Designing the U.S.S. NORTH CAROLINA (BB-55)

When the U.S. Congress approved the building of new battleships in the early 1930s, ship designers had to accept compromises imposed by a worldwide treaty. The Washington Naval Treaty of 1922 limited the weight of capital ships (battleships) to 35,000 tons standard displacement and the main guns could not exceed 14 inches. These restrictions meant there were trade offs among the battleship’s armament, armor, speed and endurance.
 
The United States needed battleships to travel across the Pacific Ocean. And that meant designing a ship’s hull large enough to carry extra fuel and water for the boilers. So the battleship needed a large, heavy steel hull and great engine power (heavy machines) to move it. These factors meant more compromises in armament, armor and so forth. Over 50 designs for the new NORTH CAROLINA-class were prepared and evaluated.
 
The NORTH CAROLINA was a state-of-the-art battleship for the late 1930s. Design innovations included:

• Sweeping flush deck unbroken from bow to stern
• Hull shaped to reduce resistance and increase efficiency at high speed
• Massive superstructure with multiple platforms for men and equipment
• Fire control directors with sweeping fields of vision
• Secondary battery (5-inch) guns on or above the main deck in rotating armored mounts
• Engine rooms arranged lengthwise, separated by strong watertight bulkheads

 

The Battleship’s keel was laid on October 27, 1937. The immense steel I-beam was nearly as long as the ship. Smaller I-beams were attached at right angles to form the ship’s ribs and more were attached lengthwise. Steel plates were riveted or welded to the beams to form the hull. Construction lasted more than 2-1/2 years. The hull was so immense by the standards of the day that the building ways at the New York Navy Yard were lengthened and strengthened.
 
June 13, 1940, the NORTH CAROLINA was launched into the East River, New York.
 
The NORTH CAROLINA spent another 10 months “fitting out,” a continuation of the building process. A ship is usually launched with the main hull structure done but without the thousands of tons of machinery, weapons and equipment. A fitting out pier had heavy cranes to work alongside the ship from bow to stern.
 
On April 9, 1941, the NORTH CAROLINA was commissioned. The ship and her company were ready to begin tests and training operations at sea. The event received international news coverage and Secretary of the Navy Frank Knox declared “the NORTH CAROLINA is one of a new line of ships that will give the United States unchallenged supremacy on the seas.”
 


Basic Design  

 
The battleship is divided into decks. Below the main deck, in order, are: second deck, third deck, first platform, second platform, inner bottom. A platform deck does not run the full ship’s length. Forward of Turret I is a half deck for officers’ quarters between the main and second decks.
 
Each deck is divided into compartments formed by bulkheads (walls). There are more than 1,000 compartments on board. These are divided into about 130 watertight spaces. In the event of collision or battle damage flooding is kept isolated so the ship can remain afloat.
 
The superstructure rises above the main deck, 120 feet above the waterline. Its elevations in order are 01 level, 02 level, 03 level, and up to the 0-10 level, which is 15 “stories” above the inner bottom. This soaring tower replaced the tripods and cage masts of earlier ships.
 
The main deck has a teak surface to help absorb shrapnel, sound, heat and cold. Teak contains a great deal of oily resin which helps the wood resist dry rot and other wood-destroying fungi. It also protects the steel from the effects of sun, salt and water, and provides more cushion underfoot. The sailors would routinely holystone the deck, which meant using a brick to scrub it with soap, water and pumice. The oily resin rose to the top and refinished the deck. The original teak deck was replaced in 2001.
 
Notice the markings on the ship’s hatches. Certain hatches had to be closed during general quarters to maintain watertight integrity. The markings told the crew which hatches to close and when they could be opened.
 

Armor
 

Varying thicknesses of armor protect the battleship. An armor belt on the exterior of the hull, inclined at 15 degrees, tapering from 12 to 6.6 inches protects the center portion of the ship below the main and second decks. Inside this box-like structure, a “citadel,” the ship’s vital components are protected from the shells of opposing battleships, torpedoes and bombs. Additional patches of armor protect the gunpowder magazines. The Battleship’s armor was designed to withstand the probable enemy’s main guns. In the 1930s that meant 14-inch guns firing 1,500 pound projectiles at ranges between 19,000 and 30,000 yards.
 
The decks are made of steel plate, designed to help protect the ship from new, high explosive bombs. Under the teak, the main deck armor (1.45 inches) was thick enough to trigger the bomb’s detonator. The second deck (5 inches) was designed to absorb the full explosion. The third deck (.75 inches) stopped any flying pieces of the second deck from reaching vital areas below. The Battleship has about 15,000 tons of steel armor plate, which is about 42% of her weight.
 
A Japanese torpedo struck the Battleship’s hull 20 feet below the waterline, well below the side armor of Turret I. It tore a hole 18 feet high x 32 feet wide, killed five men, and flooded the area with about 1,000 tons of seawater. The ship was designed to withstand a torpedo blast up to 700 pounds of TNT. The Japanese torpedo carried a charge of 891 pounds. Based on this experience, the newer IOWA class ships had improved underwater protection.
 

Second Deck, August 1941
 

The ship’s daily living spaces are located on the 2nd deck. On this deck are sleeping (berthing), eating (messing), and food preparation areas. Also found here are the barber shop, sick bay, post office, stores, church, and other areas that make the ship seem like a floating city. More guns and men were added to the ship during the war, so more berths were needed. For instance, “Crew’s Mess C-205-1L” on the stern was changed into a berthing space.
 

Third Deck, August 1941
 

The 3rd deck contains a variety of spaces, including offices, repair shops (electrical, machinery), store rooms, crew’s quarters, and two radio rooms. Aft, near the stern, are the laundry, cobbler, tailor, and print shop. During the war, the Battleship was home to about 2,300 men and they had to be fed three meals a day. Large refrigerated compartments on the 3rd deck provided 8,000 cubic feet of space for frozen meat and fresh vegetables, fruits, butter and eggs. The ship’s capacity for fresh provisions was 90 days. The ship’s Brig is also located on the 3rd deck.
 

First Platform, 1941
 

Radio central, coding room, damage control, and the main (16-inch guns) and secondary (5-inch guns) battery plotting rooms are located deep inside the protected armored citadel. The areas were designed so they could be sealed airtight for up to ten hours. An air conditioner unit provided cooled, purified, and recirculating air.
 

Change Over Time
 

The Battleship commissioned in April 1941 is not the same ship you see today. There have been changes over time to the ship’s design. The Battleship made visits to Navy yards during the war for repairs, new guns and equipment. The ship stayed in dry dock for one or two months depending on the work. The schedule included:
 
• Pearl Harbor, October 1942
• Pearl Harbor, March and April 1943
• Pearl Harbor, May 1944
• Bremerton, Washington, August and September 1944
• Pearl Harbor, May and June 1945
 
The first changes to the Battleship began to happen in December 1941 when orders were issued for “strip ship;” a process to prepare for wartime conditions. Extraneous items and flammable materials were removed. The list was long and varied, including ladders, deck awnings, boats, tables, built-in movie machines, excess bedding, door and window curtains, sofas, officers’ trunks, the spare anchor and items that could become a fire or missile hazard. Linoleum from the interior decks was stripped. Rugs were removed from the wardroom, the captain’s, admirals, and executive officer’s cabins. The silver service and its cabinet were removed.
 
The Battleship was designed with a beautiful library, managed by the ship’s chaplain. When “strip ship” orders came through Chaplain Albert convinced the captain to keep the library books so that the crew could have some limited recreation. The glass fronts on the bookcases were replaced with metal mesh.