"Simple Simon" wrote in message

Negative a chord is a straight line joining two points on a curve.

This contradicts what you said here...

The convex side of the sail or the leeward side directs the air
over a longer path. This longer path for the air lowers the pressure
because said air must move faster to cover the increased cord.


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Wally
I demand rigidly-defined areas of uncertainty!
www.art-gallery.myby.co.uk