Originally Posted by yachtvalhalla
Would you please tell this old salt why you think great circle calculations are necessary?
Umm..... Is this a trick question?
Generally, if your sailing more than a few hundred miles, the shortest distance is the great circle route. Granted, if you're sailing from Boston, US to Falmouth, UK, you would need to portage Nova Scotia, Newfoundland, and a bit of the British Isles. As well, there may be other reasons not to adhere to the strict great circle course... fog, ice, currents, adverse wind, no wind, storms... sea serpants, sailing off the egde of the world... So you pick a couple of way points around these obstructions but the shortest distances between these
points, separated by a thousand miles or more will be ... ummm ... the great circle routes.
Given that, I like to plot my intended course and then track my route so I can see where I am relative to where I thought I would be. True, you can calculate a few intermediate waypoints, plot those and then sail the straight line segments of the great circle(s) but wouldn't it be easier to start with the great circles?
I dunno, maybe in 40 years of sailing, I just haven't learned very much.