Like your drawings Tony. Some people can draw and some can't, you obviously can.
I have occassionally thought that the Voyager shuttle had a good shape for a submarine apart from the relatively flat viewports. It would definately make a good ambient pressure sub, but from the hatchway your thinking dry sub.
Perhaps two hulls, the outer as in the shuttle and within two pressure pods. Check out my pressure pods for the one person sub I am designing at psubs.org
Incidentally I am using TurboCad and finding it a very good program. If I had the cash and a more powerful computer I would use AutoCad but TurboCad has everything I need for the present. Definately worth the effort to learn this program. If you don't mind I will see if I can sketch over your handdrawings for a basic cad look alike to see how it looks.
Cheers, Lawrie go right ahead, i don't mind, make it better if you can!!!