How to Install (and Remove) a Keel Guard on a Trailer Boat

Megaware sizes its guards by boat length and says the recommended length is the minimum: the guard should run past the lowest point of the hull so its tail end doesn't catch and peel when you beach or load. Don't cut a guard shorter than the maker says. Measure your keel line with a tape before ordering if you're between sizes.

The adhesive is only as good as the surface under it. If the gelcoat is gouged, cracked or worn through to fiberglass, fix that first (see /guides/gelcoat-repair). For deep gouges, Practical Sailor describes washing, drying, roughening the edges, then filling with epoxy and an epoxy filler and fairing it smooth. Let any repair cure fully as the product says before going on.

If the boat has antifouling, strip it from the keel area down to sound gelcoat (see /guides/bottom-paint-stripping), and follow the paint maker's rules for sanding dust.

Megaware says to start the guard 4 to 6 inches above the resting waterline at the bow, measured with the boat loaded normally (people, fuel and gear). Mark that point. Don't start it lower even if you only care about beaching: Megaware explains that when the boat comes up on plane, water pressure on a front edge set too low can tear the adhesive and peel the guard off, and it doesn't recommend any part of the start sitting below the waterline. Then mark the keel centerline back along the hull with masking tape or a grease pencil so you can keep the guard straight.

Factory mold release and wax stop adhesive from sticking. Discover Boating and Megaware both say to etch the keel area with the scuff pad supplied (a fine pad that won't hurt the gelcoat) until all the gloss is gone. BoatTEST describes the supplied pad as a mild 320-grit equivalent; if you use sandpaper instead, go no coarser than 180 grit. Megaware's FAQ is blunt: most failures they see come from poor surface prep, and the surface should be dull, not shiny.

Wipe the area with isopropyl alcohol or acetone on a clean rag, then wipe again with a fresh rag. Discover Boating warns not to use paint thinner or other petroleum-based cleaners, which leave a film that hurts the bond. Let it flash off and dry completely.

Apply a thin, even coat of the adhesive primer supplied with the kit over the whole area the guard will cover, especially the edges. Discover Boating points out the primer is not a cleaner; it reacts with the adhesive and the bond gets stronger over time. Let it dry as the kit says.

Unroll the guard and let it relax and reach the same temperature as the hull; Discover Boating suggests a few minutes in the sun if it's cool. Hold it against the keel without removing the liner to check the start point, centerline and length. Many guards have a liner scored down the middle to help with centering.

Once the adhesive touches the primed surface, it is permanent, so line it up carefully before you let it touch. Peel back the center strip of liner for the first couple of feet, align the guard on your centerline at the start mark, and press it down along the center. Then peel one side's liner and press that side down, working from the center outward so no air is trapped. Do the other side the same way.

Continue toward the stern in sections of a few feet at a time: center, then one side, then the other. Keep checking that it stays on the centerline. Don't touch the adhesive with your fingers.

Go over the whole guard with the burnishing tool using strong pressure, paying attention to the edges. A rubber mallet adds pressure on stubborn spots. If your guard crosses raised strakes or a chine, Megaware says to seal any small gaps between the hull and the guard with a marine adhesive sealant so water can't creep under the adhesive.

If you use bottom paint, you can paint over the guard once it's installed. Check your kit's instructions for any wait before launching. Discover Boating notes the primer bond keeps getting stronger over time, so go easy on beaching for the first few outings.

Rinse and wipe the guard when you pull the boat. Look at the edges, especially the front end and over strakes. Seal small lifted spots with marine adhesive sealant before water gets under them. If a section tears or peels, contact the maker; warranties usually need registration and proof of purchase.

To replace or remove a guard, peel it back slowly from one end; Megaware says the foam core of the adhesive is designed to split in the middle. Take off the leftover adhesive with a plastic putty knife and a rubber decal-eraser wheel on a drill, kept moving so it doesn't heat the gelcoat. Clean the remaining residue with isopropyl alcohol or acetone, then inspect the gelcoat, repair any damage and wax the area if you're not fitting a new guard.