Preventing Condensation In Aluminum Boats: Tips And Tricks

Condensation is a common problem in boats, especially during the winter months. It occurs when hot air or steam becomes cool and turns into water droplets that collect on cold windows, lockers, and other surfaces. This can lead to the growth of mould and mildew, causing an unpleasant smell and potentially damaging the boat's interior. To prevent condensation, it is important to minimise temperature variations, keep surfaces above the dew point temperature, and reduce the amount of water vapour present in the boat. This can be done through proper insulation, ventilation, and the use of dehumidifiers or heaters.

Insulate the boat with Armaflex

Insulating your aluminium boat with Armaflex is a great way to prevent condensation. Armaflex is an elastomeric, dry-cell foam with an antimicrobial closed-cell structure that prevents moisture from wicking, making it an efficient insulator with an R-value of 4.2 per inch of thickness.

To insulate your boat, you will first need to determine how much Armaflex you require. Armaflex is sold in flat sheets of three by four feet, with wall thicknesses ranging from half an inch to two inches. Rolls are typically supplied in four-foot widths of continuous lengths, with thicknesses ranging from three-eighths of an inch to two inches. The Armaflex website offers a free program that can help you determine the thickness you will need based on your specific requirements.

Once you have purchased the required amount of Armaflex, you can begin the insulation process. Start by cleaning the interior surface of your boat with isopropyl alcohol and allowing it to dry. Create mock-up templates of the sections you want to cover and transfer the patterns onto the backsides of the Armaflex sheets. Cut out the patterns with a knife or scissors, then simply pull off the adhesive protective backing, line up the sheet on the surface, and press it on.

If there are any small cracks between sections, you can use self-adhesive Armaflex sealing tape to bridge the gaps. The tape will not only seal the cracks but also provide a finished look to your insulation job.

Armaflex is an excellent choice for insulating your aluminium boat due to its ease of installation, exceptional material properties, and ability to provide a finished look in exposed interiors. It is a safe and durable option that will effectively control condensation, making your boat more comfortable and pleasant to spend time in.

Use a dehumidifier

Dehumidifiers are a great way to keep your aluminium boat dry and free of condensation. They work by drying out the air, reducing the moisture that can condense and collect inside your boat. This is especially useful if you are living aboard your boat for extended periods of time, or if your boat is stored on land during the colder months when condensation can be a bigger issue.

There are two main types of dehumidifiers: condensate dehumidifiers and rotary desiccant dehumidifiers. Condensate dehumidifiers use a cold plate to lower the temperature and induce condensation, but they are ineffective at lower temperatures. Rotary desiccant dehumidifiers, on the other hand, are effective down to freezing temperatures. When choosing a dehumidifier, it is important to consider the ambient temperature of the environment in which you will be using it. For example, if you plan to use your boat in colder climates, a rotary desiccant dehumidifier may be a better option. Additionally, consider the power consumption of the dehumidifier, especially if you have limited access to shore power or solar energy. Some dehumidifiers can be run off diesel or propane, but these fuel sources may not be feasible or safe for all boats.

When using a dehumidifier, it is important to have proper ventilation to allow the moist air to escape. Opening hatches or using a cockpit tent can help with this. Additionally, you will need to empty the water collection tank regularly, as it can fill up quickly, especially in high-humidity environments. To make this process easier, you can connect a hose to the dehumidifier to drain the condensation directly into the bilge. This is a more convenient option than having to manually empty the tank every few days.

Dehumidifiers can be expensive to run, so it is important to use them efficiently. Try to use the dehumidifier in conjunction with other condensation prevention methods, such as insulation and proper ventilation. This will help reduce the amount of moisture in the air and decrease the workload on the dehumidifier. Remember, the key to preventing condensation is to keep your boat's interior warm and dry, and a dehumidifier is a great tool to help you achieve that goal.

Minimise temperature variations

Minimising temperature variations is a key strategy to reducing condensation on your boat. Here are some ways to achieve this:

Insulation

Insulating your boat is a highly effective way to minimise temperature variations and prevent condensation. When choosing insulation, opt for materials with a closed-cell structure, as these are the most suitable for marine applications. They will prevent water and moisture absorption, as well as inhibit bacterial growth. Recommended insulation materials include spray urethane foam, Reflectix, and Armaflex.

Spray urethane foam is a common choice for steel and fibreglass boats. It is applied more easily before the interior skin is installed, but it can also be sprayed into remote areas after installation, although this is best left to professionals. While spray urethane foam is very effective, it usually needs to be covered due to its rough surface, and it can pose a fire hazard, especially on metal boats.

Reflectix is a radiant barrier insulation with two layers of reflective metalized aluminium separated by an enclosed air space. It is flexible, easy to install, clean, and non-toxic. However, it typically needs to be covered unless installed in an enclosed space.

Armaflex is a flexible, elastomeric, thermal insulation with antimicrobial properties. It is resistant to mould, fungi, and bacteria, and is safe, toxin-free, and fibre-free. It has a matte black finish and can be applied as a stand-alone material without the need for a cover. Armaflex is more expensive than other options but is easy to work with and provides a finished look.

Heating

Using heaters can help to minimise temperature variations and reduce condensation. However, it is important to note that heaters only allow the air to hold more moisture, and the water is still present. Therefore, heating should be combined with proper ventilation to effectively remove moisture from the boat.

Ventilation

Ventilation is crucial to minimise temperature variations and prevent condensation. Opening hatches, using cockpit tents, and installing fans or ventilators can improve airflow and reduce moisture build-up.

Cockpit tents are particularly useful as they allow you to keep the top hatch open while cooking, even in windy or rainy conditions. They also provide a space to dry wet clothes and towels, helping to minimise moisture inside the boat.

Computer fans, such as those used for extractors, can be installed to gently blow air into specific areas of the boat, effectively reducing condensation. Positive Input Ventilation (PIV) systems, commonly used in houses, can also be adapted for boats to increase airflow and force excess moisture out.

Cooking

Cooking is a significant source of moisture, so adopting cooking practices that minimise moisture production is essential. Use lids when boiling water or cooking with pans. A pressure cooker is ideal for recipes that require a lot of water, as it reduces steam generation. Alternatively, use a thermos flask for cooking rice—simply heat the rice and water in a pan until it boils, then pour the contents into a preheated flask and let it sit for 20-25 minutes.

Clothing and Bedding

Wet clothing and bedding contribute to moisture levels on boats. Whenever possible, dry these items in a cockpit tent or on deck, taking advantage of warm and sunny conditions. When leaving the boat for extended periods, prop up mattresses and cushions to allow for airflow and ventilation.

Keep surfaces above the dew point

Keeping surfaces above the dew point is a crucial strategy in preventing condensation on your boat. Here are some ways to achieve this:

Insulation

Adding insulation to your boat's hull and deck can effectively keep surfaces above the dew point. The key is to ensure the insulation thickness and material are appropriate for your boat's specific needs. The insulation should be dimensioned so that its surface temperature exceeds the dew point. Urethane spray foam, Reflectix reflective insulation, and Armaflex elastomeric dry-cell foam are all recommended options for marine insulation. Each has its advantages and disadvantages in terms of cost, ease of installation, and effectiveness.

Temperature Control

Maintaining a consistent temperature and reducing temperature variations can help keep surfaces above the dew point. Avoid drastic temperature changes by adopting a "comfortable approach" that utilises heating and ventilation. Use heaters to warm the boat, especially in colder months, and ensure proper ventilation to allow moist air to escape. Open hatches, portholes, and vents can facilitate air circulation.

Dehumidifiers

Dehumidifiers are essential in controlling moisture levels in the air. They work by drying out the air, reducing the amount of moisture available for condensation. Electric dehumidifiers, such as the Eva-Dry brand, can operate safely and continuously, automatically shutting down when full. Desiccant-based products like DampRid, Dri-Z-Air, and NoDamp are also effective in pulling water out of the air.

Ventilation

Proper ventilation is crucial in preventing condensation. Air that is stagnant provides an ideal environment for mould and mildew to flourish. Air dryers, cabin heaters, and portable electric heaters can help improve air circulation. Combining these with a slightly cracked hatch or porthole allows warm, moisture-laden air to escape, taking the water with it.

Cooking Strategies

Cooking produces a significant amount of moisture, so employing strategies to minimise condensation in the galley is essential. Use lids when boiling water, and consider using a pressure cooker or a thermos flask for recipes that require a lot of water, such as rice. If possible, cook outside or in a cockpit tent to allow cooking moisture to escape directly out of the saloon.

Personal Measures

People produce a considerable amount of moisture through breathing and perspiration. To minimise this impact, ensure adequate ventilation in sleeping areas and consider using a dehumidifier when occupying the boat. When leaving the boat for extended periods, take soft furnishings like bedding and towels with you, and prop up mattresses to allow air circulation.

Ventilate the boat

Ventilation is key to preventing condensation in an aluminium boat. The air inside a boat is often damper than the air outside, so creating air exchange with the outside is important.

Firstly, ensure that all leaks are fixed to limit water from entering the boat. Keep the bilge as dry as possible.

Next, consider installing a fan to increase air circulation. A computer fan, for example, can be fitted to a dorade vent to gently blow air into the boat. These are available in different voltages and speeds; slower, quieter versions are ideal for this purpose.

If your boat is stored on land, a simple and cost-effective solution is to open the hatches and allow air to circulate. If your boat is stored in water, a fan can be fitted to blow into an anchor rope access hatch, allowing air to pass through the boat and escape through limber holes and gaps behind the panelling.

Another option is to use a dehumidifier. These are most effective when the boat has access to shore power. There are two main types: condensate dehumidifiers, which use a cold plate to induce condensation, and rotary desiccant dehumidifiers, which are effective down to freezing temperatures.

Finally, consider using desiccant products such as Damp Rid to absorb moisture from the air. These are inexpensive and can be placed in cups or trays around the boat.

Frequently asked questions