Ganz wrote:

It's also quite dependent on weather.

Yes.

It's also tedious to do the numbers.

No, not unles you venture into lunar distances or trying to do it by pure
math. Using H.O. 249 or doing noon hights is not that complicated.

But, I agree, it's worth knowing. Then, when you miss Hawaii, you can say
with certainty... well, I only probably missed it by 60 nm.

You have a point. Celestial navigation on a boat does not have the accuracy
that we get used to from GPS, but I think you should be able to do at least
10 times better.