[AdrianX]

Hmmm - similar experiences with SatNav while driving across London and being taken on peculiar routes - never as good as a Black Cabbie and his "rat runs"....

For what it is worth, and probably off-topic, I did find some interesting reading and thought I would add it here. Generally the books on navigation or weather never combine how you plan routes (racing or cruising) for a given weather forecast - possibly too applied in nature I guess. However, the following recent articles on Sailing World were a good read and gave an overview of how a boat's polar curve can be used in this context:

http://www.sailingworld.com/from-the-exp...61573.html

http://www.sailingworld.com/from-the-exp...61206.html

And in case there are some talented programers viewing keen to build an add-on the MacENC I found an academic articles on the topic (titled: Optimal Sailing Routes in Uncertain Weather).

I would have to image that with the America's Cup in NZ for several years, some creative engineering lecturers took inspiration for the sailing frenzy that engulfed NZ - see link bellow:

http://www.orsnz.org.nz/conf35/papers/An...onAndy.pdf

Cheers