Naval Gunnery

Naval Gunnery

In the modern era, from Dreadnought to Missouri, the problem of putting rounds on target with the new big guns was grappled with by the best mathematicians. There were so many factors involved with the new long-range warfare that it meant low hit rates which in turn led to the doctrine of firing as many shells as possible as quickly as possible... which of course led to installing lots of the new big guns on warships.

The need to have the maximum number of guns firing in a single salvo caused accuracy problems. The blast from one gun interfered with the others fired at the same time. This resulted in dispersion at the target with some shells landing far outside the center of the firing pattern. Shells even sometimes hit each other in flight on the way to the target. Obviously the disturbed air around the big shells was a problem for accuracy. The British experimented with moving the center barrel of a 3 barreled turret back from the other two. But the issue was eventually solved by delay coils -- electrical devices that allowed a pause in the firing circuit which meant the guns didn't fire exactly at the same time. The accuracy of the big guns improved with the delayed firing sequence.

The USN tested different timing and came up with a 0.06 second timing delay. The gun firing order for the 16-inch turrets was left, right, center with no delay for the left barrel. So the left gun would fire on the trigger pull and six hundredths of a second later the right gun would fire and then six hundredths of a second after that the center gun would fire.

Source, Battle Line: The United States Navy, 1919-1939