@Mikhayl: Yes, this is exactly what I have in mind. And pretty much the same solution that Virtual Sailor uses, IIRC.
@OLC: Hey, one can dream a bit, eh?! What we have now, the somewhat, ummm....medieval linear scale by Vanjast is certainly good enough, and I'm sure that a guy like Frank Worsley could navigate with GPS-like precision with that thing. But then.....I'm not Worsley!
