[capt vimes]

RichH - i think you missunderstood the article...
I have not read the full article, but mr gentry speaks clearly of faster and slower airflow around an airfoil and thus creating a pressure difference which in turn produces lift...
Point 2.5 of the linked article.

What he did was introducing an circulation flow to simply model the airflow around an airfoil because the standard theories and models did not produce the right figures...
Pernouille is still valid and telltales on the leading edge of a sail may point forward because the airflow seperates there, producing vortices...
There is no circulation flow around a sail!

 

[capt vimes]

first of all - the fastest sail"boat" is this one:

top speed over 500 m: 65.45 kts...
and secondly - i do not see hydroptere to be mast headed:

edit:
it is not even mast headed in your image... look closely again: the hounds are probably 9/10 of the mast - the tapered wingmast gives the look as being mast headed...

 

[capt vimes]

well - in your image they were flying the jib and the main with the first reef...
in mine the main still with one reef and the smaller staysail, the jib furled away...

 

[capt vimes]

another point might also be - but i could be wrong - that with new materials for the sails the main improved in performance a lot...
i see so many boats nowadays with fully battened mains from whatever-stuff-that-be and thus hugely increased performance when you compare it to the old white cloth hanging lousily from the mast...
the main is also easier and better to trim and thus there was a shift from small main, huge jib to huge main, small jib...

oh - and higher aspect ratio sails, i.e. smaller foresails with less J on a taller mast, just perform even better to windward...