How to Fix a Hole in Your Boat

Any boat owner is susceptible to holes and cracks in their boat. Whether it’s from an object floating in the water or a stray rock striking your boat while you’re transporting it on the highway, damage to your boat’s body can significantly affect how well it can support you in the water. For marine enthusiasts and aspiring marine technicians, knowing how to fix a hole in your boat will let you return to the water and keep your boat working well.

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For owners of metal and wooden boats, fixing a whole is as easy a welding it shut or nailing a board over it, respectively. But ATC is here to show owners of fiberglass boats how they can repair any holes themselves.


–          Cleaning solvent

–          Electric grinding wheel

–          Fiberglass cloth

–          Bonding resin

–          Polyester catalyst

–          Magic Sculpt hardener/epoxy

–          Sander

Step 1: Preparation

Before you begin patching the hole, you need to prep the area around it by washing the area down with cleaning solvent. Then, using your electric grinding wheel, cut a circle around the damaged area.

Cut a piece of fiberglass cloth about twice the size of the hole in your boat. This fiberglass will go on the inside of the boat to act as a backing. You want to cut multiple layers; how many will depend on how thick or thin the boat’s wall is.

Mix together your bonding resin and your polyester catalyst. You’ll use significantly less catalyst than resin in your mixture, but your resin container should list the precise ratio based on how much you’re mixing. For example, if you use a half quart of resin, you want to mix in ¼ oz. of catalyst. Too much catalyst will harden your mixture, but too little catalyst means the mixture won’t be able to cure your hole. Make sure you stir while mixing and for a minute after everything is added.

Step 2: Applying the Fiberglass

Spread your mixed resin material around the hole of the boat and then lay your first piece of fiberglass over it. Then spread more resin over the piece of fiberglass that you just put down and add your second cut piece of fiberglass on top. Repeat this process until you’ve added all of your fiberglass layers.

Think of this process as making a multi-layer sandwich with your fiberglass and resin.

Step 3: Filling the Hole

Using a Magic Sculpt hardener or epoxy, you can fill in the hole on the exterior of the boat but only after the fiberglass-resin sandwich has dried. Magic Sculpt can sometimes be a two-part clay that needs to be mixed together. But once your filling is ready, form it into a thick ball that can be spread out to cover the exterior of the hole.

Let it sit and then sand the area down so it’s nice and smooth, and then your boat is ready to hit the water again.

Have other questions? Contact our experts at our Warminster campus!

For more information on restoration that you can do at home, you can download our free ebook Dents and Damage: The Car Lover’s Guide to Vehicle Restoration.

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