A hole in your fiberglass looks bad and can lead to water damage but it can be repaired with patience. Fiberglass is a strong material that will bond to almost any surface if prepared. It is applied by cutting the mat into the size of the repair and layering. The resin, mixed with hardener, is applied to the mat. See our 1 Quart fiberglass repair kit.
Most professionals recommend exposing the sound fiberglass around the damaged area to have a firm base. Grind down the edges to firm fiberglass and then clean the damaged area with acetone, or solvent provided, to remove any dust or grease that may remain. If repairing from the inside, place tape over the outside of the hole or crack to prevent resin from running down the finished face.
Cut the fiberglass into layers for size of repair. Mix the resin and hardener as directed, in small amounts as it will harden quickly. Layer the fiberglass and resin until level with the surrounding area, completing with the cloth overlapping well onto the sound hull surface.
After cured remove irregularities in the patch surface with a disc sander or drill with sanding attachment…don’t over sand, just smooth. Move to finer paper until it matches the contour. If using gelcoat to finish off patch see our gelcoat application guide or gelcoat repair guide.