As I said above, finding Latitude would be peace of cake in the northern hemisphere: if Polaris is 40š above the horizon, you are at 40š North. It just couldnīt be simpler. Of course, bad weather would make finding Latitude harder.
Regarding Longitude, we would "just" need two clocks: one of them showing either GMT time or the time at your base and the other clock showing local time (the time where the sub is positioned). The time difference between them would increase/decrease as we sail, giving us our Longitude. We wouldnīt even have to rely on dead reckoning. Not completely, at least
This clock thing is, of course, where the difficulties begin. I just donīt have the skills nor the time to try to acquire them. I donīt even know if the current clock in SH5 shows local or GMT.
However, if anybody was able to create the clock(s) needed...
...that would be great
