How to Repair a Fiberglass Boat Hull

What You'll Need
Fiberglass repair kit
Wax removal solvent
36 grit sandpaper
Screw driver
Paste wax
Felt roller
Polyvinyl alcohol

One of the worst things that can happen to any boat is damage to the hull. Fortunately, if you have a fiberglass boat hull, there are repair options available which can remedy your problems. If the damage is significant, the boat should be taken out of the water and thoroughly inspected before carrying out any repairs. If the damage to the hull is fairly minor and located above the waterline, you can normally carry out the repairs without taking the boat out of the water.

Step 1 – Remove the Damaged Section

You should not attempt to repair fiberglass that is actually damaged. Instead it should be removed using a circular cut. You will also need to refinish the surrounding area which in the case of a small damaged area will be about twelve inches larger. If you can carry out the repairs from inside the boat, you will save yourself a great deal of trouble as there will be less refinishing work to be done on the hull.

Step 2 – Remove the Wax

Before you can start working on the area, you need to remove any fax and mold release found on the outside of the hole. Use a special wax removing solvent for this.

Step 3 – Prepare the Surface

Prepare the surface by sanding it down. This will give you a stronger bond for the repair to adhere to. Use a disk sander to go over the area around the hole that you cut out. Grind out the interior of the hole to form a rectangular area. It is highly recommended that you wear safety goggles and a dust mask when grinding or sanding fiberglass as the dust created can cause extreme irritation and discomfort. Finally, use a rag soaked in acetone to move away any dust left behind.

Step 4 – Mask the Area

Apply the paste wax to the area to be prepared. This should be used only on the hole’s exterior. Apply a backing area to the hull with appropriate tape. Apply Formica soaked in polyvinyl alcohol to the area. This should assume the hull’s shape.

Step 5 – Use the Fiberglass Repair Kit

Take the fiberglass fabric from the repair kit and cut a layer that is about one inch wider the hole itself. The number of layers that you will need depends on the depth of the hole. Cut each layer slightly narrower than the previous one so that the filling tapers towards the back of the hole. Apply a mix of resin with about two percent catalyst into the area to be repaired.

Refer to the instructions with the fiberglass repair kit for more details on working with your chosen brand. After this, apply the colored polyester resin from the repair kit. Apply each layer of the cut fiberglass fabric to the hole, wetting the layers with the resin. Use a roller to compress it in place.

Step 6 – Refinish the Surface

Refinish the repaired area by sanding it down so that the repaired area blends perfectly with the surrounding fiberglass.