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Paul Thompson wrote:
David Tyler wrote:Can we get it finished for the NZ rally? Watch this space...
I've no doubt you can, there are two of you, you have a lot of experience and it's only one sail. In fact I'd be astonished if you could not do it.
Well, actually, it's not only one sail.
"What!" I hear you cry, "not another new rig for Tystie!"
It's like this:
- My wingsails are now more than 50,000 miles old. They are still sound, but somewhat stretched, chafed and patched. How much life do they have left?
- Wingsails seem to have turned out to be an evolutionary cul-de-sac. Except for Bertrand Fercot, nobody else is following me down that track. It's getting kinda lonely, in a minority of one. Only if a major manufacturer sets it up for series production will that situation change. Isn't going to happen, in my sailing lifetime.
- And anyway, I feel like a change. I'm never content to leave things as they are. I'm always wondering what would have happened had I taken the other fork in the road, and whether I can improve on what I've done already. Once a designer, always a designer.
So what do I do?
- I've tried my utmost to design a ketch rig JR with high-peaked yards, fanned planform and cambered panels, and I can't do it; at least not so as to fit on Tystie's masts where they are, with the centre of area far enough forward.
- I've tried to design a ketch rig with a "split-rig" main, to get the centre of area further forward, and I still can't do it; at least, not without looking brutal and futuristic, and I want to get back to having a beautiful rig. Wingsails seldom look beautiful, no matter how well they might drive a boat.
- I actually liked sailing with the big red fanned sail I had before the wingsails. It performed well when the wind blew, and the fanning came into play, but less well in lighter winds, because I hadn't put enough camber in the lower panels. Also, the very high-peaked yard didn't make deep reefing very satisfactory.
- In Fantail's new rig, I feel I've got things balanced better. Not so much fanning at the top, more camber at the bottom, less positive stagger to the battens, and less yard length and lower yard angle, to make deep reefing more satisfactory. When sailing in company with Fantail, over the holiday period, I found that it was very difficult to catch her, in light airs; and she always looked good, whether at close quarters or at a distance. I think I've finally "got it right", as far as a single sail rig goes.
- So, I want one like Fantail's got, and like Footprints is going to get. David Thatcher and I will be making two sails, one of 53 sq m, and one of 59 sq m, but otherwise to the same pattern (it is easy to scale the sail up or down, using CAD, and I can easily do that for anyone else who is seriously in the market for a good sail).
Building large sails like this is hard work, and I have been studying how to make it a little easier. The hardest part of working with large, cambered panels is rolling them to feed them under the arm of the sewing machine, to use the standard sailmakers' methods. So, the way around that is not to feed them under the arm of the sewing machine! How obvious is that? Arne's way, of laying one panel on top of another, and stitching the edges together, is the method that I propose to use; but I have never liked the way that the pocket is formed from the edge of the panel, in "amateur method a", and variations of it. "Amateur method b" is much better, and allows for a good finish at the ends of the pockets. It may well be the method that I use on Tystie's sail, with round section battens, but it will not be so good on Footprints' sail, if she retains her rectangular section wooden battens. I can see a way to adapt the method, still using separate batten pockets, still with no need to pass a rolled panel under the arm of the machine, but making a rectangular section pocket; and I shall be reporting on this in due course.
Another not-so-usual feature is that we will be putting the yards into sleeves. I did this about 8 years ago for a sail of similar size, and the owner reported well of it. It improves the loading situation at the throat and peak, and provides a round, faired-in leading edge for the airflow.
Watch this space...
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