Marine Mold - Prevention and Treatment

Marine Mold - Prevention and Treatment


Enjoying your boat is the best part of being a boat owner! Although, the maintenance and repairs can be never ending. A moist, damp, and poorly insulated environment makes your boat the perfect home for mold that can cause irreversible damage!

Sources of Mold


A single water leak can start spores growing. So, the first thing to do is find and seal leaks. Check portlights, windows, loose stanchions, the deck core, cockpit scuppers, under quarter berths, v-berths, settees, lockers, lazarettes, under seats, drains, and hidden areas. 

Still Air

Constantly changing water, air, and hull temperatures create condensation allowing mold to thrive. Ensure that your boat is well ventilated. Opening hatches or portholes to create cross ventilation can help to prevent this.


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Fresh Air

Exchanging inside air for outside air, greatly reduces mold formation. When you visit your boat be sure to open it up and let fresh air in while you're doing an inspection. 

Keep It Clean and Open

Keep all lockers and other enclosed spaces clean, empty, and open when possible to help circulation and reduce moisture. Take home bedding, mattresses, clothing, towels, and other items that can attract moisture when not in use, as these can be ruined by mold.


A good rule of thumb is to replace the air inside the boat every hour. Make sure you have a proper, waterproofed canvas cover for your boat, free of rips and tears, to allow fresh air to get in without water seeping through. Passive waterproof ventilators like ports and hatches provide access paths for air to enter or leave the interior of the boat. But if the air is not moving, you may need active ventilators which use a fan to keep air moving. Chemical dehumidifiers also help prevent mold. These tubs and bags are safe, inexpensive, easy to put anywhere, and available at most marine stores.

Winter Care

During the winter check your boat once a month to make sure that everything on your boat is working and looking as it should. Check for any cracks, leaks, or standing water around windows and doors that could promote the growth of mold. Shrink-wrap is great for protecting a boat but it limits how much air can get below. Vents should be installed in the shrink-wrap or consider leaving the cabin doors open under the shrink-wrap so air can better circulate.

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Remove Marine Mold and Mildew With RMR-86M!

RMR-86M Marine Mildew Stain Remover contains a Sodium Hypochlorite formula that works instantly to remove mold and mildew stains from vinyl seat cushions, vinyl covers, vinyl dashboards, fiberglass, and other marine surfaces* without requiring repeat applications or rigorous scrubbing. RMR-86M is the fastest and easiest way to tackle stubborn boat stains and permanently eliminate discoloration with 5x the cleaning power!

* Do not use on fabric, clothing, carpet, wood, or painted surfaces, and avoid prolonged contact with metals or porcelain

Why RMR?

At RMR, we create powerful solutions to everyday problems. Our industrial strength Marine Mildew Stain Removal product works well anywhere from your boat to your home, removing stubborn stains and leaving behind a clean, modern orchard scent. For quality products and great value, try RMR 86M Mildew Stain Remover, the best marine stain removal product for your boat! 

Proudly made in the USA! Using top-quality, industrial-strength ingredients.


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