How to Get Rid of Stubborn Boat Smells

Your boat stinks. What’s the fix? Mike Smith considers Glade, vinegar, ozone, bleach, elbow grease and something called thermo accelerated nano crystal sanitation.

Your boat stinks. What’s the fix?
Mike Smith considers Glade, vinegar, ozone, bleach, elbow grease and something called thermo accelerated nano crystal sanitation.

Have you ever boarded your boat looking forward to a relaxing sojourn afloat but when you open the cabin door you’re assaulted by a pong that makes your eyes water? Your boat smells like a refuse heap with undertones of sewer gas and old gym socks. Folks in adjoining slips are starting to complain. It’s time to do something about it—but where do you start?

Fighting odors is a two-pronged mission. First you have to kill the smell, then kill the source. Neutralizing the smell is easy, any spray will do, but finding and eradicating the source can be difficult. Chances are it lives in the farthest nooks and crannies of your bilge, or in some other nearly impossible-to-reach area that hasn’t been properly cleaned recently or maybe ever. Or the stank was born in a puddle of moisture from a leak, one whose source even Sherlock Holmes would be hard-pressed to find. But mold and mildew can find it, and they love it. You’ve got a job ahead of you. Grab some soap, water, bleach, brushes, sponges, buckets and whatever other implements of destruction seem appropriate, and get to work.

Once you’ve opened all the hatches and ports, and there’s enough fresh air below decks to support life, kill the foul smells temporarily with air-freshening sprays. Most folks go for the Glade, but a mixture of white vinegar, baking soda and water makes a cheaper, non-aerosol alternative. Combine a teaspoon of baking soda, a tablespoon of vinegar and two cups of water; mix thoroughly and dump the solution in a spray bottle. Give your cabin a few sprays and it will smell like a salad at first, but the vinegar dissipates quickly, taking the other odors with it. Tiny droplets of the solution will end up on cabin surfaces, but that’s okay: Wiping down the joinery with a weak mixture of vinegar and water will help keep below decks air fresh, too.

If you want something stronger that will not just clear the air but also attack the odors at their source, at least according to the manufacturers, you’ll find environmentally friendly odor fighters at your local supermarket or chandlery. AtmosKlear Odor Eliminator is biodegradable and nontoxic; the manufacturer says it removes the odor, and doesn’t just mask it. PureAyre says their Marine Formula Odor Eliminator uses natural ingredients to combat boat smells from gasoline and diesel fuel, holding tanks, fish gurry, dirty bilges and human-created smells. It’s made from plant-derived enzymes, purified water and essential oils, and it’s safe to use around food.

Some folks swear by ozone generators to kill smells, but according to the EPA, ozone at safe levels removes neither odors nor airborne contaminants, and at higher concentrations is dangerous to breathe. Studies by Consumer Reports, the National Institute of Occupational Safety and Health and the EPA concluded that ozone can react with other chemicals in the air to form carcinogens. But, as always, there’s another side to the story, so investigate the many ozone air treatment systems on the market. Max-Blaster, for example, builds a line of ozone generators designed for marine use. I recommend running the ozone system when nobody’s on board—ozone degrades back into oxygen quickly. But when the ozone’s gone, the smell might be back. The safest way to control odors is maniacal cleaning to remove the source of the odor.

Clean It and Steam It

A dirty bilge, MSDs in need of sanitizing, overflowing holding tanks, mold and mildew and leaking fuel will all create eye-watering boat odors: Cure them once, then keep up with cleaning and maintenance and they don’t come back. This requires hand-to-hand combat using soap, water and elbow grease. Scrub every place you can reach, from the depths of the bilge to the overhead, from the V-berths to the transom. It’s not rocket science but be thorough—you’ll be sick of the job long before it’s finished. That’s why it’s okay to use your checkbook for hiring professional boat cleaners who will do a much better job than you or me. It’s money well spent, especially if they arrive with a TANCS steam cleaner.

TANCS (Thermo Accelerated Nano Crystal Sanitation) technology is used to clean hospitals, restaurants, health clubs and government buildings—anywhere people, and their germs, congregate. According to Advanced Vapor Technologies, builder of Vapor Jet steam cleaners, TANCS turns the natural minerals in tap water into energized nano crystals in the steam, lethal to odors and to a raft of bacteria and allergens, including MRSA, C-Diff, E-coli, influenza, mildew, bedbugs and lice. Steam is less hazardous than bleach and does a better job, too. If your upholstery smells like a wet sheep, steam will make it sweet again.

In the engine room, steam will break up smelly grime and grease using a minimal amount of water and no chemical cleaners. Bilge areas beyond arm’s length can be cleaned using a long extension nozzle and attachments but the process works best when you can wipe off the surface after steaming. A clean bilge, especially around the engines and genset, makes it easy to spot smelly fuel, oil and other fluid leaks. (If you smell gasoline or diesel in the bilge, call a mechanic right away.) If you’ve let your boat get way too funky belowdecks, find a professional boat cleaner with a VaporJet.

Choose a professional with not only a steam cleaner, but also lots of boating experience and know-how. A pro cleaning team will often find bona fide problems you may never see. Sure, some of their recommendations will be in the cause of pumping up their profits, but sometimes a knowledgeable pro will find something amiss that really ought to be fixed—maybe a missing hose clamp, a fluid leak under the engine, loose wiring in the bilge, drips from the stuffing box—that sort of thing. Let your cleaners be your eyes and ears in the farthest reaches of your boat—use their profit motive to your advantage.

Holding Tanks Rarely Smell Sweet

If you have a good nose, you’ll find the source of the smell and many times it’s from the head, holding tank and associated plumbing. You’re basically carrying a septic tank on board, so naturally it’s liable to stink. Step one is to keep everything clean. Periodically, empty the holding tank and pump in lots of fresh water and whatever disinfectant your MSD manufacturer recommends. Fill the tank through the heads, so the lines get a rinse, too. Let the clean water/disinfectant mix percolate for a few days (follow the directions for the disinfectant), then pump the tank again. Make it standard practice to empty the holding tank whenever it’s half-full, and if you don’t have a tank-level indicator, install one.

Sanitation hoses don’t last forever, so inspect yours using the hot-rag test: Soak a cloth in very hot water, wrap it around the hose and let it cool. Then take a whiff of the cloth—if it smells like sewage, odor is permeating through the hose. Test each hose this way and replace those that fail. Otherwise, you’re fighting a losing battle. Check all hose connections for leaks, especially the hard-to-see joints at the holding tank. Ensure all the hoses in the system are certified for waste; don’t try to save a few bucks by using the wrong hose.

If you’re buying a new boat or refitting an older one, consider installing toilets that flush with fresh water. Fresh water introduces fewer organisms into the holding tank, so not as many nasties grow in there and it’s easier to keep the smell controlled. Sure, they’ll use some water from your tanks, but it’s easier to refill than deal with eye-watering-smelly plumbing. Freshwater toilets require no seawater intake, so that’s one fewer through-hull to worry about. If you boat mostly in no-discharge zones, you don’t need a Y-valve, macerator pump and the associated Rube Goldberg plumbing for overboard discharge. That’s another through-hull gone, and fewer hoses and connections to leak and smell.

Kill Stinky Critters

The hardest smell to eradicate is the musty odor of mold and mildew, which can grow wherever there’s moisture and food for the little critters. Standing pockets of bilge water, damp upholstery from leaking ports or hatches, wet clothes left in a hanging locker and even the anchor rode can all incubate mold and mildew. The cure? Dry everything out. Take berth and settee cushion covers off and dry the foam in the sun. Take the covers to your dry cleaner or, if they’re washable, to a nearby sailmaker— sailmakers use giant machines for washing sails. Vinyl cushions can be cleaned with soap and water, or a proprietary cleaner. Pull the anchor rode out of the locker, wash it and leave it stretched out on the dock until it dries. This is a good time to check splices, shackles, and the chain as well.

You’ll find many mold and mildew removers online or on chandlery shelves, many of them with strong concentrations of bleach. Some folks prefer trying chlorine-free cleaners first, for environmental reasons. While I’m as good a friend to Mother Earth as anyone, when it comes to fighting mold I don’t hesitate to bring out the heavy artillery right away. Wear a respirator against bleach fumes when working in enclosed areas.

Once the mold is gone, keep things dry and ventilated. If the V-berth cushions keep getting wet, for example, find out why ­maybe there’s a leaky port, or a drip from a bow-rail fastening. Tracing leaks back to their source can be a pain, but it’s worth the effort. When you leave the boat, latch open any hanging-locker doors that you can, so air circulates inside. Improve airflow from outside the cabin by adding solar-powered, low-profile ventilators. The hatch cover above the V-berth is a good spot for one and makes for an easy, wiring-free installation. You might also want to consider a dehumidifier(s) to help combat your boat’s moisture levels when you’re not running the AC.

Fighting foul boat odors demands few tools and skills other than determination. Once you get your boat clean and smelling fresh, keeping it that way takes minimal time and effort; both will be repaid many times over when guests come aboard and don’t wrinkle their noses in disgust. The folks in slips nearby will thank you, too.

View the original article to see embedded media.

This article originally appeared in the November 2022 issue of Power & Motoryacht magazine.