From the IP Factory...
According to the 'bible', the 40 water tank send was 12" deep. It is hard to tell exactly from the notes, but it appears it was threaded into a fitting on top of the tank instead of held in using a 5 hole mounting flange.
Let me know if you need anything further.
Cheers,
Warren Sweet
Island Packet Yachts
(800) 828-5678
www.ipy.com