Fiberglass is what is used as the base of the boat. These are the strands underneath the gelcoat that you typically do not see. (unless there is a gouge!) Over the fiberglass usually gelcoat is applied at the factory. If the surface is scratched gelcoat is the same color throughout; if the surface has been painted when scratched it will show what is underneath.
Need a repair?
If it is just a gouge and not penetrated all the way through the boat, then you would need to fill in the gouge with 3M premium marine filler (just one product that will work but our most popular for this use). After you have filled in the gouge and sanded it down, you would then apply the topcoat of gelcoat. (gelcoat is the top finish that you see on your entire boat.) Gelcoat is typically much thicker than a paint and is designed to protect the underlying fiberglass as well as provide a smooth shiny appearance. Be sure to leave the marine filler about 1/8″ lower than the surrounding gelcoat. This will allow you to apply enough gelcoat and be able to feather the surrounding area once your done. If you leave the marine filler flush, then once you apply the gelcoat you will have a lump on the area you are repairing (gelcoat should be thick enough or it could release from repair).
Here are the products that you would need.
The amount that you will need is dependent on the size and number of gouges. If you have many gouges, you may consider buying a quart of gelcoat. However, the nice thing about the gelcoat repair kits is that they come with tints so that you can try to match your existing gelcoat color.
What is difference between gel coat and paint?
Gelcoat is usually much thicker than paint and is engineered to protect the underlying fiberglass as well as provide a smooth shiny appearance. However, the nice thing about the gelcoat repair kits is that they come with tints so that you can try to match your existing gelcoat color. Paint is thinner and typically much easier to apply. Unlike paint, gelcoat will not adhere to existing paint, wood, metal or concrete. Gelcoat also has a limited shelf life of around 3-4 months at around 70 degrees whereas paints that are solvent-based can last up to 15 years while latex and water-based ones may last for up to 10 years.