Understanding The Different Types Of Marine Paint
Marine paint is designed to protect boats from all the bad stuff they’re exposed to above and below the water – blazing sun, brackish water, briny sea spray, and bottom-hugging barnacles – to name a few.
Different types of boat paint are applied above and below the waterline, which is where the surface of the water touches the boat hull.
A topside finish is any paint applied above the waterline on a boat, including interior and exterior surfaces such as decks, bilges, cabin walls, and hull sides. Topside paints are formulated to have various properties such as UV resistance, abrasion resistance, color retention, durability and flexibility. Once cured, they also resist cracking, chipping, and peeling, and are much more durable than household paints.
Topside finishes include marine enamel paints and marine-grade polyurethane paints. One-part alkyd enamel paints are easy to apply, and are less expensive than one-part polyurethanes, but they’re not as durable. One-part polyurethanes are durable, easy to apply by brushing, rolling or spraying, have good UV resistance, and good color retention. These paints can be solvent based or water based. Water-based polyurethanes have the added benefits of low odor, low VOCs, and they clean up easily with soap and water.
Different Topside Paints for Different Parts of Your Boat
Choosing the best topside finish for your boat depends on the surface you’re painting, the type of protection needed, and the level of gloss desired.
Boat hulls see a lot of sun and sometimes salt and sand, so they need a coating that’s UV resistant and abrasion resistant. A colorful, high-gloss topside paint will give your boat a head-turning showroom shine, while protecting the surface underneath.
Boat decks require a durable, non-skid paint that prevents slips and falls and holds up under heavy foot traffic. These anti-slip paints typically have a low-sheen finish to prevent glare. You can also make your own non-slip deck paint by blending a non-skid additive into a compatible topside polyurethane paint.
Boat bilges are dank, dirty, oily places that can benefit from an epoxy-based bilge paint that repels any acids, grease, moisture, oil, and solvents that end up there. Painting your bilge makes it easier to maintain, easier to find things you drop in accidentally, and easier to spot problems, such as leaking antifreeze. This type of paint is also ideal for other damp, mildew-prone places such as the anchor locker, the engine room, compartments, and lazarettes.
Interior boat surfaces such as cabin ceilings, cabin walls, cabinets, trim, doors, bulkheads, lockers and lazarettes require a mildew-resistant cabin paint. Both polyurethanes and water-based enamels are suitable. Water-based finishes are easy to apply, easy to clean up, have no harsh fumes, and hold up well to every-day wear and tear.
Boat transoms showcase boat names and custom artwork. For boat lettering, we recommend a gold metallic paint.
Boat Bottom Paint
Bottom paint, also called antifouling paint, is designed to prevent barnacles, mussels, weeds, and slime from clinging to the bottom of your hull below the waterline. Not only does marine fouling look bad, it can be costly and dangerous. It affects your ability to maneuver safely, and increases fuel costs because your engine works harder to move your boat through the water.
There’s not one type of bottom paint that’s perfect for every boat. Some antifouling paints are more effective at keeping the bottom of your boat cleaner in high-fouling areas vs. low-fouling areas, some are better for racing because they can be burnished to make them slicker, while bottom paint for aluminum boats is formulated to prevent galvanic corrosion, and copper-free bottom paint or water-based bottom paint are best for areas with environmental restrictions on the use of copper-based and solvent-based antifouling paints. And don’t forget bottom paint for an inflatable boat or RIB – because barnacles, weeds, and slime will cling to the underside of everything underwater.
Types of Antifouling Paint
With so many choices, it can be hard to understand why some bottom paints are better than others, and which one is best for your boat and boating conditions. To make it simple, know that bottom paints are typically either hard or ablative. Each of these types has several variations that vary in effectiveness depending on how much time the boat spends in the water and how frequently it moves.
Hard bottom paints contain biocides on the surface of the coating. They release biocide continuously while the boat is in the water – even if the boat isn’t moving. When the biocide has completely leached out, the coating might still look like it’s in great shape, but the paint is no longer effective at repelling growth. Hard bottom paints lose their effectiveness faster if the boat stays out of the water for a period of time. They’re effective for a single boating season, but the downside Is that they build up season after season. Eventually, all the built-up layers must be removed before you can apply new bottom paint. Examples of hard bottom paints include hard modified epoxy paints, Teflon bottom paints, and vinyl bottom paints. Hard bottom paints are best for boats that sit in the water for long periods of time without moving.
Ablative bottom paints contain biocide throughout the coating layers, not just on the surface. These paints are also called ‘self-polishing’ because they release fresh biocide gradually – either as the boat moves through the water, or as water from tides or currents moves under the bottom of the boat. Certain types of ablatives, such as copolymer and hybrid copolymer ablative antifoulings, wear away gradually, but don’t require the boat to be moving in the water. At the end of the season, there’s no paint build-up to remove because the paint wears away completely. Depending on the type of ablative paint, the effectiveness can last for a single season or multiple seasons.
Here’s more information to help you decide which TotalBoat bottom paint to use on your boat.