Here's the full procedure:
http://www.maritime.org/fleetsub/chap18.htm#18A
Remember a Gato is a lot heavier than the average u-boat, which means it responds more slowly to every input. Also look down to D: Phraseology. It lists all the orders and everything which must be done during the dive process.
@flintlock: Good point about the cook, but on an American boat they don't say "Alarm", they say "Clear the bridge! DIVE! DIVE!" and ring the klaxon twice. Get's peoples' attention real good.