SOL and great circles

[Whitelighter]

How do you effectively sail a GCR in SOL?

Looking at the maps it seems to be a rhumb line rather than a great circle, so how do people calculate the correct route?

 

[sarabande]

the map projection used in SOL is a form of Mercator.

To see the GC route, use the yellow/black "compasses" icon, click and drop a red button on one side of the Atlantic, then drag to another point on the other side. The curved line you see is the GC route.

If you play around with large scale maps, and N and S of the equator, you will see how the GC bends more with E and W headings, and nearer the Poles. GC courses running N or S have very little - if any - curve.

 

[Whitelighter]

OK, so the SOL model is set up to use the GCR. That's all I really needed to know.

Cheers

 

[Martin_J]

Yes.. when you do a point to point line on the map you will see the great circle.... It gets interesting when you're round the Southern Ocean legs and the great circle will show the shortest route passing through the edge of Antarctica.. There you will need to stay in the best wind rather than the shortest distance.

It does get interesting adding up distances.. You will add up dozens of different routes and work how on each how much faster you will be.. then spend hours considering which route to take!

Hope this helps.