I almost got one of these with mount. I tried real hard but it never happened..
..
Well, I'm stumped. I tried some in depth research to find out what ship that might be.
Notice.... It's a WWII vintage 20mm cannon and is obviously on some type of museum ship. It's close to the water indicating a smaller ship like a destroyer or cruiser, not a carrier, and has a marina very close aboard.
Can't be San Diego because the only museum ship they have is the carrier Midway, no marina that close aboard.
Looked at my satellite photo archives of all the museum ships I know of in the lower 48, and can't find anything that matches that photo with a non carrier and very close marina.
Patriots Point ....USS Laffey