I was looking at this picture (Figure 1) of the USS Missouri firing a six-gun salvo and I thought that I could learn something from it.
Figure 1: Battleship Missouri Firing a Six-Gun Salvo.
In Figure 2, I highlighted the six shells in the air. The shells from each gun on a turret appear to be fired at a different time.
Figure 2: Circle Shows the Salvo Shells in the Air.
I started to search around the web and I dug up some information. The following quote was very interesting (Source: Battle Line: The United States Navy, 1919-1939). I have highlighted a particularly interesting piece:
The emphasis on maximizing the number of guns firing in a single salvo led to unexpected problems. The blast from one gun could interfere the accuracy of others fired at the same time if the guns were close together. This would result in increased dispersion and “wild shots” — shells landing abnormally far from the center of the pattern. Occasionally, shells were even observed to “kiss” – to brush against each other — in flight on the way to the target. The problem was solved by the introduction of delay coils, electrical devices designed to allow a slight pause in the closure of the firing circuit to ensure that neighboring guns did not fire exactly at the same time. After their introduction, accuracy noticeably improved.
I found the following quote on this web page for the USS New Jersey, a battleship of the same class as the USS Missouri.
GUN FIRING ORDER L, R, C, BARRELS.
FIRING DELAY 0.06 SECOND. THERE IS NO DELAY FOR THE LEFT BARREL.
So it looks like there is 60 msec of delay between the guns.
Math Encounters Blog 