Choosing the Best for Antifoulant Paint Your Boat
Antifoulant Paints - How They Work
Antifouling paint keeps marine growth such as barnacles, mussels and sometimes oysters, and plant growth from attaching to your vessel. Most antifouling paints use the dispersion of metals within the paint to block these foul critters from adhering. Copper (cuprous oxide) and tributyl tin are two metals that have proven to be successful as biocides, but tin, banned worldwide on ship hulls in 2009, was so toxic that it decimated marine ecosystems.
Copper compounds are now universally accepted, but the cost of the copper raw material has risen substantially. In addition, high copper concentrations have dissolved in the water of harbors in several places in the USA placing limitations on the application of copper-based paints.
Paint manufacturers continue to develop a number of new antifouling technologies that tackle these and other troubles.
New Paint Products
- Composite Copper: Substitutes the traditional cuprous oxide with silica, lowering the copper content by up to 40%. The outcome is a copper based biocide that gives excellent protection for your boat, with a base that is made from resources found in the sea.
- Water-Based ablatives: Water replaces the solvents found in standard bottom paints. Low-odor formula allows painting inside. Application is problem free and clean up requires only soap and water.
- White copper: Clean and white in color, white copper (cuprous thiocyanate) requires 50% less content than the dark copper used in traditional antifouling paint.
- Econea: Paint manufacturers believe that, a metal-free biocide developed by the pharmaceutical industry, is the future of antifouling paint. Advantages include protection at low usage levels, they degrade quickly and are biodegradable. Unlike some metal-based antifouling agents, ECONEA can be used to easily develop lighter and brighter paints, resulting in bright colors with better uniformity. Because it is a metal-free compound, ECONEA will not cause galvanic corrosion on aluminum hulls. This eliminates the difficulty and price of thick barrier coats. ECONEA-based paints add less weight to a boat when applied at the same film thickness as metal-containing paints.
Antifouling Paint Choices
Copolymer paints are typically used on slow vessels such as trawlers and sailboats and release biocide at a steady controlled rate all through their lives, wearing away or "ablating" much like a bar of soap. Paint wears off faster in higher drag areas on the hull and appendages. These paints work well in high-growth areas and continue to be effective after haul-out and relaunch. Copolymer paints offer true multi-season protection, lasting as long as there is an acceptable coating thickness. Because they expose new biocide until the coating is worn completely away, additional coats add to their longevity. We recommend a covering of two coats on each application. Copolymer paints with anti-slime additives are best for nutrient-rich, heavy fouling areas.
Modified epoxy paints are best if you own a fast planning – hull boat. Contact leaching paint releases the biocide at a steadily decreasing rate, leaving the hard coating of the original thickness at season's end. Higher copper content, rather than the type of paint binder as with ablative paints, generally means greater effective performance in this paint type. Modified epoxy paints stick to most surfaces, and can be applied over most types of paints. On the down side, they lose effectiveness when the boat is stored out of water. In addition, after several applications, the existing paint will begin to build up requiring removal.
