Oh No, We Have Mold!!

Mold is not only disgusting,  it is unhealthy.  It has been linked to multiple health issues. My father in law started having lung issues.  The doctors seem to think it was due to some type of mold or bacteria in his house .  He was breathing it in on a daily basis.  He passed away from lung issues two years ago.

Mold has also been linked to joint inflammation diseases like Fibromyalgia, allergies, headaches, and extreme fatigue.  It is nothing to ignore or try to cover up. If you can smell musty,  you have a problem.

Mold Must Go

I hope I just scared you enough to think about preventing mold on your boat.  Unfortunately, mold is a fact of life while living on a boat.  Boats give it a very happy home.  For your health and sanity you need to get rid of it and keep it away. It is easier to keep it at bay than it is to get rid of it.

You can’t see the spores before you see the mold growth. It is important to treat everything as if it is mold contaminated.

What is Mold?

Mold is a fungus that smells horrible, especially in a small closed up boat. Mold and or mildew can seem to  pop up literally overnight.  It loves dark damp areas.  A sailboat  in a warm high humidity area is the perfect place for mold to happily thrive. The problem is unlike mosquitos and bacteria it is not killed by freezing, it just goes dormant till spring.

Mold can take on many different appearance depending on the type.

What Causes Mold

In a sailboat the temperature inside and out changes constantly. It is this difference in temperature that creates the dampness that make mold happily grow.  Have you ever noticed after a chilly night that things inside feel damp or maybe your walls are slightly damp?  This is condensation from temperature change and because you are breathing inside. Now, you can’t stop breathing but, you can use a heater to minimize the temperature difference and dry the air. You can also use a dehumidifier but they take a considerable amount of electric.  Unfortunately, electric unlike mold is in short supply on a sailboat.  We will cover the non-electrical remedies to this problem.

Stop the Source of Moisture

When we bought our boat it had many leaks.  They were not major issues.  They were small leaks around stanchions, chain plates, screws that had worked loose, and around our rub rail.  You can see how this water created the perfect mold environment. It is important to rid the boat of any moisture sources and or leaks.  If you  have a shower, run a fan to clear out the steam and moisture.  If you boil water open a window and blow out the steam.

How Not to Get Rid of Mold

They are no longer recommending you use bleach to remove mold. It may remove the discoloration but it does not kill the spores. It can actually cause them to divide and come back when conditions of dampness returns. I have also read that when the bleach comes in contact with the mold it becomes toxic.  Not to mention it also takes the color out of everything it touches. Let’s not forget the dangers of inhaling bleach on a small boat.  Bleach should not be used in any small confined area.

Washing the surface with soap and water may get rid of the discoloration but it won’t kill off the spores.

Do not just try to brush it off or vacuum it off. You will just make the spores airborne.

How Do You Make it Go Away

If you have mold, it’s not necessary to dress like this to clean up your sailboat.   With that said,  you don’t want to clean it up without a face mask and gloves.  Scrubbing the effected area causing some of the spores to go airborne and you don’t want them in your lungs.


First, take everything you can out of the boat.  You need to be able to access all corners.  Since we are still living in our house we do this every fall. We take everything out and store it in the house.  While the boat is empty we wash everything with a mixture of borax and water.   This will remove any stains if you have mold.  We turn a heater on to dry the boat faster.

After, the borax cleaner dries,  I wash thing off with 1 part white vinegar and 2 parts water.  I let this dry thoroughly.  Once that is dry I spray Concrobium

Mold Control spray in the corners, under the sink and in the back of the lockers. You can buy this on Amazon, Home Depot, or Menards.  It sometimes leaves a  white film but, this is easily wiped away.

Concrobium kills the spores and prevents them from coming back.  I don’t start with Concrobium because it only kills it.  You will then be stuck with the stains.   You want to remove the staining, then kill the left over spores. I use the aerosol spray not the pump.  The spray gets into the corners better.  If you can’t remove everything you can fog.  Home Depot rents the foggers.  it does leave a slight residue in areas where the fog settles wet.  This is not toxic and easily wiped off.  It is nothing like the residue from bug bombs.

Just make sure you open up all the doors, lockers, and closets to keep air circulating all winter long.  Another important item I use consistently is the DamRip hanging moisture absorbers.  They come in boxes of 3.  I  use one box around the boat in the fall and I don’t need to replace them until late winter. So two boxes will do the job until we are ready to go sailing again. That is about a $20.00 investment.  Do not get the cheaper brands at places like the Dollar Store.  They do not work as well. I put one in our boat, it didn’t collect even half the moisture the Damprid brand collected.

Treating In the Spring

In the spring before we put everything back in its place, I wash all the winter grim off with 3 parts water, 1 part vinegar solution.  After that dries I spray the Concrobium in the back of the closets, cabinets, and lockers.

I have noticed that moisture collects between the vinyl on the back of my seat cushions and under the mattress.  To keep the fuzzy stuff from growing, I spray Concrobium on the fiberglass before we install everything.  I called a chemist friend to make sure this stuff is non-toxic.   I did not want to use something dangerous in my bed.

Cleaning In Your Boat

To clean in the boat I use a spray bottle with vinegar and water.  I also use vinegar and water wipes.  It is important not to use furniture polish.  Mold loves to grow in furniture polish. If you don’t believe me spray some in a petri dish.  Wiping everything with vinegar prevents mold from returning.  If I get a greasy mess or something is really dirty, I will use dawn and water first. But, I rinse with vinegar water.

To make the vinegar wipes you will need 2 pop-up containers from either diaper wipes or wet-ones wipes, a roll of Brawny paper towels, vinegar and water. Cut the paper towel rolls in half with a hacksaw.  Take out the cardboard center.  Now place each half in a container and cover with vinegar and water.  Leave it sit overnight then drain off the extra liquid.  Feed the middle piece through the pop up and there you have them for quick cleanups.  Hint:  I have tried cheaper brands of towels and they fall apart too easily, use the Brawny.

We haven’t had one spot of mold since I started doing these things faithfully.

Material Loves to Grow Spores

I don’t want to find mildew on clothes and towels we don’t use very often. To prevent this I seal them up in large Food Saver bags.  This not only prevents moisture from entering and causing mildew, it shrinks them down so they take up less space.

When we put towels and clothing out on the lifelines to dry, we make sure they are in the sun and fully dry before we store them away.

Cardboard and Paper

Cardboard and paper hold in moisture and become a friendly environment for that fuzzy stuff and bugs.  I hate both, so we try to keep cardboard and paper off our boat.  All our manuals are laminated and in a notebook.  We take labels off cans and write the name in permanet marker on the top of the can.   Any prepared foods come out of the box and are stored in Ziploc bags or Food Saver bags.

Sails, Canvas and Cloth

Chances are your sails were originally sprayed with  a  similar chemical to Wet and Forget.  We plan to re-treat ours every 2 or 3 years. We treat our bimini every fall.

If you see stains on any of your fabric items or sails you can clean them with a mixture of borax and water.  If it is a large item such as a tarp or sail,  you may want to soak it overnight in a big tote with borax and water. This should remove the stains as well.  It is probably a good idea to spray them with Concrobium after they dry out.  Make sure they are fully dry before you fold them back up for storage.

If you see anything that looks like mold, treat it as if it is a full blown mold outbreak and clean clean clean.