Sailrite Kits... Do it yourself sailmaking

[NornaBiron]

Originally Posted by sailr69

I am not a sailmaker or sail designer but I can have some input on this discussion. using a cad program makes sail designing much easier for the tri-radial and complex type sails. but that is good only for the designers who use them. the actual shape of the sails have been with us for many years. they can best be done using a crosscut design. just don't last as long or keep thier shape in different wind speeds. chord shapes and selection of them are not hard to do. they were done long before computers. but radial designs without the plaid cut would be impossible without a computer. as for the sewing, the expert sewer only sews sails, not designs them, they are good because they sew straight and fast. almost any sailrite sewing machine owner can sew the sail and have the same sail. won't look as good perhaps but if he didn't screw up too badly he would have the same sail as a expert sewer. I make all my own sails; for a soling 1 meter. (rc boat)

One of the biggest problems we've found is getting the fabric through the arm on the Sailrite machine. We made sure that we joined each panel with the bulk of the sail away from the machine and held the panel to go under the arm in a fairly tight roll with split drainpipe as clips. That works pretty well for the building of the sail but becomes more problematic when finishing, I.e. adding the sacrificial strip - reinforcing fan patches are almost impossible to roll as they are 10 - 12 pieces of fabric thick. Several needles were broken when trying to force the patches through!

[Kestrahl]

Originally Posted by sailr69

I am not a sailmaker or sail designer but I can have some input on this discussion. using a cad program makes sail designing much easier for the tri-radial and complex type sails. but that is good only for the designers who use them. the actual shape of the sails have been with us for many years. they can best be done using a crosscut design. just don't last as long or keep thier shape in different wind speeds. chord shapes and selection of them are not hard to do. they were done long before computers. but radial designs without the plaid cut would be impossible without a computer. as for the sewing, the expert sewer only sews sails, not designs them, they are good because they sew straight and fast. almost any sailrite sewing machine owner can sew the sail and have the same sail. won't look as good perhaps but if he didn't screw up too badly he would have the same sail as a expert sewer. I make all my own sails; for a soling 1 meter. (rc boat)

OK. Using a CAD program makes sail designing easier for all sails. Without it you are ball park on shape, unless all the sails you are making are for the same boat and you can do some trial and error. You can easily make a radial cut sail without the computer and only shape the horizontal seams. One sail maker in NZ still makes radial skiff gennakers without the computer. Just being radial cut doesn't make a sail last longer or keep its shape, depends on fabric used, type and size of boat etc. Most race Dacron sails are cross cut.

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[thannever]

This is probably not the right thread, but I was looking for advice on DIY nylon downwind flat sails for multihulls. I have a tri and was planning on tacking the two lower points of a triangle on the amas and hauling up the third with the spin halyard. I thought I saw advice and some instructions on that somewhere on this site a couple of months ago but cannot find it now. I have a considerable amount of tradewinds downwind in my future, I hope. thanks for any thoughts.

[cwyckham]

This is commonly done with symmetric spinnakers. Many are available cheaply used

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[w32honu]

Originally Posted by thannever

This is probably not the right thread, but I was looking for advice on DIY nylon downwind flat sails for multihulls. I have a tri and was planning on tacking the two lower points of a triangle on the amas and hauling up the third with the spin halyard. I thought I saw advice and some instructions on that somewhere on this site a couple of months ago but cannot find it now. I have a considerable amount of tradewinds downwind in my future, I hope. thanks for any thoughts.

Used sails is a great way to go. If you decide to DIY the folks at Sailrite would most likely provide some advice. These days most all sailmakers use CAD programs to design their sails. They are no exception. The kits consist of precut panels. All materials are provided to paste the panels together for stitching. Easy to follow instructions. And good support if you run into a road block.

Don't mean to promote a total endorsement of Sailrite. I have no vested interest in their business. I just through that out because that is the thread topic.

Not sure I would worry too much about cutting an overly flat downwind sail. Especially a spinnaker. If you go with a symmetric spin tacked down to the Amas. You could just depower by choking the sail down…….ease up for more power. Seems to me an asymmetric would work equally as well. That totally opens up the used sail market for you……….

Good luck with the sailing plans. We are envious.

[w32honu]

Thannever,

Not sure if you read the entire thread………

But there is a short video in the earlier pages that shows a spinnaker that was built from a kit. Might help to have a look at that……. Gives us an idea of what is possible.

[cwyckham]

Originally Posted by w32honu

Not sure I would worry too much about cutting an overly flat downwind sail. Especially a spinnaker. If you go with a symmetric spin tacked down to the Amas. You could just depower by choking the sail down…….ease up for more power. Seems to me an asymmetric would work equally as well. That totally opens up the used sail market for you……….

Good luck with the sailing plans. We are envious.

Yes, in lighter conditions (when you'd be using a spinnaker), you're often faster on a bit of a broad reach. An assym would be better for that (still tacked to the windward ama).

Either way, if you're using it for downwind, I don't think you want it to be very flat.

It might be worth asking around the catamaran forums or groups for your particular boat to see if people are using symmetric or assymetric.

[thannever]

thanks for the suggestions. my concern about a spinnaker is that all the extra material that gives that sail the shape and power when used right makes it harder to deal with when things go wrong and I am liable to be short handed
(by choice!?). Not having a lot of experience with spinnakers I am worried about wraps and lowering the sail on deck instead of the ocean although I guess a sock mostly solves that problem and I have used that a few times successfully on a smaller boat. I have successfully used a large genoa tacked to an ama for a variation on a wing on wing rig, but it wasn't ideal largely due to the heavy weight of the genoa. I am not sure what was meant by choking down on the spinnaker. Does that mean suck part of it into the sock? All i really want is a failsafe sail that will keep me moving 12 to 15 knots in a straight line down the trades.

[cwyckham]

Originally Posted by thannever

thanks for the suggestions. my concern about a spinnaker is that all the extra material that gives that sail the shape and power when used right makes it harder to deal with when things go wrong and I am liable to be short handed
(by choice!?). Not having a lot of experience with spinnakers I am worried about wraps and lowering the sail on deck instead of the ocean although I guess a sock mostly solves that problem and I have used that a few times successfully on a smaller boat. I have successfully used a large genoa tacked to an ama for a variation on a wing on wing rig, but it wasn't ideal largely due to the heavy weight of the genoa. I am not sure what was meant by choking down on the spinnaker. Does that mean suck part of it into the sock? All i really want is a failsafe sail that will keep me moving 12 to 15 knots in a straight line down the trades.

12-15 knots? What boat do you have?

I love my sock. You may also think about using a heavier spinnaker. They're a bit harder to find on the used market, but certainly around. Racers call them a "shy kite."

[w32honu]

Choking down a symmetric spinnaker would be to run two lines from each clew on the sail..…..one led aft like normal and one forward almost at the bow of the Ama. Tensioning the forward led sheet would choke down or flatten the spinnaker somewhat. That should de-power the sail.

That said this technique is usually used for better control and to dampen rolling on a monohull. So in the big scope of life I wouldn't think twice about it in your case. I just tossed that out because you were considering a "flat" cut spinnaker which seemed like defeating the purpose of a spinnaker in the first place.

Personally I would consider an asymmetric. You would probably get much more utility from it by tacking it down to the windward ama when on a deep run. And then you would have the versatility of tacking it down to the bow of the main hull to sail on a close reach, much higher on the wind. Lots of bang for the one sail.

What trimaran design do you have?? We have become interested in the trimaran club as well…………………

Cheers

[cwyckham]

I didn't notice that you're on a tri. If you really are going to be up in the 10-15 knot range for boatspeed, then you're starting to get into the realm of apparent wind sailing where you're reaching everywhere. You'll be on a close reach when at 150 degrees to the true wind in the right conditions.

In this case, an asym is going to be your sail of choice for sure, as w32 says.