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BB61 USS Iowa BB61 broadside USN

USS Iowa (BB-61) fires a full broadside on 15 August 1984 during a firepower demonstration after her recommissioning.

The Iowa Class Battleship was a battle ship class used by the United States of America. It was commissioned and decommissioned several times between 1943 and 1992. Two of them are now being used as museum pieces., while the other two are looking to be sold, but whoever buys them must keep and maintain them in a constant state of readiness encase the United States Navy ever needs them again, in which case they would be transferred back to the Navy.

Armor[]

Like all battleships, the Iowa carried heavy armor protection against shellfire and bombs with significant underwater protection against torpedoes. The Iowa’s armor scheme was 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) away. The magazines and engine rooms were protected by an armored belt 12.2 inches (310 mm) thick, which sloped to give an effective vertical thickness of 13.5 inches (340 mm). Their armor was not sufficient to protect against guns equivalent to their own 16-inch/50-caliber guns; increasing the armor would have increased weight and reduced speed. Missouri and Wisconsin incorporated the most significant change in armor from the South Dakota class: the increase from 11.3 inches (290 mm) to 14.5 inches (370 mm) of the vertical armor on the forward armored bulkhead, the conning tower, and the turret barbettes. The extra armor provided protection from fire directly ahead, which was considered more likely given the high speed of the Iowa class. The installation of armor on the Iowa-class battleships also differed from those of earlier battleships in that the armor was installed while the ships were still "on the way" rather than after the ships had been launched.  

Armament[]

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 the barbettes. These guns fire explosive– and armor-piercing shells, and can fire a 16-inch (410 mm) shell approximately 23.4 nautical miles (40 km). The guns 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 (410 mm) 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 pounds (121,500 kg) with the breech. They fire projectiles weighing from 1,900 to 2,700 pounds (850 to 1,200 kg) at a maximum speed of 2,960 ft/s (820 m/s up to 20 miles (32 km). At maximum range, the projectile spends almost 1½ minutes in flight. The maximum firing rate for each gun is two rounds per minute.

Uss iowa bb-61 pr

USS Iowa firing

800px-USS Wisconsin (BB-64) launching Tomahawk

USS Winconsin

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 between 85 and 110 men to operate.The turrets are not actually attached to the ship but sit on rollers, although they do have retaining clips. 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 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.

The large-caliber guns were designed to fire two different conventional 16-inch (406 mm) shells: the armor-piercing Mk. 8 round for anti-ship and anti-structure work, and the Mk. 13 high-explosive round designed for use against unarmored targets and shore bombardment. Interestingly, when firing the same conventional shell, the 16"/45 caliber Mark 6 gun used by the fast battleships of the North Carolina and South Dakota classes had a slight advantage over the 16"/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 the Mark 6: 23.64 miles (38.04 km) vs 22.829 miles (36.740 km).

All or a portion of this article consists of text from Wikipedia, and is therefore Creative Commons Licensed under GFDL.
The original article can be found at Iowa Class Battleship and the edit history here.

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