Keeping the boat extra dry over the winter

Have you prepped your boat for the cold yet? I dug out all my air warmers from the garage and took them down to the boat a couple of weeks ago.  Keeping the air on the boat warm and moving is important over the winter because moisture inside the boat causes trouble when there is poor ventilation. Moisture allows mold and mildew to grow and makes the boat smell bad. Even if your moisture problem doesn’t get quite that bad, the bed sheets can have a damp feeling to them–which is not nice if you like to overnight a few weekends during the winter!

A few years ago, a broker friend of the family suggested I try using a real dehumidifier on the boat over the winter. I did a little research and decided it was worth the cost and hassle (more on that later). I ended up getting a DeLonghi dehumidifier. This unit has a built in pump to push the water upwards which allows me to place the output hose in the sink–I didn’t want the water draining downwards into the bilge.

My big, heavy but effective dehumidifier

The unit was not cheap (around $300 on Amazon, link here) and it’s a total pain to lug down to the boat and lift it from the dock on to the swim step and then get it down into the mid-cabin. However, after using it for a few winters, I can say that all the trouble is well worth it. That boat smells and feels dryer. To back up these claims, I purchased a couple of humidity monitors and placed one in each stateroom. These are relatively cheap at around $10 (Amazon link here). The photo below is before turning on the dehumidifier:

Humidity monitors showing “before” numbers.

The range without the dehumidifier on is usually around 60-70%. After the dehumidifier has run for a while, those numbers will be in the 35-50% range…much dryer!

Because we use our boat year-round, I also have a heater in the engine room and another in the lazarette (my batteries and water tank are in the lazarette). I then open all outside washdown spigots and every faucet on the boat. I leave a little yellow sticky above the water pump breaker which reminds me to close them all before turning on the water pump! I try to make sure all systems get used when we’re on the boat as I believe it’s good for moving parts to be moving and not stay stationary all winter.

In typing all of this up, it seems like there should be more winterizing I do but I think that’s it.  What tips and tricks do you use over the winter? What am I forgetting?!