DIY Tips on Boat Hull Repairs

August 7, 2022

Over time, your boat hull will need to be repaired. From minor weathering to scratches and deeper cracks, it’s important to protect the integrity of your boat hull. DIY repairs are possible and cost effective when done correctly.

In this article, our boating safety  experts list some of the best DIY tips on how to repair your boat hull effectively.

Repair a fiberglass boat hull

Repairing a fiberglass boat hull can be done with different materials like gel coats and resins.

Use a gel coat

Gel coat is a material commonly used for repairing fiberglass boat hulls.

With its resistant and mechanical properties, gel coat is a resin that hardens in contact with air about 1-2 hours after its application. As a result, the hull structure is solidified and cracks are filled.

Use these steps to apply a gel coat:

  1. Clean and prepare the cracks by digging out the indentations and polish these edges
  2. Prepare gel coat filler following the instructions on the label
  3. Pour the mixture into the cracks and press it in as much as possible to avoid air pockets. For proper application, the gel coat should overlap the area by at least 7 mm
  4. Once you generously apply the gel coat, wait 1-2 hours for the coating to set and harden. Sand the area using P80 grit paper
  5. Apply a finishing coat in the color of your choice
  6. If needed, reapply a final coat of gel coat for a new-like finish

Use a polyester resin (or polyester filler)

Depending on which part of your boat has the crack, you can use a polyester resin. The use of polyester resin is best suited for a defect on a hull that is above the waterline.

Like a gel coat solution, once the polyester filler is applied and dried, you sand it down and apply a varnish on the hull of your boat.

Use an epoxy resin (or epoxy putty)

Epoxy resin is best used when the damage is below the waterline. Epoxy is more water resistant than polyester resin.

Great care must be taken when using an epoxy resin. If the mixture lacks the catalyst, it will not harden and will remain liquid. Once the solution is applied, it is necessary to act quickly since the catalyst will quickly harden the resin. It is best to have all the necessary equipment at hand to carry out the repair. To avoid health risks, apply the mixture in an open, ventilated area and read the instructions on the label carefully. Wear gloves, goggles, and a face mask to avoid any problems with the fumes and stickiness of the resin.

Repair a plastic boat hull

Unlike fiberglass boat hulls, plastic hulls have a construction that does not need materials such as resins or epoxy. Instead, materials with a similar makeup to plastic like polyethylene sticks should be used. Polyethylene is derived from plastic and will fill cracks and scratches in a plastic boat hull perfectly.

To use polyethylene sticks, first heat the stick and then spread the application with a knife or metal spatula. It is always best to apply a generous amount of product. Then delicately melt the product down once dried and reapply your choice of paint to the plastic boat hull..

Repair an aluminum boat hull

It is possible to repair an aluminum boat hull with few materials, but some professional experience may be required.

Weld the aluminum boat hull

Depending on where the damage on the hull is, place an aluminum sheet over the crack and weld the parts to make the repairs. A professional welder is highly recommended.

Sandblast the aluminum boat hull

Sandblasting is best to remove dents and small scratches on an aluminum boat hull. This technique uses pressurized air and an abrasive sand to remove the scratches.

Use epoxy resin on the aluminum boat hull

Epoxy resin is a component that reinforces the hull’s structure and acts as a protective layer on it. This material can be used for aluminum hulls to fill and strengthen them.

Repair a wooden boat hull

A wooden boat hull needs more attention. Over time, wood tends to rot or mold. When scratches and cracks happen on a wooden boat hull, the waterproofing layer has been damaged and needs to be reapplied.

The first step is to burn the area on the hull to be repaired to remove paint residue and harmful mildew. Then fill the scratches or cracks with materials such as resin or epoxy. Sand down the dried compounds and apply a gel coat to waterproof and reinforce the damaged areas.

If the issue is mold and mildew, deep clean your boat hull and then burn the affected areas to remove the paint and mildew. Then reapply a protective varnish or gel coat to the entire hull.

How much money does it cost to repair a boat hull?

The cost of repairing a boat hull ranges because of the type of repair your hull needs and the material of the hull itself. The price of the repair also depends on if you do it yourself or if you hire a professional.

A professional boat repair service includes the costs of materials and parts as well as labor. The average boat hull repair can cost around $3000.

Doing the repair yourself is possible and can range around $250 for the materials. It may even be less if you already have the materials. Consider the value of your time and experience to make the best repairs on your boat hull.

Take the boater exam course with National Boating Safety School

It’s not always easy to take care of all the parts of your boat, knowing the main items to inspect and repair will help you handle your boat in the best possible way.

If you or a family member has yet to obtain your Pleasure Craft Operator Card, take our Transport Canada-certified online boating exam to take advantage of driving your boat now!

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