Features January 2013 Issue

Best Boat Soaps for Regular Washdowns

PS searches for marine soap Holy Grail: affordable, eco-friendly, won't strip wax.

Marine Soap
Photos by Chris Landry

Marine soap test searches out the best cleaner for regular boat baths—one that is easy to use, affordable, eco-friendly, and won't take the wax of your topsides.

Sticking to a regular boat bath regimen has multiple benefits. It not only keeps a boat looking good, but it also helps protect it from unnecessary, accelerated wear and tear. When left to bake in the sun over time, dirt, bird droppings, and environmental detritus can take their toll on fiberglass and wood finishes, and the longer you wait to swab your deck, the tougher the task will be.

“Grime and dirt attract more grime and dirt,” explained Bill Lindsey, marketing vice president for Star brite, a maker of marine maintenance products. “And grime and dirt lead to advanced wear: Abrasion takes its toll on vinyl, fiberglass, plastic, and so on. Metal surfaces begin to show surface corrosion, which left unchecked leads to full-on rust. If you don’t maintain your boat, it will wear out much more quickly than if you clean it.”

Getting a boat sparkling clean will always require a little elbow grease and muscle, but using the proper equipment and an effective soap will make the job easier and faster—allowing you more time for sailing. For this report, we tested more than a dozen boat soaps in search of those that are effective, easy to use, affordable, don’t remove wax, and won’t harm the marine environment. Check out “From Bubbles to Beads” for details on how we tested the soaps.

The Boat Soaps We Tested

PS tested 13 products—aerosol sprays, gels, powders, and liquids—advertised as either boat soaps or wash-n-waxes. We may have missed a few, but the group offers a good cross-section of available products. The test field comprised seven liquid concentrates, three liquid sprays, one aerosol, and two gel concentrates.

The liquid- and gel-concentrate products seem to be the most logical choice for all-around cleaning and working on large areas. With these, the tougher the job, the more cleaner and less water should be used.

Sprays are useful for smaller or hard-to-access areas that need more attention. Many of the wash-n-wax products claim to clean and shine—and a few claim to clean, shine, and protect. Most can be used on fiberglass, wood, metal, and painted surfaces.

The test lineup included products from well-known marine maintenance manufacturers—Star brite, Interlux, Woody Wax, Nautical Ease, 3M, Sudbury, and Marykate—as well as some familiar in the automotive and home cleaning industries—Mothers, Ecover, Eagle One, and K2r.

Most claim to be biodegradable and to remove dirt, mold, and mildew. A few say they remove salt deposits (we expect all boat soaps to remove salt), and the majority can be used with salt water—although we don’t recommend it as the salt is abrasive to gelcoat and wood finishes.

For the most part, the products all carry safety warnings, and several recommend eye and skin protection. In our opinion, all cleaners should list active ingredients on their bottle—especially if they have safety warnings—but not all of the test soaps featured this. We like to know what we’re dealing with, so we noted those soaps that failed to list their formulas.

Our test group initially included two acid products marketed as oxidation and waterline stain removers. But because they are more specialty cleaners—what we refer to as “nasty, last-resort cleaners”—than general-purpose cleaners, we dropped them from this round of tests.

best marine soaps

What We Found

To the eye, all of the test soaps and wash-n-waxes removed the dirt, mud, and residue from their respective fiberglass sections, so that raised the level of importance of our white-rag wipe test.

Mothers Marine Wash-n-Wax and Nautical Ease Spray Boat Cleaner fared the best, earning Excellent ratings, with no residue on their white cloths. K2r Ship Shine, Star brite Biodegradable Citrus Boat Wash & Wax, and K2r Super Spray, also did well, garnering Good ratings.

Trailing these products were Interlux All-purpose Boat Soap, Woody Wax Ultra Pine, Star brite Sea Safe Boat Wash & Wax, Ecover Ecological Boat Wash, Marykate Heavy Duty Roll Away Boat Wash, 3M Marine Boat Soap, Sudbury Boat Zoap, and Eagle One Nano Wash & Wax. All earned Fair ratings. They left the most residue on their white cloths.

In our water-beading test, two of the products completely removed the applied wax: Nautical Ease Spray Boat Cleaner and K2r Super Spray. After the second freshwater spraying, no beads formed on their panel sections. The sections cleaned with Mothers Marine Wash’n Wax and K2r Ship Shine showed only a few water beads. Interlux All-purpose Boat Soap, Woody Wax Ultra Pine, and Star brite Sea Safe Boat Wash & Wax left the healthiest sheet of water beads.

In the pH test, three products scored high (8.4 on the pH scale): Nautical Ease, K2r Super Spray, and Marykate. Star brite Sea Safe and Interlux scored the lowest (6.2 or less). These results confirmed our performance and water-beading tests, as the stronger, higher-pH products (more alkaline) were more effective at getting the panels clean, but they also removed more of the wax protectant. In our experience, cleaners that are more alkaline—like Marykate, 3M Spray Boat Soap, Nautical Ease, and K2r—also tend to be better de-greasers.

None of the test products indicated fiberglass-drying chlorine (or sodium chloride) as a main ingredient. However, the 3M Marine Boat Soap did test positive for it. Testers were unable to explain the result, but we did note that the 3M soap has a very small amount of caustic sodium hydroxide, an ingredient in bleach that can be toxic to marine life.

marine soaps


For a boat soap, Star Brite Citrus Boat Wash & Wax and Mothers Marine Wash’n Wax posted the best all-around ratings. Mothers garnered an Excellent cleaning rating, Good chemical-level scores, and got a Fair in the bead test. Star brite Citrus earned Good cleaning and bead-test ratings. Both are concentrated, eco-friendly, and safe to use on fiberglass, vinyl, metal, glass, plastic, and rubber surfaces.

We found Mothers to be less expensive at 24 cents per ounce compared to 69 cents per ounce for Star brite Citrus. Mothers also got a better cleaning score, but the Star brite scored better in the bead test, and we prefer to do our regular washings with a general-purpose boat soap that leaves wax on the boat. We reserve the harsh stuff for seriously stubborn waterline stains and pre-waxing washdowns. (For the results of our waterline-stain remover test, check out the November 2007 issue.)

Other recommendations: The Star brite SeaSafe Boat Wash & Wax was a good all-around performer and got an Excellent in the bead test; Woody Wax Ultra Pine Wash-n-Wax Boat Soap, Eagle One Nano Wash & Wax, and Ecover Ecological Boat Wash and Wax fall into the same category of solid performers. The 12-cents-per-ounce Eagle One, because it is primarily marketed as a car-wash product, is less expensive than most other products. It and the Ecover, which was the least expensive of the bunch, get our picks for Budget Buy soaps.

The spray products are really for smaller areas, so we judged them separately. Nautical Ease did a great job cleaning, but it is strong, will strip wax, and registered higher chemical levels than most others. The same can pretty much be said for the K2r Super Spray: an impressive cleaner (less expensive than Nautical Ease, too), but so strong that it takes away wax and has more harsh chemicals than others. Save these guys for mildew-ridden vinyl, galley counters, the head/shower, and smaller sections of filthy nonskid or storage lockers.

The top picks in this test are great for regular boat baths. For more on marine cleaners—including tests of specialty cleaners and gelcoat restorers, and maintenance tips—check out our downloadable, three-part e-book, “Marine Cleaners: The Complete Series.”

Comments (6)

OK- I'm a bit confused. I thought you were looking for soaps that would not attack a waxed surface. On closer look, almost all your products are wash and WAX.... so I think the test should be divided. There are times I do NOT want to leave or add a wax layer.

Posted by: stuart c | July 23, 2013 6:43 PM    Report this comment

You missed Imar yacht soap. I think it would top your tests, tho it is a little pricey.

Posted by: stuart c | July 23, 2013 6:23 PM    Report this comment

This was a great read, however I seem to have had better luck with Sudbury Boat products. Maybe because I use the complete line, they have eco versions as well, that work well.

I also have to agree with Raymond. They're the same.

Posted by: Irathebeboating | January 23, 2013 11:58 AM    Report this comment

I wish Awl-Wash had been included as a painted boat detergent and that Joy (or her sister Dawn) had been included as a low cost, biodegradable, and convenient alternative.

Sodium chloride is table salt, the stuff in salt water. Sodium hypochlorite is the chlorine producing compound in Chlorox bleach. They are not the same thing.

Posted by: wsmurdoch | January 17, 2013 8:29 AM    Report this comment

In your sidebar, "Boat Cleaning 101", you discuss the use of muriatic acid and hydrochloric acid as if they are different compounds, whereas they are the same...

Posted by: Raymond S | January 6, 2013 11:21 AM    Report this comment

Awl-wash is considered the "gold" standard. Surprised you did not include this in your comparison.

Posted by: 630 | December 30, 2012 9:28 AM    Report this comment

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