On Oct 9, 10:27*am, Wayne.B wrote:
...*The only graphical solution with
dividers that I would have much faith in would be on the surface of a
globe using a taut string. ...

If you have just the right projection it can be done but you'd need a
custom chart which is going to be harder to come by than a
programmable calculator. I haven't been following Skip's path closely
enough to know, but I suppose he was heading near enough to true south
that the rhumb line distance can be taken as the great circle distance
with negligible error.

In a desperate attempt to add some content I want to point out that if
you are going to do sailings calculations by calculator and are
looking to Dutton's (at least up the edition 14) for guidance beware
that the sailing chapter is full of errors large and small. This is a
better source:
http://williams.best.vwh.net/avform.htm

--Tom.