North Carolina Class, U.S. Battleships

Naval Historical Center #NH 80988

ONI 222

Specifications:

The North Carolinas were the first U.S. battleships commissioned since the Colorados in 1921-1923, and plans were started in 1928, years before they were actually laid down. Under the treaty framework, tonnage was limited to 35,000 tons and guns were initially limited to 14" (356mm). This was increased to 16" (406mm) after they were laid down but before they were launched. Proposed designs were generally "slow" (23 knots) or "fast" (30 knots) and varied from the odd (hybrid battleship-carriers with three catapults and 20 bombers forward and two quadruple turrets aft, Scheme F) to more conventional designs. Design philosophies shifted as different designers entered and left the design group, and a wide range of design concepts were reviewed. Eventually, some speed (27 knots instead of 30 knots) and armor (protection against 14" shells instead of against 16") were sacrificed to attain the desired armament (twelve 14" guns as laid down, nine 16" as completed). The speed requirement was selected specifically to allow the North Carolinas to exceed the speed of the Japanese Kongos; Naval Intelligence was unaware that the Kongos had already been modernized to a speed of better than 30 knots.

The ships were designed during a period of rapid improvement in machinery. The Bureau of Engineering initially pushed for the adoption of a 1,200 psi / 950 degrees F plant, but eventually agreed to a 565 psi / 850 degrees F plant — still remarkable at a time when plants being used in most other ships were 300 psi / 572 degrees F. This advanced machinery made the speed of the North Carolinas possible. The twin rudders provided a very tight turning radius, which allowed Washington to turn inside of British carriers and battleships when she served with the British Home Fleet in 1942.

Machinery dispersal was enhanced by the use of a unit arrangement, with four self-contained compartments each with two boilers and one set of engines. This was cramped and made heavy armor protection impossible for the uptakes, but it minimized the effects of single torpedo hits.

The North Carolinas had excellent firepower, and their numerous 5"/38s made for a substantial antiaircraft capability. They also featured a sloped armor belt, which improved its effectiveness by perhaps 30%, so that a 12" belt nominally gave the same protection as a 16" belt. The zone of immunity was 20,000 to 30,800 yards (18,200 to 28,200 meters) versus 14" shells and 21,300 to 32,000 yards (19,500 to 29,300 meters) versus light 16" shells. The deck armor was designed to be proof against a 1600 lb (726 kg) armor piercing bomb dropped from up to 8750 feet (2670m). If there was anything lacking in the design, it was the machinery and underwater protection.

Once launched, problems with vibrations were encountered, which led to a lengthy delay before the ships were considered combat ready. Various fixes were tried, and North Carolina earned the nickname "Showboat" for the large number of day voyages out of New York harbor. The use of four bladed propellers on the outboard shafts and five bladed propellers on the inboard shafts reduced the vibrations enough to permit the ships to join the fleet. But the problem was never entirely fixed: The after range-finder vibrated excessively at certain speeds, the after fire control tower had to be fitted with large external braces, and the turbine and gear casings also had to be braced.

North Carolina was hit by a torpedo from I-15 on 15 September 1942. The torpedo hit the most vulnerable portion of the ship (abeam the #1 turret) and penetrated the side protective system, with the flash from the explosion penetrating the forward turret handling room. This put #1 turret out of commission, but effective damage control allowed a high speed of 18 knots to be maintained and eliminated the 5.5 degrees of list within six minutes.

Washington took part in the Naval Battle of Guadalcanal and gutted Kirishima with nine 16" shells (out of 75 fired) and 40 5" shells from a range of 8,400 yards. The Japanese scuttled Kirishima the following day. On 1 February 1944, Washington rammed Indiana, demolishing Washington's bow. The captain of Indiana admitted responsibility for the collision at the subsequent Board of Inquiry and was relieved of command.

Both North Carolina and Washington finished out the war in the Pacific. They were retained in the postwar fleet slightly longer than the subsequent South Dakota class, largely because of their greater habitability due to a less cramped design.

Units in the Pacific:

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References

DANFS
Dullin and Garzke (1976)
Friedman (1985)

Gogin (2010; accessed 2013-2-4)

Whitley (1998)

Worth (2001)

The Pacific War Online Encyclopedia © 2007-2009, 2013-2014 by Kent G. Budge and John E. Kollar.  Index

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