Cpt Ed, intoodeep and Tracy, Thanks for the compliments and PM's sent.
Tracy, You're right, I modeled this after the Steward or Sculler type Lyle gun. like the photo below.

Also, If you want it closer to the original, I can cut the elevation tabs down to three holes high.
Douglas, Would this be a ship made of pallets? I can see a line throwing contest happening. That would be interesting and you would never have to leave the firing line to retrieve the projectile. Just need to find a volunteer to hold the line like the video below.

Victor, You're making more work for me good buddy.

In all seriousness, I'll consider this. It's not the easiest place on a barrel to stamp letters though.