Solvent-based antifouling paint is currently the most common paint available on the market.
Most people known it as bottom paint that comes in a metal can and smells awful, requiring a respirator for application. Formulas have been refined over many years and it has proven its effectiveness.
Increasingly, there's been an environmental push to reduce and ban solvent-based paints because of the toxicity of their solvents, and the high level of VOCs (volatile organic compounds) they contain. Select states have already eliminated the use of solvent-based paints.
The alternative to solvent-based antifoulants is water-based antifouling paints. There are many misconceptions about water-based antifouling paint, including the notions that water-based antifouling paint will dissolve or run in water, and will not work when applied over solvent-based paints.
It's been proven that both statements are wrong. If applied properly and allowed to dry thoroughly, water-based antifoulants are just as effective as solvent-based paints. Water-based paints will still have a slight odor, but it's minimal compared to solvent-based paints.
Another benefit of water-based paints is that cleanup is as easy as using soap and water.
Commonly, water-based antifouling paints come in plastic containers and can be copper-based or copper-free.
Both are effective in preventing marine fouling, but personal preference determines whether you want to use solvent-based or water-based paint.