How to Prevent and Get Rid of Disgusting Mould On Your Boat

30 May 2023

boats docked in a marina where they are exposed to moisture.

Mould can be terrible for your boat. These fuzzy fungi come in a variety of colours such as black, brown, blue, white or grey can easily spread on a boat and sometimes can be hard to remove and stop their infestation. In best-case scenarios, it just makes your boat looks unkempt and shabby and it interferes with your preference over it and lowers its resale value. Sadly, mould is not only an eye sore, it can cause serious problems that affect your boat’s functionality and can cause health problems such as respiratory infections. So, if you have asthma or allergies, mould can worsen your symptoms.

Fortunately, you can prevent mould buildup if you take a proactive approach and eliminate it if they are already showing up in your Polycraft boat:

Preventing Mould

Your first line of defence is prevention. In an ideal world, you’d be able to prevent all forms of mould and mildew from appearing on your boat but sadly, that’s not possible as mould thrives in damp areas. However, you can work to minimize its appearance.

Find and seal leaks: Check all around your boat for potential leaks. If you’re getting water in it could easily leak which could eventually result in a major mould infestation. If you notice a leak, check for core rot and get rid of it. Then, reseal the area and reinstall the hardware making sure they are placed properly where any leaks could not get through.

Use a boat cover: A good boat cover will keep out moisture and prevent air from getting into your boat. Keep a cover on your boat whenever it’s not in use; it can make a huge difference.

Ventilate your boat: Stagnant air is a perfect breeding ground for mould and mildew. Still air holds moisture and allows mould to develop easier. But if there’s a constantly moving flow of air, it will carry that moisture away and make it much harder for mould and mildew to thrive. Ventilation is the way to ensure the air keeps moving. You should install vents throughout your boat and ensure all areas of your boat have adequate airflow. Keep your bilge covers, cupboards, and lockers open whenever possible.

Use a dehumidifier: Mould and mildew need moisture to thrive, so if you deprive them of moisture, they’ll be unable to survive. The most straightforward option here is to run an electric dehumidifier when you’re occupying the boat. However, you should not leave a running dehumidifier unattended, or you could risk a fire. A better long-term option is using a chemical dehumidifier, such as calcium chloride, to absorb moisture onboard when you’re not present.

How to Eliminate Mould?

Clean and eliminate mould at the first sign. If you notice a small spot of mould or mildew and allow it to remain to spread around your boat, it will quickly grow and infest other areas of your boat. Try to clean it as soon as you see it to prevent it from getting out of hand. You can either use a homemade mixture or a mould remover.

For a homemade mixture, you can mix together bleach, trisodium phosphate (TSP), and powdered laundry detergent with water to create a diluted mould-killing formula. You may also use a mixture of vinegar and water in a 1:3 ratio for a simpler if less effective solution.

Commercial mould removal products can also be used if you don’t want to create a homemade mixture and you want to avoid being exposed to bleach. They’re also easier to find and require less upfront manual work. They also typically come in spray bottles, which can make them easier to apply. You can purchase them in marine shops or in hardware stores.

After applying one of these solutions, let it sit for a while. The bigger the area and the stronger the mould seems, the longer you’ll need to let it sit. This will allow your cleaning product to fully penetrate the colony, killing it entirely.  Use a stiff brush to begin scrubbing the area after you’ve allowed the cleaner to sit. Make sure to scrub gently to avoid damaging the area. Consider using a toothbrush for crevices and other hard-to-reach areas. After your first line of scrubbing, make sure to wash the area well. Use a basic soap and water mixture to remove the cleaner, rinse again, and dry completely. Even a single mould spore can cause new growth.

If you follow these steps and still have a mould problem, it may be time to contact a professional. Some mould infestations are too deep to be handled individually.

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