Boaters have been painting their boats since time immemorial. It's an annual pre-season or pre-launch maintenance ritual for many. Here in the northeast, boatyards and marinas that are silent in the winter become hives of activity in early spring with everyone from professional boat painters to do-it-yourselfers getting ready for the season ahead. A fresh coat of paint, whether its on the hull, topside, or deck, improves your boat's appearance and helps keep it in good condition by protecting the surfaces underneath.
Now, 'marine paint' is very much a general term used to describe the many different formulations intended for use on boats. The type of paint you use depends on what part of the boat it is being applied to.
For example, boat bottom paint refers to marine finishes applied at and below the waterline. Bottom paints are protective coatings generally applied to prevent fouling such as weed, slime, barnacle, and or mussel build up that can hamper your boat's performance.
Topside paints are marine specific finishes applied above the waterline, upper hull and deck areas. These coatings are more than decorative. Topside paints protect your boat from long term damage that the sun (UV rays) and sea (moisture and salt) can cause.
Marine varnishes are specifically engineered for use on interior and exterior woods on boats. Varnish ingredients are usually a blend of oil, resin, solvent, dryers and ultra-violet additives.
Nearly all boat painting projects involve pre-paint surface preparation ranging from scraping old paint to priming bare hulls. In fact, the adhesion and durability of the finish is almost always directly proportional to the quality of surface prep. Paint primers and undercoats are used with marine paints for maximize adhesion over old paints or bare aluminum, fiberglass, steel, and wood hulls.
For the best results, it's critical that manufacturer's painting conditions guidelines be followed. Ambient temperature can significantly impact dry and recoat times. Various thinners and additives are used to speed up or slow down paint drying time. The use of additives or thinners also depends on whether you are rolling, brushing, or spraying.