It is an expensive solution up front, but this epoxy-based antifouling option is effective, hassle-free, easy on the environment, and can last a decade or more.

Wooden ship bottoms were sheathed in copper to ward off worms, barnacles, and other growth. In modern times, especially since the invention of fibreglass, we haven’t been worried about worms, but we’ve been using bottom paint infused with high concentrations of copper to keep fouling at bay.

There are antifouling paints that combine copper with biocides and other antifouling agents and a few that use other compounds and metals, like zinc, but copper is still the most widely used antifouling material. It’s simple, and it works.

Unfortunately, there are downsides to copper paint, and antifouling paint in general. If it’s a hard paint, eventually it flakes and has to be stripped away. If it’s an ablative (sloughing) paint, it can still flake if the application isn’t ideal, and it eventually releases large amounts of copper and other chemicals into the water. There are plenty of national and local regulations restricting the use of copper bottom paints.

And now the paint is getting expensive – very expensive and even most “multi-season” paints are only as effective as application, locale, and boat usage permit. Some are effective for three years, some for only one.

There’s an alternative called Coppercoat which is in many ways a return to the old concept of copper sheathing. Instead of hammered-on sheets of pure copper, it consists of a high concentration of copper powder stirred into an epoxy matrix at the time of application. It’s rolled on in multiple layers to a substantial thickness, usually about 12mm, and ends up forming, essentially, a shell on the bottom of the boat. It’s sanded before being put in the water, and that abrasion exposes a fixed layer of copper to the surrounding water.