How to Paint a Boat Bottom

Keeping your boat bottom painted not only prevents aquatic life from attaching itself, but also helps your vessel look its best. We’ll teach you how to paint a boat bottom to keep it looking great. 

Materials Needed

• Hose
• Scour brush
• Power washer
• Dewaxing solvent
• Clean rags
• Chemical paint stripper or scraper
• 80-grit and fine sandpaper
• Primer
• Roller brush
• Antifouling paint

Step #1 – Priming Your Boat Bottom

Before you paint a boat bottom, you need to clean and prime it. Remove your boat from the water and rinse the bottom. Use a hose to blast away any loose dirt. If there are barnacles or algae attached, you’ll need to use a scouring brush to scrub it loose. You won’t need any soap to get the boat clean. Just clean the bottom beneath the waterline. If you have hardened or stubborn grime, don’t be afraid to use your power washer. To remove the wax sealant, you’ll need to utilize a dewaxing solvent. Dip your clean rag into it and gently rub away the wax coating. Then, rinse it clean with another damp cloth. If the paint job is damaged, strip it away with a chemical paint stripper or scraper. If the paint is still relatively smooth, there’s no reason to remove the previous coating. Then, you’re ready to sand the bottom of your boat and get it ready for the primer. Use 80-grit sandpaper until you see a dull appearance to it. Once this is done, apply your primer with a roller brush. Once your primer is dry, use your fine grit sandpaper on the surface before you begin painting.

Step #2 – Paint a Boat Bottom

We recommend antifouling paint to avoid growth on the boat. There are three varieties you can purchase:

• Ablative – designed for slower boats in constant use.
• Hard bottom – designed for faster boats or ones that don’t get used often.
• Hybrid – combine benefits of the other two and designed for fast, frequently used boats.

Stir your paint with a stick before applying. Mix until everything is even. Then, apply it to your keel with a roller. Don’t use the paint above the waterline. Once the first layer is dry, sand your boat again with fine-grit sandpaper. Then, add a second coat. This doubles the lifespan of your work. Some brands might need three to four layers, just be sure to read the instructions. You’ll want to sand between every coat for the best results. You can also apply a top coat that’s a different color. This helps you recognize when you need to do another paint job. Allow your paint to dry completely before doing anything else. Remember, that drying times are going to varying greatly depending on the paint and weather conditions. Read the directions to see what the manufacturer recommends. Don’t ever put the boat back in the water until the paint has fully cured.  This could take overnight, so plan accordingly about where you’ll store your boat. Make sure you keep it free from debris and dirt while it’s drying.

Final Thoughts on How to Paint a Boat Bottom

With these simple steps, anyone can learn how to paint a boat bottom. Just take your time and ensure that you do everything properly for the best results. In no time, you’ll be back in the water with maximum protection and a fresh coat of paint. While we're discussing your boat, consider replacing your carpet with Durabak.