I've already posted this at the SubCommittee and Steelnavy sites.
Torpedo Junction <<
http://www.sonic.net/~books/ >> has "The Fleet Submarine - Navpers 16160" (a reproduction) available for $25.
At this price, I've already ordered it. He's liable to have a run on it, so don't wait long. It has drawings not included in your drawings from Floating dry dock. To do a good Gato you really do need both this, and the Floating Drydock stuff.
There is one down side. If you've got both, you've got no excuse to get something wrong.
On the up side, if you're doing a Gato/Balao/Tench boat, it's hard to get anything wrong. If you do it, one of the boats, probably, did it, too.
Mike K.