Skidmark, I recognize your new entry! That's the big 15" Rodman Gun M1861 on the Western Bastion at Fort Pickens on the western tip of Santa Rosa Island, Florida. I baked my brains out for 8 hours in July studying this gun in 2003. I spent more time acting as an unpaid artillery answers guy for tourists than I did getting dimensions off that big gun. This gun was not there in 1861 when the Battle of Santa Rosa Island was fought in October. The terrific bombardment of Fort McRee across the channel into Pensacola Bay, from Fort Pickens to the east and the Union flotilla to the south almost wrecked that semi-circular fort. Hurricanes in subsequent years did wreck it and washed it into the drink. Nothing of Fort McRee is visible today. Fort Barrancas to the north was damaged to by fire from Pickens, but not seriously. Ft. Pickens was lightly damaged and also fended off a Rebel force of about 1,200 intent on capturing it. Ft. Pickens was one of only three seacoast forts never taken by the Rebels. Also included in this number was Ft. Monroe, Hampton Roads, Virginia and Ft. Jefferson in the Dry Tortugas Islands 85 miles WSW of Key West, Florida.
Tracy