How To Keep Moisture Out Of Boat Compartments – Multiple Options

After a round of cleaning your boat, you may see that the water on the deck takes time to evaporate. Things get worse during winter as the boat looks foggy, and things stored in the boat are becoming moldy. Of course, this is a tragic thing that most sailors encounter in their lives. If you’re just starting your journey as a sailor, it’s good to be taking preventive measures today. So, how to keep your boat compartments free from moisture?

The highly recommended method to keep moisture out is to ventilate sufficiently. Alternatively, to prevent even mildew from settling in, you may have to try these methods – install a dehumidifier, use calcium chloride, fix leaks, and set a regular routine towards cleaning the boat and keeping the moisture out. 

Each method to get rid of moisture in a boat compartment involves adherence to a specific procedure. Otherwise, it could go wrong. This article details procedures for these methods to guide aspiring, new, and experienced sailors. 

5 Different Ways To Keep Moisture Out Of Boat Compartments

Boaters encounter the problem of moisture in boat compartments quite regularly. There are various reasons for moisture to develop in the boat and create a huge fuss. For instance, it can be because of incomplete drying after a round of cleaning, leaks in the boat, insufficient ventilation, and the need for a dehumidifier to reach inaccessible areas where ventilation doesn’t happen. 

Let’s look at the different ways to prevent moisture in detail.

1: Ventilation

Out of the 5 different options here, ventilation is the first and foremost. Irrelevant to the size of the boat, ventilation is needed in all areas so that the fungus cannot grow inside your boat. Most importantly, this is the best starting point to remove moisture from your vessel. 

Your boat doesn’t always need a high temperature to dry the compartment quickly. As long as the windows and doors are opened, and the air is circulating, ventilation is happening. 

The problem with some boats lies in the type of customization. Such boats need special equipment like small fans to help with air circulation and aid in the control of moisture. 

As a boater, you should prioritize regulating the temperature and monitoring pollutants. Whenever your passenger cites a change in smell or when you spot a strong odor that’s unusual, it’s a clear sign of poor ventilation. As soon as you dock your boat, prioritize ventilation and review the condition of the internal environment daily until the issue is gone.

2: Dehumidifier

While ventilation is the most natural solution to keep boat compartments free from moisture, there can also be a need to tackle humidity changes. In such cases, you should invest in a reliable dehumidifier made exclusively for boats. 

Regulating humidity is the key to lowering the entry of indoor pollutants and making the boat more dry and livable. 

Did you know that mold grows faster in humid environments? You may not want that, as it can question the longevity of your boat or cause health concerns. 

Let’s look at the ideal type of dehumidifier you should choose. There are desiccant humidifiers and electric humidifiers. Desiccant humidifiers work well in terms of portability and cost-effectiveness. For instance, you can get one ready by filling empty areas with calcium chloride units. You may have to replace it quite frequently due to its quick dissolve rate. Also, be careful when handling this as it can be toxic to humans. Some prefer replacing calcium chloride with silica gel since it is reusable and less messy.

Contrarily, an electric dehumidifier is durable and serves the purpose. If you’re planning to sail in the long run, you should blindly go ahead with an electric dehumidifier. The best part is that it comes with a drain hose that lets out the excess moisture and regulates the humidity. This will allow you to focus on more important things during your sailing.

Thinking of purchasing an electric dehumidifier? Gather answers to these questions. 

  • Do you have a good electric supply? Otherwise, a short circuit can hamper the dehumidifier. 
  • Are you planning for longer sails? Electric dehumidifiers are more expensive than chemical dehumidifiers. Hence, you should make a calculated decision. 
  • Do you need to fit the dehumidifier in each cabin? You should choose the model or size of the dehumidifier accordingly. 
  • How has your average humidity score been? Did natural ventilation fail or not achieve your desired outcome?

When you answer these questions, you should know your boat’s need for a dehumidifier. 

3: Calcium Chloride

The use of calcium chloride is highly relatable to people since a similar approach is followed even in homes when the humidity isn’t balanced. So how does calcium chloride help your boat compartment in getting rid of moisture?

It’s a chemical salt that works by gathering water vapor from the air and then spreading it around. Let’s assume that you’ve left a unit of calcium chloride in the storage cabin. In a few hours, calcium chloride would begin its work of regulating humidity and getting rid of excessive moisture within the cabin. 

While it’s an inexpensive option, it’s essential to know more about it. 

  • You are comfortable handling this chemical? Make sure you read all the safety labels before handling any type of chemical.
  • During the winter, add multiple units to a container and then place these containers in different regions of the boat. 
  • During the spring, this salt would’ve turned liquid to dry crystals and then regulated the humidity. 

Tip: Purchase it during the offseason to strike a better deal.

While it’s a beginner-friendly material used to dehumidify an environment, it’s good to go with the instructions mentioned on the label. 

4: Leak Detection

Along with the periodic maintenance of your boat, it’s extremely crucial to inspect the boat for potential leaks. Sometimes, negligence in this aspect can cause a never-ending development of mold and affect the surface in due course. 

As you dock your boat, your first step should be to inspect any possible leak areas around hatches, ports, cleats, and bow rollers. When you find a leak, remember to delve in and reseal it properly. If you’re unsure of how to do it properly, you can always hire a professional to get the job done. 

Most boaters tend to store sealants in their storage units so they can seal leaks on the go. However, remember not to skip the instructions mentioned on the label about the use of sealant.

5: Routine 

Keeping your boat clean is an essential part of boat maintenance. Sometimes, early detection of low air quality helps in fixing the problem entirely. As a regular boater, you may have to follow these activities to get rid of moisture from boat compartments:

  • Ensure that there isn’t wet equipment inside the cabin. This can impact the humidity level. 
  • Allow cleaned areas to dry out completely. It’s essential to control boat condensation. 
  • Try to leave various chemical dehumidifying packs in those regions that are vulnerable to mildew. 
  • Inspect for leaks throughout the boat each week. This will save you money and effort. 
  • Keep natural dehumidifying and mold-eliminating solutions handy. 

If you’d prefer a natural way to get rid of moisture, you can always go with tea tree oil gels. Placing the gel in places with high moisture can kill mold quickly. Alternatively, you can also attempt these methods:

  • Mixing 1 portion of vinegar with 3 portions of water to clean damp, moisture-filled areas. 
  • Adding a quarter tablespoon of baking soda to a bottle of water and then spraying it on the dew areas will repel the development of mold. 
  • When the moisture is extremely high, you can choose hydrogen peroxide or other commercial moisture absorbers. 

As a rule of thumb, most moisture-removal products used in houses are appropriate for boats as well. However, remember to read the instructions to avoid wrong usage or wrong proportion. 

For more information about cleaning your boat please see my other article here.

Bonus Method

When it’s winter time, the best way to get rid of moisture is to invest in a boat cover. This will prevent the entry of water and the formation of mold inside the boat compartment. While it’s true that the boat cover can turn the space compact and limit air circulation, you can still give this a try after ensuring that the boat is completely dry. 


How Much Does It Cost To Remove Moisture From Boat Compartments

Removing moisture from the boat compartment can cost anywhere between $50 and $1000 depending on the degree of moisture, type of product used, engagement of a professional, and the season of the year. 

Cleaning your boat regularly is one way to cut down excess costs in removing moisture from the boat. 

Final Thoughts

Seeing the growth of moisture inside the boat can be depressing for boaters, especially if they’re new to it. However, with some easy-to-use methods that are effective and affordable, it’s feasible to get rid of moisture. 

The major point of concern is to ensure that you’re using the right method and following precautionary measures to regulate humidity and moisture in the first step. This will save you money in the long run. Perhaps, this can extend the longevity of your boat as well. 

Start inspecting your boat today! Cheers!


Boatlifehq owner and author/editor of this article.

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