Really Big Bore


Can anyone help settle a friendly argument? One guy says that when the battleship Iowa fires all nine of its 16-inch tubes simultaneouly with the turrets aligned 90 degrees to the ship’s centerline, the ship moves sideways some distance. This guy served on Iowa, and ought to know. Another guy says no way. Even at 2,000 pounds per projo (9 tons total), the ship’s mass is so great, it would not move.

Here’s a pic that seems to show the ship moving sideways.

Any opinions? Look at the wake right at the bow (the very front of the ship) at the waterline.




That question is older than most Gunners Mates. There’s no simple answer. Read about it here. … REING.html



Mel–The Laws of Physics says the firing would be like a fly on an elephants back. The ship would not move even an inch. On the Old Forum, this was discussed in detail with a reference to a web site with all the mathematics showing how insignificant the firing is. You might try searching the Archives for that thread. Or a Google search should turn up that web site I mentioned.



It looks like there are two threads on the same subject. Perhaps you can combine them and make it easy for me to decide which one to reply on?!?

If you do, please use your skills to remove this post!


Dave–They are now merged. It seems my answer was trumped by the link given by Ray. BTW, that link is NOT the web site I referred to. I’ll see if I can find it.


Found it. Here is the web site with all the math on this subject.


Thanks Ron,

Great site in general and a very good analysis of the physics at hand.

My take on this eternal question has always been: Yes, there is movement, (has to be) but not very much at all and certainly not enough to see. The very interesting aspect of water movement as displaced by muzzle blast I had never considered! The entire site Ray referenced is also worth a good look at by the way.

Sad we won’t likely see such fine big guns in use ever again.



DaveE is correct, there has to be movement. For every action there is an equal and opposite reaction. The question is whether it amounts to actual movement in the water or just rocking the ship sideways. Since these salvos are usually fired when the ship is under way you would get some movement i would imagine, a bit like a car getting caught by a momentary crosswind.


Wasn’t the last time the 16" guns were used in combat the 1991 Gulf War?


My though would be that, with the guns being fired perpendicular to the centerline, due to it being applied to one extreme of the ship it would create a torque force that would rock the ship but not push it sideways, much like a person firing a rifle or shotgun.
Now if the turrets were aligned fore and aft and the rear turret was fired I would expect an increase in speed, however small (possibly only hundredths of a knot) and vice versa if the forward turrets were fired.
Now due to water displacement I can see it pushing the ship sideways some and then sucking it back in.

I have just read the link Ray provided which puts an end to my theory.

Falcon-Looks like she was decommissioned in 1991


I think the New Jersey fired a few rounds into Lebanon way back when. Maybe in the '80s. That’ll give me something to research.


OK, here’s what I’ve found. It appears that the USS Wisconsin BB64 was the last battleship to fire her 16" guns in anger on Feb. 28, 1991. Having fired a total 528 16" rounds into Iraq in support of the 1st Gulf War.

Here’s a little vid of what is purported to be the LAST firing(not in anger) of these guns.

Got to see a salvo of 6" fired a couple of times. Can only imagine what these mammy-jammies sounded and felt like.

And just found this snippet. … re=related

And this : … re=related


Now that you’ve seen what GMGs (Gunners Mate Guns) got to play with, here’s what REAL shootin’s all about.

GMMs (Gunners Mate Missiles) toyed with some of the biggest Estes rockets made.
The gun shots in the second half are from a similar mount that I was allowed to fire two rounds from. 5" 54cal. Really liked the guns. Loved the missiles. … re=related

Rick (GMM2 '72-'76)

Hey Ray, did they have rockets when you were in? Oh yea, now I remember, some guy wrote a song about it:

“. . . and the rockets red glare, gave proof. . . .”



Size doesn’t matter.



That’s what she said.