Hey McHub lovin the idea's, You should check out the links below to a few SH3 mods that you might not be aware of, The Modders FlakMonkey, Diving Duck and lucagaeta have added in some great stuff into the interior of the sub, Maybe chat to them to help you out, Ya keep it up.
http://www.subsim.com/radioroom/showthread.php?t=160385
http://www.subsim.com/radioroom/showthread.php?t=159772