Yo Ho Ho

I've finally decided to learn ocean navigation, seamanship, etc., from the Almanac (1981) and a work about sea kayaking that we have in our shelves. A while ago I took to Wikipedia to read up on square-rigging, fore-and-aft rigging, genoa rigs and Bermuda rigs, gaff sails and so on, but having forgotten quite a bit of it and wishing to learn more, I want to figure out how to sail theoretically, not only using present-day technology but especially Viking or Renaissance or other methods.

After learning six kinds of knots — aside from the ninth knot (the bowline), it's the 'double sheet' as well as the 'carrick' bends* that will need improving — I went on to the mathematical side of things. As it turns out, determining geographical position from the location of the moon, stars or sun is more difficult than I had thought. There are observation correction tables that factor in height of the eye, refraction, etc., and yet no Latitude Calculations for Dummies explanations as far as I have seen.

* bend = knot that ties two ropes together

While I happen to know the north and south directions already, I wanted to know where the sun, the moon and the visible constellations were in the sky. Not a great deal of these latter are visible, except as motes that one can discern after staring at the spot for a while; but I think I found Orion, and the Big Dipper was evident enough. The last time I did that much stargazing, it was during an astronomy unit in Grade 7(?) in rural-ish Canada, with plenty that was visible. Despite the haziness, though, I think it was fortunate that the skies have been clear at times in the past week and that the moon was visible, as well as the sun.

To figure out how to do the latitude calculation, I remembered that there was a description in Jules Verne's Mysterious Island. From reading that, it seems that there are things — like altitude above sea level, and a true horizon — which I'd have to approximate.