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How do I counter humidity on board?

2014 April 1

Dear Boat Doctor,

I need some help with humidity control in my boat. I live in Tennessee but keep my boat in Fort Lauderdale. I spend a few days a month aboard but the boat sits closed up most of the time. I prefer not to run my air conditioner when I am not there but I want to keep the boat dry.The boat gets pretty damp in summer. What's the solution?

Michael Ramsey
Chattanooga, Tennessee

Dear Michael,

You're right to be concerned about humidity in your boat; mildew is bad news.

The first place to start is by making sure your vents are open and consider adding more. You can also add ventilating "tiles" under the cushions or prop them up when you leave to allow for good airflow around them.

Make sure the moisture down below is coming from the air. If you have any deck leaks or a wet bilge the interior humidity can rise dramatically.

You might also want to consider space dehumidifiers such as the ones from H2Out (www.h2out.com). These devices are basically hygroscopic resin in a perforated aluminum tube. Put a couple down below and they'll pull moisture from the air. They last a long time and are reusable. When they are saturated, you bake them in the oven to dry them out and they are ready to dehumidify again.