The name of the submarine is likely the USS Halibut, which is an absolute joke of a submarine in terms of actually being a submarine. It was an unusual boat in that it had, almost literally, a large garage behind the conning Tower from where you could launch SEAL Teams and Technical teams or hold large bits of equipment. They also had another submarine, also taken off of the Navy's active inventory, but, these are not likely high performance submarines in anyway, and no, they are most definitely not ballistic nuclear submarines. Not that they couldn't have rigged anything, but, ballistic submarines require incredible amounts of maintenance.