Did your boat lose all of its gun mount superstructure? The point is if you are in a position to make such improvements, please understand some basics of restoration so you don't paint yourself into a corner, so to speak. Pick a focus date (what ever is best documented and achieveable) and then stick to it. If you were to pick a 4-in. gun for Batfish, then you'd have to remove the late WWII stuff that was put aboard when she was given the 5-in. she ended the war with. I would say that a good workable focus date would be the Batfish that sank all those enemy subs (you would be making the most of her unique historical claim to fame)... hopefully that was in her last configuration. If not, then consider that last war-time mode. She should have drawings and shipyard pictures available at National Archives. Based on those, you can't go wrong. The gun mount for a 5-in. is pretty standard and doesn't need to support men besides the 7-ton gun. The deck planks support the crew. Well, the gun does support the two men on the seats, but again, if it can handle a 7-ton gun, it can support two gun crew, even if they're my size (250 lbs). It takes a lot of plate 1/2-in.?? and a good plasma cutting bench, not to mention a good
overhead crane. But it's not impossible for local fabricators.
Finding a gun:
The best, and maybe only source, for deck guns is a military base or VFW post that is closing. Ballast Point sub base, NOT CLOSING, has two 5 in. wet mounts, that would require some negoitations with the local subvets and Navy to obtain. The last CO of the base said he would let them go if the local vets go behind the move and approved it. There you go! Damn little can be done in the way of major restoration without a national reach, as in joining HNSA and or getting contacs at various other places (NHC, in DC, Ballast Point, etc.)... it is almost impossible to get much specialized work done by staying within the city limits where you boat is located, I'm sorry to say. I might be able to get some photos of our mount within a week.
PF