North Carolina class battleships

The two North Carolina class battleships were the first new American battleships to be built after the 'building holiday' agreed in the Washington Naval Treaty.

The design of the North Carolina class ships evolved over some time, and changed repeatedly. This was partly because the US Navy had a decade to think about its new battleships and partly because the 35,000 ton limit imposed by the Washington Treaty was only 2,400t above the weight of the Colorodo class ships, the last US battleships completed after the First World War. Despite this limited increase in weight the new ships were expected to carry more powerful main guns and to be better armoured.

At first the US Navy's General Board wanted to follow the same design principles as on their earlier ships, focusing on firepower and armour at the cost of speed - the Colorado class had reached 21kts, the cancelled first South Dakota class would have made 23kts and the plan was to aim for a similar speed. The General Board did acknowledge that other countries were adopting a different plan, and in 1935 it examined the fast, well-armoured and well-armed ships being built overseas (many of which came in somewhat over the 35,000ton limit). After this study was complete the Board approved a design for a 30kt ship armed with nine 14in guns and armoured to resist 14in shells. At the last minute the Chief of Naval Operations rejected this design and proposed an alternative capable of 27kts and armed with 11 (later 12) 14in guns carried in three turrets. The higher speed was chosen partly because of the threat from the Japanese Kongo class battlecruisers, capable of 27.5kts, and partly because the new battleships needed to operate with the faster aircraft carriers.

Early in the design process it wasn't clear what size guns the ships would carry. During negotiations for a new naval treaty the British were pressing for the adoption of a maximum size of 14in guns in new battleships. The US Navy wasn't keen on this idea, but in October 1935 agreed to this limit as long as all signatories to the earlier Washington Treaty agreed to the new limit. In the meantime the navy began work on the design of a battleship that could be armed with either quadruple 14in turrets or triple 16in turrets. The final decision only came after Japan rejected the 14in limit in March 1937 (just as they were about to begin work on the 18in armed Yamato class). This allowed the US to evoke the 'escalator clause' in the London Treaty and adopt 16in guns for their new ships.

The armour on the North Carolinas was designed to be immune to 14in fire over the magazines at 20,000-33,000 yards. The immune zone was reduced to 21,000-27,000 yards against 16in shells. It was actually thinner than the armour on the Colorado class ships but was sloped more effectively, retaining the same amount of protection but saving weight. More weight was saved by using three triple turrets in place of the four twin turrets of the Colorado class.

More weight was saved by the use of more modern high-pressure boilers with high-speed double reduction turbines. These were lighter than the engines used on the Colorado class but provided four times more power!

The two North Carolina class ships were authorised as part of the Fiscal Year 1938 budget. North Carolina was actually laid down in October 1937 and Washington in June 1938. Both ships were launched in June 1940 and were commissioned in April and May 1941, months before the attack on Pearl Harbor.

Both ships entered service just before the US entry in the Second World War, but they weren't full effective until early in 1942 because of propeller vibration problems.

The North Carolina class ships were more comfortable than the second South Dakota class ships which followed, although the South Dakotas were probably more effective warships.

Neither ship was greatly modified during the war, although they did get a more powerful mix of light and medium anti-aircraft guns. Both ships ended the war with fifteen quad 40mm mountings. The North Carolina received thirty six 20mm guns in twenty single and eight twin mountings while the Washington got sixty three single, eight twin and one quad 20mm mountings for a total of 83 20mm guns. 

The North Carolina supported many of the island invasions of 1943-45, performing a mix of carrier support and bombardment duties. She was also present at the battle of the Philippine Sea but as with all of the fast battleships missed the chance of surface combat. She was briefly used as a training ship for midshipmen but was decommissioned in 1947.

The Washington had a similar career, but with one major difference. On 13-14 November 1942 she became the only one of the US fast battleships to fight an enemy capital ship when she inflicted mortal damage on the battleship Kirishima (she was built as a Kongo class battlecruiser but rebuild in 1927-30 when her armour was almost doubled). She was decommissioned in 1947 and struck off in 1960.

Displacement (standard)

37,484t

Displacement (loaded)

44,377t

Top Speed

28kts

Range

17,450nm at 15kts

Armour – belt

12in-6.6in on o.75in STS backing

 - armour deck

5.5in-5in with 1.45in weather deck and 0.62-0.75in splinter deck

 - bulkheads

11in

 - barbettes

14.7in-16in

 - turrets

16in face, 7in roof, 9.8in side, 11.8in rear

 - CT

14.7in-16in, 7in roof

Length

728ft 9in

Width

108ft 4in

Armaments

Nine 16in/45 guns in triple turrets
Twenty 5in/38 guns in twin turrets
Sixteen 1.1in guns in four quad mountings
Twelve 0.5in guns
Three aircraft

Crew complement

1880

Ships in Class

 

USS North Carolina BB55

Preserved 1961

USS Washington BB56

Sold 1961

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How to cite this article: Rickard, J (13 June 2012), North Carolina class battleships , http://www.historyofwar.org/articles/weapons_north_carolina_class_battleships.html

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