Canoes commonly get damaged on their way to the water, usually by falling off a car top. Small holes and leaky seams can easily be fixed by using a variety of methods that work equally well on wood, plastic or aluminum canoes.
Field repairs - Locate the hole. If it isn't obvious, dry off the canoe bottom, put water in the canoe and watch to see where the water escapes.
Small holes can be temporarily patched with duct tape. For the best adhesion, make sure the repair area and the tape are warm.
For a leaky seam, try a favorite old-timer's trick: Using a small stick, apply pine pitch along the leak. Pine pitch, the sticky gum found on pine trees, is extremely durable and waterproof.
Permanent repairs - Dry the canoe thoroughly.
Remove any dents around the damaged area if possible. Dents in plastic or aluminum canoes are sometimes pushed out from the inside.
Using a pair of scissors, cut a piece of fiberglass cloth slightly larger than the repair area.
Mix fiberglass resin and hardener in a paper cup according to the manufacturer's directions. Stir well with a wood strip such as an ice-pop stick.
Coat the repair area with the resin mixture. Place the fiberglass cloth over the repair area. Saturate the cloth with the mixture. Smooth the cloth with a wood strip to remove any air bubbles caught underneath it.
Watch for the resin mixture to become firm. Be prepared to trim any excess cloth or mixture with a sharp knife before the repair is fully hardened.
Smooth the repair with sandpaper once the mixture has hardened completely. Start with 100-grit paper to remove the roughest sections, then use 220-grit and finally finish with 400-grit.