My method for converting a windsurf sail to a land yacht sail.
This has worked better for me and is way easier to do than laying out predetermined coordinates or transferring the bend curve via a template.
Some sails Sailworks, Neil Pryde, work better for this than others. When buying sails I look for the ones with a flatter foot, a straighter luff, 4-5 battens max and grommets for the tack and clew.
I also look for sails that will end up being from a 3.0 - 5.0 when it's done. I'm usually removing 1.0 - 2.5m from the sails.
Select just about any sail.
Rig sail and tighten the piss out of it!
Lay rigged sail on it's side and mark the sail with a sharpie holding it vertical along the sail side of the mast.
Stand rig back up and while still rigged, remove the lower mast sock. Cut stitching along one side by laying a razor blade across the center of the stitching, This is how I usually cut all the stitching during sail prep. Take care here, you don't want to cut into the sail, just the stitching. No "picking" required!
While still rigged measure the height of the clew and mark the new boom position at the tack two inches lower than the clew. The clew on this sail was 48".
Unrig the sail.
The new luff curve marked on the sail.
More to come....
To re-shape the foot, sharpie a line with a straight edge ( you can also make a downward curved line if you like more shape in the foot). The line has to be lower than the tack in order for the center of the tack to come out to your measurement, shown here as 46".
Drill out any rivets if needed.
Cut along your line for the new foot.
More to come....
Remove the binding stitching, just like the luff sock.
Cut off the tack patch layup.
Remove the remainder of the batten pocket, if needed.
Mock up the patch at the tack and mark the reinforcements on each end. This makes it easier for sewing.
More to come....
While the patch is mocked up be sure to mark it's location on the sail in order to notch it out for tack clearance.
Radius the corner.
Cut out to clear the tack. Back side shown.
Measure the piece of the sail you removed in order to figure out what the new sail size is.
More to come....
Nice pics. You must sail in fairly windy conditions to use sails that small? 3-5m2.
"Landyacht" (Paul) showed me how you strip the stitching in a sail with a trimmer blade as I had been unpicking it in the past.
I now clamp both ends of the sails stitch line to my long bench and ease up one side of the material snicking the first few stitches and lifting them apart and running along all the stitching (in between the material) as you pull it away as it's cut with a snap blade knife or trimmer. Takes longer to do up the clamps than rip the seams.
I can fully strip a sail including all the batten pockets/webbed binding/edging in about 20 minutes.
It's amazing how much sand the seams can hold!!!!!
The pictures I posted are pretty much in step by step, chronological order.
The actual conversion numbers are...
Sailworks revolution 3.4 down to a 2.96.
Sailworks revolution 4.6 down to a 4.17.
Sailworks revolution 4.7 down to a 4.26.
Neil Pryde 4wd wave 5.5 down to a 5.06, the largest sail I have converted.
For light wind days (anything under 15mph) I use my Fed 5 clone sails.
I did mention earlier that I remove more material than I actually did on any of the sails listed here. Those figures are for the much larger sails in order to bring them down to size.
All said and done, it takes me just under three hours to complete one (without pictures). The Fed 5 clones take me about a week though.
The average yearly wind speed here is 21.7mph. Ther are many, many days that the winds are 35+ from the end of April through September. I have to replace shingles on both sides of my roof every year.
The way you and Landyacht rip the seams is almost like a zipper. Works good, no doubt!
I always do it in steps so I don't cut anything I don't have to. I have yet to try doing it all at once so I don't quite know how long it takes me to strip them. I'm sure you agree that taking all the photos takes longer than anything.
Laying the blade over the top of the stitching works pretty good but you still have to run it between the layers on some of the bar tacks and three or four point seams.
Thanks for adding some comments and tips.
I used t47 bonded polyester thread with a size 100/16 needle.
On a $10 yard sale home sewing machine.
The important thing when selecting a machine is that it have the ability to sew zig-zag or multistep zig-zag (three step).
Cog belt drive machines (brother and others) are usually a good choice, they don't slip the belt and have more punching power.
A machine like this is a regular V belt drive and at the bottom end of being able to convert windsurf sails. You really have to manipulate the sail and be sure to anchor down whatever machine you use.
It is fine for 4oz. Dacron sailcloth up to 6 layers using v69 thread with a 100/16 0r 110/18 size needle!
I used this machine to show that it is do able.
I use 2" clear packing tape for the patches and the binding.
I stick it to the edge of the table and nick it with my knife to remove a piece.
Don't use cheap tape, it tends to shred when you try to remove it.
Good tape stays together and usually comes of easily.
Place the tape, sticky side up, under the sail.
Align the binding or patch and press the edge down over the tape.
While holding the edge fold the tape over the edge and press the tape down.
After the sewing is finished, remove the tape!
Re-rig the sail.
The sail lays pretty flat and the LE of the sail is 1/4" past the TE of the mast.
I will run this sail as is, for now.
Drink a beer....
The end of the luff sock needs a little help to keep from tearing away from the sail.
Layout where you will sew on some polyester or nylon webbing.
Any webbing over 1" wide will work. I use 1 1/8".
Make sure you make it long enough to attach past the "new" luff curve mark you made earlier.
It's just held in place with a clamp to give you a visual on what modification you are adding.
I will add this mod, take some pics then sail it.
Chances are that there will no other mods to this sail but if there are I will add that info and sail performance conclusion.
I am anticipating it working fine just like it is.
This is to show that you can mod a sail for yourself or others.
The purpose of this type of sail conversion is to get you sailing without a huge learning curve, taking some of the guess work out of it and give you some ideas.
This is a pretty easy conversion to undertake and can be done on any sail in a matter of a few hours.
Try not to make more out of it than what you really need. And that is to just sail!!
Fun type sail, not intended for competition!
No machine needed, this can all be sewn by hand!
Thanks for posting this... lots of good info here