PDRacer Sailboat

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This is another easy set of techniques that I have found for making polytarp sails. Please note that it isn't the "best", but rather just another set of methods for making tarp sails. There are many, many different techniques that you can employ when making the sails, you need to decide for yourself which ones you employ. And since the sails are so easy to make, have fun and experiment around with different ideas.

For this sail, I wanted to do the technique where the original edge of the polytarp is used, and then make a "mother dart" to create the shape of the sail. Jim Michalak has some great essays on making sails in this method, he also has accurate calculations on exactly how big the darts should be.

I started off by moving all of the furniture out of my livingroom so I could have some clear workspace. Notice the white tarp, this sail was being made for a fiberglass sailboat that I wanted to resell, so I bought a higher grade of white tarp from Dave Gray at PolySail.com. It is much stronger than the blue stuff you can get at the local store, also it looks more normal like a dacron sail.

Knowing the dimensions of my sail, I found where I wanted the center of the draft to be ane marked it.

Folding a dart over from the tack area, the dart ends at the point I previously marked. I am not a very good seamstress, but have noticed that the secret to sewing seems to be marking your work accurately, and pinning it in place. A trick I picked up from Bill Tosh at TCBoats.com is to use clear packing tape to hold the seams. You can easily sew right thru the packing tape, and pull the tape off later. Some people use duct tape and then sew thru it, but I have heard the duct tape will grab the needle, so you have to grease it up with vasaline often, and be careful.

With the dart held in place, I can mark the rest of the sail. I just drew straight lines from the head and tack, back to the clew. Many people will make a small inside curve on the leech of the sail, this is called "hollowing out the leech". It will prevent the leech from fluttering in the wind. I just made a straight line, it won't flutter (atleast won't flutter that much).

To sew the dart, you have to do something with all the extra material on the the sewing machine side of the sail. I roll it up on the top side, so I can feed it thru and sew one side of the dart. Then pull it out, and feed thru again and sew the other side of the dart.

A mistake I made when I first started sewing was to bunch the material up instead. What happened is that a loose flap of material went right under the sewing foot attaching it to the dart. Had to cut the threads loose, and re-sew it again.

For the foot and leech, I need to fold the edges over twice and then tape them into place. Doing it free hand is rather difficult to create a straight edge. One technique is shown here, you stretch the material between two solid places, then fold and tape.

Looking at it from this angle, I have created a little bit of curvature to the edge, but it was simple and fast. Taping down the seam with more packing tape, then run the edge thru the sewing machine.

Repeat for the leech.

Since the original edge of the polytarp has grommets in it, and I used that edge for the luff, with the head ending at a grommet, the only thing left to do on the sail is make the clew.

I took a scrap piece of tarp that had a grommet in it, and folded it, then sewed onto the clew of the sail. Not only does it make a grommet for me to attach the sprit to, but it forms a reinforcement patch to strengthen that corner of the sail.

More pictures of this sail are on the Leg-O-Mutton Sprit, page 2

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