How to Patch a Sail

In Cruising World magazine a while back they showed how they repaired sails with various glues, and tested them. They decided 3M 5200 Marine Adhesive was the best of what they tested, so I thought I would give it a try. A student sailed too close to a boat house roof and ripped a Sunfish sail, so I repaired it summer of 2003 and it is still fine. My Flying Scot jib tends to hang on the spinnaker ring, and an overzealous crew can rip the jib. Here there are two rips in the leech, one of which I have let get pretty long. This is going to make a great test! I did this patch in the fall of 2003.

The materials I used for this patch. A piece of an old Laser sail I had, some leftover 3M 5200, scissors, two squeegies cut from a plastic bottle, paper towels, and also a pencil. Milk jugs are too thin for the squeegies, find a bottle with thicker plastic. Some bottles have a filtration device for water. I cut this piece of sail so it would cover about 3 inches around the rips.

After cleaning the cloth with rubbing alcohol, I laid the patch where it would go and drew a line 1/2 smaller so I would know where to put the adhesive. The tube had been opened 6 months ago and had cured near the ends. I had to punch a hole in the middle to get some good adhesive. This line was enough to reach from the rip to the edge of the patch.

I spread the 5200 with a squeegie as evenly as I could from the rips out to the line. In this and following steps some of the 5200 went through the sail and onto the table, not good. Now when patching a sail I first tape the sail flat with wide packing tape, that clear stuff about 3" wide. This holds the sail together and also prevents the 5200 from getting on the table. After the 5200 has cured the tape comes off easily.

Here the 5200 is ready for the patch. I tried a piece of plexiglass for backing when I patched Sunfish sail and the 5200 bonded to it pretty well, so this time I'm using a glass table top. The glass worked much better but still stuck a little. Now when patching a sail I first tape the sail flat.

Using a squeegie I spread the 5200 evenly and thin, first filling the rips and then pushing the excess out to the edge where I could scrape it off and transfer to paper towels. It helps to go slowly, or the squeegie rides up over the 5200 without thinning it out.

The finished patch, time spent 30 minutes. I'll leave it to cure and try it out tomorrow. A razor scaper helps separate the patch from the glass neatly.

Flying again! We test the patch in 15mph winds and with extreme tension on the jib sheets. It is also very flexible, it can be folded easily.

This repair was done in Fall of 2003, how long will it last? Being on the leach of the sail it flaps in the wind often.

Update: Now it's May 2004, I'm still using this sail with the patch, and have been out several times on windy days with gusts to 35 mph and racing so pushing the boat to the limit. So far the patch is still holding fine, I've used it in 4 regattas so far and many more classes. Would like a new one but want to see how long this patch will last. I also used 3M 5200 to fix my batten pockets and a rip in my spinnaker.

Update: June 2004. Patches are still holding well. While this method does make the sails a bit stiffer and heavier (especially the spinnaker) they still work. In fact we won 1st place in the 2004 Austin Yacht Club Centerboard Regatta in June with these old patched sails!

Update: October 2004. Still racing and sailing with this sail, patches still holding. I'm in first place in the Texas Centerboard Circuit with one regatta to go.

Update: December 2004. Still using the sail, won 1st place in the Texas Centerboard Circuit using this sail in every regatta.

Update: Summer 2005, I sold the boat, with this sail still in use. Not just used for racing, I also teach sailing and have several classes per month. I always used this sail, so it has been in the sun a lot and has been wet countless times.

Update: January 29, 2006, Jack invited me to go sailing on my old boat. He is STILL using this sail, and the patches are holding fine.

Boat Repair Articles Index

If your local sailboat shop doesn't carry 3M 5200 you can order it below.

High-performance polyurethane adhesive/sealant becomes tack-free in 48 hours, completely cures in 5-7 days w/no shrinkage. Retains its strength above or below the waterline. Flexible; allows for structural movement. Stress caused by shock, vibration, swelling or shrinking is effectively absorbed. Excellent resistance to weathering and saltwater. Bonds and seals fiberglass deck to fiberglass hull, wood to fiberglass, portholes and deck fittings, motors on fiberglass transoms, under moldings, hull seams above and below waterline, center board trunk joints, between struts and planking, stern joints, deck housing, etc. Easy to apply with manual caulking gun. Remains workable up to 4 hours after application. Won't sag or flow in vertical or horizontal seams. - Type: TUBES * Color: White * Size: 3 oz
There are many other sizes and colors of 3M 5200 Marine Adhesive/Sealants and also other 3M fiberglass and boat care products.