High-Performance Bottom Coatings

Looking for a way to improve performance and keep growth off your hull and running gear? Try one of these three coatings.

July 18, 2014
Wilson Custom Coatings offers three products that repel growth and improve performance.
Wilson Custom Coatings
Technology: Nanotechnology
For: Hulls, props, gear cases, running gear
Application: DIY and professional
Interlux’s Intersleek Pro provides boaters with a cleaner, more efficient hull bottom.
Intersleek Pro
Technology: Fluoropolymer
For: Hulls, props, gear cases, running gear
Contact: Interlux at
Buy: Not for retail sale
Application: Professional only
Propspeed’s silicone-based protectant delivers gains in top speed combined with decreased fuel consumption.
Technology: Silicone
For: Drives, gear cases, props, running gear
Contact: Propspeed at
Application: DIY and professional

Nothing puts a damper on your boat’s performance — or your season — like having to haul the boat halfway through the year to remove fouling such as barnacles, plant growth and slime growing on its bottom and on its drives, lower units or running gear. And let’s not forget that growth costs you money too. That’s because, in addition to robbing speed, the drag created by fouled hulls and drivetrains causes the engines to burn more fuel.

When it comes to protecting your investment, increasing speed and enhancing efficiency, there are three ways you can go in terms of technology or methodology. You can go high-tech and high-dollar with a nanotechnology-based coating such as the new product from Wilson Custom Marine of Stuart, Florida. Next, there’s the tried-and-true Intersleek product from well-known marine coatings company Interlux. It’s a ­­­fluoropolymer-based (a fluorocarbon-based polymer with multiple strong carbon-fluorine bonds) coating for hull bottoms and running gear. And, there is Propspeed, a silicone-based coating applied only to drives, propellers and running gear.

Each protectant has its pros and cons, and more than likely, you’re going to want a professional to handle the work. Let’s take a closer look at each one to determine which would be right for your boat.


Nanotechnology: Wilson Custom Coatings
Just the word nanotechnology makes people think of a sci-fi movie, but at its simplest level nanotechnology means working at the molecular level.

The technology has been available for a few years, said Mark Wilson, co-owner of Wilson Custom Marine, which distributes Wilson Custom Coatings and which has long been known as an expert in the field of blueprinting performance hulls, drives and propellers. The biggest advantage that nanotechnology has is how well the product bonds to the surface to which it’s applied.

“All the other coatings sit on the surface, and with the nano product, it becomes more one with the substrate,” Wilson said. “It bonds to the product you’re putting it on and it then becomes a single structure.” He added that propellers coated with the product have come back to his shop bent, but the coating has stayed intact. It will also stay on surface-piercing propellers, a testament to its robust adhesion.


This spring, Wilson and his son Craig had just started working with the product on yacht propellers and a couple of high-performance catamarans, but they didn’t have any before-and-after speed data. Wilson did, however, say the captain of a Pershing 74 that had its propellers coated claimed a noticeable speed increase with the coating.

Wilson also said that his coating had done an excellent job of repelling growth. After letting the boat sit in south Florida for two weeks, the captain of the Pershing noticed some growth on the props. He bumped the Arneson drives in gear at the docks with the boat still tied up, and afterward the props were shining like new. After leaving it for another week, the skipper took the boat for a no-wake cruise on the Intracoastal Waterway, and when he returned to the slip, he could see the white dots where barnacles had been blown off the surface of the blades.

One thing that sets apart Wilson Custom Marine’s products from other coatings is that there are three different formulations. The hull coating is a different formula than the propeller coating, and there’s a third metal coating that you put on anything metal above the water. All three are sprayed on, and the propeller coating is basically the metal coating with a catalyst to make it harder. In commercial and industrial applications, the Wilson Custom Coatings metal coating (without the catalyst) has lasted 10 years on a bridge. Mark Wilson said he expects it to last two years on a boat. He added that running through sand doesn’t even remove the coating from a propeller. Here’s an interesting tidbit: “The coating scores 7 on the Mohs scale of mineral hardness. That’s comparable to the hardness of quartz. A diamond scores 10, the highest Mohs scale rating.”


To apply the coating, you must first finish the prop with a 180-grit sanding pad and wipe it down with a dedicated chemical cleaner to ensure there are no impurities on the surface. Then the coating is sprayed on in two successive coats that must be applied within 10 minutes of each other. Because of its nanotech formula, the spray is super light. A gallon of Wilson coating for propellers weighs 6.5 pounds compared to eight pounds per gallon for water and an average of about 15 pounds per gallon for conventional anti-fouling paint. Wilson estimated that 80 percent of the fluid actually evaporates into the air when it’s being applied. That would explain the $1,000 price for the two-part kit for propellers.

Props are dry to the touch in an hour, but full cure takes 48 hours. While the projected performance increases will be beneficial, Wilson admits that stopping the growth is what’s going to draw the attention of most boaters. “It really is the holy grail, trying to find something that stops the growth,” he said.


Fluoropolymer: Interlux Intersleek Pro
Like the Wilson Custom Marine products, Interlux’s Intersleek can be used on running gear and on the hull bottom. The fluoropolymer coating can most easily be compared to Teflon, and it has no anti-fouling properties. It’s a foul-release coating that, in lay terms, is so slippery that any plant or animal that attaches just can’t hang on. When Intersleek was first introduced about 20 years ago, Interlux started with silicones, but they didn’t hold up as well so it changed the formula to the current configuration.

“It’s better against slime and grass growth as well as shell growth,” said Jim Seidel, marketing manager at Interlux. “Barnacles will grow on it, but you can push them around with your finger. If you left the boat in the slip without using it all summer, barnacles would grow on it, but you could wipe them off with your hand.” In most cases, simply using the boat will clean the bottom, since the growth won’t be able to grip against the flow of water. If diving and cleaning are selected as a method to defoul, less force and time will be required. Either way, a cleaner, more efficient hull bottom results.

Intersleek Pro came out in the fall of 2013. It replaced Intersleek 1100, which had taken the place of Intersleek 900. Seidel explained that Intersleek 900 was used primarily on freighters and cruise ships, and the fleet owners reported a 9 percent reduction in fuel cost. Captains of high-speed ferries also said that they were reaching top speed at lower engine rpm. Saving that much fuel would be intriguing to owners of long-ranging boats, such as sport-fishing vessels and cruisers, looking to extend range and owners of performance boats for the potential to add higher speeds.

Because Intersleek Pro is not a bottom paint, Seidel said that, after getting the hull surface down to bare fiberglass or metal, you need to apply an initial coating of an epoxy-based product such as Interlux’s Interprotect 2000. Follow that with what Seidel called a tie coat, which is a coating product made to go on the surface prior to Intersleek Pro. It’s basically required to get Intersleek Pro to stick to the hull bottom. Intersleek Pro can be rolled or sprayed. You need two coats with a roller or a single one if spraying it on. In either event, a total film thickness of 6 mils is suggested. Applied by roller, coverage is about 400 square feet per gallon at 3 mils dry film thickness (DFT); if you use airless spray application, coverage increases to about 200 square feet per gallon at 6 mils DFT. So, depending upon application method, Seidel estimated that the whole process would cost $5,000 to protect the hull of a 30-foot boat.

Seidel said that Interlux hasn’t pushed the Intersleek products for recreational use because of the price and the fact that it primarily should be applied by trained professionals. He said that Interlux hasn’t approached performance-boat owners because the go-fast crowd traditionally hasn’t wanted to put any coatings on their hull bottoms, with true enthusiasts either trailering their boats or using a boat lift.

Silicone-Based: Propspeed
Designated exclusively for propellers and running gear, Propspeed is a silicone-based protectant developed about 25 years ago by the New Zealand-based Oceanmax International Limited. It’s a two-part coating with a primer and a catalyst that must be applied exactly according to the instructions.

“The Propspeed system is really dependent on the surface profiling that needs to take place before we put the [protectant] on the running gear or propellers,” said Mark Billingsly, technical support manager at Propspeed USA in Fort Lauderdale, Florida.

“Surface profiling” is fancy talk for the prep work required to be performed on the surface of the propellers and running gear. Even if another process such as sandblasting is used to remove other coatings that may have been on the hardware, the Propspeed system requires that the surface be scratched with 60- to 80-grit sandpaper because the primer is designed to fill the specific scratch pattern left by a specific abrasive grit.

That’s only the first step. The primer and catalyst are mixed in a 4:1 ratio. For DIYers, Propspeed recommends that you pour all the catalyst into the can of primer, stir it up, and then go back and use the catalyst can as a mixing pot. Once you mix the primer and apply it, you’ve got five minutes to get the clear coat on. While the primer can be applied with a small foam roller or a natural bristle brush, the clear top coat can only be applied with the latter.

Billingsly did say that 80 percent of the Propspeed kits sold are professionally applied. The 1-liter kit retails for $469.99, while the 500-milliliter kit goes for $359.99 (both at West Marine). The 1-liter kit covers 72 square feet, and total curing time is eight hours. “In south Florida, it’s a $3,000 application in labor and materials, and you’ll save as much as 10 percent on fuel,” Billingsly said.

Most Propspeed customers are sport-fishing captains who have seen significant gains in top speed combined with decreased fuel consumption. The longevity of Propspeed is environmentally driven. It’ll last about 18 months in Florida, but in New England, you can go as long as three years before reapplication. When the time does come to reapply, the old coating has to come off so you can start with bare metal surfaces.

Got You Covered
These coatings are not for every boater. Many boaters will prefer to trailer their boats, or keep them on a lift, so as to keep a clean, efficient bottom. But for those who keep boats in the water, the coatings-technology advancements represented by Intersleek Pro, Propspeed and Wilson Custom Coatings may just be the ticket to a faster, more fuel-efficient ride.

Quick Tip: Always use proper safety equipment when applying or handling chemicals. Face shields, gloves and protective clothing are the minimum DIY boaters should have on hand.


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