All of this leads me unavoidably into another book recommendation. The most thorough book I know of on US naval guns (muzzle-loading) is Spencer Tucker's ARMING THE FLEET U.S. Navy Ordnance in the Muzzle-Loading Era, U.S. Naval Institute, Annapolis MD 1989.
The strength is the drawings and photos (all black and white.) Tucker went into the National Archives and photographed hundreds of original drawings of US Navy cannons, then redrew them to the same scale for presentation side-by-side in the plates of his book. His scholarship is unquestioned, he's a Phd in History and has held various prestigious "chairs" at institutions including lately VMI, his alma mater.
Tucker was working from one disadvantage, he wasn't a "cannon buff" in the same way Ripley and Olmstead were. Therefor you will find errors such as his confusion over the M1835 Coehorn, which I'm sure he found embarrassing when Olmstead or someone else pointed it out, if they ever did. I've recently begun talking to Dr. Tucker, since he's here in VA, about some of the never-answered questions I have on ordnance, and he's been very helpful and accommodating.
I just found another error I'm going to tell him about, on pp. 154 he states "No Treadwell guns of the Army pattern survive..." Of course, that's wrong, the one known gun of that pattern is in my collection and I might have even posted pix of it on this board.
You should be able to pick up the Tucker book from one of the internet sales venues quite reasonably since it has been out for a good while.
I recommend this book highly as it is unique information (particularly the drawings) available nowhere else today.
It is certainly a "must have" for anyone building any kind of model naval cannon.
