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post #1 of Old 03-10-2003 Thread Starter
Don Casey
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Sail Repair 101

Self-reliance when it comes to sail maintenance can earn you time on the water and money in the cruising kitty. Some sailors become as proficient as the owner of the O’Day 35 seen above who made his own storm jib.
The ability to make a few basic sail repairs can get you out sailing when you might otherwise be waiting on your sailmaker. If, for example, a halyard jam lets a fresh breeze exploit shroud-chafed stitching, an hour or two at the sewing machine will close those open seams and get you back on the water.

Sail tape, wonderful though it is for an emergency, is a poor substitute for stitching. Duct tape is even less desirable. While it is true that you can make a strong repair with contact cement, it stains the sail and its grab-'n-grip nature risks potentially disastrous alignment problems. For permanently joining two pieces of woven fabric, nothing beats thread.

Small repairs can be done by hand, but only a masochist (or an around-the-world racer-same thing) would take on hand-stitching several feet of opened seams. A sewing machine, however, takes most of the work out of common sail repairs. You don't need anything special; virtually any domestic machine is capable of sewing through two or three thicknesses of Dacron sailcloth.

Having a good sewing machine takes most of the work out of sail repairs. Consider having one of these on board at all times.
Seams    Restitching is by far the most common sail repair. Because the stitching stands proud on the hard sailcloth, the thread is subject to chafe. Exposure also takes its toll. Eventually the stitching becomes too weak to do the job and a little extra stress on the seam pulls it apart.

Restitching a seam is not particularly difficult, and as long as you maintain the original alignment of the two panels, your repair will have no effect on sail shape. The existing needle holes simplify alignment, but because sailcloth is as slippery as cold butter, the trick is maintaining alignment while you sew. Sailmakers use basting tape, a Mylar film with adhesive on both sides. A roll of Seamstik would be a good addition to your ditty bag but an office-supply glue stick also works quite well to glue seams together for sewing. Never, ever try to restitch a seam without gluing the two halves together first.

For permanent sail repairs you need polyester fiber thread-the same kind your sailmaker uses-in either V-69 or V-92 thread weight. If sooner rather than later you are going to have the sail restitched-a very good idea-then almost any heavy duty polyester thread will serve for a season. Never use cotton, nylon or monofilament.

Use the largest ball-point needle your machine will handle, probably a No.16 or a No.18. Set the stitch length on your machine to its longest setting. If you have a zigzag machine, adjust the seam width to get a square pattern, or each stitch at 90 degrees to the previous one. A zigzag stitch is not essential. If foot pressure is adjustable, set it to its maximum. Sew a few practice stitches on two thicknesses of sailcloth (or through the leech tape if you don't have scrap sailcloth) and adjust the top-thread tension until the threads form a tight knot on the underside of the seam. Sailcloth is too hard for the interlock to bury inside the fabric.

Some sailors get very resourceful when it comes to sail handling while sewing. A perfect example is the above table for onboard repairs.
Sail Handling    Roll the material on both sides of the seam like a scroll. Spring clamps are good for keeping the sail from unrolling. If your sewing machine is portable, putting it on the floor will make the job easier. Feed the smaller roll through the underarm of the machine. Operating the foot pedal with your knee, run your first row of stitches to place one side of the zigzag at the edge of the top panel, or straight stitches a stitch-length (about 5 mm) from the edge.

Feeding will be your biggest problem; feed dogs tend to slide on the slick Dacron, so you have to help them by pulling the cloth through the machine. Experiment with how much pressure you need to apply to get regular stitches. Rubber fingertips-like bank tellers use-on the fingers of your left hand can give you better stitch control by allowing you to push the fabric through the machine. Enlist a helper to handle the rolls as they come out the back.

Reverse the sail end for end and again place the edge of the zigzag at the edge of the top panel, or straight stitches a stitch-length from the edge. Finish the repair with a third row of zigzag stitches or two more rows of straight stitches between the first two.

Next time, we'll cover how to repair tears and batten pockets, so don't fall apart at the seams just because your sails are in need of some attention. Just get out the sewing kit and get to it.

Sail Repair Materials

Doing your own sail repair can save you a lot of money in the long run. Here are the few essencials that you must have before embarking on any such project:

  • A roll of Seamstik or office-supply glue stick

  • Polyester fiber thread, V69 or V92

  • Large ball-point sewing machine needle, No. 16 or No. 18


  • A pair of spring clamps

  •  Bank-teller type rubber fingers

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