Wanting a swivel gun or similar

[Fly103]

Ive been shooting flintlocks for 2 decades now and have a pair of kibler builds under my belt. One of my other hobbies has me looking for a cannon though. As a member of the local sailing club I think it would be wonderfuly naval to start our races with a cannon shot vs a buzzer. So I'm looking for a "noise maker" resembling a swivel gun or signal cannon. I was considering just using a spare harpers ferry pistol barrel for the task but I thought I would ask here first to see if someone knew of a manufacturer making a barrel for a stanchion mounted swivel gun or signal cannon. Need not fire projectiles, just powder and a wad. Polished brass or bronze would almost be better in this case just for looks.

Anyone know of anything similar to what I'm after?

Chris