Selecting the proper bottom paint can be a daunting task even for veteran boat owners. Here are some distinctions to keep in mind as you consult with your service expert and make the best decisions for your boat.
Ablative or hard paint
Two types of paint commonly used in our region are ablative and modified epoxy, also called hard paint. “Most ablative paints have an antifouling agent that works when the boat is moving through the water,” explains George Dunigan, technical sales representative for Interlux Paint. “The movement of the boat causes the paint and any growth to gradually slip off the hull, exposing fresh antifouling agents.”
In order for the paint to be effective, the boat needs to be used about once a week. There are some newer ablatives that offer controlled release, according to Dunigan. They contain self-polishing copper or copolymers. Some last several years with a light sanding each spring—although most ablatives need a fresh coat each spring. Hard paint or modified epoxy works all the time, even when the boat is not in motion.
“The disadvantage with hard paint is its antifouling agents, which contain copper, lose potency when out of the water for more than about 60 days, because the paint begins to lose copper at a faster rate,” says Dunigan. Don Zabransky, vice president of sales and marketing for Pettit Marine Paint further explains, “Hard paints are best for boats that stay in the water for two to three years and for boats that spend a lot of time at the dock.” Since they don’t wear away like ablatives, after several years of build-up, hard paints will need to be stripped.
Choosing the proper paint
Erik Norrie, CEO of Sea Hawk Paints says, “Over the years I’ve found that it helps boat owners to think through the application of antifoulings in three parts: pre-application, the application process itself, and post application. Breaking a bottom job into digestible segments helps eliminate confusion, ensure expected results, and quantify value in the process.
“Adjust your mindset to embrace the fact that combating marine fouling is an on-going event, not a one-time deal, and begin with the end in mind. Think about the type of antifouling system and the type of hull maintenance your vessel will require. From there, consider hull type, the type and temperature of water your vessel will run in, the time it will be in the water, and what fouling agents you need to combat. The answers to these questions can lead you to an effective antifouling system and program.”
“When it comes to choosing a bottom paint, there isn’t one kind of paint that’s best for every boat,” says Zabransky. “The Chesapeake has some of the most extremely diverse conditions in the country. Some areas are very brackish, while others have mostly fresh water. The Southern Bay and urban areas tend to stay warmer, while on the Eastern Shore, there’s runoff from farms that impacts the water.
The best thing to do is to pick the paint that suits your specific conditions. It’s a good idea to consult the manager of your boatyard or local marine store and ask which type of paint is best your particular creek or harbor.” All of the professionals we spoke to recommended engaging a reputable boatyard to ask about the challenges that face your boat and coating type recommendations.
Safeguarding your bottom
Be sure to get a warranty, says Norrie. “Understand the warranty conditions and keep the necessary records so you are covered in the rare case of a failure. Because many warranties may not apply to do-it-yourself jobs, be fastidious in your prep-work and application techniques.” Norrie continues, “Maintain the hull with routine cleanings. You can contract a pro to do this or set a schedule on your calendar to remind you to do it yourself. Today’s high tech paints are easy to clean and will last much longer with routine maintenance. Additionally when using a self-polishing antifouling paint, apply the first coat in a different color. When you see that color showing through, it’s time for a repaint.”
Water-based paints
The introduction of water-based paints has been a big advancement, as they are more user-friendly and kind to the environment. Zabransky says, “With a water-based paint, we take out the solvent, so it has very little odor and cleans up with soap and water. It holds its color and works just as well as the old solvent paint. For boats that stay on a trailer or rack, they’re tough enough to take hitting the bunks.” Today’s water-based paints come at several price levels. “Top of the line water-based paints contain Teflon, which makes them slick. If speed is your goal, this may be the paint for you. But if not, there’s no need to pay more for unnecessary additives,” says Zabransky.
What about gelcoat?
Steve Uhthoff, owner of Annapolis Gelcoat, explains, “Gelcoat is a base that contains the original pigment and is sprayed into the mold as part of the factory production. Paint is usually applied to the hull after the factory gelcoat, but whether the boat owner leaves the gelcoat or applies paint depends on how the boat is used. Gelcoat doesn’t apply easily, and it has to be wet sanded and polished. It’s hugely labor intensive. So once a boat’s been painted, it’s difficult and expensive to go back. “A boat that stays in the water has to have paint, which contains the antifouling biocide. Because gelcoat is a naturally porous material, it must be coated with primer or a water barrier before the application of antifouling bottom paint to decrease the chance of blisters. Bottom paint won’t be as smooth as gelcoat, but a boat living in the water has to have it. Where speed is important, there are special paints with Teflon, which are smooth and shiny and create little resistance.”
When Selecting Paints
- What's the water temperature and salinity where the boat is used?
- Does the boat stay in the water all season or come out on a lift or trailer?
- Does the boat stay in the water for multiple years?
- How often and at what speeds do you run the boat?
- What kind of paint is on the bottom now?
- How long do you expect the paint to last?
- How much can you afford to spend?
DIY Safety and Prep
- Wear a mask, goggles, and protective clothing.
- Read the paint data sheet for temperatures, overcoat windows, safety standards, and precautions.
- Use proper tools for sanding, spraying, and rolling.
- Buy your gear and equipment at marine supply stores to ensure you're buying the right stuff for the job.
- Avoid shortcuts in hull preparation and coatings application (sanding, priming, and painting).
Find Expert Advice
- Manufacturers' booklets, data sheets, and other written materials, such as "Antifouling 101: A Comprehensive Guide from Interlux," available at yachtpaint.com
- Manufacturers' websites for videos, charts, and interactive guides
- Manufacturers' apps for cell phones and tablets
- Manufacturers' help lines. Chat over the internet or by phone with company reps
- Marine supply store reps, paint guides, and websites
- Yard owners and managers