One of the things that the basic boat owner should have some knowledge about is boat hull repair. This type of repair is necessary if you run aground, run into a rock, or have cracks caused by age and use. Hull repair is fairly easy for someone who owns a small fiberglass boat of their own.
Clean off Cracked Portions
Working with fiberglass, or even a wooden hull, you will need to start by cleaning out the crack and the affected area. A simple sanding with an orbital sander will be enough for this.
Use Quick Drying Epoxy
Many marine retailers will have quick-drying, or 5-minute, epoxy. Be careful with this type of epoxy as it will dry quickly and is very hard to remove from clothes, skin, and anything else that you do not want it on. Spread it with a plastic spreader and smooth it until it is seamless with the rest of the hull. Make sure you also spread epoxy on the inside portion of the hull.
Paint after Drying
Once the epoxy has dried you may need to wet sand it a little to rough it up enough for the paint to adhere correctly. Paint with approved marine paint. Make sure to paint to at least 1 inch above where the water line would be with the boat loaded.