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BoatUS Foundation Puts 'Green' Boat Cleaners To The Test

Many manufacturers claim their boat-care products are environmentally friendly. But how effective are they at getting your boat clean? The BoatUS Foundation finds out.

Cleaning a boat hull with a yellow sponge filled with soap and water

Our cleaning tests were carried out on fiberglass gelcoat (shown); Hypalon, used to make inflatable dinghies; and sections of nonskid decking. (Photo: Mark Corke)

The staff at our BoatUS Foundation, dedicated to clean water and safe boating, started this "green cleaners" test with two questions: What does "green" mean when it comes to the products we all use to clean our boats, and how well do they clean? In search of answers, we recently gathered in a driveway, soaking wet, covered in soap suds, cleaning dirty boats with a variety of cleaners, specifically those advertised as being safer for the environment.

This is the second time the foundation tested "green" boat cleaners. Many of the products we tested in 2009 are no longer available, and many new cleaners have since entered the market as more boaters have embraced these alternatives. It was time for a new test.

The first challenge was labeling. We found that there are no federal requirements or specific standards that manufacturers must follow to make claims like "biodegradable" or "environmentally safe." The Federal Trade Commission only requires that all claims "must be qualified and backed up by competent and reliable scientific evidence."

In 2009, some products we looked at were marked with the "Design For The Environment" logo, now called "Safer Choice," a certification initiative by the Environmental Protection Agency (EPA) to help consumers make smarter choices. Products with the Safer Choice logo contain ingredients that have been screened, but not tested, by EPA. This means that where two or more ingredients perform the same function, the one with the lesser environmental impact has been chosen and incorporated into the final product. Booyah Clean was the only product in our test carrying the Safer Choice logo.

Products carrying the Safer Choice logo aren't necessarily more environmentally safe than those without it, though. The program is voluntary and requires participating manufacturers to go through a lengthy process and disclose all ingredients, a proprietary issue for some companies.

The aims of our BoatUS test were to assess the cleaning products, first on their ability to clean; second on their effect on marine life. Our findings are presented in a chart below to help you decide which products are right for your particular situation.

Common cleaning products

Photo: Mark Corke

The Contenders

While there are many boat cleaners available, we chose nine commercially available products conveniently available from local boating-supply stores, like West Marine. All products included some kind of "biodegradable" or "environmentally safe" marketing claim on their labels or in marketing materials. And none were included in our previous test. We put the off-the-shelf products up against two common homemade cleaning solutions often touted as the gold standards for eco-friendly cleaners — including on our own BoatUS Foundation website.

When it came to testing the products, we followed the manufacturers' recommendations for use. The majority were diluted in a bucket with water. A couple came in spray bottles intended for spot cleaning, which we used full strength as instructed. The two homemade cleaners included a vinegar/water solution, and a solution of baking soda, white vinegar, lemon ammonia, and water. Both were applied as spot cleaners using spray bottles.

Adding Elbow Grease

In 2009, we tested the cleaners on a fiberglass boat hull. This time we tested each on three different surfaces: Hypalon, used for making the tubes on many inflatable dinghies; stippled nonskid fiberglass; and smooth fiberglass gelcoat. Both the Hypalon and nonskid were cut into 12-inch squares from boats beyond economic repair. The third test sample consisted of carefully marked-off sections on the hull of a small bowrider sitting on a trailer.

Green Cleaner Rating Chart

To be as fair and consistent as possible, we first rinsed each test panel with fresh water to remove any loose dirt before applying the cleaners. Cleaner was applied to Hypalon samples with a Scotch-Brite pad, the nonskid using a nylon-bristled scrub brush, and the smooth gelcoat with a sponge — all tools that the average boat owner might employ.

We also kept an uncleaned sample of each of the surfaces as "control" so at the end of the test, when everything was dry, we could make side-by-side evaluations.

While some cleaners clearly worked better than others, not all were equally effective on all three surfaces. As expected, the smooth gelcoat was the easiest to clean, and all the cleaners scored well on that surface. The Hypalon and nonskid seemed to hang on to the dirt and showed less difference before and after cleaning.

10 Tips For Greener Boat Cleaning

  1. Rinse your boat with freshwater after every trip. It will go a long way in keeping the boat clean and can prolong the periods between using detergent products.
  1. Apply a good boat wax at least once per year to help prevent dirt, bird droppings, and airborne contaminants from adhering to the boat to make cleaning easier.
  1. Follow the manufacturer's instructions, especially regarding dilution levels. During our product tests, we found that increasing the detergent-towater ratio did not improve cleaning power.
  1. If your marina has a designated wash-down area, use that for all boat cleaning. A boat cleaned out of the water will likely have less of an impact on water quality than one cleaned afloat where the runoff has a direct path to the water.
  1. Most products require treatment in a wastewater treatment plant to be truly nontoxic and biodegradable, so use them in an area that doesn't drain directly to the water.
  1. Some cleaners, although they may not be as environmentally friendly as others, clean better using less product, so overall environmental impact may be decreased. So, always start by using less product, which may be quite enough to do the job.
  1. For overall cleaning, use a general-purpose boat wash and a spot cleaner to remove tougher stains.
  1. When a using a spot cleaner, wipe the area with a cloth that can be disposed of ashore rather than rinsing off with water.
  1. For boats stored in the water in coastal areas, wash the boat on an outgoing tide, which allows any soap runoff to be carried away from shore.
  1. Avoid cleaning the boat in full sun. Warmer temperatures make cleaners evaporate faster, and you'll end up using more product.

Off To The Lab

A scientist in a lab coat examing a sample of the shrimp-like mysida
In the lab, shrimp-like mysida were monitored several times daily under
controlled ­conditions. (Photo: Mark Corke)

Finally, for the nonpartial scientific evaluation of the impact, if any, that these cleaners could have on the environment, samples of each cleaner were sent to the Chesapeake Biological Laboratory in Solomons, Maryland, to assess the cleaners for their effect on marine life. Testing was carried out under the auspices of Dr. Carys Mitchelmore, a professor at the university and expert in this type of research.

To test each product, a sample was mixed according to the manufacturer's instructions then combined with a consistent, measured amount of seawater containing 10 neonatal mysida (Americamysis bahia). Mysida are small shrimp-like crustaceans, also called opossum shrimp, which have long been used as test subjects as there is considerable data regarding their sensitivity to myriad environmental contaminants.

Under carefully controlled laboratory conditions, each of the samples was monitored at fixed intervals, noting the time it took for the mysida to die. Essentially, the faster they die, the more negatively impactful the cleaner is on marine life and environment. Testing was limited to marine-life toxicity; no testing was done on biodegradability claims.


Visit this article on the BoatUS Foundation website to see the results of our green cleaner test from 2009.

The Bottom Line

As expected, no one product we tested walked away as the clear winner in every category. Some cleaned one material really well, others had different attributes; some cleaned everything adequately but killed our mysida test subjects more quickly. The takeaway? Depending on what you need to clean, consider having two cleaners on hand — one for reliable general cleaning, and another for more difficult occasional jobs such as nonskid or hypalon. There are many good options that work well and do less harm to the environment.

Another great takeaway? The clear consensus was that the cleaners that scored highest on our test stacked up in cleaning power — in our staff's years of personal boat-owning and boat-cleaning experience — to the majority of cleaners on the market that make no claim to be less environmentally toxic. So use these high-scorers with confidence, use the manufacturer's recommended amount, minimize any product runoff, and enjoy happy times aboard, knowing you're doing your part to keep our aquatic playground as clean as possible.

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Mark Corke

Contributing Editor, BoatUS Magazine

A marine surveyor and holder of RYA Yachtmaster Ocean certification, BoatUS Magazine contributing editor Mark Corke is one of our DIY gurus, creating easy-to-follow how-to articles and videos. Mark has built five boats himself (both power and sail), has been an experienced editor at several top boating magazines (including former associate editor of BoatUS Magazine), worked for the BBC, written four DIY books, skippered two round-the-world yachts, and holds the Guinness World Record for the fastest there-and-back crossing of the English Channel — in a kayak! He and his wife have a Grand Banks 32.