A boat canvas can need repair for several reasons. The stitching can deteriorate in sunlight, the canvas can be worn through or torn by the frame or nearby fittings, or it might have been cut or torn by a sharp object. Depending on the type of damage and the condition of the canvas, it is sometimes possible to repair the canvas. But in many cases it is better to just replace the canvas. Sealing your marine canvas with a good canvas fabric and seam sealer will not only make it more waterproof, but will also lengthen the life of the cloth and the thread — so when you do replace your old canvas, be sure to seal it properly to help it last as long as possible.

Repairing Canvas Wear and Tear

If your boat canvas has been worn through from contact with its own frame or with other parts of the boat, it can probably be repaired, and if the wear and tear will be repeated, it is a good idea to reinforce the canvas in that area by sewing on some leather or isinglass, both of which resist abrasion quite well. To repair your boat canvas, you can buy canvas repair kits with small swatches of cloth and some thread and needles, and start sewing. In my experience, the canvas will look like a three year old got loose with some of mom's sewing stuff. If you want nice, clean seams and a waterproof repair, you might want to go to a professional marine canvas shop to have your canvas repaired.

Repairing Simple Tears or Cuts in the Canvas

A simple tear or cut in the canvas can be stitched back together, but will deform the surrounding cloth if it is drawn tight. The area of the repair will not be all that water resistant, and it should be patched with another piece of canvas sewn on.

When to Repair Your Boat Canvas

For a boat canvas on which the stitching is failing, it may or may not be worthwhile to have the canvas re-stitched. Canvas tends to shrink over time in the sun, so a tight canvas can rip its own stitching in some cases, especially if the thread used was not a high quality UV resistant thread. If the thread has failed but the canvas cloth itself is in decent condition, it can be re-stitched. If the canvas material is becoming brittle and crunchy from sun exposure, it is probably not worth re-stitching it.

If your canvas gets damaged or torn while you're out cruising, a temporary canvas repair can be a good idea. Even if you know you will be replacing the canvas once you're back at your home port, a temporary repair can help protect your sails or other parts of your boat until you're able to replace the damaged canvas. It can be helpful to keep a canvas repair kit on board your boat for just such situations.

If the repair will result in a couple more years of service from a boat canvas, it is fairly inexpensive to have an old canvas repaired, but if it is on the way out anyway, why waste time and money on it? A new Sunbrella canvas will last for years, so it makes sense to look at the annual cost of of your canvas, not just the initial price. If your restitching job is close to the annual cost of owning a new canvas, and your old one is about done anyway, it's time for some new canvas. After all, the cost of the new canvas will be far less than the cost of replacing or repairing damage to the boat and its fixtures that the canvas will prevent.