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post #5 of Old 09-21-2019
Jeff_H
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Re: Dickerson Farr 37. I have questions

Quote:
Originally Posted by gedaggett View Post
Great info guys! That is exactly the info I was looking for. the boat under consideration has dealt with some of those single handed concerns but there is no substitute for weight I the rail and I get that. It is part of my hesitation.
So here's the thing, almost any racer-cruiser from the IOR era was designed to sail with a lot of weight on the rail. A 37-38 footer might have had 9-10 people onboard in heavy air with everyone perched on the rail upwind and reaching.

But that also meant carrying a couple thousand pounds of people and gear. So while it meant that you could carry more sail area into higher wind speeds, it also meant that you also needed to carry more sail area to offset the greater weight.

IOR era boats would carry very large sail inventories. They might have a light#1, Heavy#1, #2, #3,#4, and storm jib, and sail changes were very common.

With modern high modulus sail cloth, the wind range of any of these sails is greatly increased.

Because a high tech sail is much lighter than a Dacron sail with similar stretch characteristics, the high tech sail will maintain it's flying shape into much lighter winds. Because a high tech sail actually stretches less than a Dacron sail, the same sail can be carried into a much higher wind as well.

What I did to develop my short-handed sail inventory was to develop a skewed SA/D for my boat. For displacement, I started with the published dry weight and I added 500 lbs for normal sailing gear, water in the tanks and consumables, and 1500 lbs for crew and their gear. I then calculated the sail area with the 155% Genoa, and calculated the SA/D in that configuration.

I then took off the 1500 lbs of crew weight an calculated the sail area needed to achieve the same SA/D without the weight. By subtracting the mainsail, I came up with the smaller size Genoa that I wanted for the single handed Genoa.

The reality is that there will be some performance loss due to the lack of added stability from crew on the rail, but it is no where near as bad as you might think.

This is partially true because modern sails can be bladed out much more effectively than Dacron or the old Kevlar sails. It's partially true because less weight means less drag and less drag means that you don't need as much sail area.

In real racing conditions, single-handing I often correct out over fully crewed boats in a broad range of conditions but particularly in lighter winds and heavy air.

While high tech sails cost more initially, they have a much larger wind range replacing 2 or 3 sails. But also a good quality and properly spec's high tech sail will last longer than a lower tech sail in terms of holding it's shape which is why many one design classes which previously prohibited high tech sails to keep costs down, now permit high tech sails.

By way of example, my prior AP high tech jib lasted 10 years and was only destroyed when I got caught in 40 knots of wind and could not furl it.

Jeff


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Curmudgeon at Large- and rhinestone in the rough, sailing my Farr 11.6 on the Chesapeake Bay

Last edited by Jeff_H; 09-21-2019 at 09:44 AM.
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