|Topic Review (Newest First)|
|01-26-2012 06:25 AM|
A nice, simple explaination.
Originally Posted by Sea Diamond View Post
3. Ventilation also "dries" the air if heat is in use; the colder exterior air is always drier because it is cold and cold air holds far less moisture. Houses generally ventilate through leakage; boats are much tighter and much smaller. The clothes drier and bathroom fans can also pull a lot of humid air out of a house.
4. Moisture comes from many sources, but the main source for live aboards is exhalation, perhaps 1/2 gallon per person per day. Add to that cooking, showers, and wet bilges.
|01-26-2012 05:23 AM|
Ventilation is key. I concur with the earlier recommendation to get a copy of and read "The Warm Dry Boat" by Roger McAfee.
In the near term, take the doors off your lockers to increase ventilation of the lockers and even out the temperature differential.
|01-25-2012 06:26 PM|
Insulation and vapor bariers aside, in a nutshell you need to start with 2 simple things.
1. Heat the interior warm enough so moisture will evaporate off the walls and "float around" in the air. The walls will appear dry but the moisture will still be in the air. Hopefully your heaters will have fans to move the air around, and hopefully they are safe. (I personally dislike electric heaters on a boat for safety reasons).
2. Use a dehumidifier to capture that "floating moisture" - read the instructions that come with the DH as to what happens when the interior is not warm enough.
Then save up for a diesel hot air furnace.
|01-25-2012 05:41 PM|
Originally Posted by SanDiegoChip View Post
|01-25-2012 05:18 PM|
Yes, doing something inside the lockers would be nice. We have been thinking of options. Spray foam seems the best way as gluing closed cell foam in there would be difficult.
We will be using AC in the future in Mexico so moisture is not going to be an issue but keeping out the heat will.
|01-25-2012 04:51 PM|
40 years of living aboard full time in BC has convinced me that the 1 1/2 inches of spray foam insulation is the only reasonable solution here. My boat is warm and dry, thanks to the insulation and the wood stove. If I turn my salt shaker upside down, it will completely empty itself . I have zero condensation problems. The ceramic bead insulating paint addative from High Tech sales in Florida, is a simple solution which may work in sunny San Diego.
The more insulation the more comfort, period.
TBTF as a paint addative for mold prevention is available in some paint stores. If it is not available in the US , you could get it in Mexico.
I've heard a painting with a borax solution also works , tho I've never tried it.
|01-24-2012 05:14 PM|
We placed the unit in the head for now. It is a bit larger than we thought. We set the humidity level to 40. It is recommended for the room humidity to be between 30-50. We left it on over night and we used the heater. We got up as usual for work only this time the boat was dry!
Sometimes we up it to 60-70 as we like some moisture and the boat still stays dry.
We let this run at night to keep the boat from getting too wet. We use an electric heater with a thermastat to keep the boat from being too cold at night.
The boat still will get chilly but not real cold.
This hatch is over the bed. When this Sky Shade is closed it still stays mostly dry.
This one is in our head and is closed but stays dray any way.
Our port holes and windows stay dray and the boat never gets stuffy as the air moves about.
On our 36' sail boat we alwasy have the fan on low when we have the unit runing. The fan has three settings. Unless we are cooking spaghetti or something with bowling water.
For us it has been well worth it.
|01-24-2012 05:54 AM|
|unomio||If you are living aboard in San Diego we are extremely jealous of your condensation problems. The Pacific Northwest so far wins our award for creating "indoor rain" but Tonga is a close second. Our solution in the Northwest was a sizable dehumidifier, _after_ insulating with closed cell foam all areas next to the hull or deck not already insulated at the factory and installing an Espar forced air heater. In particular, the inside of the coaming (raised bulwark where the hull/deck joint is located) seemed to create rivers of water. At anchor in Tonga, with the relative humidity approaching 100%, we couldn't use a dehumidifier because it draws too much power and the air is 'way too hot anyway. We used a combination of Breeze Boosters, awnings, and open ports and hatches, plus cabin fans (especially in the V-berth peak). I recommend reading The Warm Dry Boat as a sort of primer for figuring out what your particular boat needs.|
|11-26-2011 03:36 PM|
Originally Posted by SanDiegoChip View Post
After three winters living aboard in the Pacific Northwest, I believe I can safely say that dehumidifiers and insulation will help but will not solve the problem. Ventilation and circulation of air and cooking and heating fuel that does not give off water vapor or at least minimizes it are the only permanent solutions to the condensation problem. Electric heat is best, propane is the worst.
If the boat is occupied, shoot for a complete exchange of air in the boat every hour or 15 CFM (Cubic Feet per Minute) per crew member (900 CF per hour) minimum. The typical 30 foot sailboat has about 1000 CF of volume IIRC. The more complete air exchange you can achieve the better. You will probably need to improve air flow (Cut holes in) lockers at least and probably install circulating fans to ensure dry storage spaces throughout the boat. Pay particular attention to the exhaust vents in your sleeping cabin and galley area and don't forget the lazarette.
A couple of four inch active exhaust vents with fans forward and a couple of passive vents aft may be enough but more will be better. Intake and exhaust vents should be as far apart as possible. An unoccupied boat may get away with one four inch solar exhaust vent forward and one passive vent of equal size aft.
OTOH, it is probably wiser to just sail to the tropics where you can simply open up everything and let the trades blow through
|11-22-2011 03:04 PM|
Soleus Air DP1-30-03
We just purchased the Soleus Air DP1-30-03 30 Pint Room Dehumidifier. Our boat is getting very wet at night from running the electric heater. We have an electric mattress pad with duel controls that helps a lot. But the boat does get cold and damp. While here in San Diego we will use this to keep the boat dry.
Let you know how this works out.
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