[R-390] OT: Submarine navigation

[Blair Batty]

Sorry for the off topic, but I know there are lots of ex-military types
here; I don't know where else to ask.

How did a submarine navigate during WW2? Did a compass work underwater
inside an iron tube? Did they just look thru the periscope to see where
they were going? Dead reckoning? Or were they mostly a surface vessel.

I suppose today they have all sorts of magic, electronic gps devices, so
they can travel for months without every surfacing. But what was available,
say in the 60's-70's?

Sincerely
/b

Questions inspired by a cold war submarine movie last night...