Ficaria interessante!
http://www.pigboats.com/subs/r-14.html
This shot of the R-14 shows the gun placement. The R-14 is famous for an incident off Hawaii. Searching for the the sea-going tug Conestoga in May 1921, the R-14 ran out of fuel southeast of Hawaii. Sails were made by sewing blankets and mattress covers together forming sails. The submarine arrived in Hilo, Hawaii on May 15 after 5 days under sail.
The R-14 was a Fore River Shipbuilding Co, Quincy, MA built boat.