle the construction of a ship more than 58,000 long tons (59,000 t), and vessels built there had to be low enough to clear
4238-402: A top speed of 35 knots (65 km/h; 40 mph) and a range of 20,000 nautical miles (37,000 km; 23,000 mi) when traveling at the more economical speed of 15 knots (28 km/h; 17 mph). Their plan fulfilled these requirements with a ship of 50,940 long tons (51,760 t) standard displacement, but Chantry believed that more could be done if the ship were to be this large; with
4401-507: A total of 12,500 kW of non-emergency electrical power at 450 volts alternating current . The ships were also to be equipped with two 500 kW emergency diesel generators. The turbines were rated to produce 43,000 hp (32 MW) each, for a total propulsive power of 172,000 hp (128 MW). The propulsion system was intended to produce a design speed of 28 knots at 70,500 tons displacement. The Montana s were designed to carry 7,500 long tons (7,600 t) of fuel oil and had
4564-465: Is sloped at 19 degrees, equivalent to 17.3 in (439 mm) of vertical class B armor at 19,000 yards. The armor belt extends to the triple bottom, where the Class B lower portion tapers to 1.62 inches (41 mm). The ends of the armored citadel are closed by 11.3-inch (287 mm) vertical Class A transverse bulkheads for Iowa and New Jersey . The transverse bulkhead armor on Missouri and Wisconsin
4727-484: The AN/SPY-1 Aegis Combat System radar on the battleships – were suggested in 1962, 1974, and 1977, but as before, these proposals failed to gain the needed authorization. This was due, in part, to the possibility that sensitive electronics within 200 ft (61 m) of any 16-inch gun muzzle may be damaged from overpressure. In 1980, Ronald Reagan was elected president on a promise to build up
4890-625: The Battle of the Atlantic against German U-boats that were raiding the supply convoys to Britain. Additional work on the design continued into 1942, including detail work on the anti-aircraft batteries to be carried. The Bureau of Ships suggested the armor decks could be increased in thickness, but these changes were not pursued. All five ships were ultimately cancelled on 21 July 1943, as production priorities had shifted decisively toward aircraft carriers, destroyers, and submarines . The time spent refining
5053-587: 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 Iowa s were far enough along in construction and urgently needed to operate alongside the new Essex -class aircraft carriers, their orders were retained, making those completed
Montana-class battleship - Misplaced Pages Continue
5216-486: The Brooklyn Bridge at low tide . Consequently, the yard's number 4 dry dock had to be enlarged and the ships would be floated out rather than conventionally launched. In October, the General Board asked for new twelve-gun designs that were sufficiently armored, which was estimated could be accomplished on a displacement of around 50,000 long tons (51,000 t). The Preliminary Design department at C&R responded with
5379-645: The Fast Carrier Task Force and also shelled Japanese positions. During the Korean War , the battleships provided naval gunfire support (NGFS) for United Nations forces , and in 1968, New Jersey shelled Viet Cong and Vietnam People's Army forces in the Vietnam War . All four were reactivated and modernized at the direction of the United States Congress in 1981, and armed with missiles during
5542-400: The Iowa class was to consist of only four battleships with hull numbers BB-61 to BB-64: Iowa , New Jersey , Missouri , and Wisconsin . However, changing priorities during World War II resulted in the battleship hull numbers BB-65 Montana and BB-66 Ohio being reordered as Illinois and Kentucky , respectively; Montana and Ohio were reassigned to hull numbers BB-67 and BB-68. At
5705-708: The Iowa s carried the Vought OS2U Kingfisher and Curtiss SC Seahawk , both of which were employed to spot for the battleship's main gun batteries – and, in a secondary capacity, perform search-and-rescue missions. By the time of the Korean War, helicopters had replaced floatplanes and the Sikorsky HO3S-1 helicopter was employed. New Jersey made use of the Gyrodyne QH-50 DASH drone for her Vietnam War deployment in 1968–69. The Iowa class were
5868-496: The Iowa s have a double bottom hull that becomes a triple bottom under the armored citadel and armored skegs around the inboard shafts. The dimensions of the Iowa s were strongly influenced by speed. When the Second Vinson Act was passed by the United States Congress in 1938, the U.S. Navy moved quickly to develop a 45,000-ton-standard battleship that would pass through the 110 ft (34 m) wide Panama Canal . Drawing on
6031-731: The Japanese Kongō class and serve as the "fast wing" of the U.S. battle line . The Iowa class was designed to meet the Second London Naval Treaty 's "escalator clause" limit of 45,000-long-ton (45,700 t) standard displacement. Beginning in August 1942, four vessels, Iowa , New Jersey , Missouri , and Wisconsin , were completed; two more, Illinois and Kentucky , were laid down but canceled in 1945 and 1958, respectively, before completion, and both hulls were scrapped in 1958–1959. The four Iowa -class ships were
6194-545: The Mark 7 , that was both lighter and smaller in outside diameter; this allowed it to be placed in a turret that would fit in the smaller barbette. The redesigned 3-gun turret, equipped as it was with the Mark 7 naval gun, provided an overall weight saving of nearly 850 long tons (864 t) to the overall design of the Iowa class. The contract design displacement subsequently stood at 45,155 long tons (45,880 t) standard and 56,088 long tons (56,988 t) full load. In May 1938,
6357-450: The Montana ' s plant enabled the machinery spaces to be considerably more subdivided, with extensive longitudinal and traverse subdivisions of the boiler and engine rooms. The machinery arrangement was reminiscent of that of the Lexington class , with the boiler rooms flanking the two central turbine rooms for the inboard shafts, while the turbine rooms for the wing shafts were placed at
6520-553: The Montana design was not entirely a waste, as the arrangement of the propulsion system was modified for the Midway -class aircraft carriers . As authorized, the Montana -class ships (design "BB 67-4") would have been 890 ft (270 m) long at the waterline and 921 ft 3 in (280.80 m) long overall . At the waterline, their beam was to have been 115 ft (35 m), but their maximum beam increased to 121 ft 2 in (36.93 m). The ships were to have had
6683-416: The Montana -class ships was to be twenty 5 in (127 mm)/54 cal Mark 16 dual-purpose guns housed in ten two-gun turrets along the superstructure. These guns, designed for the Montana class, were intended to improve the effective range over the shorter-barreled Mark 12 guns then in service. They fired a 70 lb (32 kg) projectile at a muzzle velocity of 2,650 ft/s (810 m/s) and had
Montana-class battleship - Misplaced Pages Continue
6846-820: The New Jersey was reactivated in 1968 for the Vietnam War, she was outfitted with the ULQ-6 ECM system. Like all battleships, the Iowa s carried heavy armor protection against shellfire and bombs with significant underwater protection against torpedoes. The Iowa s' " all-or-nothing " armor scheme was largely modeled on that of the preceding South Dakota class, and designed to give a zone of immunity against fire from 16-inch/45-caliber guns between 18,000 and 30,000 yards (16,000 and 27,000 m; 10 and 17 mi) away. The protection system consists of Class A face-hardened Krupp cemented (K.C.) armor and Class B homogeneous Krupp-type armor; furthermore, special treatment steel (STS),
7009-432: The New York Navy Yard , the lead shipyard, conducted the final detail design. These revisions included changing the design of the foremast, replacing the original 1.1-inch (27.9 mm)/75-caliber guns that were to be used for anti-aircraft (AA) work with 20 mm (0.79 in)/70 caliber Oerlikon cannons and 40 mm (1.57 in)/56 caliber Bofors guns , and moving the combat information center into
7172-545: The Norden bombsight further fueled these concerns. While the design of the Iowa s was too far along to adequately address this issue, experience in the Pacific theater eventually demonstrated that high-altitude unguided bombing was ineffective against maneuvering warships. When they were commissioned during World War II, the Iowa -class battleships came equipped with two aircraft catapults designed to launch floatplanes . Initially,
7335-488: The Pacific Theater of World War II , and accounted for roughly half of all Japanese aircraft shot down between 1 October 1944 and 1 February 1945. Although successful in this role against WWII aircraft, the 40 mm guns were stripped from the battleships in the jet age – initially from New Jersey when reactivated in 1968 and later from Iowa , Missouri, and Wisconsin when they were reactivated for service in
7498-619: The RIM-2 Terrier missile after World War II. One such proposal came from Rear Admiral W.K. Mendenhall, Chairman of the Ship Characteristics Board (SCB) ; Mendenhall proposed a plan that called for $ 15–30 million to be spent to allow Kentucky to be completed as a guided-missile battleship (BBG) carrying eight SSM-N-8 Regulus II guided missiles with a range of 1,000 nautical miles (1,900 km; 1,200 mi). He also suggested Terrier or RIM-8 Talos launchers to supplement
7661-600: The belt armor to protect against the heavier shell would increase displacement to as much as 55,000 long tons (56,000 t). None of the initial proposals was deemed acceptable, and there were concerns about the feasibility of the quadruple turrets. Other guns were suggested, ranging from 18 in (457 mm) guns to experimental 16-inch/56 caliber guns. C&R provided another series of studies beginning with "65F". Several of these proposals experimented with mixed quadruple, triple, and double turrets for either ten or eleven guns to save weight but still increase firepower over
7824-407: The conning tower sides would have 18 in (457 mm) Class A. Montana ' s torpedo protection system design incorporated lessons learned from those of previous US fast battleships, and was to consist of four internal longitudinal torpedo bulkheads behind the outer hull shell plating that would form a multi-layered "bulge". Two of the compartments would be liquid loaded in order to disrupt
7987-418: The "escalator clause" that would permit maximum standard capital ship displacement of 45,000 long tons (45,700 t). Using the additional 10,000 long tons (10,200 t) over previous designs, the studies included schemes for 27-knot (50 km/h; 31 mph) "slow" battleships that increased armament and protection as well as "fast" battleships capable of 33 knots (61 km/h; 38 mph) or more. One of
8150-508: The "slow" designs was an expanded South Dakota class carrying either twelve 16-inch/45 caliber Mark 6 guns or nine 18-inch (457 mm)/48 guns and with more armor and a power plant large enough to drive the larger ship through the water at the same 27-knot maximum speed as the South Dakota s. While the "fast" studies would result in the Iowa class, the "slow" design studies would eventually settle on twelve 16-inch guns and evolve into
8313-454: The 16-inch guns and a quartet of Mk 37 gun fire control systems with Mark 12 fire control radar and Mark 22 height finding radar to direct the 5-inch gun batteries. These systems were upgraded over time with the Mark 13 replacing the Mark 8 and the Mark 25 replacing the Mark 12/22, but they remained the cornerstones of the combat radar systems on the Iowa class during their careers. The range estimation of these gunfire control systems provided
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#17328590716758476-738: The 16-inch/50 gun, and were well protected against the super-heavy shell. During discussions in March, the decision was made to revert to externally applied belt armor, since the internal armor belts of the South Dakota and Iowa classes were more difficult to install and repair in the event of battle damage, and the weight savings associated with them no longer mattered now that displacement limits were gone. Two additional designs were produced in June: 65-9 and 65-10, which were 28-knot ships. By July, Navy's senior leadership still could not agree on design priorities, and disagreed sharply on points ranging from top speed to
8639-588: The 1941 fiscal year program, the third and fourth Iowa -class battleships were authorized, but in May, two more ships were added to the program. These were to have been built to the next battleship design, but the Secretary of the Navy , Frank Knox , decided that these should be additional Iowa -class ships to speed up production. Though the 33-knot design had been chosen for Iowa , it was clear to naval leadership that these would be exceptions to normal Navy doctrine, and that
8802-471: The 1980s, as part of the 600-ship Navy initiative. During Operation Desert Storm in 1991, Missouri and Wisconsin fired missiles and 16-inch (406 mm) guns at Iraqi targets. Costly to maintain, the battleships were decommissioned during the post- Cold War drawdown in the early 1990s. All four were initially removed from the Naval Vessel Register , but the United States Congress compelled
8965-467: The 1980s. The powerplant of the Iowa s consists of eight Babcock & Wilcox boilers and four sets of double reduction cross-compound geared turbines , with each turbine set driving a single shaft. Specifically, the geared turbines on Iowa and Missouri were provided by General Electric , while the equivalent machinery on New Jersey and Wisconsin was provided by Westinghouse . The plant produced 212,000 shp (158,000 kW) and propelled
9128-414: The 2,700-pound (1,225 kg) Mk 8 "Super-heavy" APC (Armor Piercing, Capped) shell for anti-ship and anti-structure work, and the 1,900-pound (862 kg) Mk 13 high-explosive round designed for use against unarmored targets and shore bombardment. When firing the same conventional shell, the 16-inch/45 caliber Mark 6 used by the fast battleships of the North Carolina and South Dakota classes had
9291-408: The 35,000-long-ton (36,000 t) South Dakota class. The first plans made for this indicated that 30 knots (56 km/h; 35 mph) was possible on a standard displacement of about 37,600 long tons (38,200 t). 33 knots (61 km/h; 38 mph) could be bought with 220,000 shp (160,000 kW) and a standard displacement of around 39,230 long tons (39,860 t), which was well below
9454-424: The 45,000-long-ton (46,000 t) limit. An apparent savior appeared in a Bureau of Ordnance preliminary design for a turret that could carry the 50-caliber guns and also fit in the smaller barbette of the 45-caliber gun turret. Other weight savings were achieved by thinning some armor elements and substituting construction steel with armor-grade Special Treatment Steel (STS) in certain areas. The net savings reduced
9617-602: The AA guns and proposed nuclear (instead of conventional) shells for the 16-inch guns. This never materialized, and Kentucky was ultimately sold for scrap in 1958, although her bow was used to repair her sister Wisconsin after a collision on 6 May 1956, earning her the nickname WisKy . In 1954, the Long Range Objectives Group of the United States Navy suggested converting the Iowa -class ships to BBGs. In 1958,
9780-582: The Bureau of Ships offered a proposal based on this idea. This replaced the 5- and 16-inch gun batteries with "two Talos twin missile systems, two RIM-24 Tartar twin missile systems, an RUR-5 ASROC antisubmarine missile launcher, and a Regulus II installation with four missiles", as well as flagship facilities, sonar, helicopters, and fire-control systems for the Talos and Tartar missiles. In addition to these upgrades, 8,600 long tons (8,700 t) of additional fuel oil
9943-509: The Japanese Kamikaze attacks used during the latter half of World War II and were subsequently phased out in favor of the heavier Bofors 40-millimeter (1.6 in) AA gun. When the Iowa -class battleships were commissioned in 1943 and 1944, they carried twenty quad 40 mm AA gun mounts, which they used for defense against enemy aircraft. These heavy AA guns were also employed in the protection of Allied aircraft carriers operating in
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#173285907167510106-681: The Japanese battle line was therefore a major driving force in setting the design criteria for the new ships, as was the restricting width of the Panama Canal. For "fast" battleships, one such design, pursued by the Design Division section of the Bureau of Construction and Repair , was a "cruiser-killer". Beginning on 17 January 1938, under Captain A.J. Chantry , the group drew up plans for ships with twelve 16-inch and twenty 5-inch (127 mm) guns, Panamax capability but otherwise unlimited displacement,
10269-491: The Japanese fleet into battle. Even the new standard battle line speed of 27 knots, as the preceding North Carolina -class and South Dakota -class battleships were designed for, was not considered enough and during their development processes, designs that could achieve over 30 knots in order to counter the threat of fast "big gun" ships were seriously considered. At the same time, a special strike force consisting of fast battleships operating alongside carriers and destroyers
10432-491: The London Treaty's "escalator clause" maximum limit of 45,000 long tons (45,700 t). These designs were able to convince the General Board that a reasonably well-designed and balanced 33-knot "fast" battleship was possible within the terms of the "escalator clause". However, further studies revealed major problems with the estimates. The speed of the ships meant that more freeboard would be needed both fore and amidships,
10595-490: The Mark 6: 23.64 miles (38.04 km) vs 22.829 miles (36.740 km). In the 1950s, the W23, an adaptation of the W19 nuclear artillery shell , was developed specifically for the 16-inch guns. The shell weighed 1,900 pounds (862 kg), had an estimated yield of 15 to 20 kilotons of TNT (63,000 to 84,000 GJ), and its introduction made the Iowa -class battleships' 16-inch guns
10758-525: The Mk 8 armor-piercing shell due to the weapon's increased muzzle velocity and improved shell penetration; increasing the armor would have increased weight and reduced speed, a compromise that the General Board was not willing to make. The Iowa s' torpedo defense was based on the South Dakota s' design, with modifications to address shortcomings discovered during caisson tests. The system is an internal "bulge" that consists of four longitudinal torpedo bulkheads behind
10921-479: The Navy to reinstate two of them on the grounds that existing shore bombardment capability would be inadequate for amphibious operations . This resulted in a lengthy debate over whether battleships should have a role in the modern navy. Ultimately, all four ships were stricken from the Naval Vessel Register and released for donation to non-profit organizations. With the transfer of Iowa in 2012, all four are museum ships part of non-profit maritime museums across
11084-487: The Oerlikons were to have been mounted individually, although the number of Bofors and Oerlikon mounts would likely have increased considerably had the ships been built. The Bofors guns fired 1.98 lb (0.90 kg) shells at a velocity of 2,890 ft/s (880 m/s), and they had a maximum ceiling of 22,800 ft (6,900 m). The Oerlikon guns were supplied with .27 lb (0.12 kg) shells, which they fired with
11247-536: The SK-2 air-search radar and SG surface-search radar; the Iowa class was updated to make use of these systems between 1945 and 1952. At the same time, the ships' radar systems were augmented with the installation of the SP height finder on the main mast. In 1952, AN/SPS-10 surface-search radar and AN/SPS-6 air-search radar replaced the SK and SG radar systems, respectively. Two years later
11410-477: The SP height finder was replaced by the AN/SPS-8 height finder, which was installed on the main mast of the battleships. In addition to these search and navigational radars, the Iowa class were also outfitted with a variety of fire control radars for their gun systems. Beginning with their commissioning, the battleships made use of a pair of Mk 38 gun fire control systems with Mark 8 fire control radar to direct
11573-579: The SPT-1 and SPT-4 equipment; passive electronic support measures (ESM) were a pair of DBM radar direction finders and three intercept receiving antennas, while the active components were the TDY-1 jammers located on the sides of the fire control tower. The ships were also equipped with the identification, friend or foe (IFF) Mark III system, which was replaced by the IFF Mark X when the ships were overhauled in 1955. When
11736-473: The Second World War, including every major ship type and many smaller warships constructed between 1934 and 1945. They were considered to be "highly reliable, robust and accurate" by the Navy's Bureau of Ordnance. Each 5-inch/38 gun weighed almost 4,000 pounds (1,800 kg) without the breech; the entire mount weighed 156,295 pounds (70,894 kg). It was 223.8 inches (5,680 mm) long overall, had
11899-480: The U.S. Navy's traditional 21-knot battle line of "Standard-type" battleships would be too slow to force these Japanese task forces into battle, while faster aircraft carriers and their cruiser escorts would be outmatched by the Japanese Kongō -class battlecruisers, which had been upgraded in the 1930s to fast battleships . As a result, the U.S. Navy envisioned a fast detachment of the battle line that could bring
12062-409: The US Navy had consistently advocated armor and firepower at the expense of speed. Even in adopting fast battleships of the North Carolina class, it had preferred the slower of two alternative designs. Great and expensive improvements in machinery design had been used to minimize the increased power on the designs rather than make extraordinary powerful machinery (hence much higher speed) practical. Yet
12225-633: The US military as a response to the increasing military power of the Soviet Union . The Soviet Navy was commissioning the Kirov class of missile cruisers, the largest type of surface combatant since World War II . As part of Reagan's 600-ship Navy policy and as a counter to the Kirov class, the US Navy began reactivating the four Iowa -class units and modernizing them for service. Kong%C5%8D-class battleship Too Many Requests If you report this error to
12388-460: The US. The vessels that eventually became the Iowa -class battleships were born from the U.S. Navy's War Plan Orange , a Pacific war plan against Japan. War planners anticipated that the U.S. fleet would engage and advance in the Central Pacific, with a long line of communication and logistics that would be vulnerable to high-speed Japanese cruisers and capital ships. The chief concern was that
12551-656: The United States Congress passed the Second Vinson Act , which "mandated a 20% increase in strength of the United States Navy ". The act was sponsored by Carl Vinson , a Democratic Congressman from Georgia who was Chairman of the House Naval Affairs and Armed Services Committee. The Second Vinson Act updated the provisions of the Vinson-Trammell Act of 1934 and the Naval Act of 1936, which had "authorized
12714-519: The United States unilaterally withdrew all of its nuclear artillery shells from service, and the dismantling of the US nuclear artillery inventory is said to have been completed in 2004. The Iowa s carried twenty 5-inch (127 mm)/38 caliber Mark 12 guns in ten Mark 28 Mod 2 enclosed base ring mounts. Originally designed to be mounted upon destroyers built in the 1930s, these guns were so successful that they were added to many American ships during
12877-629: The Washington Treaty expired, the US Navy began building the North Carolina -class fast battleships in 1937 to replace old pre- World War I ships that were by then obsolescent. But by the late 1930s, the Washington system, which had been extended by the First and Second London Naval Treaties , had begun to break down after Japan refused to sign the Second London Treaty in 1936. This prompted
13040-409: The addition of 6 knots (11 km/h; 6.9 mph) over the South Dakota s. Rather than retaining the 16-inch/45 caliber Mark 6 guns used in the South Dakota s, they ordered that the preliminary design would have to include the more powerful but significantly heavier 16-inch/50 caliber Mark 2 guns left over from the canceled Lexington -class battlecruisers and South Dakota -class battleships of
13203-495: The after end of the machinery spaces. Montana ' s machinery arrangement combined with increased power would eventually be used on the Midway class. The primary armament of a Montana -class battleship would have been twelve 16-inch (406 mm)/50 caliber Mark 7 guns , which were to be mounted in four three-gun turrets. The turrets were placed in two superfiring pairs, one forward and one aft. The guns fired two types of shells:
13366-539: The armored hull. Additionally, in November 1939, the New York Navy Yard greatly modified the internal subdivision of the machinery rooms, as tests had shown the underwater protection in these rooms to be inadequate. The longitudinal subdivision of these rooms was doubled, and the result of this was clearly beneficial: "The prospective effect of flooding was roughly halved and the number of uptakes and hence of openings in
13529-466: The barbettes. These guns fire high explosive- and armor-piercing shells and can fire a 16-inch shell approximately 23.4 nautical miles (43.3 km; 26.9 mi). The guns are housed in three 3-gun turrets: two forward of the battleship's superstructure and one aft, in a configuration known as "2-A-1". The guns are 66 feet (20 m) long (50 times their 16-inch bore, or 50 calibers from breechface to muzzle ). About 43 feet (13 m) protrudes from
13692-409: The belt and main armored deck aft of the citadel to armored tubes around the shafts, with the steering gears becoming its own armored compartment. This design was immune to the super-heavy shells when fired at ranges between 18,000 and 31,000 yards (16,000 and 28,000 m); their resistance to standard 16-inch AP shells extended to 16,500 and 34,500 yards (15,100 and 31,500 m). The final version of
13855-406: The bow and stern could aim from −150 to 150 degrees; the others were restricted to −80 to 80 degrees. They could be turned at about 25 degrees per second. The mounts were directed by four Mark 37 fire control systems primarily through remote power control (RPC). The 5-inch/38 gun functioned as a dual-purpose gun (DP); that is, it was able to fire at both surface and air targets with
14018-409: The bow to reduce the amount of water taken on in heavy seas. The Montana class would have carried three aircraft for reconnaissance and gunnery spotting. They would have been operated from catapults on the ship's fantail, as was standard for US battleship designs of the period. The propulsion plant of the Montana s would have consisted of eight oil-fired Babcock & Wilcox two-drum boilers with
14181-588: The centerline, extending down to the main armor deck. The conning tower armor is Class B with 17.3 inches (439 mm) on all sides and 7.25 inches (184 mm) on the roof. The secondary battery turrets and handling spaces were protected by 2.5 inches (64 mm) of STS. The propulsion shafts and steering gear compartment behind the citadel had considerable protection, with 13.5-inch (343 mm) Class A side strake and 5.6–6.2-inch (142–157 mm) roof. The armor's immunity zone shrank considerably against guns equivalent to their own 16-inch/50-caliber guns armed with
14344-866: The citadel and 10.3 in (262 mm) thick over the magazines. The outboard section would have had 6.1 in (155 mm) Class B laminated on 1.25 in (32 mm) STS for a total of 7.35 in (187 mm) second deck and a 0.75 in (19 mm) splinter deck. The total thickness for the outboard section of the deck would have been 8.1 in (206 mm). The main batteries were designed to have very heavy protection, with turret faces having 18 in (457 mm) Class B mounted on 4.5 in (114 mm) STS, resulting in 22.5 in (572 mm) thick laminated plate. The turret sides were to have up to 10 in (254 mm) Class A and turret roofs would have 9.15 in (232 mm) Class B. The barbettes would have been protected by up to 21.3 in (541 mm) Class A forward and 18 in (457 mm) aft, while
14507-430: The class to have a lengthened forecastle and amidship, which would increase speed, and a bulbous bow . The Iowa s exhibit good stability, making them steady gun platforms. At design combat displacement, the ships' (GM) metacentric height was 9.26 ft (2.82 m). They also have excellent maneuverability in the open water for their size, while seakeeping is described as good, but not outstanding. In particular,
14670-475: The construction of the first American battleships in 17 years", based on the provisions of the London Naval Treaty of 1930; this act was quickly signed by President Franklin D. Roosevelt and provided the funding to build the Iowa class. Each ship cost approximately US$ 100 million. As 1938 drew to a close, the contract design of the Iowa s was nearly complete, but it would continuously evolve as
14833-432: The cost and logistical challenges of the larger designs. The Board requested another round of design studies from Preliminary Design, which responded with nine-, ten-, and twelve-gun ships that, again, included slow and fast variants. The Board finally selected one of the designs, "BB 65-5A", which was armed with twelve guns on a displacement of 57,500 long tons (58,400 t), and capable of 28 knots. The Board submitted
14996-463: The design continued well into 1941, which included replacing the original battery of light anti-aircraft guns, which were to be the ineffective 1.1 in (28 mm) guns with Bofors 40 mm (1.6 in) guns . The searchlights were rearranged, the navigational rangefinders were removed, and the waterline hull length was increased slightly to 890 ft (270 m). Displacement was increased slightly, to 60,500 long tons (61,500 t), while
15159-473: The design for the 60,500-long-ton (61,500 t) Montana class after all treaty restrictions were removed following the start of World War II. Priority was given to the "fast" design in order to counter and defeat Japan's 30-knot (56 km/h; 35 mph) Kongō -class fast battleships, whose higher speed advantage over existing U.S. battleships might let them "penetrate U.S. cruisers, thereby making it 'open season' on U.S. supply ships", and then overwhelm
15322-485: The design proposal to rebuild these two ships as aircraft carriers and they were cleared for construction as fast battleships to conform to the Iowa -class design, though they differed from the earlier four that were built. Eventually, the Cleveland -class light cruisers were selected for the aircraft-carrier conversion. Nine of these light cruisers would be rebuilt as Independence -class light aircraft carriers. After
15485-452: The design to Knox, which he approved on 19 August. The ships were not actually authorized at that point, and design work continued. Because the battleships that would have received the BB-65 and BB-66 hull numbers had been assigned to the Iowa class, the next design was labeled "BB 67-1". This design shortened the hull to 880 ft (270 m) at the waterline, likely to keep the length within
15648-490: The design, dated March 1941, was designated "BB 67-4". The General Board planned to build four ships to the new design, which would have constituted a single battleship division , but five were authorized by the Two-Ocean Navy Act on 19 July 1940. Work was intended to begin later that year, but shortages of the necessary steel caused delays. Work on the new locks for the Panama Canal was also halted in 1941, also owing to
15811-438: The designers discovered that the propulsion system could be reduced in power, from 212,000 to 172,000 shaft horsepower (158,000 to 128,000 kW ), which allowed smaller and lighter propulsion machinery. These changes provided further savings in weight that allowed the bomb deck to be extended further aft, and improvements to the light anti-aircraft battery. Protection of the propulsion shafts also changed from an extension of
15974-440: The early 1920s. The 16"/50 turret weighed some 400 long tons (406 t) more than the 16"/45 turret already in use and also had a larger barbette diameter of 39 feet 4 inches (11.99 m) compared to the latter's barbette diameter of 37 feet 3 inches (11.35 m), so the total weight gain was about 2,000 long tons (2,030 t). This put the ship at a total of 46,551 long tons (47,298 t) – well over
16137-401: The effects, the third deck and triple bottom structure behind the lower armor belt were reinforced and the placement of brackets was changed. Iowa s' system was also improved over the South Dakota s' through closer spacing of the transverse bulkheads, greater thickness of the lower belt at the triple bottom joint, and increased total volume of the "bulge". The system was further modified for
16300-422: The empty compartment behind it absorb any remaining energy. However, the Navy discovered in caisson tests in 1939 that the initial design for this torpedo defense system was actually less effective than the previous design used on the North Carolina s due to the rigidity of the lower armor belt causing the explosion to significantly displace the final holding bulkhead inwards despite remaining watertight. To mitigate
16463-420: The first set in the use of 5-inch and 6-inch secondaries. All of these designs were only protected against the 2,250 lb shell, but since "C" and "D" were below the displacement limit, C&R attempted to use the free weight to strengthen their armor with design "BB 65E". They realized that though the deck could be improved to provide a relatively narrow zone of immunity against plunging fire , strengthening
16626-553: The four largest battleships the US Navy produced were not much more than 33-knot versions of the 27-knot, 35,000 tonners that had preceded them. The Iowa s showed no advance at all in protection over the South Dakota s. The principal armament improvement was a more powerful 16-inch gun, 5 calibers longer. Ten thousand tons was a very great deal to pay for 6 knots. Norman Friedman , U.S. Battleships: An Illustrated Design History , p. 307. The Iowa -class battleships are 860 ft 0 in (262.13 m) long at
16789-468: The gas bubble of a torpedo warhead detonation while the bulkheads would elastically deform and absorb the energy. Due to the external armor belt, the geometry of the "bulge" was more similar to that of the North Carolina class rather than that of the South Dakota and Iowa classes. The design of the Montana ' s torpedo defense system addressed a potential vulnerability of the South Dakota -type system, where caisson tests in 1939 showed that extending
16952-420: The gun house. Each gun weighs about 239,000 pounds (108,000 kg) without the breech, or 267,900 pounds (121,500 kg) with the breech. They fired 2,700-pound (1,225 kg) armor-piercing projectiles at a muzzle velocity of 2,500 ft/s (762 m/s ), or 1,900-pound (862 kg) high-capacity projectiles at 2,690 ft/s (820 m/s), up to 24 miles (21 nmi; 39 km). At maximum range,
17115-459: The gun lost some of its effectiveness in the anti-aircraft role; however, toward the end of the war, its usefulness as an anti-aircraft weapon increased again because of an upgrade to the Mark ;37 Fire Control System, Mark 1A computer, and proximity-fused shells. The 5-inch/38 gun would remain on the battleships for the ships' entire service life; however, the total number of guns and gun mounts
17278-401: The inboard pair consisting of five-bladed propellers 17 ft (5.18 m) in diameter. The propeller designs were adopted after earlier testing had determined that propeller cavitation caused a drop in efficiency at speeds over 30 kn (56 km/h; 35 mph). The two inner shafts were housed in skegs to smooth the flow of water to the propellers and improve the structural strength of
17441-611: The last US Navy battleships to be commissioned . During the interwar period , the US Navy was primarily concerned with its rival in the Pacific Ocean, the Imperial Japanese Navy . The international naval arms limitation system initiated by the Washington Naval Treaty in 1922 had accorded the US Navy superiority over Japan in terms of total tonnage. After the ten-year construction moratorium that had been imposed by
17604-462: The last battleships commissioned in the U.S. Navy. All older U.S. battleships were decommissioned by 1947 and stricken from the Naval Vessel Register (NVR) by 1963. Between the mid-1940s and the early 1990s, the Iowa -class battleships fought in four major U.S. wars. In the Pacific Theater of World War II, they served primarily as fast escorts for Essex -class aircraft carriers of
17767-484: The last little bit of energy from the steam. After leaving the LP turbine, the exhaust steam passes into a condenser and is then returned as feed water to the boilers. Water lost in the process is replaced by three evaporators, which can make a total of 60,000 US gallons per day (3 liters per second) of fresh water. After the boilers have had their fill, the remaining fresh water is fed to the ship's potable water systems for drinking, showers, hand washing, cooking, etc. All of
17930-421: The last two ships of the class, Illinois and Kentucky , by eliminating knuckles along certain bulkheads; this was estimated to improve the strength of the system by as much as 20%. Based on costly lessons in the Pacific theater, concerns were raised about the ability of the armor on these battleships to withstand aerial bombing, particularly high-altitude bombing using armor-piercing bombs. Developments such as
18093-416: The latter requiring an additional foot of armored freeboard. Along with this came the associated weight in supporting these new strains: the structure of the ship had to be reinforced and the power plant enlarged to avoid a drop in speed. In all, about 2,400 long tons (2,440 t) had to be added, and the large margin the navy designers had previously thought they had – roughly 5,000 long tons (5,080 t) –
18256-551: The lighter HC shells had a slightly reduced range of 41,604 yd (38,043 m). The shells had a flight time in excess of eighty seconds at those distances. At a realistic engagement distance of 20,000 yd (18,000 m), the AP shells could penetrate 20 in (508 mm) of steel armor. The guns had a rate of fire of two shots per minute, and had a rate of train of four degrees per second. They had to be returned to 5 degrees elevation for reloading. The secondary armament for
18419-584: The limits of the new slipways being built at the Norfolk Navy Yard and the Philadelphia Navy Yard . This variant displacement increased to 61,200 long tons (62,200 t). Further iterative improvements of the armor layout produced "BB 67-2", which had a slightly reduced displacement of 59,700 long tons (60,700 t). This version incorporated an internal lower belt that provided additional protection against underwater shell hits. Detail work on
18582-424: The long fine bow and sudden widening of the hull just in front of the foremost turret contributed to the ships being rather wet for their size. This hull form also resulted in very intense spray formations, which led to some difficulty refueling escorting destroyers. The primary guns used on these battleships are the nine 16-inch (406 mm)/50-caliber Mark 7 naval guns, a compromise design developed to fit inside
18745-457: The lower Class B armor belt to form the holding bulkhead between them. The greater beam of the Montana s would allow a higher system depth of 20.5 ft (6.25 m) compared to 18.5 ft (5.64 m) of the North Carolina s. Iowa-class battleship The Iowa class was a class of six fast battleships ordered by the United States Navy in 1939 and 1940. They were initially intended to intercept fast capital ships such as
18908-419: The main armor belt that tapers to the keel to act as one of the torpedo bulkheads had detrimental flooding effects due to the belt's rigidity. South Dakota ' s and Iowa ' s systems were modified in light of these tests, and Iowa ' s system was also further reinforced. Like on the South Dakota and Iowa classes, the two outer compartments would be liquid loaded, while two inner ones be void with
19071-413: The most heavily produced anti-aircraft guns of the Second World War, entered service in 1941 and replaced the 0.50-inch (12.7 mm) M2 Browning MG on a one-for-one basis. Between December 1941 and September 1944, 32% of all Japanese aircraft downed were credited to this weapon, with the high point being 48.3% for the second half of 1942; however, the 20 mm guns were found to be ineffective against
19234-412: The new battleships. As the bureaus were independent of one another, they did not realize that the two plans could not go together until November 1938, when the contract design was in the final stages of refinement. By this time, the ships could not use the larger barbette, as it would require extensive alterations to the design and would result in substantial weight penalties. Reverting to the 45-caliber gun
19397-482: The new super-heavy shell had significantly better penetrating power than older, lighter shells. None of the existing designs, from North Carolina to Iowa , were proof against the 2,700-pound shell, and the General Board wanted the next design to be better protected. They requested proposals from the Bureau of Construction and Repair (C&R) that conformed to the 45,000-ton limit, armed with twelve 16-inch guns, and capable of 27-knots. C&R initially responded with
19560-418: 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 Montana s would have been the largest, best-protected, and most heavily armed US battleships ever. They also would have been
19723-445: The nine-gun Iowa design that was two knots slower but better protected, an enlarged Iowa variant that maintained the 33-knot speed but displaced 53,500 long tons (54,400 t), and several twelve-gun designs that had speeds ranging from 28 to 33 knots. These were given designations from "BB 65-1" to "BB 65-8". Displacement on these proposals increased to as much as 67,000 long tons (68,000 t). All of these designs were armed with
19886-437: The nine-gun South Dakota s. One proposal, "65J", suggested adopting a twelve-gun 14 in (356 mm) ship that would be well-protected against the 2,700 lb AP shell. The 18-inch gun was ruled out after a design study demonstrated that only six of the guns could be mounted within the 45,000-ton displacement limit. By September 1939, one of the ten-gun variants had been selected, which carried two triple-turrets forward and
20049-470: The only battleships with the speed required for post-war operations based around fast aircraft carrier task forces. There were several proposals in the early Cold War to convert the class to take into account changes in technology and doctrine. These included plans to equip the class with nuclear missiles, add aircraft capability, and – in the case of Illinois and Kentucky – a proposal to rebuild both as aircraft carriers instead of battleships. Initially,
20212-526: 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 Naval Act of 1938 . The Japanese attack on Pearl Harbor delayed the construction of the Montana -class. The success of carrier combat at
20375-553: The other major naval powers to begin rearmament programs, beginning in the United States with the South Dakota -class battleships in 1938. Funding for the first two new ships was provided in Fiscal Year 1937, though work would not commence until 1939. The Second Vinson Act of 1938 added two more South Dakota s; it also authorized the construction of two more battleships yet to be designed. The US Navy had already begun design work on
20538-417: The outer hull plating with a system depth of 17.9 feet (5.46 m) to absorb the energy of a torpedo warhead. The extension of the armor belt to the triple bottom, where it tapers to a thickness of 1.62 inches (41 mm), serves as one of the torpedo bulkheads and was hoped to add to protection; the belt's lower edge was welded to the triple bottom structure and the joint was reinforced with buttstraps due to
20701-428: The powder bags used to fire them. Each turret required a crew of between 85 and 110 men to operate. The original cost for each turret was US$ 1.4 million, but this figure does not take into account the cost of the guns themselves. The turrets are "three-gun", not "triple", because each barrel is individually sleeved and can be elevated and fired independently. The ship could fire any combination of its guns, including
20864-401: The preliminary design displacement to 44,560 long tons (45,280 t) standard, though the margin remained tight. This breakthrough was shown to the General Board as part of a series of designs on 2 June 1938. However, the Bureau of Ordnance continued working on the turret with the larger barbette, while the Bureau of Construction and Repair used the smaller barbettes in the contract design of
21027-568: The pressure to speed construction of new warships. The first two ships ordered to the 33-knot improved South Dakota design— USS Iowa and New Jersey —were ordered under the 1939 fiscal year. The passage of the Two-Ocean Navy Act on 19 July 1940 provided significant increases to the Navy's strength, including an increase of some 385,000 long tons (391,000 t) for battleships alone, along with hundreds of thousands of tons for new aircraft carriers , cruisers , and destroyers . Under
21190-401: The projectile spends almost 1 + 1 ⁄ 2 minutes in flight. The maximum firing rate for each gun is two rounds per minute. Each gun rests within an armored turret, but only the top of the turret protrudes above the main deck. The turret extends either four decks (Turrets 1 and 3) or five decks (Turret 2) down. The lower spaces contain rooms for handling the projectiles and storing
21353-482: The recommendations of the Battleship Design Advisory Board, which was composed of the naval architect William Francis Gibbs , William Hovgaard (then president of New York Shipbuilding ), John Metten, Joseph W. Powell, and the long-retired Admiral and former Chief of the Bureau of Ordnance Joseph Strauss . The board requested an entirely new design study, again focusing on increasing the size of
21516-435: The restrictions on their own new battleship designs. On 31 March 1938, the US, Britain, and France exchanged notes indicating that they would accept increasing the displacement limit to 45,000 long tons (46,000 t). As the US Navy's designers worked on proposals for the new ships, two distinct strains emerged: a comparatively slow, heavily armed and armored variant and a much faster, but lighter-armed and armored vessel that
21679-417: The second consisting of 5.8 in (147 mm) Class B laminated on 1.25 in (32 mm) STS for a total of 7.05 in (179 mm), and a third 0.625 in (16 mm) splinter deck. Over the magazines, the splinter deck would be replaced by a 1 in (25 mm) STS third deck to protect from spalling. Total armor thickness on the centerline would therefore have been 9.925 in (252 mm) over
21842-491: The ship against the heavier shells. A second variant, "BB 65B" substituted twelve new 6 in (152 mm) /47 guns in place of the existing twenty 5 in (127 mm)/38 cal guns for their secondary batteries , but this increased displacement even further. Another pair of designs, "BB 65C" and "65D", adopted three quadruple main battery turrets instead of four triple turrets, which accounted for some 1,600 long tons (1,626 t) of weight savings. This latter pair mirrored
22005-402: The ship have a Casualty Power System whose large 3-wire cables and wall outlets called "biscuits" can be used to reroute power. The earliest search radars installed were the SK air-search radar and SG surface-search radar during World War II. They were located on the mainmast and forward fire-control tower of the battleships, respectively. As the war drew to a close, the United States introduced
22168-862: The ship up to a maximum speed of 32.5 kn (60.2 km/h; 37.4 mph) at full load displacement and 33 kn (61 km/h; 38 mph) at normal displacement. The ships carried 8,841 long tons (8,983 t) of fuel oil which gave a range of 15,900 nmi (29,400 km; 18,300 mi) at 17 kn (31 km/h; 20 mph). Two semi-balanced rudders gave the ships a tactical turning diameter of 814 yards (744 m) at 30 kn (56 km/h; 35 mph) and 760 yards (695 m) at 20 kn (37 km/h; 23 mph). The machinery spaces were longitudinally divided into eight compartments with alternating fire and engine rooms to ensure adequate isolation of machinery components. Four fire rooms each contained two M-Type boilers operating at 600 pounds per square inch (4,137 kPa ; 42 kgf/cm ) with
22331-419: The ships were still "on the way" rather than after the ships had been launched. The Iowa s had heavily protected main battery turrets, with 19.5-inch (495 mm) Class B and STS face, 9.5-inch (241 mm) Class A sides, 12-inch (305 mm) Class A rear, and 7.25-inch (184 mm) Class B roof. The turret barbettes' armor is Class A with 17.3 inches (439 mm) abeam and 11.6 inches (295 mm) facing
22494-413: The slight knuckle causing a structural discontinuity. The torpedo bulkheads were designed to elastically deform to absorb energy and the two outer compartments were liquid loaded in order to disrupt the gas bubble and slow fragments. The outer hull was intended to detonate a torpedo, with the outer two liquid compartments absorbing the shock and slowing any splinters or debris while the lower armored belt and
22657-410: The splinter deck is replaced by a 1-inch (25 mm) STS third deck that separates the magazine from the main armored deck. The powder magazine rooms are separated from the turret platforms by a pair of 1.5-inch STS annular bulkheads under the barbettes for flashback protection. The installation of armor on the Iowa s also differed from those of earlier battleships in that the armor was installed while
22820-403: The stern. Each of the four engine rooms has a pair of 1,250 kW Ship's Service Turbine Generators (SSTGs), providing the ship with a total non-emergency electrical power of 10,000 kW at 450 volts alternating current. Additionally, the vessels have a pair of 250 kW emergency diesel generators. To allow battle-damaged electrical circuits to be repaired or bypassed, the lower decks of
22983-474: The successors to the South Dakota s in 1937, which was to become the Iowa class ; the Navy sought larger, faster ships that would handily exceed the 35,000 long tons (36,000 t ) limit on battleship displacement imposed under the Washington Treaty system. Because Japan had already refused to abide by the terms of the Second London Naval Treaty, the other major naval powers moved to loosen
23146-442: The surrender of the Empire of Japan , construction on Illinois and Kentucky stopped. Illinois was eventually scrapped, but Kentucky ' s construction had advanced enough that several plans were proposed to complete Kentucky as a guided missile battleship (BBG) by removing the aft turret and installing a missile system. A similar conversion had already been performed on the battleship Mississippi (BB-41/AG-128) to test
23309-555: The third deck greatly reduced." Although the changes meant extra weight and increasing the beam by 1 foot (0.30 m) to 108 feet 2 inches (32.97 m), this was no longer a major issue; Britain and France had renounced the Second London Naval Treaty soon after the beginning of the Second World War . The design displacement was 45,873 long tons (46,609 t) standard, approximately 2% overweight, when Iowa and New Jersey were laid down in June and September 1940. By
23472-570: The three designs. "A" was the largest, at 59,060 long tons (60,010 t) standard, and was the only one to still carry the twelve 16-inch guns in four triple turrets (3-gun turrets according to US Navy). It required 277,000 shp (207,000 kW ) to make 32.5 knots (60.2 km/h; 37.4 mph). "B" was the smallest at 52,707 long tons (53,553 t) standard; like "A" it had a top speed of 32.5 knots, but "B" only required 225,000 shp (168,000 kW) to make this speed. It also carried only nine 16-inch guns, in three triple turrets. "C"
23635-442: The time the Iowa s were completed and commissioned in 1943–44, the considerable increase in anti-aircraft armament – along with their associated splinter protection and crew accommodations – and additional electronics had increased standard displacement to some 47,825 long tons (48,592 t), while full load displacement became 57,540 long tons (58,460 t). For half a century prior to laying [the Iowa class] down,
23798-448: The time these two battleships were to be built a proposal was put forth to have them constructed as aircraft carriers rather than fast battleships. The plan called for the ships to be rebuilt to include a flight deck and an armament suite similar to that placed aboard the Essex -class aircraft carriers that were at the time under construction in the United States. Ultimately, nothing came of
23961-428: The treaty and in particular refused to accept the 14-inch gun caliber limit or the 5:5:3 ratio of warship tonnage limits for Britain, the United States, and Japan, respectively. This resulted in the three treaty powers, the United States, Britain, and France, invoking the caliber escalator clause after April 1937. Circulation of intelligence evidence in November 1937 of Japanese capital ships violating naval treaties caused
24124-477: The treaty powers to expand the escalator clause in June 1938, which amended the standard displacement limit of battleships from 35,000 long tons (35,600 t) to 45,000 long tons (45,700 t). Work on what would eventually become the Iowa -class battleship began on the first studies in early 1938, at the direction of Admiral Thomas C. Hart , head of the General Board , following the planned invocation of
24287-430: The triple bottom and be mounted on 0.75 in (19 mm) STS. The ends of the armored citadel would be closed by Class A traverse bulkheads 18 in (457 mm) thick in the front and 15.25 in (387 mm) in the aft. The deck armor would be in three layers: the first consisting of 0.75 in (19 mm) STS laminated on 1.5 in (38 mm) STS for a total of 2.25 in (57 mm) STS weather deck,
24450-475: The urinals and all but one of the toilets on the Iowa class flush with salt water in order to conserve fresh water. The turbines, especially the HP turbine, can turn at 2,000 rpm; their shafts drive through reduction gearing that turns the propeller shafts at speeds up to 225 rpm, depending upon the desired speed of the ship. The Iowa s were outfitted with four screws: the outboard pair consisting of four-bladed propellers 18.25 ft (5.56 m) in diameter and
24613-441: The waterline and 887 ft 3 in (270.43 m) long overall with a beam of 108 ft 2 in (32.97 m). During World War II, the draft was 37 ft 2 in (11.33 m) at full load displacement of 57,540 long tons (58,460 t) and 34 ft 9 + 1 ⁄ 4 in (10.60 m) at design combat displacement of 54,889 long tons (55,770 t). Like the two previous classes of American fast battleships,
24776-414: The waterline, the belt tapered to 10.2 in (259 mm). To protect against potential underwater shell hits, the ships would have a separate Class B homogeneous Krupp-type armor lower belt, 8.5 in (216 mm) by the magazines and 7.2 in (183 mm) by the machinery, that would also have served as one of the torpedo bulkheads , inclined at 10 degrees; this lower belt would taper to 1 inch at
24939-426: The world's largest nuclear artillery and made these four battleships the only US Navy ships ever to have nuclear shells for naval guns. Although developed for exclusive use by the battleship's guns it is not known if any of the Iowa s actually carried these shells while in active service due to the United States Navy's policy of refusing to confirm or deny the presence of nuclear weaponry aboard its ships. In 1991,
25102-405: Was also deemed unacceptable. The General Board was astounded; one member asked the head of the Bureau of Ordnance if it had occurred to him that Construction and Repair would have wanted to know what turret his subordinates were working on "as a matter of common sense". A complete scrapping of plans was avoided only when designers within the Bureau of Ordnance were able to design a new 50-caliber gun,
25265-458: Was also suggested to serve in part as ballast for the battleships and for use in refueling destroyers and cruisers. Due to the estimated cost of the overhaul ($ 178–193 million) this proposal was rejected as too expensive; instead, the SCB suggested a design with one Talos, one Tartar, one ASROC, and two Regulus launchers and changes to the superstructure, at a cost of up to $ 85 million. This design
25428-448: Was being envisaged; such a force could operate independently in advance areas and act as scouts. This concept eventually evolved into the Fast Carrier Task Force , though initially the carriers were believed to be subordinate to the battleship. Another factor was the "escalator clause" of the Second London Naval Treaty , which reverted the gun caliber limit from 14 inches (356 mm) to 16 inches (406 mm). Japan had refused to sign
25591-403: Was increased to 14.5 inches (368 mm); this extra armor provided protection from raking fire directly ahead, which was considered more likely given the high speed of the Iowa s. The deck armor consists of a 1.5-inch-thick (38 mm) STS weather deck, a combined 6-inch-thick (152 mm) Class B and STS main armor deck, and a 0.63-inch-thick (16 mm) STS splinter deck. Over the magazines,
25754-540: Was later revised to accommodate the Polaris Fleet Ballistic Missile, which in turn resulted in a study of two schemes by the SCB. In the end, none of these proposed conversions for the battleships were ever authorized. Interest in converting the Iowa s into guided-missile battleships began to deteriorate in 1960 because the hulls were considered too old and the conversion costs too high. Nonetheless, additional conversion proposals – including one to install
25917-401: Was primarily intended to catch Japanese cruisers and counter the fast Kongō -class battleships . The latter type, which eventually emerged essentially as an improved South Dakota , was capable of a speed of 33 knots (61 km/h; 38 mph), but work on the former proceeded at the same time. The General Board intended it to become the next generation of standard-type battleships , which
26080-439: Was reduced from twenty guns in ten mounts to twelve guns in six mounts during the 1980s' modernization of the four Iowa s. The removal of four of the gun mounts was required for the battleships to be outfitted with the armored box launchers needed to carry and fire Tomahawk missiles. At the time of the 1991 Persian Gulf War , these guns had been largely relegated to littoral defense for the battleships. Since each battleship carried
26243-410: Was similar but added 75,000 shp (56,000 kW) (for a total of 300,000 shp (220,000 kW)) to meet the original requirement of 35 knots (65 km/h; 40 mph). The weight required for this and a longer belt – 512 feet (156 m), compared with 496 feet (151 m) for "B" – meant that the ship was 55,771 long tons (56,666 t) standard. In March 1938, the General Board followed
26406-433: Was suddenly vanishing. The draft of the ships was also allowed to increase, which enabled the beam to narrow and thus reduced the required power (since a lower beam-to-draft ratio reduces wave-making resistance ). This also allowed the ships to be shortened, which reduced weight. With the additional displacement, the General Board was incredulous that a tonnage increase of 10,000 long tons (10,200 t) would allow only
26569-509: Was to be set at 45,000-ton ships armed with twelve 16 in (406 mm) guns, and capable of 27 knots (50 km/h; 31 mph), the same speed as the South Dakota s. By 1939, it had become apparent to the naval leadership that war was approaching, and so the need for new ships had become pressing. The start of World War II in Europe, and particularly the Fall of France in June 1940 only increased
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