County of plaque: Ne Hanover County
Location of mark: Battleship North Carolina, Wilmington
Plaque erected by: national Park Service
Generously Funded by Charles Smith, Gunner's Mate 3/c, NORTH CAROLINA "Gunner Gang:" United States Navy 1945-1949
Marker text:
40mm Quadruple Mount
This is a 40mm Swedish Borfors medium range anti-aircraft gun. The Battleship began installing 40mm guns in the fall of 1942. They replaced the inadequate 1.8 inch guns initially installed on the ship.
World War II started in Europe in 1939. The counties at war developed better and faster aircraft. The United Stats Navy soon realized that our ships would need to add more anti-aircraft guns to protect themselves.
Most of the 40mm gun crew consisted of ammunition loaders and passers. They worked hard to keep the ammunition flowing to meet the guns' rapid rate of fire. Ammunition came in a clip of four shells. Ammunition loaders placed clips into the openings at the top of the guns.
The 40mm guns were normally electro-hydraulically power driven. The slow hand-cranked manual method was used when power was disabled.
This gun mount was aimed and fired by a nearby director.
Mark 51 Director:
Aiming & Firing 40mm Guns
Director refers to a gun director. It directs the aim and fire of the assignor gun. Two mwn, called a pointer and range setter, used the nearby director to aim and fire the 40mm quadruple gun mount.Their targets were enemy aircraft.
By World War II, aircraft were so fast taht by the time you fired a gun, the aircraft was beyond the place you aimed. A director could calculate an aircraft's dimension of flight and speed as well as the speed and flight of the bullets. The pointer looked through the gun sight which tracked the target. He also fired the gun. The range setter stood to the right side and made changes in the range (distance) setting as needed.
You may have climbed on the 40mm guns, turned the hand-wheels, and watched the barrels elevate (move up and down) and the entire mount train (turn from side to side). This manual method of operation was slow, difficult, and not very accurate. It was available is the power drive were not working.
The 40mm guns were normally electro-hydraulically power driven with the nearest director controlling aim and fire.