Do I need to work up how the ship got there. I not have a ship that can sail at open sea. 

It can join as a ship that was scrounged up and maybe was part of a battered and escaped river flotilla, or joined the last stand at the mouth from down river maybe. 


Also do I need super accuatte stats like gun weights and calibres. 

I was generally going with the guns being longer barreled and higher velocities. 

Fitted out for sieges they fire longer, and hit hard but that they take longer to reload and bring to ready again. 

Even with they swinging back on a cradle to counter there lengh meaning the muzzle cannot be loaded otherwise and offset so they can fit each gun swinging the full width of the ships lower deck. 

Halves your gun volume but increases the armaments possible size over larger number of regular guns. 

Maybe im ovr planning this lol