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How to Manage Moisture Problems Using a Dehumidifier For Boat

  • 13 Dec 2022

It happens to the best of us. Your pristine expensive yacht performs perfectly all summer then one day, while at sea, the boat begins to have engine issues or the body starts to lose its pristine condition. Unbeknownst to you, high humidity is the main culprit, which is why you should get a dehumidifier for boat asap!


Although boats are built to sail, they don't do so well in the highly humid environment of the sea. When water seeps through the fibreglass to the core, moisture damage ensues.

What absorbs moisture in a boat?

Boats are built with water-resistant materials to keep them sturdy while sailing at sea. Over time, the boat's fibreglass body will absorb a bit of moisture, but not a lot to cause any significant damage. However, a boat that is constantly exposed to excess moisture will start to show significant damage, especially to its core, which is mostly made of wood.


The main moisture-related issues in a boat can be summed up as;

● Structural damage

● Mechanical damage

● Electrical problems

● Aesthetic damage


Structural damage

Boats are built with fibreglass sandwiched in layers of wood, cardboard, and foam. Some parts of the boat's interior like the doors and furniture are made of wood as well. Excess moisture can cause wooden surfaces to swell and warp. It can result in doors that refuse to close or open and furniture like chairs not balancing well.


Mechanical damage

Although most of the mechanical parts of a boat are built with corrosion-resistant materials, prolonged exposure to high humidity can still cause rust. In addition, moisture will reduce the lubrication of mechanical parts, causing them to malfunction. Boat owners complain of reduced performance and power of their boats when sailing in damp or humid conditions.


Electrical damage

Moisture getting to your boat's electrical can cause damage and be dangerous if not contained. It will cause damage to electric circuits feeding into your boat's main control system and other electronics within the boat. Moisture getting to the electricals could also cause a fire.

Morris boat dehumidifier to avoid mould



Besides ruining the structure of your boat, high humidity will ruin the outward appearance of your boat too. When moisture sits in your boat for too long, it can cause mould and mildew to grow inside or outside your boat. Those black mould spots take away from the decorative look of your boat. In addition, mould and mildew will cause a bad odour that makes your boat uninhabitable.

How to get rid of humidity on a boat

Having a boat dehumidifier with drain hose can make the difference between finding your yacht or ship fresh and pristine or mouldy and musty next sailing season. Also, you have to get the right size dehumidifier to ensure it effectively reduces moisture without consuming a lot of power.

Do dehumidifiers work on boats?

Absolutely. Getting a dehumidifier for boat is a great investment that ensures you protect the structure, functionality, and aesthetics of your boat. There are all kinds of boat dehumidifiers available today, and the one you choose should be able to serve your boat efficiently. You can also read more about the different kinds of dehumidifiers in our comprehensive blog “13 Must-know Dehumidifier Answers.


Morris boat dehumidifier with drain hose


What size dehumidifier do I need for my boat?

Some things to consider when determining the best-sized dehumidifier for boat are dimensions, weight and tank capacity. Is the boat dehumidifier big enough to fit your yacht or boat and still serve the entire vessel? Are you able to ferry the unit to and from your boat without hurting your back?


For dimensions, we do recommend choosing a boat dehumidifier with a slim profile. The Morris 12L Quiet Dehumidifier, for instance, measures 22 cm by 25.5 cm by 47 cm. It is slim, compact and won’t take up much space in a smaller boat.


Secondly, a dehumidifier for boat should be lightweight enough to move around when needed. The Morris line of boat dehumidifiers has four wheels at the bottom that improve mobility. Place it anywhere in your boat to reduce excess moisture and keep your boat dry.


The tank size in a dehumidifier determines how long it can run before emptying its reservoir. A 12L Dehumidifier is perfect for a cuddy cabin or deck boat that houses 4 to 8 people. On the other hand, if you are sailing through Lymington in a catamaran, you would need something bigger like a 20L portable dehumidifier to keep moisture at bay. Also, you can opt for a boat dehumidifier with drain hose to continuously remove excess moisture in all compartments of the boat.


How to remove mold on boat?

Do not fret if your boat is already mouldy and musty. These boat mould removal hacks should help in clearing any mould and mildew in your boat, restoring its once pristine and fresh look;

● Invest in a high-quality dehumidifier for boat to manage excess humidity. If you will be leaving your boat docked all winter, a smart dehumidifier with Wi-Fi can help remotely monitor humidity levels in your boat.

● Fix any leaks on the roof, walls, or floor of your boat. An easy trick to uncover hidden leaks is to leave a trail of paper towels on the floor and find the wettest patch. You could also add food colour to water to unearth leak points.


Morris ideal dehumidifier for boat


● Reduce dampness in your boat by improving air circulation. Leave doors and windows open to prevent moist air from being trapped inside your boat and causing dampness.

● Clean any mould spots with boat mould removal products such as hydrogen peroxide, dilute vinegar, baking soda, and dilute bleach, Tea tree oil is another organic mould removal with fungicide properties.

● Always wash the boat’s canvas with fresh water to remove the saline water of the sea.

● Perform regular checks on your boat even when not in use. Catching those minor issues early will help prevent severe moisture and mould damage to your precious sailer.


If you have been wondering, ‘Do I need a dehumidifier for my boat?’ We hope that this blog has settled all doubts. We also included useful tips on how to stop mould in the boat using 6 easy hacks. Regulating humidity in your boat will not only save its engine, but it preserves the overall aesthetics of your boat’s structure.


Let us know in the comment section which of our Morris portable dehumidifiers would be perfect for your boat, cuddy, or catamaran.

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