"Gogarty" wrote in message
...
In article ,
llid says...



"Gogarty" wrote in message
news
I have been doing a lot of Googling but I can;t find an answer.

You have no doubt noticed that the sails on the current crop of
America's Cup challengers are not triangular -- even with a huge
roach
-- but trapezoidal. How do they maintain that shape at the head? Is
there a gaff at the head parallel to the boom? How do they keep the
head
of the sail from falling way off to leward? Is there some arrangment
of
masthead sheets that keep the head parallel to the boom?


How about using your friggin' eyes for once? Sail shape is held by
battens. Doh!

http://media3.washingtonpost.com/wp-...6/PH2007051601
455.jpg

Wilbur Hubbard

Doh! yourself. According to the North Sails artricle that top batten
has a
square or rectangular section. It is might stiff and bends very
little. But
what keeps it from going to leeward?

Tension along the leech.


How is that "gaff" kept parallel to the
boom? The article also said the ideal sail would be a rectangle. Wait
a
minute...

Tension along the leech. Caused by either the mainsheet or the vang or
both.

As for a rectangular sail being optimal. It might well be for the light
winds those boats sail in and the height restrictions on the mast. They
won't even go out in anything above 18 knots and that's sad. Imagine
that. Boats costing millions and so unseaworthy a Catalina 25 takes
higher winds in stride.

Wilbur Hubbard