Tarp & Dehumidifier
Try to keep the boat dry inside to help prevent mold and mildew and keep the air circulating. I'd be just as concerned about mold and mildew as freezing and high winds. Mold and mildew may take some time to get started on a boat but once it's there it can be difficult to eradicate so the best plan is prevention. The firs step is to keep the boat dry inside and the second is to keep the humidity at 50%RH or less. A tarp will help keep water from getting inside either the boat or the deck/coachroof. Either way this is a plus. Consider a plastic tarp from Costco - they're heavy duty and have one side silver which can face upward. No need to get fancy as long as it sheds water and it's secured to prevent it from being blown away during high winds.The next thing I'd recommend is a dehumidifier to keep the humidity down and due to the cool temperatures it should have "auto-defrost" which one probably needs a 40-quart model to get it. The dehumidifier also has a fan to circulate the air and the exhaust air is a couple degrees warmer than ambient so that helps too. Wal-mart had some when we got ours but we bought ours at Home Depot.The last two years we had ours on board, with a tarp cover, there has been absolutely no mildew issues what so ever. Also, the electric bill has been less than with the little heaters because it shuts off when it reaches it's set point (user adjustable). We used 35%RH last year and we're using 40%RH this year.Set it on the galley counter and run the drain hose into the sink.Also consider a shaft seal to keep the bilge dry and prepare the boat for the high winds that come every winter.
Try to keep the boat dry inside to help prevent mold and mildew and keep the air circulating. I'd be just as concerned about mold and mildew as freezing and high winds. Mold and mildew may take some time to get started on a boat but once it's there it can be difficult to eradicate so the best plan is prevention. The firs step is to keep the boat dry inside and the second is to keep the humidity at 50%RH or less. A tarp will help keep water from getting inside either the boat or the deck/coachroof. Either way this is a plus. Consider a plastic tarp from Costco - they're heavy duty and have one side silver which can face upward. No need to get fancy as long as it sheds water and it's secured to prevent it from being blown away during high winds.The next thing I'd recommend is a dehumidifier to keep the humidity down and due to the cool temperatures it should have "auto-defrost" which one probably needs a 40-quart model to get it. The dehumidifier also has a fan to circulate the air and the exhaust air is a couple degrees warmer than ambient so that helps too. Wal-mart had some when we got ours but we bought ours at Home Depot.The last two years we had ours on board, with a tarp cover, there has been absolutely no mildew issues what so ever. Also, the electric bill has been less than with the little heaters because it shuts off when it reaches it's set point (user adjustable). We used 35%RH last year and we're using 40%RH this year.Set it on the galley counter and run the drain hose into the sink.Also consider a shaft seal to keep the bilge dry and prepare the boat for the high winds that come every winter.