I have a 41′ Fraser, currently living aboard. Am having water/humidity/mold problems. Would a dehumidifier be a solution?

Stephen Davison


Hi, Stephen,

A dehumidifier certainly would help, but dehumidifiers deal with the effects of excessive moisture in the boat, not the causes. Broad brush, the real solution is to replace high-humidity inside air with lower-humidity outside air, and to circulate air through the boat to fight “dead spots” where mold can form.

Especially during the colder winter months, living aboard makes moisture problems more pronounced. Our bodies give off moisture. Breathing gives off moisture. Showers give off moisture. Food gives off moisture as it cooks, and if you cook with alcohol, kerosene or propane, their open flames give off considerable moisture.

This is why you have to get inside air out, and outside air in. Intake ventilators tend to be installed aft, and exhaust ventilators, forward. You may have to install fans to move air around.

I suspect your boat doesn’t have a diesel range in the galley. If it did, the range would draw cold, moist air in, and exhaust it up the stack. The range would be left burning around the clock for heat. Air would circulate, and you probably wouldn’t have the problems you’re facing now. In the summer, of course, you might not be as charmed. The range wouldn’t run around the clock, it would be slow to heat up for cooking, and the range would heat the boat while it was in use.

There’s a good book on this subject. It’s titled Warm, Dry Boat: A Handbook for Liveaboards, by Roger McAfee. Roger is a regular contributor to Pacific Yachting and a number of other publications. The book should be available at Nanaimo marine supply stores.

Bob Hale

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