Re: Asymetrical spinnaker or drifter measurements?
Posted by: bccodyssey
Date: March 31, 2010 05:50PM
Category: Sails and canvas
I am still working on getting an asymmetrical. I emailed Elliott-Pattison Sails and was told the dimensions they have used were ave been told were
a luff of 39.9?, leech of 32.75?, and a foot of 25.5? and that the total sail area would be 805 sq feet.
I sent these dimensions to Lee Sails and got the following response:
The sail area based on the current dimensions you gave, would be
In our data base we have a drifter listed for your boat, with
Luff = 38.0', Foot = 29.42', and Leech = 31.67', Sail area = 455sq/ft.
The formula given for asymmetrical cruising spinnakers for a
Bristol Channel Cutter is: Luff x Girth x .95625 = sail area.
Girth is calculated by multiplying J x 1.5. Your J, do to the bow sprit
is 17.75, so 17.75 x 1.5 = 26.625 girth.
Therefore: 38.0 x 26.63 x 0.95625 = 967sq/ft????? That is wrong
of course, caused by the bow sprit, making your J 17.75' on a 28' boat.
In my eight years with Lee Sails, I never had an cruising spinnaker
order for a boat with a bow sprit, so I will ask the help from the loft.
The quick and easy way to get the exact info is to ask your friend
Ron for the Lee Sails product number of his spinnaker, located on
a white tag, near the tack of the sail. They can trace that number
and give us the exact dimensions/sail area. Drifter sail areas calculated
like jibs, using Luff, Foot and Leech dimensions, reather then girth.
Assuming the dimensions you just gave me are correct, and the sail area
is 416sq/ft, your radial head spinnaker, made fro 1.5oz Bainbridge ripstop
Nylon would cost $603.00, and the dousing sock $120.00, plus sales tax.
The nylon color samples I mailed you are the ones available.
Is it possible for you to find the product number so that I can be sure of ordering a sail that matches yours? I assume that providing them with the dimensions you originally posted should create the same sail, but it causes some worry when different sail makers come up with sail areas that vary between 400-800 sq ft.