Here are some pix I took in the USNA museum back in March 1986. I took dig. pix of my color prints.
The mortar is about a foot long and as I recall, 4.5-inch bore.
The dimensions on the 20 pounder rifle on "boat" pivot carriage are: Barrel length 11 in., Bore 3/4 in., Marked on top: an anchor/Dahlgren At breech: U.S.N.Y. Washington 1200 lbs., 142 pre. N.1. Left trunnion: P/G.B., Right trunnion: 20 pdr./1866
The wheeled model is that of a "small" Dahlgren boat howitzer. Model's dimsnsions are approx. 6/5-inch long barrel, bore 3/4 in. bore, 5.75 in. dia. wheels. It is fully marked as a large cannon. Among the tiny markings are: Top of barrel: anchor/12 pdr./Boat Howitzer/1865/G.B. At breech: U.S.N.Y. Washington 300 lbs. 24 pre N.1. The models were made at the Washington Navy Yard in the years marked on them, and sent USNA as a teaching aid.
