How are battle ship gunnery caliberated?

Answer 1

Battleship guns in WW2 were divided into categories. The main guns/turrets were used against surface targets and shore targets. Later on in the war a projectile, similar to a shotgun shell, were used in antiaircraft rolls. Next guns were the five inch guns. These were dual purpose guns used on air, surface and shore targets. Both the main guns and secondary guns could be controlled either locally or from fire control. Local fire used sights mounted on each gun to aim and each gun fired independently of one another, on order from the commanding officer. Remote control was sighted by either a fire control director or gun plot in gunnery control. The main guns were aimed by plotting the target on a map, entering inputs into the fire control computer. Yes computer, they had them in WW2 but not like a computer of today. This computer is mechanical. Using gears that are timed to give an answer to the problem entered using hand cranks to enter ship corse, speed, temperature, barometric pressure, bearing to target, projectile. These are many inputs that this mechanical computer will give a solution to Lay and point the main guns. When on target the guns are fired from gun control or also called gun plot. Now to what you call calibrate we called synchronize the gun with the director to the computer. First there are what is called benchmarks on the same deck as the gun. These are precision aligned and welded in reference to the ship centerline. These are angled so that they are visible to both the gun and the fire control director. The fire control director is located several decks above the gun as well as the pilothouse. It is so high because it can see further than the sights on the gun. This is so that the maximum range can be achieved. These benchmarks are nothing more than a cross. The sight of the gun and the director are laid on the cross. The difference between the two is recorded and put into the computer. These guns are not one shot kill guns. Usually corrections are given to plot from fire control who is watching the fall or splash of,the projectiles. Corrections are constantly given due to the ship moving and if firing at a surface target the movement of the target. The corrections are dialed into the computer with is hooked through synchros to the main guns. Usually a target hit could be had after no more than three salvos.