How to Patch a Fiberglass Boat

If you ever find a hole in the fiberglass hull of your boat as a result of an accident, you’ll need to patch that hole promptly and properly to avoid taking on water during your next trip. Read on to learn how to patch a fiberglass boat so you can remain safe on the seas.

Assess the Damage

Repairing a modest hole in your boat’s fiberglass is a job that is within reach for most boat owners, as long as you are comfortable with basic tools and DIY work. However, a large hole or other kinds of major damage will likely need attention from a professional. So, the first step in this process is to carefully inspect the damage to your vessel. Here are a couple of key points to watch for:

  • Size of the hole. Measure the diameter of the hole to get an idea of the challenge you are facing. If the hole is only a couple of inches across, there is a good chance your repair efforts will be successful.
  • Cracks. The main hole caused by the incident may only be a couple of inches in diameter but be sure to check carefully for cracks extending from the center. If long cracks are running through the hull, this repair job may be more extensive than it looks.

Make a Clean Break

With your exam complete, it’s time to get down to work. The first main step is to take out everything that has been damaged, including those cracks you found. Use a saw to cut out this area so you are left with a “clean” hole. Once the hole is cut out, you will have a specific, defined area that needs to be patched. The hole you cut doesn’t need to be a perfect circle but try to keep it relatively regular in shape.

Get the Right Kit

You are going to need a repair kit to complete this job. It should be easy to find a fiberglass repair kit at a marine store near you, or you can always shop online. The kit should include the polyester resin you need to make the actual repair, and it may include some other items such as basic tools. Be sure the kit you purchase is suitable for the size of the hole you need to patch.

Preparing the Area

With a kit in hand and your hole cut out to size, there are some steps you need to take before the material for the patch can be put in place.

  • Add a backing. With a hole in the hull, your patching material will have nothing to attach to if you just try to put it in place as is. First, you need something to temporarily fill the back of the hole. This can be a piece of cardboard wrapped in plastic wrap, or a piece of wood. Whatever it is, it should be shaped to match the hull and should be held firmly in place from the inside.
  • Sand down the outside. You’ll also need to prepare the outside of the hull, so your finished patch looks natural and blends nicely with the rest of the boat. This can be accomplished by sanding down an area on the hull that is a couple of inches bigger than the hole itself. The goal is to taper down through the gel coat to the solid fiberglass, working from outside to inside.

Patch, Wait, and Finish

Much of your time on this project will be spent doing prep. With that out of the way, the actual patching job can go quite quickly. Follow the instructions on your fiberglass patch kit to do the job and then be sure to wait at least as long as recommended for it to cure. You don’t want to rush anything here as you could undo some of your hard work.

Use BoatLIFE Products

We hope you’ve learned how to patch a fiberglass boat. To wrap up this project and help your boat look its best, you’ll want to apply a new gel coat to the affected area. If possible, work with the builder of your boat to get a gel coat that will match the color of the finish. Then, clean your boat from top to bottom with BoatLIFE products. This way, your vessel will be ready to shine on the water once again!

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