Antifouling Bottom Paint
Antifouling bottom paint is applied at a boatyard. The first step in painting your boat is hauling it out of the water and blocking in in the yard. With your boat out of the water, the crew will start prepping your boats hull and running gear. Wax residues, loose paint, and residual growth is removed by pressure washing, sanding, solvents, and sandblasting. After the hull and running gear are properly prepped, bottom paint is applied. The active ingredient in antifouling paint is copper, or cuprous oxide. Copper slows the growth of marine flora and fauna on the bottom of your boat. Not all antifouling paints are the same. Bottom paints contain different amounts of copper, have different ways of releasing the copper, and have different binders. One difference in antifouling paints is the amount of copper the paint contains. The percentage of copper a paint contains will give you an idea of how long the paint will last, but remember that binder type, water conditions, boat speed, frequency of boat use, etc. will also affect service life. There are two basic types of bottom paints, epoxy hard paints and ablative soft paints. Both have strengths and weaknesses. With epoxy hard paint the copper is evenly spread throughout the hard paint film. Once the boat is in the water, the particles closest to the surface dissolve, but the paint itself does not. When the copper dissolves, there is a hole which lets the water dissolve copper further inside the paint. This happens repeatedly until all the copper is gone. Epoxy hard paints tend to last longer in this area. The weaknesses of hard paints are they can build up with repeated paintings and if stored out of the water for extended periods the paint surface can harden to a point that the paint is rendered ineffective. Ablative soft paints work quite differently. With these paints, the paint itself wears away continually exposing new copper. The rate of erosion is determined by a number of factors including the chemical composition of the paint, boat speed, and turbulence. I will inspect the effectiveness of the antifouling paint while cleaning your boat. I will contact you when the paint has lost its effectiveness and we can discuss painting and boatyard options.