Sail repair question

[Bill R]

I have a small tear in the mainsail for my little bleach bottle. It is L-shaped, about 2" on each leg.

What is the best way to repair this? I don't know exactly what the material is other than some type of obviously man-made synthetic. I need to get a couple more years out of these sails.

Thanks in advance

[bill johnson]

first find some sail cloth, nylon, dacron, etc. cut piece at least 3/4" larger than the tear, same shape, and stitch using machine or sail needle and synthetic thread all around the perimeter of the tear.

[Bill R]

Thank you.

[Yeadon]

I've recently read a suggestion that it's not a bad idea to lay down one side of the sticky tape ... flip the sail over, waterproof glue the rip ... then lay the second side down of sticky tape over the glued tear. Then sew the perimeter of the patch.

Seems like a smart extra step to me, though I've never actually bothered to do the gluing part.

Sailmaker's Apprentice is a good reference, too. (http://www.amazon.com/Sailmakers-Apprentice-Emiliano-Marino/dp/0071376429)

[John B]

Like Yeadon says... stickyback for a quick fix. You round the corners of the patch( es) .

[Todd Bradshaw]

First, lay out the area, flat and smooth so that the rip isn't distorted, and tape over the tear with masking tape on one side. This makes sure that things don't move while you are putting the patch on the other side.

Option #1 - (easy and usually adequate on small sails) Get a chunk of "Insignia Dacron". This is a light Dacron fabric with a peel and stick backing on one side. It's used on sails for sail numbers and class insignias. You will need to get it from somebody who deals with, or sells, real sailmaking materials. Cut a square patch that's 1"-1.5" bigger than the torn area (don't attempt to fool around with an "L"-shaped patch). No matter what material or method you are using, it is absolutely critical to match the weave of the patch fabric to the weave of the fabric underneath the patch. If you don't, the patch will make a distorted spot on the sail once it is full of wind in use. Round the corners of your patch a little bit (trace something about the size of a quarter to get a decent radius). Peel and stick the patch over the tear, matching the weave direction. Flip the sail over, remove the masking tape and stick a similar patch on that side, too. Then use something sturdy (rolling pin, pickle jar, etc.) and roll the patch down tight on a smooth surface. A line of zig-zag stitching around the outside isn't absolutely critical, but does make the patch hold better and resist peeling at its edges. You can also zig-zag through the patches along the edges of the "L"-shaped tear for a bit more strength. This patch will usually outlast the rest of the sail on small boat sails (dinghies or small-ish cruisers).There is, however, a limit to its strength. If you happen to be repairing a big-boat sail, made from heavy dacron, you would need heavier patch material.

Option #2 (a proper patch) is to use regular Dacron sailcloth, similar to the weight of the original cloth. Again, you would need to contact somebody who deals with sails and could most likely get a scrap for free or buy a small chunk so that you have a reserve of the stuff. Masking tape the hole closed on one side, as before. Cut your patch about 3/4" bigger than the area with the hole. You can round the patch corners if you want (it often looks neater, but is not critical) You will want to stick the patch down along its edges. The best way is with 1/2" wide, sail-basting double-sided tape like "Seamstick". You run a line of tape along the outside edges of the patch, peel the tape's backing off and stick the patch down to the side of the sail that doesn't have the masking tape. Again, match the weave of the patch to the weave of the sail. Before they invented Seamstick tape, we used to baste panels and patches using a small bead of household silicone sealer. It will work fine if you don't have the tape, but it's a little more messy and you have to wait for the sealer to dry before you can sew the patch down.

Next, you want to sew around the edges of the patch using a zig-zag stitch. Thread for machine sewing should be white polyester. If you buy it locally at a fabric store, the heavier grades (button and carpet-weight threads) are stronger and last longer. For industrial polyester thread, the V-69 weight would probably be the best choice. White is natural polyester (undyed). Polyester doesn't take dye easily and is usually weakened somewhat by the dying process, so white is stronger. Use a pretty large zig-zag (1/4" wide or better) and adjust your stitch length so that the "corners" of the zigs and zags are pretty close to 90 degree angles. Sew right along the edge of the patch so that the outside of your stitch line falls just beyond the patch's edges (prevents edge raveling). Go all the way around the patch and overlap your starting point by 3/4" or so (no back-stitching needed - it can make puckers if your machine isn't perfectly adjusted for the task).

Now that your patch is stuck down and sewn along its outside, turn the sail over and peel off the masking tape. Next, cut out the damaged area, 3/4" inside of the patch's sewn edge. It's not a bad idea to take a pencil and draw a cutting line to keep everything neat and an even seam width. Corners of the cut can be either square or rounded to match the patch. Now sew around the inside of the cut-out area. This should yield a neat-looking 3/4" wide seam all around the patch where it joins the sail's main fabric, similar to a panel seam. The advantages of this method are that the patched area is now just about as strong as any other spot on the sail, it should last forever and if the weave was properly aligned, there should be no chance of the patch distorting the sail or making a stiff spot, even when the sail is getting a lot of strain on a bias to the weave.

Patches can, of course, be hand-sewn, rather than machine sewn, but most folks don't hand-sew particularly neatly or evenly without some serious practice first. On really soft, old cloth, the edges of the patch and the cut hole can also be turned under for a neater edge, but this isn't generally needed or desired on modern stiff Dacron in decent shape (more prone to distortion). In general, the whole deal with patching is trying to replace or reinforce the damaged fabric with something that's as similar as possible in weight and bias stretch (or lack of bias stretch) to the original cloth and to do it securely, but without excessive build-up. We want the area to flex, stretch (or not) and perform similarly to the way it did before being damaged.

Sailrite.com is probably the easiest place to find the supplies you need and put together a small repair kit for future use - some thread, a yard or two of fabric, a hunk of insignia Dacron (good for temporary repairs and other stuff, even if you don't use it for permanent patching) a roll of seam tape, a couple real hand-sewing sail needles, some sail twine, etc.).

Figure that a small patch like this one is probably worth $20-$25 if you have it professionally repaired. They aren't very difficult to do and if you can do them yourself, a couple patches would offset the cost of a pretty good repair kit.

[rbgarr]

I was waiting for you (Todd) to answer this question of Bill's. I felt like suggesting the unstitched insignia cloth patch (I've got a couple on my sail even now and there are rolls of it in white on eBay now) but wonder if you'd recommend your second approach depending on where in the sail the rip is, i.e., where strains are greater on different parts of the sail?

[Bill R]

Thanks Todd. I was hoping you would chime in.

[Todd Bradshaw]

Rbgarr, A real patch is nearly always better as it will match the stress lines on the original fabric better, but sticky-back is often adequate for small stuff as long as it's real insignia Dacron. The ripstop peel-and-stick repair tape sold for sleeping bags at places like REI doesn't last long. The adhesive dries out and they fall off. Real insignia cloth may peel and get ugly right along the edges, but it almost never falls off unless the orientation is crooked and it's getting a lot of bias stretch. Once you start patching areas which get a lot of stress or are close to, or crossing seams, the sewn, proper-style patch is often the only way to go if you want it to hold up very long. Out in the middle of a panel though, sticky-back usually works decently on small holes.

On really old sails, where there is obvious sun-rot happening, sticky-back may be the only hope of repairing breaks in the cloth. Sewing a patch sometimes just adds a new, perforated line of needle holes, which might as well have a label on it that says "tear here". Reinforcing using sticky-backed fabric, but without sewing may be the only good way to eek a bit more life out of a rotten sail.

I don't like sticky-back patches on spinnakers though. They are perfectly strong enough, but almost always make a hard spot that can't stretch and move to match the surrounding fabric. A proper, taped and sewn patch on a spinnaker will be much smoother and virtually disappear into the sail's in-use shape. They're really easy to do on a home machine, too - especially if it had a two-or-three-step zig-zag (where each zig or zag is made from several small straight stitches). You tape the patch over the hole, matching the weave, make one pass around the perimeter with the zig-zag, flip it over and cut out the bad section.

Back when I worked on balloons there were some brands where it was FAA approved to patch small holes with pieces of matching fabric, glued on with Goodyear Pliobond (a heavy-duty contact cement found in most hardware stores). It's sort of a "make your own sticky-back" scenario and very strong, though the glue is yellow and tends to show, so they aren't pretty. In a pinch, it would work on most sailcloth.

It's interesting to note that even in a thread about a simple little patch like this, I have mentioned cloth weave orientation so many times - partially because I tend to beat the issues to death whenever I write instructions, but also because this factor is critical in almost every aspect of sailmaking. It's all about thread-line orientation.

[rbgarr]

Thanks for clearing that up!

[John B]

Great tip re the masking tape Todd. Thanks for that( on top of the usual well communicated other options and data of course).

[Bob Cleek]

What Todd said! He's the resident sailmaking guru!