The battleship USS North Carolina

The battleship USS North Carolina

Mounted atop the large fire control tower was a bow Mk-38 sight director for the main artillery. Not far from the bow conning tower there were two relatively thin standalone funnels for exhaust gases from the boilers (the first funnel was the slightly taller of the two). On both sides of the first funnel was located a Mk-38 sight director for controlling main and secondary artillery fire. Caps were fitted to the tops of both funnels to direct exhaust fumes towards the stern and protect fire control posts from smoke. The space between the funnels was initially used to mount boats and launches. At a later stage they were replaced with 40 mm (1.75”) L/56 Mk-2 Bofors anti-aircraft guns and their associated sight directors and fire control radars.
On the roof of a small stern conning tower another main artillery Mk-38 sight director was installed. It was based significantly lower than the one at a bow to protect the fire control post from smoke and the necessity to reduce the so called lifted weight. At the very end of the stern conning tower there was an Mk-37 long-range fire control sight, and on its sides the were solid cranes used for the lifting and lowering of boats. Interestingly both of these heavy devices survive on the battleship up to this day, although all life boats and launches were removed at the start of the Second World War.

 North Carolina in 1947 with a Measure 13 camouflage. Light anti-aircraft artillery has been removed. Visualization 3D: Stefan Dramiński

Armor protection system

The USS North Carolina’s armor was to fully protect the battleship against 356 mm (14”) Mk-16 projectiles fired from Mk-10 and Mk-11 guns and 406 mm (16”) Mk-5 projectiles fired from Mk-5 L/45. The development of heavier Mk-8 APC projectiles and the new Mk-6 L/45, Mk-8 L/45 and Mk-7 L/50 guns in June 1939, caused the necessity of strengthened the ships’ passive defence. However, it was too late to introduce major adjustments to the design and new battleships were not fully defended against new types of projectiles. It has to be remembered, though, that the latest American heavy guns were exceptionally powerful weapons and there was no match for them in the world. Bearing this in mind, the North Carolina’s armor deserves the highest grades, especially that many of its elements could not be damaged with the latest guns.
Main 305 mm (12”) thick [under water, 1.6 m off the lower edge, the thickness decreased to 168 mm (6.6”)] and 5.5 m wide belt armor made of A3 class armor based upon „all or nothing” system was 136 m long. Starting at the front of main artillery gun turret number 1’s barbette, it ended at the stern barbette of tower number 3. The ship’s side armor was angled outwards 15 degrees to increase its effective thickness against incoming enemy shells.. Armored sheets were bolted to the side plating (19 mm of STS steel) with huge double-sided bolts made of NS steel, welded at nuts on both ends. There was a 50 mm wide gap filled with concrete between armored sheets and side plating, which served as a sealer. Near the ammunition chambers behind the main board armor, there was yet another belt, 95-51 mm (3.7-2”) thick, inclined by 10 degrees. There were two vertical cross bulkheads, 282 mm (11.1”) thick, protecting the citadel at the bow and at the stern.
From the very beginning, North Carolina was designed for medium and long distance combat, and an appropriate system of horizontal armor was incorporated. The first (upper) deck was designed to cause the detonation of lighter bombs and projectiles, before they could reach the second (main armored) deck. It was 37 mm (1.45”) thick and was made of STS steel. The second deck, that is the main armored deck, was constructed from a combination of 92-104 mm (3.6-4.1”) B2 class special armor and 36 mm (1.4”) STS steel. Its function was to stop (shatter or damage) heavy bombs and armor-piercing projectiles before they reached the lower deck. The third (lower) deck was made of 16-19 mm (5/8-3/4”) STS sheets. Its function was to stop the remains of the projectile, minimize the explosive’s effects and catching the shrapnel which could be propelled off the construction elements of the main armored deck. At the stern, near the steering gear, the lower deck was covered with two layers of sheets: 166 mm (4.6”) STS on top of 36mm (1.4”) STS.
The main armament and turrets were very heavily armored. The barbettes were made of 406 mm (16”) A3 class armor, sides of turrets of 249 mm (9.8”) on 19 mm (3/4”) STS plating, rear walls of 300 mm (11.8”) on the same kind of plating; the roofs made of 178 mm (7”) B2 class armor were attached to solid MS steel girders with 19 mm STS plating. Amazingly thick (406 mm of superior B2 class armor on 19 mm STS base), inclined at 35 degrees turrets’ front plates need to be noticed. The main command post was also heavily armored. There was 406-373 mm (16-17.7”) thick armor on the sides and 178 mm (7”) B2 class armor plating on the roof.
Secondary artillery gun turrets were equipped with light, 49.5 mm (1.95”) thick armor, the pilot house and navigation bridge were covered with 51 mm (2”) armor, and there was 37 mm (1.47”) plating protecting funnels, conning tower and sight directors. All these elements were made of STS Mode 2 class steel armor.

Underwater protection system