Maybe it's been posted already but I did not find reference to this in the forum.
The San Francisco Maritime National Park has a web page the includes an extensive training manual the describes WWII fleet submarine functionality. It was a publication made just after the war.
So if you enjoy reading about the main hyrdraulic and lubrication systems and standard watch routines of WWII fleet subs, take a look:
http://www.maritime.org/fleetsub/index.htm