Proven Boat Mold Removal Techniques | Become A Cruiser

Proven Boat Mold Removal Techniques

Proven Mold Removal Techniques On A Boat
  • Save
Try these proven boat mold removal techniques to keep you away from cleaning, giving you more time to enjoy your life on the ocean.

Over the past four years of living on a boat in the tropics, I have literally tried every boat mold removal technique anyone has suggested to me. Some have worked for a day or week, and some haven’t worked at all. Eventually, after two years, I found the mold removal techniques I still use today. I’d like to save you years of effort, trying to clean mold. By sharing these mold removal tips with you.

Spoiler Alert! : Once mold gets into caulking it’s there to stay. If you catch it VERY early you may be able to rub it with a magic eraser or rub acetone on it to remove it. Once it’s in the caulking, new caulking is the only solution.

After living on a boat for a while, you will eventually come across mold and mildew. Mold grows in warm places, with high levels of moisture. It is in the air so it enters your boat on the breeze. Cleaning boat mold is a part of life for sailors. Unfortunately for us, you can get rid of mold for a period of time, but eventually, it comes back. So the trick is to find a way to remove the mold and extend the period of time between time-wasting cleanings.

Cleaning mold is one of my least favorite jobs on the boat! Still, it’s better than being the designated boat sanitary repair person, so I did luck out taking this job. Because I don’t love cleaning mold, I did a lot of research into mold removal techniques and tried them all. Finally, I found a good way to extend the time between cleans. I used to have to clean mold once every second or third week. Now, I clean mold about every month and a half. Sometimes I luck out and only need to clean mold every three months if the weather is dry.

In The Caribbean, we didn’t really have much of a problem with mold and mildew. I’m not saying that there wasn’t any mold, but not loads of it. That changed when we reached Panama in the rainy season. The boat mold was crazy! One day we went on a provisioning trip, closed up what looked to be a clean boat, and on returning that afternoon, the whole salon ceiling was covered in mold… Ewww!

Techniques To Slow Down Mold Growth

boat Mold likes warm, moist, dark places. Here are some techniques you can use to slow down mold growth:

  • Keep your boat ventilated, open curtains, hatches, and portholes. Allow sunlight and breeze into the cabins. If a room seems musty, turn on a fan to get the air moving. Open the curtains, let the sunlight in.
  • If your boat has air conditioning. Turn it on for an hour or so after a rainy day or days.
  • Hang damp clothing or towels up outside, don’t leave them inside the boat. I would go as far as to say, hang them out in the rain, the worst that will happen is they’ll get an extra rinse. If you need to hang them inside, hang them in the bathroom until it’s sunny.
  • Have a freshwater rinse when you return to the boat, and hang up any damp clothing. The salt in the seawater seems to keeps things damp for longer.
  • If possible, wash your clothes in hot water. If the laundry has had mold on it, add half a cup of Borax to your laundry load to kill the mold.

Boat Mold Removal Techniques

Proven Mold Removal Techniques On a Boat
  • Save
Mold around a hatch. The rest of the boat was free of mold. This hatch had the curtain drawn on a rainy day and the mold blossomed with the lack of airflow.

The Best Boat Mould Prevention Technique – A Dehumidifier or Air Conditioning

Because mold grows in places with a lot of moisture, a dehumidifier or air conditioner is the best prevention strategy. Close everything up, run the dehumidifier or air conditioner for a few hours, and voila, a dry boat! This is great if you have air conditioning installed on your boat. As with most cruising catamarans we don’t.

Unfortunately, It’s not practical to have a dehumidifier running all the time with the boat all closed up. I do suggest, however, if you are leaving your boat for a period of time and happen to be in a marina. Make sure that there is a dehumidifier on the boat left running on a timer. If not, you are in for a nasty moldy surprise when you get back to the boat. When buying dehumidifier make sure to buy a model with a drain hose you can route into a sink drain.

Boat Mold Removal Strategies

Concrobium Mold Control Spray

Concrobium Mold Control Spray is fantastic. It removes boat mold, mildew, and the horrible musty smells that go with mold.

Just spray it onto the moldy area and let it dry. There is no need to scrub or clean it off.

The best part about this wonderful product is there are no harmful ingredients in it. So it’s safe for the environment. I always try and choose the most environmentally friendly options. I just hate adding nasty chemicals into the ocean.

I totally recommend Concrobium as my favorite mold removal product. And make sure to pick some up whenever I can get my hands on it. We use it on gel coat, wood, and fabric. It works like a dream. Heads up: When you are in your local hardware store, it is found in the paint section of the store, and not with the cleaning supplies or you can get some from Amazon. Once you leave the US Concrobium is almost impossible to find.

Formula B – My # 1 Boat Mold Removal Technique

When you become a cruiser and start sailing further away from home, you find that the products you used at home are either difficult or impossible to find. You have to come up with Plan B, or should I say Formula B in this case. Formula B is quick and easy to make. It works extremely well. I think of Formula B as the world traveler’s answer to boat mold removal. Of all the ways I have tried to remove boat mold, Formula B is my best mold removal technique.

Formula B Mold Removal Recipe



Mix it all together in a spray bottle

Spray the Formula B onto the mold, leave it for about 30 seconds, wipe off with a microfibre cloth. When you are finished cleaning the visible mold away, spray a light coating of Formula B to the area to slow down new mold growth. For tougher stains, put some Formula B in a bowl. Scrub onto the stain with a scrubbing brush, then wipe off with a microfibre cloth.

Before using Formula B on fabric, do a spot test to make sure it doesn’t harm the fabric. I have not had a problem, but I do test a small area of any new surfaces before I put Formula B on it.

Removing Mold and Mildew from Sunbrella Fabric

Sunbrella fabrics don’t grow mold or mildew easily. Although, I have found mold growth on some Sunbrella fabrics in the past.

Sunbrella Mold Removal Recipe


  • One gallon of water
  • 1 cup of bleach
  • 1/4 cup mild soap (dish washing soap)


Mix it all together in a spray bottle

Spray the entire surface area so you don’t end up with stains or water rings. Leave the mixture soak into the material for 15 minutes. Clean the area with a clean towel, a soft brush, or sponge. Rinse well to remove any leftover soapy residue. Leave to air dry.

If the mold or mildew growth is bad increase the amount of bleach in the the mixture.

If hope you find my advice in this post useful. If so please share this post with your friends.

Proven Mold Removal Techniques On A Boat
  • Save

Hi, I’m Nic! Our Family of four have been out cruising since 2016. We have sailed about 15,000nm, almost halfway around the world. We sold everything, took the leap of faith, and bought a 10-year-old Lagoon 380 ex-charter catamaran. We’ve fixed every system on the boat, often more than once. Cruising has been such a wonderful, positive experience for our family that I want to share my tips to help you Become a Cruiser.

Join In or Start the Discussion.

I love reading your comments and will be sure answer any questions or comments you leave.

To keep the spammers out. You may comment with only your name and email (your email will not be shown, shared, or added to my mailing list).

Leave a Comment

Your email address will not be published. Required fields are marked *

Become a Cruiser Scroll to Top
Copy link