How to Clear Coat a Boat

Trailer the boat home if its currently in the water. Place the boat under an eve or carport if possible. Loosen the bilge drain plug with a socket or end wrench and let the bilge water drain. Remove the outboard motor (if so equipped) or the out-drive unit if you wish to perform an extensive clear coat paint job. Remove any hull fittings or components, like the transom backing plate and drain plug housing.

Wash the hull with a mild detergent dish soap. Mix a cup of soap to three gallons of water in a bucket. Use a fiber washing mitt to scrub the surface thoroughly. Remove all light oxidation, oil and fingerprints. Rinse completely and let air dry.

Sand the entire boat with 400-grit sandpaper. Wrapping the sandpaper around a stiff sponge sanding block allows you to follow the curves of the hull without cutting into the sharp edges, especially on lapstrake runners. Do not apply too much pressure; avoid sanding down into the original gel coat finish. Sand the surface in sections, and take frequent breaks. Sand the hull again with 800-grit sandpaper.

Wipe down all sanding residue with towels and rubbing alcohol. Do this in sections, and change towels frequently. Wipe the hull down until you see little or no color on the towels. If you discover any flaking on the hull's surface, like old clear coat, re-sand the area until it's gone.

Cover all areas that will not receive clear coat with blue masking tape and newspaper. Your dividing line might start at the rails and trim. If the boat has aluminum bow or stern rails, mask off the braces far enough up so you will not over-spray them. Mask the boat registration label if you wish.

Set a large plastic tarp under the boat to catch any drippings. Agitate your paint can so the clear coat mixes thoroughly. Don goggles, a particle respirator and gloves to protect your eyes, lungs and skin. Dip a wide-bristle paint brush (fine hair) into the can and begin painting from the highest point on the hull, using smooth, even, horizontal strokes.

Work your way down, concentrating on one large section at a time. A three- or four-foot wide section is good. Once you have reached the bottom portion of the hull, use the brush (with no paint) to make vertical strokes over the entire painted area. This will help avoid runs, ripples and "tiger stripes," which result from from overly thick coats of paint that run down the surface in waves. Paint the entire hull in this manner.

Apply a second coat if you desire a deeper gloss finish. Use the same technique as you did for the first coat. Occasionally back-track over previous painted areas and look for wrinkling, runs or tiger stripes. Use a clean towel to wipe the areas, then re-paint the surface. When finished, let the hull air dry according the paint directions.