: I'm getting closer to making a sail somewhat like the Balogh sail, but out of
: white poly tarp. I think there are three battens in this sail but I'm not
: sure if there is a fourth at the bottom. Does anyone know? There are
: different ways of making the belly (camber) in a sail besides cutting it
: in the curvature of panel edges. One way is to cut a curve in the luff and
: foot and the other is to add darts. I will try the luff and foot curvature
: to start with. If I knew roughly the camber depth I can cut and recut
: until I get something close.

: Thanks for any ideas,
: John

Hi John,

Camber should be around about 15% of the chord (fore and aft dimmension) of the sail. It's an airfoil afterall and that's the camber of a fairly thick airfoil, which is the ideal for a low speed one.

Btw, full length battens are ideally tentioned into their pockets holding the shape of the sail, also creating a P.I.T.A. when tacking in light winds when the battens don't always want to reverse direction.

Bill H.

Bill H.