Preventing biofouling is not a one-shot-and-you’re-done deal, and no bottom paint is best for every boat. Your decision depends on answers to these practical questions.

What type of hull do you have?

Most bottom paints contain copper as their antifouling biocide, which is fine for wooden, and fiberglass/gelcoat hulls, but causes galvanic corrosion, which will destroy a pontoon boat or an aluminum hull. For use on aluminum hulls, aluminum bottom paint typically uses a copper-free biocide such as Econea. Underwater metals such as outdrives and trim tabs also need this metal-free antifouling paint.

And don’t forget the bottom of your inflatable, it needs protection, too. Inflatable bottom paint is ablative, so it wears away gradually, and is designed not to crack or peel while the boat is being rolled up, or after drying.

What kind of water is your boat sitting in, and what’s the water temperature?

In terms of temperature, biofouling levels are typically higher in warmer waters than cooler waters.

Fresh water biofouling, while not as severe as saltwater (marine) biofouling, still poses problems which are compounded if the water is brackish or polluted. By far the biggest challenge comes from hard, marine biofouling organisms such as zebra mussels and barnacles, which destroy the hull surface and allow moisture in, causing blistering and other expensive damage.

If moderate to heavy fouling is a problem in your region, you might consider a bottom paint that offers greater protection and lets you haul and relaunch without repainting, such as a multi-season paint. In lower fouling waters, you can get adequate single-season protection from a more economical bottom paint.

The copper biocide (cuprous oxide or cuprous thiocyanate) or copper-free biocide (Econea) in these paints is designed primarily to combat hard shell marine growth. If slime is a problem in your area, use a slime-shedding bottom paint boosted with a slime-fighting agent (zinc pyrithione) that controls slime growth at the waterline.

How and when do you use your boat?

For example, do you trailer your boat? If so, you should use a harder ablative bottom paint that can withstand trailering. Do you race it or just like to go fast? Try a hybrid copolymer ablative that allows you to burnish the surface, and provides good single or multiple season protection. Do you go out every weekend? Every day? Do you want to be able to do your bottom painting at the end of the season so you’re ready to launch first thing in the spring? At TotalBoat, we’re DIY boaters that create products to suit every type of use in all types of waters.

Do you live in an area that restricts the use of solvent and copper-based bottom paints?

To address ever-increasing environmental regulations, some ablative bottom paints are now water-based and/or copper-free, containing an environmentally friendly biocide called Econea™, and fewer volatile organic compounds (VOCs). Other water-based ablatives contain copper for added antifouling protection, but offer easy soap and water cleanup.

How much money do you want to spend on bottom painting?

With bottom paint, usually the more biocide, or different types of biocide, the greater the cost. Also certain properties, like self-polishing, single or multi-season effectiveness, or slime-fighting ability, require the inclusion of certain additives, which can increase the cost. If you don’t need it, you shouldn’t have to pay for it, which is why we created a complete line of bottom paints to balance every boater’s needs and budget.

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