Iowa class battleship

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USS Wisconsin after the 1980s refit
United States
Builders:	New York Navy Yard Philadelphia Navy Yard Norfolk Navy Yard
Operators:	United States Navy
Preceding class:	South Dakota
Following class:	Montana
Commissioned:	21 April 1961
Decommissioned:	31 March 1992
In service:	22 February 1943
Out of service:	17 March 2006
Ships in Class
Ships in class:	6
Preserved ships:	Iowa New Jersey Missouri Wisconsin
Ships planned but not completed:	Illinois Kentucky
General Characteristics
Class type:	Battleship
Displacement:	45,000 tons (standard); 52,000 tons (mean war service); 58,000 tons (full load)[1]
Length:	861¼ ft between Perpendiculars; 890 ;ft overall (271.27 m)
Beam:	108 ft (32.92 m)
Draught:	36 ft (10.97 m) Maximum
Propulsion and power:	4 screws; geared turbines; 8 Babcock & Wilcox Boilers; G.E. (BB-61;BB-63); West. (BB-62; BB-64; BB-66)
Speed:	33 knots (61.12 km/h nominal);35 knots (64.82 km/h maximum)
Range:	9,600 miles (15,000 km) @ 25 knots (46 km/h); 16,600 miles (27,000 km) @ 15 knots (28 km/h)
Complement:	2,700 officers and men (World War II, Korea and Vietnam), 1,800 officers and men (1980s)[1]
Armament:	WWII, Korea, Vietnam: 9 x 16 in (406 mm) 50 cal. Mark 7 guns 20 × 5 in (127 mm) 38 cal. Mark 12 guns 80 x 40 mm 56 cal. anti-aircraft guns 49 x 20 mm 70 cal. anti-aircraft guns Cold War, Gulf War: 9 x 16 in (406 mm) 50 cal. Mark 7 guns 12 × 5 in (127 mm) 38 cal. Mark 12 guns 32 x BGM-109 Tomahawk cruise missiles 16 x RGM-84 Harpoon Anti-Ship missiles 4 x 20 mm/76 cal. Phalanx CIWS
Armor:	Belt: 12.1 in (307 mm),[2] Bulkheads: 11.3 in (287 mm),[2] Barbettes: 11.6 to 17.3 in (295 to 439 mm),[2] Turrets: 19.7 in (500 mm),[2] Decks: 7.5 in (191 mm)[2]
Aircraft complement:	WWII: 3x Vought OS2U Kingfisher/Curtiss SC Seahawk; Korea/Vietnam: 3x helicopters; Cold War/Gulf War: 8x RQ-2 Pioneer Unmanned aerial vehicle

The Iowa-class battleships were six battleships constructed by the United States Navy in the late 1930s and early 1940s for use as escorts for the Fast Carrier Task Forces operating in the Pacific Theatre of World War II. They comprised the final class of U.S. battleships. Four were completed in the early to mid-1940s; two more were laid down but were cancelled prior to completion and ultimately scrapped.

Built with cost as no object, the Iowa class was arguably the ultimate in the evolution of the capital ship.^[3] The Iowa class was ranked first in the Discovery Channel's list of 10 ships that shaped naval warfare.^[4] Yet even as these behemoths entered service, they were being eclipsed by aircraft carriers as the most important naval vessel.

The Iowa-class battleships have seen service in every major U.S. war of the latter half of the 20th century. In World War II, they defended aircraft carriers and shelled Japanese positions before being placed in reserve at the end of the war. Recalled for action during the Korean War, the battleships provided artillery support for UN forces fighting against North Korea. In 1968, New Jersey was recalled for action in the Vietnam War and shelled Communist targets for U.S. forces near the Vietnamese Demilitarized Zone. All four were reactivated and armed with missiles during the Cold War as part of the 600-ship Navy. In 1991, Missouri and Wisconsin fired missiles and 16-inch guns at Iraqi targets during the Gulf War. All four battleships were decommissioned in the early 1990s, and were removed from the Naval Vessel Register in 2006.

[edit] History

The Iowa-class battleships were shaped by naval treaties signed by various countries during the 1920s and 1930s, and by the need to keep up with aircraft carriers and protect them from aerial attack.

The Washington Naval Treaty was proposed by U.S. Secretary of State Charles Evans Hughes and forged during a November 1922 conference attended by Great Britain, France, Germany, and Japan. The attending nations agreed to abandon ongoing construction of battleships and battlecruisers, to limit ships to 35,000 tons, to cap armament at 16 inch guns, and to limit replacement tonnage.^[5] The London Naval Treaty further restricted battleship construction and banned new battleships through 1937.^[2][6] These treaties stopped U.S. construction of battleships and battlecruisers.

In 1935, during the Second London Naval Conference, the Empire of Japan denounced the naval treaty and withdrew their delegates from the conference. In response, those at the conference agreed that if Japan did not sign the treaty by April 1937, other nations would be free to build guns up to 16 inch, the maximum size under the Washington Naval Treaty in 1922. Tonnage limits were also relaxed.

In 1937, when the treaty limitations expired, the United States began construction on the North Carolina and South Dakota-class battleships. These new battleships could steam at 28 knots, fast for a battleship but not fast enough to keep pace with the aircraft carriers being planned.^[2]

[edit] Birth of the Iowa class

The Iowa class, like the South Dakota class and North Carolina class, began in response to the need for fast escorts for the Essex-class aircraft carriers. Design began in early 1938 with a study at the idea of creating an extended South Dakota class. The study indicated that a 45,000 ton Extended-South Dakota would make 33 knots. Originally, the ships were to mount the Mark 2 16 inch (406 mm) / 50-caliber gun, which had been intended to arm the battleships and battlecruisers cancelled in 1922. But due to a miscommunication between the Bureau of Ordnance and the Bureau of Construction and Repair that left the ship's barbettes too small, the Mark 2 guns were replaced in the design by the new, lighter Mark 7 16 inch (406 mm) / 50-caliber gun.^[7] The Mark 7 was originally intended to fire the same 2,240 lb shell as the 16 in/45-caliber gun, but as the design was being completed a new 2,700 lb shell was developed. The armor was only designed to resist 2,240 lb shells, but adding armor would have pushed the ship's weight over the 45,000 ton limit.

Under the direction of then Secratary of the Navy Charles Edison, the design was finalized and a contract was signed with the shipyards in July 1939. Originally BB-61, BB-62, and BB-63 were to be of the same design while BB-64, BB-65, and BB-66 were intended to be larger, slower ships mounting 12 16 inch guns. But by late 1939, it was apparent that the navy needed as many fast battleships as possible and it was decided that BB-64, and later BB-65 and BB-66, would follow the same design as their sisters.^[8]

[edit] Service history

When brought into service during the final years of World War II, the Iowa-class battleships were assigned to operate in the Pacific, primarily to defend U.S. aircraft carriers and often as their anti-aircraft screen. None of the Iowas engaged a surface ship during the war. At the end of the war, Iowa, New Jersey and Wisconsin were decommissioned and placed in the mothball fleet.

They were recalled in 1950 with the outbreak of the Korean War, then remothballed after hostilities ceased in 1955.

In 1968, due in large part to congressional pressure, New Jersey was recommissioned and sent to assist U.S. troops during the Vietnam War, then decommissioned the following year.^[9]

In the 1980s, the battleships were recommissioned. President Ronald Reagan had vowed to rebuild the U.S. military and create a 600-ship Navy. With the Des Moines-class heavy cruisers worn out, the relatively low mileage Iowas were brought back to fill the offshore bombardment role.^[4] The ships also provided a counter to the new Soviet Orlan-class large missile cruisers, better known in the West as the Kirov-class battlecruisers. Each battleship was modernized to carry CIWS self-defense systems and missiles. They became the centerpieces of their own battleship battle groups (BBBGs). Their missions in the 1980s and early 1990s included the U.S. intervention in the Lebanese Civil War following the 1983 Beirut barracks bombing and the 1991 Gulf War, first as part of Operation Desert Shield and then as part of Operation Desert Storm. Decommissioned for the last time in the early 1990s, the Iowas were split into two groups: those that would be retained in the United States Navy reserve fleets (better known as the "mothball fleet") and those that would be donated for use as museum ships.

In the early 1990s, all four Iowas were deactivated and sent to the mothball fleet. In 1996, the National Defense Authorization Act led Iowa and Missouri to be struck from the Naval Vessel Register. Missouri was donated to the Missouri Memorial Association of Pearl Harbor, Hawaii, for use as a museum ship. Iowa was set to be donated with Missouri, but was reinstated to the Naval Vessel Register after the Strom Thurmond National Defense Authorization Act of 1999 allowed New Jersey to be donated as a museum ship.^[10] The last two Iowa-class battleships were removed from the mothball fleet in 2006, and are currently awaiting transfer for use as museum ships.^[9][11]

[edit] The ships

The Iowa-class ships were built to steam at the same speed as aircraft carriers. Their main battery and secondary battery guns were designed to take on the ships of the Imperial Japanese Navy,^[4] and to shell beachheads in advance of U.S. Army and Marine Corps amphibious assaults. They carried a fearsome array of anti-aircraft guns to defend themselves and U.S. carriers.

USS Iowa (BB-61) 

USS Iowa firing her guns during the Korean War.

Iowa was ordered 1 July 1939, laid down 27 June 1940, launched 27 August 1942, and commissioned 22 February 1943. Iowa conducted a shakedown cruise in the Chesapeake Bay before sailing to Newfoundland to counter the German battleship Tirpitz. Transferred to the Pacific Fleet in 1944, Iowa made her combat debut in the campaign for the Marshall Islands. The ship escorted U.S. aircraft carriers conducting air raids in the Marianas campaign, then was present at the Battle of Leyte Gulf. During the Korean War, Iowa bombarded enemy targets at Songjin, Hungnam, and Kojo, North Korea. Iowa returned to the U.S. for operational and training exercises before being decommissioned. Reactivated in the early 1980s, Iowa made several operation cruises in European waters. On 19 April 1989, an explosion of undetermined origin ripped through her No. 2 turret, killing 47 sailors. The turret remained inoperable when Iowa was decommissioned for the last time in 1990. In 1999, Iowa was placed in the mothball fleet as a replacement for sister ship New Jersey. Struck from the Naval Vessel Register on 17 March 2006, Iowa is currently berthed at Suisun Bay in San Fransisco, California, pending a decision on requests to turn the ship into a museum ship.^[12]

USS New Jersey (BB-62) 

USS New Jersey fires a broadside of 16-inch guns

New Jersey was ordered 1 July 1939, laid down 16 September 1940, launched 7 December 1942, and commissioned 23 May 1943. New Jersey completed fitting out and trained her initial crew in the Western Atlantic and Caribbean before transferring to the Pacific Theatre in advance of the planned assault on the Marshall Islands, where she screened the U.S. fleet of aircraft carriers from enemy air raids. At the Battle of Leyte Gulf, the ship protected carriers with her anti-aircraft guns. New Jersey then bombarded Iwo Jima and Okinawa. During the Korean War, the ship pounded targets at Wonsan, Yangyang, and Kansong. Following the ceasefire, New Jersey conducted training and operation cruises until she was decommissioned. Recalled for action in 1968, New Jersey reported for duty near the Vietnam DMZ, and remained there until 1969, whereupon she was decommissioned. Reactivated again under the 600-ship Navy program, New Jersey was sent to Lebanon to protect U.S. interests and U.S. Marines, firing her main guns at Druze and Syrian positions in the Bekaa valley east of Beirut. Decommissioned for the last time 8 February 1991, New Jersey was briefly retained on the Naval Vessel Register before being donated to the Home Port Alliance of Camden, New Jersey, for use as a museum ship.^[13]

USS Missouri (BB-63) 

USS Missouri in her 1980s configuration

Missouri was ordered 12 June 1940, laid down 6 January 1941, launched 29 January 1944, and commissioned 11 June 1944. Missouri conducted her trials off New York and shakedown and battle practice in the Chesapeake Bay before transferring to the Pacific Fleet, where she screened U.S. aircraft carriers involved in offensive operations against the Japanese before reporting to Okinawa to shell the island in advance of the planned landings. Following the bombardment of Okinawa Missouri turned her attention to Honshū and Hokkaidō, shelling the islands and screening U.S. carriers involved in combat operations against the Japanese positions. She garnered international attention in September 1945 when representatives of the Empire of Japan boarded the battleship to sign the documents of unconditional surrender to the Allied powers. After World War II Missouri turned her attention to conducting training and operational cruises before being dispatched to Korea at the outbreak of the Korean War. Missouri served two tours of duty in Korea before being decommissioned in 1956. Reactivated 1984 as part of the 600-ship Navy plan, Missouri was sent on operational cruises until being assigned to Operation Earnest Will in 1988. In 1991, Missouri participated in the Gulf War by firing Tomahawk Missiles at Iraqi target and shelling known Iraqi positions along the coast. Decommissioned for the last time in 1992, Missouri was donated to the USS Missouri Memorial Association (MMA) of Pearl Harbor, Hawaii, for use as a museum ship in 1999.^[14]

USS Wisconsin (BB-64) 

USS Wisconsin fires a Tomahawk missile

Wisconsin was ordered 12 June 1940, laid down 25 January 1942, launched 7 December 1943, and commissioned 16 April 1944. After trials and initial training in the Chesapeake Bay, Wisconsin transferred to the Pacific Fleet in 1944 and assigned to protect the U.S. fleet of aircraft carriers involved in operations in the Philippines until summoned to Iwo Jima to bombard the island in advance of the Marine landings. After the landings on Iwo Jima she turned her attention to Okinawa, bombarding the island in advance of the allied amphibious assault. In mid 1945 Wisconsin turned her attention to pounding the Japanese home islands, a job she retained until the surrender of Japan. Reactivated in 1950 for the Korean War, Wisconsin served two tours of duty assisting South Korean and UN forces by providing call fire support and shelling targets of opportunity. Decommissioned in 1958, Wisconsin was placed in the reserve fleet at the Philadelphia Naval Yard until reactivated in 1986 as part of the 600-ship Navy plan. In 1991, Wisconsin participated in the Gulf War by firing Tomahawk Missiles at Iraqi targets and shelling Iraqi troop formations along the coast. Decommissioned for the last time 30 September 1991 Wisconsin was placed in the reserve fleet until struck from the Naval Vessel Register 17 March 2006. She is currently berthed in Norfolk, Virginia, pending a formal transfer of the battleship for use as a museum ship.^[15]

USS Illinois (BB-65) 

USS Illinois and USS Kentucky were never finished, both were ultimately scrapped.

Illinois was ordered 9 September 1940 and laid down 15 January 1945; however, her construction was canceled when 11 August 1945 when Illinois was 22% complete. She was sold for scrap in September 1958.^[16][17] Illinois differed from her earlier sisters in that her design called for an all welded construction. This would have saved weight and increased strength over a combination riveted/welded hull of the type used on the four completed Iowa class ships. There was thought of redesigning the hull with a Montana class type protection system for added torpedo protection; however, this was rejected and Illinois was being built along the regular Iowa class hull design.^[18]

USS Kentucky (BB-66) 

Kentucky was ordered 9 September 1940 and laid down on 6 December 1944; however, construction on the battleship was suspended 17 February 1947 when Kentucky was 72% complete. She was informally launched 20 January 1950 to clear a dry-dock for repairs to Missouri after she ran aground. In 1956 Kentucky’s bow was removed and shipped in one piece to Norfolk, Virginia, where it was grafted on the battleship Wisconsin following her collision with the destroyer Eaton. Later, Kentucky’s engines were salvaged and installed on the fast combat support ships Sacramento and Camden. Despite several proposals to complete Kentucky as a guided missile ship nothing along those line ever actually materialized.^[19] Ultimately, Kentucky was sold to Boston Metals Co. for scrap 31 October 1958.^[20][21]Kentucky differed from her earlier sisters in that her design called for an all welded construction. This would have saved weight and increased strength over a combination riveted/welded hull of the type used on the four completed Iowa class ships. There was thought of redesigning the hull with a Montana class type protection system for added torpedo protection; however, this was rejected and Kentucky was being built along the regular Iowa class hull design.^[18]

[edit] Armament

Main article: Armament of the Iowa class battleship

The Iowa-class battleships were among the most heavily armed ships the United States ever put to sea. The main battery of 16 inch guns could hit targets nearly 24 miles (39 km) away with a variety of artillery shells, from standard armor piercing rounds to tactical nuclear charges called "Katies" (from "kt" for kiloton). The secondary battery of 5 in guns could hit targets nearly 9 miles away with solid projectiles or proximity fused shells, and were equally adept in an anti-aircraft role and for damaging smaller ships. When commissioned these battleships carried a fearsome array of 20 mm and 40 mm anti-aircraft guns, which were gradually replaced with Tomahawk and Harpoon missiles, Phalanx anti-aircraft/anti-missile gatling gun systems, and electronic warfare suits.

[edit] Main battery

USS Iowa fires a full broadside of nine 16 inch (406 mm) / 50-caliber and six 5 inch (127 mm) / 38-caliber guns during a target exercise. Note concussion effects on the water surface, and 16 inch (406 mm) gun barrels in varying degrees of elevation.

The primary armament of an Iowa-class battleship is nine 16 inch (406 mm) / 50-caliber Mark 7 naval guns,^[22] which are housed in three 3-gun turrets: two forward 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 the gun house. Each gun weighs about 239,000 pounds (108 000 kg) without the breech, or 267,900 ponds with the breech.^[23][24] They fire projectiles weighing from 1,900 to 2,700 pounds (850 to 1,200 kg) at a maximum speed of 2,690 ft/s (820 m/s) up to 24 nautical miles (39 km). At maximum range the projectile spends almost 1½ minutes in flight.^[1]

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 the powder bags used to fire them. Each turret required a crew of 94 men to operate.^[23] The turrets are not actually attached to the ship, but sit on rollers, which means that if the ship were to capsize the turrets would fall out.^[25] Each turret costs US $1.4 million, but this number does not take into account the cost of the guns themselves^[23]

The turrets are "three-gun," not "triple", because each barrel can be elevated independently; they can also be fired independently. The ship could fire any combination of its guns, including a broadside of all nine. Contrary to myth, the ships do not move noticeable sideways when a broadside is fired.^[26]

The guns can be elevated from −5° to +45°, moving at up to 12° per second. The turrets can be rotated about 300° at about four degrees per second and can even be fired back beyond the beam, which is sometimes called "over the shoulder." The guns are never fired directly forward (in the 1980s refit, a satellite up-link antenna was mounted at the bow).

[edit] Secondary battery

A 5 inch (127 mm) gun mount emblazoned with the Eagle, Globe, and Anchor of the United States Marine Corps aboard the battleship New Jersey

The secondary battery of the ship consists of 5-inch (127mm) / 38-caliber guns in 10 twin mounts, five each to port and starboard. These guns were introduced on destroyers in 1934, but by World War II had been installed on nearly every major U.S. warship.^[27] The secondary battery was intended to fight off aircraft. Its effectiveness soon declined as Japanese airplanes became faster, then rose again toward the end of the war because of the development of the Mark 37 Fire Control System and the proximity-fuzed 5-inch shells. During the 1980s modernization, four twin mounts were removed to make room for missiles, the two farthest aft on each side. In the Gulf War, the secondary battery was largely relegated to shore bombardment and littoral defense. ^[28]

[edit] Anti-aircraft batteries

Since they were designed to escort the U.S. fleet of fast attack aircraft carriers the Iowa-class battleships were all intended to carry a fearsome array of anti-aircraft guns to protect U.S. aircraft carriers from Japanese fighters and dive bombers.

[edit] Oerlikon 20 mm anti-aircraft guns

The Oerlikon 20mm anti-aircraft gun was one of the most heavily produced anti-aircraft guns of the Second World War; The US alone manufactured a total of 124,735 of these guns. When activated in 1941 these guns replaced the 0.50"/90 (12.7 mm) M2 Browning MG on a one-for-one basis. The Orelikon 20 mm AA gun remained the primary anti-aircraft weapon of the United States Navy until the introduction of the 40 mm Bofors AA gun in 1943.^[29]

[edit] Boffors 40mm anti-aircraft guns

Bofors 40 mm anti-aircraft guns on a MK 12 quadruple mount fire from the deck of the USS Hornet in World War II.

Arguably the best heavy anti-aircraft weapon of World War II, the Bofors 40mm anti-aircraft gun was used on almost every major warship in the US and UK fleet during World War II from about 1943 to 1945. Although a descendant of German and Swedish designs, the Bofors mounts used by the United States Navy during World War II had been heavily "Americanized" to bring the guns up to the standards placed on them by the US Navy. This resulted in a guns system set to English standards (now known as the Standard System) with interchangeable ammunition, which simplified the logistics situation for World War II. When coupled with hydraulic couple drives to reduce salt contamination and the Mark 51 director for improved accuaracy the Bofors 40mm gun became a fearsome adversary, accounting for roughly half of all Japanese aircraft shot down between 1 October 1944 and 1 February 1945.^[30]

[edit] Phalanx CIWS

During their modernization in the 1980s each Iowa-class battleship was equipped with four of the United States Navy's Phalanx CIWS mounts, two which sat just behind the bridge and two which were fixed to a platform installed between the ship's funnels. Iowa, New Jersey, and Missouri were equipped with the Block 0 version of the Phalanx, while Wisconsin received the first operational Block 1 version in 1988.^[31] Phalanx CIWS mounts were used by Missouri and Wisconsin during the 1991 Gulf War; Wisconsin alone fired 5,200 20 mm Phalanx CIWS rounds.^[32]

[edit] Missiles

During the modernization in the 1980s, three important weapons were added to the Iowa-class battleships. The first was the CIWS anti-aircraft/anti-missile system discussed above. The other two were missiles for use against both land and sea targets. At one point the NATO Sea Sparrow was to be installed on the reactivated battleships; however, it was determined that the system could not withstand the over—pressure effects when firing the main battery.^[33]

[edit] Tomahawk land attack missile

The BGM-109 Tomahawk Land Attack Missile (TLAM) was first introduced in the 1970s, and entered service with the United States in 1983. Designed as a long-range, all-weather, subsonic cruise missile, the Tomahawk is capable of reaching targets at a much greater range that the 16 inch guns on the Iowa-class ships. When added to the battleships in the 1980s the Tomahawk became the longest ranged weapon carried by the battleships.^[34]

[edit] Harpoon anti-ship missile

For protection against enemy ships the Iowa class is outfitted with the Harpoon Weapons System. The system consists of four Mk 141 "shock-hardened" quad cell launchers designed to carry and fire the Boeing RGM-84 Harpoon anti-ship missile. Each Harpoon is placed in one of four Mk 141 shock-hardened quad cell canister launchers located alongside the aft stack; eight per side, in two pods of four. The weight of the Harpoon at firing is 1,530 pounds, which includes a booster weighing about 362 pounds. The cruising speed is 0.87 Mach and the maximum range is 64 nautical miles (nm) in Range and Bearing Launch mode and 85 nm in Bearing Only Launch mode.^[35]

[edit] Armor

Aside from its firepower, a battleship's other defining feature is its armor. Battleships are usually armored to withstand an attack from guns the size of its own, but the exact design and placement of the armor — factors inextricably linked with the ship's stability and performance — is a complex science honed over decades. ^[36]

The Iowa-class battleships' armor can be divided into the part above the waterline, which is designed to protect the ship against gunfire and aerial bombing, and that below the waterline, intended to protect the vessel from mines, near-miss bombs, and torpedoes.^[36]

Overall, Iowa-class armor is essentially the same as on the earlier South Dakota-class battleships. Both have an internal main belt, a change from the previous two North Carolina-class battleships that was reluctantly adopted because it was difficult to install and repair. But an external belt that could ward off 16-inch shells would have required a belt incline of 19° and a beam too wide for the Panama Canal.^[36]

The underwater armor includes side protection and a triple bottom, both multi-layered systems designed to absorb the energy from an underwater explosion equivalent to 700 pounds of TNT — the Navy's best guess in the 1930s about Japanese weapons. But unbeknownst to U.S. Naval Intelligence, the Japanese 24-inch-diameter "Long Lance" torpedo, carried a charge equivalent to 891 pounds of TNT.

The Iowa-class torpedo defense is virtually the same as the South Dakota's. Each side of the ship is protected by one tank mounted outside the hull and loaded with fuel oil or other liquid ballast, and an empty inboard tank, all running from the third deck to the bottom of the ship. The liquid tanks are to deform and absorb the shock from the explosion and contain most of the shards from the damaged structure. The inner void is expected to contain any leakage into the interior ship spaces. The armor belt is designed to stop fragments that penetrate the second torpedo bulkhead; however, tests in 1943 showed structural defects in the system.^[36]

[edit] Aircraft

The Iowa class used several types of aircraft for reconnaissance and for gunnery spotting. The early aircraft were floatplanes launched from catapults on the ship's fantail. They landed on the water, taxied to the stern of the ship, and were lifted by a crane back to the catapult.

[edit] Kingfisher

USS Missouri recovers a Vought OS2U Kingfisher during her 1944 shakedown cruise. Note the catapult below the plane, which was used to launch the planes off the battleship.

Initially, the Iowas carried the Vought OS2U Kingfisher, a lightly armed two-man aircraft designed in 1937. The ships typically carried three Kingfishers: two on the catapults and a spare on a trailer nearby.^[37]

The Kingfisher's high operating ceiling made it well-suited for its primary mission: to observe the fall of shot from the battleship's guns and radio corrections back to the ship. The floatplanes also performed search and rescue for naval pilots who were shot down or forced to ditch in the ocean.^[37]

[edit] Seahawk

In June 1942, the U.S. Navy Bureau of Aeronautics requested industry proposals for a new seaplane to replace the Kingfisher and Curtiss SO3C Seamew. The new aircraft was required to be able to use landing gear as well as floats.

Curtiss submitted a design on August 1, and received a contract for two prototypes and five service-test aircraft on August 25.^[38] The first flight of a prototype XSC-1 took place 16 February 1944 at the Columbus, Ohio Curtiss plant. The first production aircraft were delivered in October 1944, and by the beginning of 1945 the single-seat Curtiss SC Seahawk floatplane began replacing the Kingfisher.^[39]

[edit] Helicopters

Around 1949, helicopters replaced floatplanes on the Iowa class. They operated from atop of Turret 2 until the catapults were removed, allowing helicopter operations to shift to the fantail. The aft guns are forbidden to fire when a helicopter is on the aft deck.^[40]

Helicopters added a logistics role to gunnery spotting and search-and-rescue; they ferried troops and supplies between ships and to and from land bases. Like the seaplanes before them, the helicopters had no hangar facilities.^[1], but the Iowas did have support facilities for six types of helicopters: the UH-1 Iroquois, SH-2 Seasprites, CH-46 Sea Knight, CH-53 Sea Stallion and the LAMPS III SH-60B Seahawk.^[37]

[edit] Pioneer

Crewmen recover an RQ-2 Pioneer Unmanned Aerial Vehicle aboard Iowa. Pioneer drones launched from the Iowa-class battleships were steered into a large net on the ships, where they were recovered by the crew.

In 1985, the United States Navy, impressed with Israeli successes with unmanned aerial vehicles in the early 1980s, began looking for UAVs to provide imagery for gun spotters aboard the recently reactivated battleships. The result of this effort was the remote-controlled RQ-2 Pioneer, which made its first deployment in December 1986 aboard the Iowa.^[41]

Launched from the fantail using a rocket-assist booster that was discarded shortly after takeoff, a Pioneer used an aft-mounted, push-propeller engine to achieve speeds of up to 90 mph (40 m/s) with a mission endurance of about four hours. The Pioneer carried a video camera in a pod under the belly of the aircraft, which transmitted live video back to the ship so that the operators can observe enemy actions or fall of shot during naval gunnery. Because it was difficult to land the Pioneer without damaging itself or the ship, a large net was strung up for recovery as for a volleyball game, and the aircraft is flown into it.^[41]

Each battleship could carry as many as eight Pioneers, sometimes referred to as remote piloted vehicles (RPVs).

Pioneer garnered international attention for its use during the 1991 Gulf War, when it saw extensive use from the Missouri and Wisconsin. The latter became the first ship to have enemy forces surrender to one of its remotely controlled observation drone.^[41]

[edit] Engineering plant

The Iowa-class battleships are the fastest battleships ever launched, capable of sustained speeds of 33 knots (61 km/h) or better. The engineering plant consists of four General Electric double-expansion steam turbine engines, each driving a single shaft that turns one screw. The two outboard screws on the Iowa class have four blades and are just over 18 feet (5.5 m) in diameter. The two inboard screws have five blades and are about 17.5 feet (5.3 m) in diameter.^[1]

Eight Babcock and Wilcox M-Type boilers heat water in tubes to more than 800 °F (430 °C), producing 650 psi (4500 kPa) steam.^[40][1]

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 2100 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 (300 kPa) of pressure left. The LP turbine increases efficiency and power by extracting 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 the urinals and all but one of the toilets on the Iowa class flush with saltwater in order to conserve fresh water.^[1][42]

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.

[edit] Electricity

Electricity drives many systems aboard ship, including rotating the turrets and elevating the guns. Each of the four engine rooms has a pair of Ship's Service Turbine Generators (SSTGs)^[43] manufactured by Westinghouse. Each SSTG generates 1.25 MW for a total of 10 MW of electricity. The SSTGs are powered by steam from the same boilers that feed the engines. For backup, the ship also has a pair of 250-kW diesel generators.^[1]

To allow battle-damaged electrical circuits to be repaired or bypassed, the lower decks of the ship have a Casualty Power System whose large 3-wire cables and wall outlets called "biscuits" can be used to reroute power.^[44]

[edit] Radar & electronic warfare systems

Since the first commercial radar system was installed aboard the battleships USS Texas,^[45] battleships have been using radar for ariel reconascence, surface survalience, and as part of the fire control system for the battleship's guns. Since their modernization in the 1980s the four Iowa class battleships have also used electronic countermeasures systems for defense against enemy missiles and aircraft.

[edit] Radar

An AN/SPS-49 air search radar aboard the aircraft carrier Abraham Lincoln

Each of the four Iowa-class battleships are equipped with the AN/SPS-49 Radar Set, an L-band, long-range, two-dimensional, air-search radar system that provides automatic detection and reporting of targets within its surveillance volume. The AN/SPS-49 performs accurate centroiding of target range, azimuth, amplitude, ECM level background, and radial velocity with an associated confidence factor to produce contact data for command and control systems. Additionally, the contact range and bearing information is provided for display on standard plan position indicator consoles.^[46]

The AN/SPS-49 uses a line-of-sight, horizon-stabilized antenna to provide acquisition of low-altitude targets in all sea states, and also utilizes an upspot feature to provide coverage for high diving threats in the high diver mode. External control of AN/SPS-49 modes and operation by the command and control system, and processing to identify and flag contacts as special alerts are provided for self-defense support.^[46]

The AN/SPS-49 has several operational features to allow optimum radar performance: an automatic target detection capability with pulse doppler processing and clutter maps, ensuring reliable detection in normal and severe types of clutter; an electronic counter-countermeasures capability for jamming environments; a moving target indicator capability to distinguish moving targets from stationary targets and to improve target detection during the presence of clutter and chaff; the Medium PRF Upgrade (MPU) to increase detection capabilities and reduce false contacts; and a Coherent Sidelobe Cancellation (CSLC) feature.^[46]

The Iowa-class battleships are also equipped with the Radar Set AN/SPS-67, a short-range, two-dimensional, surface-search/navigation radar system that provides highly accurate surface and limited low-flyer detection and tracking capabilities. The AN/SPS-67 is a solid-state replacement for the AN/SPS-10 radar, using a more reliable antenna and incorporating standard electronic module technology for simpler repair and maintenance. The AN/SPS-67 provides excellent performance in rain and sea clutter, and is useful in harbor navigation, since the AN/SPS-67 is capable of detecting buoys and small obstructions without difficulty.^[47]

The AN/SPS-67(V)1 radar is a two-dimensional (azimuth and range) pulsed radar set primarily designed for surface operations with a secondary capability of anti-ship-missile and lowflier detection. The radar set operates in the 5450 to 5825 MHz range, using a coaxial magnetron as the transmitter output tube. The transmitter/receiver is capable of operation in a long (1.0 sec), medium (0.25 msec), or short (0.10 msec) pulse mode to enhance radar performance for specific operational or tactical situations. Pulse repetition frequencies (PRF) of 750,1200, and 2400 pulses/second are used for the long, medium, and short pulse modes, respectively.^[47]

[edit] Electronic warfare

A crew member monitors the SLQ-32 radar warning system console aboard the battleship USS Iowa

In 1967 Egypt sank the Israeli destroyer Eilat using a Soviet SS-N-2 STYX missile, prompting the Chief of Naval Operations (CNO) to consider creating a family of inexpensive Electronic Warfare suites to replace and/or complement existing and planned ship surveillance sensors in the early 1970s, a feeling increased when an analysis of the existing AN/WLR-1 and AN/ULQ-6 systems installed on most ships determined that neither system could counter an Anti-Ship Cruise Missile (ASCM) in time to prevent a hit. In addition, hard kill weapons were not effective because there was little early warning of an attack due to the characteristics of ASCMs. The resulting EW suite was the AN/SLQ-32(V), which debuted in 1979 and was capable of early warning of threat weapon system emitters and emitters associated with targeting platforms, threat information to own ship hard-kill weapons, automatic dispensing of chaff decoys, and Electronic Attack (EA) to alter specific and generic ASCM trajectories. This system, specifically the SLQ-32(V)3 varient, was fitted to the Iowa class battleships in 1980s for defense against enemy anti-ship missiles.^[48]

To counter the threat posed by enemy submarines the Iowa class were also outfitted with the AN/SLQ-25 Nixie, a towed torpedo decoy used on US and allied warships. It consists of a towed decoy device, and a shipboard signal generator. The decoy emits signals to draw a torpedo away from its intended target. The Nixie attempts to defeat a torpedo's passive sonar by emitting simulated ship noise, such as propellor and engine noise, which is more attractive than the ship to the torpedo's sensors. Active sonar is decoyed by amplifying and returning "pings" from the torpedo, presenting a larger false target to the torpedo.^[49]

[edit] Reactivation potential

USS Wisconsin, here at anchor in Norfolk, Virginia, is one of three Iowa-class battleships open to the public as museums, and was one of two maintained in the US Mothball fleet for potential reactivation.

After World War II, the United States maintained the four Iowa-class battleships in the United States Navy reserve fleets, better known as the "mothball fleet," and on several occasion reactivated these battleships for naval gunfire support. The U.S. Navy has held onto its battleships long after the expense and the arrival of aircraft and precision guided munitions led other nations to scrap their big-gun fleets.^[50][51] The United States Congress is largely responsible for this. The lawmakers argue that the battleships' large-caliber guns have a militarily useful destructive power lacking in the smaller, cheaper, faster, and longer-ranged guns mounted by U.S. cruisers and destroyers.^[52]

The Navy, which sees the battleships as too costly, is working to persuade Congress to allow it to remove Iowa and Wisconsin from the Naval Vessel Register by developing extended-range guided munitions and a new ship to fulfill Marine Corps requirements for naval surface fire support.

The Navy plan calls for the extension of the range of the 5-inch guns on the Flight I Arleigh Burke-class guided missile destroyers (USS Arleigh Burke to USS Ross) with extended range guided munitions (ERGMs) that would enable the ships to fire precision guided projectiles about 40 nautical miles inland. This program was initiated in 1996 with a preliminary cost of US $78.6 million; since then, the cost of the program has increased 400%. The results of the program have been similarly disappointing, with the original expected operational capability date pushed from 2001 to 2011.^[53] These weapons are not intended or expected to satisfy the full range of the Marine Corps NSFS requirements.^[54] The result of the latter effort to design and built a replacement ship for the two battleships is the Zumwalt-class destroyer, or DD(X). The DD(X) is to mount a pair of Advanced Gun System (AGS) turrets capable of firing specially designed Long Range Land Attack Projectiles (LRLAP) some 60 miles inland. The Navy currently expects sufficient numbers of DD (X) destroyers to be ready to help fill the NSFS gap by 2018 at the earliest.^[52]

On 17 March 2006 the Secretary of the Navy exercised his authority to strike Iowa and Wisconsin from the Naval Vessel Register, which has cleared the way for both ships to be donated for use as museums. The United States Navy and the United States Marine Corps have both certified that battleships will not be needed in any future war, and have thus turned their attention to development and construction of the next generation Zumwalt-class guided missile destroyers.

This move has drawn fire from a variety of sources familiar with the subject; among them are dissenting members of the United States Marine Corps, who feel that battleships are still a viable solution to naval gunfire support,^[55][56] members of the United States Congress who remain "deeply concerned" over the loss of naval surface gunfire support that the battleships provided,^[53] and number of independent groups such as the United States' Naval Fire Support Association (USNFSA) whose ranks frequently include former members of the armed service and fans of the battleships.^[57][58] Although the arguments presented from each group differ, they all agree that the United States Navy has not in good faith considered the potential of reactivated battleships for use in the field, a position that is supported by a 1999 Government Accountability Office report regarding the United States Navy's gunfire support program.^[54]

In response, the Navy has pointed to the cost of reactivating the two Iowa class battleships to their decommissioned capability. The Navy estimates costs in excess of $500 million,^[59] but this does not include an additional $110 million needed to replenish gunpowder for the 16-inch guns because a recent survey found that it is unsafe. In terms of schedule, the Navy's program management office estimates that reactivation would take 20 to 40 months, given the loss of corporate memory and the shipyard industrial base.^[52]

Reactivating the battleships would require a wide range of battleship modernization improvements, according to the Navy's program management office. At a minimum, these modernization improvements include command and control, communications, computers, and intelligence equipment; environmental protection (including ozone-depleting substances); a plastic-waste processor; pulper/shredder and wastewater alterations; firefighting/fire safety and women-at-sea alterations; a modernized sensor suite (air and surface search radar); and new combat and self-defense systems. The Navy's program management office also identified other issues that would strongly discourage the Navy from reactivating and modernizing the battleships. For example, personnel needed to operate the battleships would be extensive, and the skills needed may not be available or easily reconstituted. Other issues include the age and unreliability of the battleships' propulsion systems and the fact that the Navy no longer maintains the capability to manufacture their 16-inch gun system components and ordnance.^[52]

Although the Navy firmly believes in the capabilities of the DD(X) destroyer program members of the United States Congress remain skeptical about the efficiency of the new destroyers when compared to the battleships.^[54] Partially as a consequence the US House of Representatives have asked that the battleships be kept in a state of readiness should they ever be needed again.^[60] Congress has asked that the following measures be implemented to ensure that, if need be, Iowa and Wisconsin can be returned to active duty:

1. Iowa and Wisconsin must not be altered in any way that would impair their military utility;
2. The battleships must be preserved in their present condition through the continued use of cathodic protection, dehumidification systems, and any other preservation methods as needed;
3. Spare parts and unique equipment such as the 16 inch gun barrels and projectiles be preserved in adequate numbers to support Iowa and Wisconsin, if reactivated;
4. The Navy must prepare plans for the rapid reactivation of Iowa and Wisconsin should they be returned to the Navy in the event of a national emergency.^[60]

These four conditions closely mirror the original three conditions that the Nation Defense Authorization Act of 1996 laid out for the maintenance of Iowa and Wisconsin while they were in the Mothball Fleet.^[28][61] It is unlikely that these conditions will impede the current plan to turn Iowa and Wisconsin into museum ships.

[edit] Iowa class in pop culture

Illinois and Kentucky from the anime series Neon Genesis Evangelion. They are pictured here as they would have looked if they had been modernized in the 1980s

The Iowa class-battleships have been featured prominently in American culture. Iowa was the centerpiece for the book A Glimpse of Hell : The Explosion on the U. S. S. Iowa & Its Cover-Up which dealt with the events surrounding the 1989 explosion of her #2 turret. In 2001 the book was turned into a movie by the same name staring James Caan and directed by Mikael Salomon.^[62] Missouri was featured in the 1977 movie MacArthur, starring Gregory Peck, the 1983 television mini-series The Winds of War, starring Ralph Bellamy and Robert Mitchum, the 1992 movie Under Siege, staring Steven Seagal,^[63] and Cher's music video "If I Could Turn Back Time". Wisconsin was featured prominently in the news during the 1991 Gulf War, when she became the first ship to receive the surrender of enemy troops on the ground when her Pioneer drone recorded Iraqi soldiers waving white flags after being shelled by Missouri.^[41][64] Illinois and Kentucky, the two uncompleted Iowa-class battleships, made an appearance in the 1995 anime series Neon Genesis Evangelion; the two battleships become the only non-Evangelion machines to kill an angel when they destroy Gaghiel in 2015.

[edit] Notes

[edit] References

• Muir, Malcolm, Jr. The Iowa-Class Battleships: Iowa, New Jersey, Missouri, Wisconsin Blandford Press. ISBN 0-7137-1732-7
• Naval Historical Foundation. The Navy. Barnes & Noble Inc, China ISBN 0-7607-6218-X
• Keegan, John; Ellis, Chris, and Natkiel, Richard. World War II: A Visual Encyclopedia PRC Publishing Ltd. ISBN 1-85585-878-9
• William H. Garzke and Robert O. Dulin, Jr. Battleships: United States Battleships 1935–1992
• The Floating Drydock. United States Naval Vessels, ONI 222-US, Kresgeville, PA 18333
• Sumrall, Robert. "USS Missouri (BB-63) Warship Data 2". Pictorial Histories. 1-57510-050-9

[edit] Further reading

• Firing Procedure for the 16"/50 (40.6 cm) Mark 7
• Operating Instructions for Five Inch, 38 Caliber, Gun Crews

[edit] External links

Military of the United States Portal

Wikimedia Commons has media related to:

Category:Iowa class Battleships

• A comparison of seven battleship classes during WWII
• Thoughts on the battleships of WWII