SailNet Community - View Single Post - Reefing a headsail???
View Single Post
post #30 of Old 01-10-2013
ASA and PSIA Instructor
Join Date: Apr 2000
Posts: 3,840
Thanks: 13
Thanked 38 Times in 38 Posts
Rep Power: 18
Re: Reefing a headsail???

Originally Posted by AdamLein View Post
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.
So much for the back of the envelop. You are right, the correct the formula for adjusting the foretriangle area is stated as "(square root of (I squared plus J squared)/I) times the foretriangle area".

I used the correct formula in calculating the 1.05 adjustment for a 100% jib. If you calculate the foretriangle area of I*J/2 to
191, adjust by the 1.05 and you get the 200.5 that you calculated directly... several regards...
sailingfool is offline  
Quote Share with Facebook
For the best viewing experience please update your browser to Google Chrome