Fighting Mold and Mildew on Stored Boats

Most boat owners have had to deal with condensation and the subsequent mold and mildew that can quickly grow in damp conditions. Put your cover on your boat when the carpet is damp and you’ll trap in moisture. When the air under the cover cools at night, the moisture precipitates out and makes the perfect habitat for molds.

The first line of defense is to have a good boat cover made of a breathable, marine grade polyester or acrylic. Breathable fabrics will allow water vapor to escape through the cover. Some covers come with built in venting, or aftermarket vented support poles can be added. These provide an additional way for warm moist air to escape from under the cover.

The second line of defense is to install a boat air dryer or dehumidifier. These products are designed to reduce humidity in an enclosed area and work on a couple of different principles.

Chemical Boat Dehumidifiers

Chemical dehumidifiers come in a couple different forms, including disposable tub and packets, and reusable silica gel cartridges. Chemical air dryers are popular because:

• They don’t require electrical power to operate
• They are not particularly temperature sensitive
• They are fairly inexpensive.

Their limitations include:

• The need to monitor and replace or recharge regularly
• Each unit generally handles a smaller space

Tubs of calcium chloride or similar chemicals are sold under a variety of brand names. They are fairly inexpensive, but they have to be emptied and have a limited life span before they are thrown away. The potential for mess is there as the water can be spilled or overflow and may be somewhat caustic. In addition, care must be take to keep it located where pets and wildlife won’t be exposed or tempted to take a drink of collected moisture. See the No Damp Dehumidifier

Silica gel based options like the Eva-Dry use silica gel enclosed in a protective casing. (Think of the little “Do Not Eat” packets in your vitamins or other moisture sensitive products.) Silica gel absorbs water, transforming the crystals from a hard grain like consistency to a glob of clear heavy gel. Silica gel can be dried back out and used again. The Eva-Dry De-humidifiers tell you when the gel is saturated. You can then take unit to a well ventilated place, plug it in and dry out the crystals in about a day. Once dry, it is ready to be re-installed and go back to work. The Eva-dry Dehumidifiers will last up to 10 years and the gel is enclosed where it doesn’t pose a threat to animals or furniture.

See the Eva-Dry Dehumidifiers 

Electric Boat Air Dryers

Electric Boat Air dryers are special low wattage heaters designed to gently raise the temperature in an enclosed space and reduce the humidity. Because they are heating the air, they are effective through the temperate and coastal parts of the country where cool, wet winters prevail. They are not effective in extreme cold, or temperatures much above 60 degrees. Electric boat air dryers typically draw about as much power as a light bulb, and while very warm to the touch, the element is protected inside the unit. With no moving parts the units are designed to be safely used for extended periods of time without direct supervision (when properly installed and used) 

These are popular:

• Where temperatures are between 33 and around 55 degrees Fahrenheit
• Electric power is available
• It is inconvenient to access the air dryer on a regular basis

2 of the most popular brands on the market are the Davis Air Dryer and the DryWave Boat Air Dryer by Ironwood Pacific Outdoors,

For more information on Boat Air Dryers and Dehumidifiers, check out our Boat Air Dryer and Dehumidifier Resources at SavvyBoater.com.