In this article, we’ll focus on the essential maintenance step of repainting your boat’s hull with specialized antifouling paint available in our Marine Paints & Varnishes section – ensuring it stays looking good and well-protected against the ravages of salt water and the elements.
What Is Antifouling Paint?
Antifouling paint is specially formulated to prevent unwanted, detrimental marine growth of barnacles, hydroids, sea grass, green weeds, and algae that’s unavoidable on boat hulls, anchors, propellers, and other hardware – regardless of whether the boat’s in fresh water, brackish water, or salt water. They also repel mussels, oysters, tube worms, and various soft-shelled invertebrate organisms.
Antifouling paint also forms an effective moisture barrier to prevent metal oxidation, natural electrolysis, and corrosion – something that’s extremely vital where dissimilar metals are joined together, such as stainless steel fittings on alloy masts. Maintain a proper coating to protect propellers, shafts, rudders, anchors, and related hardware, and they’ll continue working as designed for a much, much longer period.
Because salt water and lake water are tough environments, fresh antifouling paint should be applied every year or two. After application, you’ll notice the boat glides easier through the water because antifouling paint contains drag-reducing thermoplastic polymers - even graphite and silicon in some mixes designed for racing boats (more on that further below). The overall responsiveness and performance of your boat will be better, and total fuel costs will be reduced – easily covering the cost of paint a few times over.
BOATiD.com offers highly-regarded bottom paints from proven brands such as Interlux, Aquaguard, Pettit Paints, Flexdel, Forespar, MDR, and Sea Hawk Paints in a wide variety of colors and container sizes to ensure you get exactly the amount you need.
Preparing Your Hull for Painting
First, let’s get the hull ready for painting. Once your boat is out of the water, start by giving surfaces a thorough wash with hull cleaner that’s formulated to loosen and remove tough scum deposits, unsightly rust stains, and equally important – old wax that would prevent new paint from being applied properly.
Apply the hull cleaner in a circular motion, and change cloths a few times to prevent excess wax buildup on each one. If your boat was well-waxed previously, use a good dewaxer such as Mother’s CMX Surface Prepare Cleaner - going over the surfaces to be painted three to four times to make sure old wax removal is complete. For better scouring of caked-on gunk, we recommend a good scrub pad such as the Captain’s Choice Grit Cleaning Pads available in light, medium, and heavy grit levels.
What Paint Is Right for You?
Because it’s important to choose the right type of bottom paint for your boat and water conditions, we’ve got antifouling paint formulated for fiberglass hulls, wood hulls, and metal hulls. However, most of the bottom paints we offer are designed to be effective on more than one of these hull materials. It’s recommended to heed any advice your boat manufacturer provides on this subject.
Copper and Biocides
When it comes to ingredients, both types of paints vary when it comes to impeding the growth of unwanted green gunk. On various product pages, you’ll see reference to “biocides” as an ingredient in some of the paints. Biocides can contain copper (cuprous oxide when used in compound form), zinc, or other active ingredients such as Econea to prevent fouling. Copper, the most common biocide, offers the benefit of durability - slowly leaching out to inhibit marine growth for a longer period. However, biocides (especially copper) can be toxic and harmful to other marine life in general. Non-biocide paints contain no active ingredients. Instead, they contain silicone, epoxy, or ceramic ingredients which are much more environmentally friendly. We’ll touch on this further below.
Antifouling paint containing copper/cuprous oxide should never be applied to an aluminum hull or underside components, because doing so would create a galvanic reaction that can be corrosive to the metal itself. Instead, use antifouling paints containing a non-metallic agent such as Econea or zinc.
All antifouling paint is classified as “ablative” or “hard” – with some “hybrid” varieties that are a combination of both.
“Ablative” Paints
For boats that stay in the water for shorter periods, or are trailered home after use, we recommend “ablative” paints. Ablative paint is designed to wear away during use, slowly sloughing off outer layers of its skin to continually present fresh paint and biocides to the water. Marine growth is prevented, and outer surfaces remain gunk-free and clean-looking. Paint build-up is also eliminated, as is the need for heavy sanding before recoating. Depending on the type of water you’re in, you may not need to sand at all.
We recommend Interlux Trilux 33 and Bottomkote ACT Fiberglass Antifouling Paint - ablative paints that can be applied to fiberglass, wood, and metal below the waterline application in sea water, fresh water and brackish water. They’re also great for use on aluminum outdrives and outboards. If you’re looking for bright hue colors, we recommend Sea Hawk’s Colorkote Triple Biocide Antifouling Paint.
Should you prefer copper-based ablative paint, we’ve got Sea Hawk Paints’ Islands 44 TF Dual-Biocide Antifouling Paint and Flexdel’s Ultraguard Premium Fiberglass/Wood Antifouling Paint. For copper-free paint, we’ve got Interlux’s satin sheen Micron CF Antifouling Paint with Econea and Flexdel’s Armor Multi-Surface Antifouling Paint for fiberglass, aluminum, and wood.
Eco-Friendly Ablative Paints
For those that prefer to remain as eco-friendly as possible, we’ve got Sea Hawk’s ablative Smart Solution Antifouling Paint and Aqua Guard’s ablative Fiberglass/Wood Water-Based Antifouling Paint. One of our best-selling eco-friendly products is the Pettit Paints’ Hydrocoat Antifouling Paint which features a low-odor formula that’s a result of replacing harsh solvents found in most bottom paints with water. It also withstands frequent trailering, beaching, and launching well.
While these paints are minimally invasive to the environment, that doesn’t mean they’re not effective. Instead of harsh solvents, these paints create a living surface that blocks the growth of bacteria, parasites, and fungal pathologens - much like mucoprotein protective slime coats naturally found on the scales of fish. Applied to your hull, marine growth is effectively blocked.
Hybrid Paints
We also offer “hybrid” paints designed to provide the best characteristics of ablative and hard paints, combining durability with slow polishing to ensure there’s always a smooth outer finish that doesn’t require sanding between coats.
For seasonal performance at a good value, we recommend Interlux’s Bottomkote NT Fiberglass Antifouling Paint, Sea Hawk’s Biocop TF Anitfouling Paint & Cukote copper-based Antifouling Paint, and Pettit Paint’s Neptune 5 Hybrid Antifouling Paint suitable for below the waterline applications on fiberglass, lead, wood, bronze or stainless steel. Looking for bright colors? Pettit Paint’s Vivid Performance Antifouling Paint is available in great colors that catch the eye.
“Hard” Paints
For boats that are kept in the water for extended periods of time, we recommend hard coat paints. Hard coat paint does not shed outer layers and wear away like ablative paint, and it’s more effective at preventing marine growth through a slow release of biocides that leach out through the paint. Between paintings, however, some sanding is typically required.
For waters where algae and slime are more of a factor, we recommend Interlux Micron Extra Antifouling Paint with Biolux formulated with organic biocides that serve as powerful anti-fouling agents to eliminate unwanted marine growth of slime, fouling shells, weeds, and algae. Another excellent choice is Pettit Paint’s Trinidad SR Antifouling Paint containing a high mixture of copper (70%) paired with a specially formulated algaecide to create an antifoulant with unprecedented resistance to barnacles, algae, slime, and other marine and fresh-water fouling organisms.
Interlux’s hard Bottomkote Aqua Fiberglass Antifouling Paint is a good all-around hard paint for fiberglass, lead and wood. It’s easy to clean, and it’s low in thickness – a factor that aids high-speed performance. For those who prefer copper-based paint, we’ve got Sea Hawk’s Sharkskin Antifouling Paint.
For Propellers, Outdrives, and Other Metal Components
Hard antifouling paints are typically good choices for protecting boat propellers, outboard motor components, outdrive hardware, and other submerged metal. Designed especially for these items is Forespar’s hard Lanocote Prop & Bottom Antifouling Paint that blocks the growth of algae, sea grass, corals, and barnacles. Should you prefer ablative paint, Interlux’s ablative Pacifica Plus Antifouling Paint is a matte finish paint formulated specifically for propellers and outdrive equipment.
For Racing Boats
If you own a powerboat, sailboat, cruising boat, or even inflatable boat that you race or want to wring the most speed and performance out of, your best bet is antifouling paints formulated for racing that reduce friction in the water with a slicker surface. This is achieved through a careful formulation using additives that create smooth, low-friction surfaces such as thermoplastic polymers, silicon, molybdenum disulfide, and even graphite. We recommend Interlux’s hard Micron VC 17m Extra Antifouling Paint with Biolux and Pettit Paint’s hard Ultra-Slick Black Widow Antifouling Paint that are designed to be applied below the waterline in sea water, fresh water, and brackish water.
For Inflatable Boats
For inflatable boats, paint must be formulated to flex with the hull as it contracts, expands, and changes shape. So when it comes to antifouling paint, we recommend MDR’s ablative Black Transducer Antifouling Paint, Aquagard’s Shark White Water Based Antifouling Paint, and Pettit Paint’s ablative Inflatable Boat Antifouling Paint – all of which will remain uncompromised even after the boat’s been deflated for storage.
In addition to antifouling paints, BOATiD.com also carries a full line of primers, varnishes, fairing compounds, cleaners, topcoat paints, and much more. We’ve also got a huge selection of all kinds of parts for boats including electronics and navigation equipment, replacement parts and hardware, plumbing-related items, maintenance, and fun upgrades to make the boating experience more enjoyable.
Whatever you’re looking for, we’re confident you’ll find the right products on the digital shelves of our online store. Visit us at BoatiD.com for all your needs, or contact our knowledgeable specialists on call seven days a week at 888-453-5144.