Repair an aluminum boat hull by locating the leak or damage, thoroughly drying the area, applying the appropriate repair compound or patch kit, and allowing it to cure. Repair procedures and the material required depend on the size and type of hull damage. Typically, the tools needed include a hammer, a small heating torch, a wire brush, a putty knife and a power drill and grinder. Small leaks may only require a sealant while large holes may need patch material.
Identifying a large hole in an aluminum boat hull is easy, but if the leak is not visible, it may be in a seam or around a rivet. Pull the boat out of the water and elevate it on blocks. Fill the inside of the hull with water and observe it from underneath for leaks. Circle all of the leaking areas with a marker and drain the water from the boat. Use a wire brush to thoroughly clean the marked areas and dry the leaks with a propane torch.
Heat small leaks in seams and rivets with the torch before applying a suitable marine epoxy with the syringe included in the kit. Coat the leaky areas liberally and allow the full amount of curing time specified by the epoxy manufacturer.
Hammer the edges of large holes and tears back into the original shape as close as possible. Grind off any burrs or torn edges and sand the surface until it is smooth. Drill some small holes in the hull around the damage to allow the epoxy to permeate both sides. Cut a suitable size fiberglass patch and adhere it over the damaged area according to the product instructions.