Those of you who opined it was a powder can were essentially correct - I was pushing you to see if you would figure out it was a *big* powder can. Because it is a big powder can, or, as the Navy terms them, "16in Tank, Mark 4."
Filed under: Historical Stuff, Artillery, Gun Pr0n - A Naughty Expose' of the fiddly bits, Ammunition, Castle Pr0n, powder tank, 16inch gun powder can, tank 16in mark 4, battleship ammunition, battleship, mk 4