BOTTOM PAINT GUIDE PART 2: DOES THE TYPE OF BOATING YOU DO AFFECT YOUR BOTTOM PAINT DECISION
In a word … Yes. While the racer, the cruiser, and the one-weekend-a-month fisherman may all own fiberglass boats, their anti-fouling needs are very different.
Different paints are designed for different types of water and weather conditions. You and your best friend may own identical 40’ sailboats, but if you keep your boat in the Caribbean and your friend’s boat is on a lake in the northeastern United States, each boat will need different anti-fouling paint.
Hard anti-fouling paints which work on contact with water are ideal for go-fast boats and racing sailboats. They are also good for boats that are scrubbed regularly, as the hard surface resists abrasion. However, if hauled out, boats with this type of anti-fouling paint cannot be re-launched without being re-painted, something to keep in mind if you dry slip your boat for the winter.
Ablative anti-fouling paint wears away with use, which can make sanding in preparation for new bottom paint a relatively easy job. However, if your boat just sits at her slip, the paint bearing the growth will not fall away. Conversely, if you run your boat at speeds over 25 knots, self-polishing paint can wear away very quickly.
Partially-soluble bottom paints are worn down by the physical action of the water across the surface of the paint, resulting in fresh biocide (commonly cuprous oxide, a form of copper) always being at the surface of the paint. Like a bar of soap that wears down but can still make suds, as long as you have paint on your boat, your anti-fouling system should be working.
Paint manufacturers are continually developing new, high-efficiency paints in an effort to come up with anti-fouling paints that will be just as good as ones containing TBT (tributyltin), but not as toxic. Copper is also toxic, or it wouldn’t keep boat bottoms clean, but it is less so than tin. New technology has allowed development of paints that use low amounts of copper, yet still keep algae and other organisms away.
The warm salt water and temperate climate of the Caribbean provide an extreme anti-fouling challenge, so how do we protect our boats now that we know how toxic tin-based paints are to the marine environment? One of your best resources for information about what type of anti-fouling paint is appropriate for your area is your boatyard manager. Bruce Merced, manager of Independent Boatyard, St. Thomas, reports that Micron 66, a new tin-free paint from Interlux, is long-lasting in Caribbean conditions and is most requested by knowledgeable boat owners. Local information, especially if you are new to boating or to an area, is vital if you are to properly protect your boat.