Bottom Paint Checkup 2015

Barnacle and slime convention takes over our antifouling paint panels at 18 months.


Boat paint panels

You know that youve been testing bottom paint too long when you start rooting for the slime and barnacles . . . or tunicates and seaweed, or sponges, or algae, or oysters . . . the whole lot of em. Go sea critters, go!

If you ever felt an ounce of sympathy for the invertebrates that sailors spend so much money trying to defeat, then here is some news that will warm your barnacle-hugging heart. We just returned from pulling our 18-month antifouling-paint test panels, and the past year and a half has been very good to barnacles.

How good was it? So good, that we had to throw our rating scale right out the window. Usually our bottom paint ratings follow the same routine as the rest of our product tests. Products are rated Excellent, Good, Fair, or Poor based on their comparative performance in our tests. To make things fair and simple, any bottom paint that is harboring barnacles or other hard growth earns to a Poor rating. This checkup, however, the best rating we could give was a Poor+, meaning that the relatively few number of barnacles and low slime growth suggested a paint still had some punch left in it.

Although our test conditions are more strenuous than most boat bottoms will offer, the simple fact remains: Paints that during prior tests were barnacle-free at the 18-month interval had conspicuously failed this time around. But why?

Tweaks to the formulas could be a factor. A few of these paints have had their formulas changed slightly-either to meet new Environmental Protection Agency (EPA) restrictions on volatile organic compounds (VOCs) or to compensate for the rising cost or lack of availability of biocides-but the majority were the same formulas we have been testing for years.

Our guess is that conditions were simply more challenging than ever before, with warmer water temperatures and higher nutrient levels. Although we don’t track temperature, salinity, etc., from year to year at our test sites, environmental factors have almost certainly played a role in past tests, though not to this degree.

The widespread failure among all paints was the headline this year, but of almost equal import were the results of new bottom paints containing Econea. Developed by a division of Janssen Pharmaceuticals, Econea is the latest chemical additive that antifouling paint manufacturers are using as a substitute for copper biocide, which has come under scrutiny by state and federal environmental agencies.

Along with a few copper-free, single-season paints for aluminum hulls, the Econea test panels were the worst of the lot. This was not a huge surprise. With rare exception (Epaint in 2010), no copper-free paint has made it past the 18-month mark in our tests. The striking part was the manner in which they failed-suddenly and completely. The potency of these paints doesn’t fade away; it abruptly halts. Econea paints that were still working at 12 months were completely carpeted at 18 months. The copper paints, by comparison, saw more gradual declines in protection.

Choosing a Bottom Paint

When choosing a bottom paint, make sure it is compatible with your existing paint, or be prepared for whatever extra prep work might be required. Usually, all that is required is some light sanding and possibly a primer coat, although in some cases, more aggressive sanding and surface prep is required.

Make sure the paint matches your needs. Most paints are formulated for specific conditions. We loosely classify bottom paints into two categories: hard paints and ablative paints. Hard paints hold up well to underwater cleaning and can usually be burnished smooth for racing. However, they leave behind paint layers that build up and eventually will need to be sanded off. Also, hard paints can require a light sanding before re-launch, or even lose their punch altogether if they are stored ashore for too long. Most ablatives can be hauled and re-launched without worry.

Ablative paints wear away, so they don’t build up paint layers over time. There are two main types-bottom-tier workboat ablatives that slough away to activate more biocide, and more expensive copolymer ablatives that release biocides at a more controlled rate.

Although ablatives are often called soft paints, some, like the new dual-resin ablatives, are relatively hard. These will usually resist light, underwater cleaning and are suitable for trailering.

The hard and ablative paints are further divided into five broad sub-categories that often overlap: freshwater paints, aluminum paints, racing paints, water-based paints (easy for the do-it-yourselfer to apply), and eco-friendly paints. Paint types are indicated in the accompanying tables, and the best paints in each category earn Recommended ratings.

In the March 2012 issue (available online), our report focused on the long-term effectiveness of paints by type. In general, the order of failure is, first to last: freshwater, eco-friendly, low-copper single-season, water-based paints, dual-resin paints, high-copper multi-season ablative, and high-copper multi-season hard. Whether or not a paint has a biocide booster does not seem to make a significant difference by the two-year mark in our tests, but biocides clearly help combat slime during the first year or so.

For more on selecting paints, see the Inside Practical Sailor blog post Choosing a Bottom Paint for Dummies, which was posted online Aug. 31, 2011.

Boat paint panels

What We Tested

This report focuses on the effectiveness of 55 different paints after 18 months of immersion. Represented manufacturers include Blue Water Paints, Interlux, Epaint, Pettit, and Sea Hawk. Although weve tested several of the paints before, the test field also includes many newer blends formulated with the non-metal antifouling agent Econea, which only recently was introduced to paints for the recreational boating market. Others are slightly modified blends, and some products are simply renamed. Any of the test paints that are new in name or chemical composition are indicated as new in the accompanying Value Guide tables.

The bottom-paint test panels were dropped in the water in June 2013 at the Sarasota Sailing Squadron in Sarasota, Fla. Results of their effectiveness after 18 months of immersion are listed in the accompanying Value Guide tables. Given the slight regional variations weve seen, we encourage boaters to also seek out recommendations from local boatyards and professionals to cross-check with this report.

How We Tested

All test paints were applied to 6-foot by 2-foot fiberglass panels for testing. Testers followed the makers instructions for preparation and application. There were no more than 10 samples per test panel.

Prior to rating the paints on each panel, testers sluiced the panel with a bucket of salt water. Paints were rated Poor+ (minimal hard growth and no or very little soft growth), Poor (moderate hard and soft growth), and Poor- (heavy soft and hard growth).

A Recommended paint performed best overall or rated best among its specialty peers (best aluminum-safe paint, best water-based paint, best racing paint, etc.). The Budget Buy paints are the least costly among the Recommended paints. All prices were double-checked online at the time of publication, but these can vary by vendor.

Any antifouling test is subject to a number of variables. How and where you use your boat, as well as the maintenance regimen, can affect longevity and performance. We suggest supplementing our data with local knowledge from independent sources.

Blue Water

We tested 16 paints from New Jersey-based Blue Water paints. The group included two hard paints, and the rest were ablatives. Four of the paints were discontinued after we began testing. These were the two dual-resin paints, Duplex 45 and Duplex Boosted 45, and two specialty, eco-friendly paints, Coronado and Shelter Island.

In the hard-paint category, even copper-loaded Copper Pro SCX 67 Hard, which was doing well at the 12-month mark, had clearly faltered at 18 months. The budget-priced Copper Shield 45 Hard, which squeaked into the Poor+ category, was the best hard paint from Blue Water this time.

Two of Blue Waters biocide-boosted ablatives, Copper Pro SCX 67 Ablative and Duplex Boosted 67 suffered a surprisingly sharp setback at 18 months, finishing among the bottom tier of our panel sets. Meanwhile, its best ablative paint was one of its cheapest: the budget-priced New England, a single-season ablative designed specifically for sailors who haul out and repaint each year.

Blue Waters discontinued, fast-drying dual-resin, duplex paints-both of which were showing fairly strong results at 12 months-experienced a precipitous decline in protection. Weve previously seen this pattern in these types of paints (although after a longer interval in the water). The advantage of being able to apply multiple coats in a single day appears to sacrifice some durability, as none of these paints have yet matched the performance of top-shelf, conventional solvent-based paints in our tests.

In the copper-free category, only Shelter Island Plus showed some muscle against hard growth. A large area of this panel had succumbed to very heavy soft growth, but the number of barnacles was relatively low.

Blue Water Paints are available through the companys website, or through distributor Donovan Marine ( The paints are also sold under the MarPro label.


Epaint specializes in photo-active, copper-free blends that release a biocide when exposed to light. The blends have consistently done well in previous tests, with EP2000 often being virtually spotless at the 12-month mark. At the fall panel check, the new SN-1HP ablative, which is boosted with the Dow biocide Sea-Nine 211, and ZO, a hard, relatively slick, hybrid finish, were both phenomenally clean; however, both suffered a drastic decline at 18 months, and were rated near the bottom of our group.

Epaint also makes a slick racing paint, ZO HP, and a freshwater paint, Ecominder, which is the companys most eco-friendly paint. If you are enthusiastic about going copper free and like the idea of going 12 to 15 months with a very clean hull, then Epaint remains a leader in this category. Keep in mind that all Epaint coatings are activated by sunlight, which is in short supply in some areas.


Interlux has developed a series of effective ablative paints that control the release of biocide. Its Micron series is particularly popular among year-round sailors, or those who like to haul and re-launch for a second summer without repainting. The top-shelf Micron 66 failed earlier than usual, but it was still one of the cleanest test panels. This paint is a saltwater paint, and unlike the other Micron paints, it is not recommended for fresh or brackish waters. The other standout in the ablative category was Fiberglass Bottomkote NT, the only quick-drying paint to rise above the pack. Interluxs eco-friendly Pacifica Plus landed near the bottom of the copper-free category, and the Econea-boosted Micron CFs best-to-worst transformation was a poster-child for the sudden failure that Econea paints experienced. At 12 months, Micron CF was one of the best paints in our test; at 18 months, it was one of the worst. The high-potency ACT, one of Interluxs most popular paints and another standout at 12 months, delivered average results at 18 months, when it was clearly past its prime.

Among Interluxs hard paints, the water-based Fiberglass Bottomkote Aqua, a good choice for do-it-yourselfers who prefer hard paints, was still fighting barnacles.

Petit/West Marine

Pettit (a Kop-Coat Marine Group brand), which also makes a line of paints for West Marine, had several top finishers. In fact, the best paint overall in the entire set was West Marines premium ablative paint, PCA Gold, which had only about 15 barnacles and a relatively thin layer of slime. West Marines hard paint, Bottomshield, also landed in the group of top-tier paints. Its CPP paint, which had scored well at 12 months, joined the many panels covered with a thick carpet of soft and hard growth.

Pettit had one hard paint in the Poor+ category. Unepoxy Plus, a hard paint with 55-percent copper by weight, topped several paints with much higher copper content, including Pettit Trinidad, a perennial favorite among warm-water sailors. Vivid, another favorite, known for its wide selection of colors, had what appeared to be the beginnings of a coral reef.

In the ablative category, Hydrocoat SR, a water-based paint boosted with the slime-fighter Irgarol, and Ultima SSA, a single-season ablative, crawled to the top of the field. The cleanest ablative paint from Pettit was Ultima SR60, which was slightly cleaner than the Hydrocoat SR.

Both of Pettits Econea-based paints, Ultima Eco and Hydrocoat Eco, had already failed at the 12-month mark.

Sea Hawk

In the wake of the recent convictions under U.S. laws regulating the use and sale of pesticides, the maker of Sea Hawk paints must follow stricter environmental compliance procedures for the next three years (see accompanying story). The Florida-based company continues to manufacture a full range of antifouling paints. Among its lineup are a number of environmentally friendly paints. Like most of the other copper-free paints, none of these looked impressive after 18 months.

We continue to watch the evolution of Smart Solution, a paint that contains no metals. The paint, which has been reformulated once since being introduced four years ago, showed promising results at 12 months, but it is still too new for us to offer any definitive judgment. The current production line is made up primarily of copper-based paints, several of them boosted with anti-slime agents. In this round of testing, Sea Hawks top-shelf Tropikote was the best performer among the hard paints, and Cukote led its lineup of ablatives.


This checkups results were disappointing, but our results still offer some important lessons-not the least of which is the unpredictable nature of field testing.

In the hard-paint category, we had only four paints that hit the Poor+ mark. Interluxs Bottomkote Aquas easy water cleanup makes it well-suited for the do-it-yourselfer. Either Blue Waters Copper Shield 45 Hard or Pettits Unepoxy Plus would be a good choice for the budget-minded cruiser who prefers a hard finish and plans to haul out within two years. Although top-shelf paints like Pettit Trinidad, Interlux Ultra, and Copper Pro SCX did not do well in this round, these have been proven to be good buys for long-term cruising sailors. Sea Hawks Tropikote also scored a Poor+.

The ablative paint category yielded a greater range of choices. Do-it-yourselfers will like Pettits water-based Hydrocoat SR. Interluxs quick-drying Fiberglass Bottomkote NT will also make life easy for the do-it-yourselfer. Budget-minded sailors should look at Pettits Ultima SSA, or our top overall finisher, West Marine PCA Gold. Of the three top-shelf ablative paints-Pettit SR-60, Blue Water Gold Coast SPC, and Interlux Micron Extra with Biolux-the Micron Extra (tied for best performance with PCA Gold) looks to be the most effective, but not by a remarkable degree. Perennial winner Interlux Micron 66 will also provide long-lasting protection for saltwater sailors. Sea Hawk had three top finishers: Tropikote, Islands 77 Plus (sold only in the Caribbean), and the ablative paint Cukote.

If you are inclined (or forced because of local legislation) to use an Econea-based antifouling paint, you can probably expect 12 months of protection; Interluxs Micron CF was the cleanest Econea paint at 12 months. But when that paint fails, it will likely fail all at once; there will be little, if any lingering protection to get you through the next six months or so, as is often the case with copper paints.

Copper is still king when it comes to long-term protection, but we heartily support any efforts to reduce the amount of biocide introduced to the ocean. Seasonal sailors and freshwater sailors might find that an Econea-based paint will provide all the protection they need in their home waters, which likely are less fertile than our test site on Sarasota Bay.

The increased volume of Econea-based paints being sold today suggests that they can perform better than our tests indicate. However, until we start applying these paints to some of our test boat hulls (we will be doing this in the spring), and putting them to real-world trials, we can’t verify these claims.

Anyone who is interested in long-term protection should also look at our March 2014 bottom paint report, which is available online. That report highlights U.S. regional preferences, and lists paints that have consistently done well at the 24-month mark.

As always, we like receiving field reports from sailors who care to share their bottom-paint experiences. We are most interested in hearing from sailors who have used an Econea-based paint. Send reports to [email protected]; please put bottom paint report in the subject line.

Hard Paints
Bottom Paint Checkup 2015
Ablative Paints
Bottom Paint Checkup 2015
Ablative Paints 2
Bottom Paint Checkup 2015
Darrell Nicholson
Practical Sailor has been independently testing and reporting on sailboats and sailing gear for more than 50 years. Supported entirely by subscribers, Practical Sailor accepts no advertising. Its independent tests are carried out by experienced sailors and marine industry professionals dedicated to providing objective evaluation and reporting about boats, gear, and the skills required to cross oceans. Practical Sailor is edited by Darrell Nicholson, a long-time liveaboard sailor and trans-Pacific cruiser who has been director of Belvoir Media Group's marine division since 2005. He holds a U.S. Coast Guard 100-ton Master license, has logged tens of thousands of miles in three oceans, and has skippered everything from pilot boats to day charter cats. His weekly blog Inside Practical Sailor offers an inside look at current research and gear tests at Practical Sailor, while his award-winning column,"Rhumb Lines," tracks boating trends and reflects upon the sailing life. He sails a Sparkman & Stephens-designed Yankee 30 out of St. Petersburg, Florida. You can reach him at