Quote:
Originally Posted by sailingfool
Hmmm. Just lose the concept that the genoa size relates to the foretriangle area  it does not. It relates solely to the LP relationship to the J. If you do the geometry, a 100% genoa will have an area equal to the (square root of (I squared plus P squared)/I) times the foretriangle area. So if the measurements of a W27 are:
I J P E
34.75ft 11.00ft 29.00ft) 10.75ft
then the area of a 100% jib will be 1.05 times the foretriangle area of 1/2*IP or 529 sq. ft.
I think.

529 ft² sounds big for a 100% jib on a 27foot boat. Isn't P just for the mainsail?
I would think jib area is LP * Luff / 2. If Luff = forestay length, then for that boat it's
100% * 11.00 ft * sqrt((34.75 ft)² + (11 ft)²) / 2 = 200.5 ft².