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.
529 ft² sounds big for a 100% jib on a 27-foot 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.