155% Genoa Measurements?

[idouglas]

Does anyone know the dimensions of a 155% genoa for a CP16XL (CP16-3)?

Dirk Sharland of National Sail Supply (Rolly Tasker Sails, Florida)  has a 155% genoa measured at: luff = 13.8', leech = 13', foot = 9.3' with a sail area of 59 sq ft.  The problem is that Hutchins reports that a 155% genoa has 65 sq ft of sail.  I've seen some measurements where the foot was 10 ft or more. 

What are the correct measurements for a 155% genoa with J = 5.5, LP = 8.65, I = 14.25?  Anyone willing to go out and measure their jenny for me?

Thanks for any and all help.

idouglas

[KPL]

Here's how I would figure the area:

Definition of 155% genoa would be 155% the area of the foretriangle J * (I/2)

I'm a bit rusty on geometry, but the math would tells me 5.5 * (14.25/2)=  39.1875 sqft for 100% for triangle.  39.1875 *1.55 = 60.75 sqft for 155% genoa.

Since we know J = 5.5 and I = 14.25, we can solve for the additional foot beyond 100% and we get 3.025 additional length on the foot.

We get a foot length of 8.525, which is a little different then the LP which is the length of a  line drawn from the clew intersecting the luff at a right angle.  (which in this case is 7.95 when you do the trig)

This would be pretty close to the NSS measurement.
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Using the an LP of 8.65, with the same J & I, I get a foot of 9.27.  Taking 9.27 - 5.5 {I}  gives 3.77. 

3.77 * (14.25/2) = 26.86 sqft + 39.1975 = 66.0575 sq ft.

This is pretty close to the hutchins number.  Doing the math for the % you actually get 168% (66.0575/39.1975)

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For both of these figures, it assumes a sail that runs perpendicular from mast at the sheer.  In reality, the sail cut will rise the clew up a little, reducing the area from my formulas....


I'm must be ill, all that math was kinda fun.....

Kevin

[steve brown]

The folks at Sailcare in Pennsylvania can help you with the Genoa. They are very knowledgeable about Compacs and have all the patterns for their sails. They restore sails and can  make you a sail to order. Good luck. Steve

[idouglas]

When I called Hutchins to ask about genoa measurements, a nice woman at Hutchins suggested that I talk with the folk at Super Sailmakers in Ft. Lauderdale (the firm that currently makes sails for Hutchins.)  Similarly another nice woman at Super Sailmakers was kind enough to share their genoa measurements.  The measurements for a 155% genoa (62 sq ft) are:

Luff:  14.42 ft
Foot:  9.59 ft
Head to clue:  13.13 ft
Head width: .12ft

Super Sailmakers will make this sail with 3.9 oz Dacron for $412.00 (hank on).

It's great to be part of a boating community where everyone wants to help by sharing information.

idouglas