[Public-List] working jib size

[brooks.glenn at comcast.net]

Thanks Mike, 


This is very helpful! 


glenn 

----- Original Message -----
From: "Michael J. Meinhold" <MICHAEL.J.MEINHOLD at saic.com> 
To: "Alberg 30 Public List -- open to all" <public-list at lists.alberg30.org> 
Sent: Tuesday, February 7, 2012 4:29:36 PM 
Subject: Re: [Public-List] working jib size 

Glenn - 
The official Chesapeake Bay A30 Rules working jib is an 82% - this is 
LP/J not an area ratio. 

I don't know about roller furling, but below is a table with the Luff 
Perpendicular worked out for each of the 
jibs shown in the A30 Sail Plan. The Chesapeake Bay One Design rules 
specify these numbers as max dimensions for the Working Jib and the #1, 
but say only that the #2 must be smaller in every dimension than the 
#1. 
The J shown in the Sail Plan is 10 feet 5 inches. 

Luff Foot Leech LP LP/J% 
Working 30.00 10.25 25.75 8.52 0.82 
#2 32.00 15.00 30.25 14.06 1.35 
#1 34.00 19.00 33.50 18.09 1.74 

LP can be found directly from the three sides of a triangle as : 
LP = sqrt ( foot^2 - ( (leech^2-foot^2-luff^2)/(2*luff) )^2 ) 

Mike 
Rinn Duin #272 
-----Original Message----- 
From: public-list-bounces at lists.alberg30.org 
[mailto:public-list-bounces at lists.alberg30.org] On Behalf Of 
brooks.glenn at comcast.net 
Sent: Tuesday, February 07, 2012 7:21 PM 
To: Alberg 30 Public List -- open to all 
Subject: [Public-List] working jib size 


Anybody have an idea of what the ideal working jyb measurements might be 
for the A-30 with roller furling? 


I have an older jyb that came with Dolce that I never use, but today 
just dusted it off and measured at (luff 24' , foot 13'). This seems a 
bit long in the foot for a working jyb, but maybe it was designed as a 
110% laper under the old cca rules. North sails quoted a working jyb at 
36' luff X 10' foot, which is about a 100% of the foretrangle area. my 
old jyb is actually about 24 Sq ft smaller than North's proposed jyb. I 
am going to put it on tghe boat and do a little sea trial in the few 
days, but am wondering in advance how the sailing characteristics may 
differ between the two different sail configurations and how it might 
affect the boat. 


Thanks for any info you all might be able to offer. 


Glenn P 
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