Great stuff!!!
About celestial navigation, I suggest all those interested to read these simple guides:
http://www.dc3airways.com/TechEd/te_nav_lr_nav.html (long range navigation in the '40s, thought for aircraft but somehow applicable also to submarines)
http://www.celnav.de/ (Henning Umland's excellent site about celestial navigation)
A sextant reading alone cannot give your exact position, and not even your latitude (unless the object you are observing is due North or due South). But two sextant readings, of two different celestial objects, under some circumstances, can give your exact position. Best readings are done on two objects that are seen at an azimuth distance of about 90° between them.
Sextant readings can be done on Sun, Moon and any star, if their position (azimut/elevation) at that time and at your expected position are known.
A very easy way to have these data is this simple program (ICE):
http://www.celnav.de/ice.zip
instead of having thousand printed pages. I know that kaleuns did not have this program, but it's a DOS program developed in the late '80s, so you are cheating of only few tens of years...
Maraz