Living on a 28 foot Cal this winter we experienced much condensation due to exhalation and the by-product of propane cooking. A cored hull would be nice but not always available in boats of choice. Any course steerage would be appreciated. Frank PS We ran a household dehumidifier which took some moisture out, but not enough.
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Try this
Davisnet.com sells an RV/Marine heater designed solely to heat the air just enough to create convection. It works for me, keeps the air dry and even dries up small leaks that occur over the week. Very safe, from what I can tell. I also have a whirpool dehumidifier under the house, but that's another story.
Davisnet.com sells an RV/Marine heater designed solely to heat the air just enough to create convection. It works for me, keeps the air dry and even dries up small leaks that occur over the week. Very safe, from what I can tell. I also have a whirpool dehumidifier under the house, but that's another story.
Ventilation, calcium carbonate
We keep some air moving through the cabin when we are aboard, even when it is cold. This reduces the condensation. We use a fan at the dock, and wind scoop on the forward hatch at anchor/mooring. While away from the boat, we set out calcium carbonate in the draining containers you can get to keep the cabin dry until we return. This seems to work pretty well for us. David Lady Lillie
We keep some air moving through the cabin when we are aboard, even when it is cold. This reduces the condensation. We use a fan at the dock, and wind scoop on the forward hatch at anchor/mooring. While away from the boat, we set out calcium carbonate in the draining containers you can get to keep the cabin dry until we return. This seems to work pretty well for us. David Lady Lillie
calcium chloride
Calcium chloride is the product you want to use as a dehumidifier, not calcium carbonate. One brand name is Damp-Rid and it is sold as a closet dehumidifier.
Calcium chloride is the product you want to use as a dehumidifier, not calcium carbonate. One brand name is Damp-Rid and it is sold as a closet dehumidifier.
Deliquescent salts......
Many 'salts' will pick up moisture frorm air, you just need a small fan to keep the air moving across or through them, and then need to dump the 'brine' occasionally. Do a websearch for "deliquescent salts". These are readily available through air compressor distributors and suppliers.
Many 'salts' will pick up moisture frorm air, you just need a small fan to keep the air moving across or through them, and then need to dump the 'brine' occasionally. Do a websearch for "deliquescent salts". These are readily available through air compressor distributors and suppliers.
Ventilation and insulation
Whenever moist air hits a cold surface you have condensation. So you have to warm the surface and/or remove the moisture. Our Pearson 323 has a hull liner that is ventilated. This air space insulates the liner from the hull and we have very little condensation. The hull still gets wet but the inside of the liner near us stays dry. Our old Macgregor even though it had a liner always sweated and was pretty wet in winter. If tied to a dock we just used a small electric heater and it was tolerable the warm air carrying away moisture. But at anchor we left the hatch partially open and even with a dorade the liner was wet by morning. Maybe exhaust your warm air into the space between the hull and the liner. This might warm the liner enough to prevent condensation on the liner. You would still have it on the hull but this should find it's way to the bilge. If you can insulate the hull. But for my pearson that isn't an option as access is very limited. Enough ventilation should solve the problem but it is hard to heat a boat with an open hatch. The problem with dehumidifiers is that warm moist air rises and the dehumidifier is usually sitting down low. Tom
Whenever moist air hits a cold surface you have condensation. So you have to warm the surface and/or remove the moisture. Our Pearson 323 has a hull liner that is ventilated. This air space insulates the liner from the hull and we have very little condensation. The hull still gets wet but the inside of the liner near us stays dry. Our old Macgregor even though it had a liner always sweated and was pretty wet in winter. If tied to a dock we just used a small electric heater and it was tolerable the warm air carrying away moisture. But at anchor we left the hatch partially open and even with a dorade the liner was wet by morning. Maybe exhaust your warm air into the space between the hull and the liner. This might warm the liner enough to prevent condensation on the liner. You would still have it on the hull but this should find it's way to the bilge. If you can insulate the hull. But for my pearson that isn't an option as access is very limited. Enough ventilation should solve the problem but it is hard to heat a boat with an open hatch. The problem with dehumidifiers is that warm moist air rises and the dehumidifier is usually sitting down low. Tom
Second
Been using calcium cloride in a plastic collander sitting on a plastic bucket inside my boat to suck up the moisture for a few years. Seems to work well. No evidence of condensation noted at the end of the cold months.
Been using calcium cloride in a plastic collander sitting on a plastic bucket inside my boat to suck up the moisture for a few years. Seems to work well. No evidence of condensation noted at the end of the cold months.
Solar vents
I have installed 2 solar powered vents on my boat. One vents the air in the main cabin and the other only goes as far as the headliner, venting that space. Because they are solar powered (with a rechargable battery backup) they run all the time including during the winter. My boat was dry as a bone when opened this spring.
I have installed 2 solar powered vents on my boat. One vents the air in the main cabin and the other only goes as far as the headliner, venting that space. Because they are solar powered (with a rechargable battery backup) they run all the time including during the winter. My boat was dry as a bone when opened this spring.
He is living aboard!!!
The question is not about a stored boat, The question is about a boat that you are living aboard. Even my old Macgregor stayed dry when no one was aboard. But after a couple of pots of tea on a cold night it was wet. It is the moisture from cooking, breathing and burning fuels that is causing the problem. I have been on boats that were wet and this was often due to leaking hatches and windows. Even in summer they were wet and mouldy.
The question is not about a stored boat, The question is about a boat that you are living aboard. Even my old Macgregor stayed dry when no one was aboard. But after a couple of pots of tea on a cold night it was wet. It is the moisture from cooking, breathing and burning fuels that is causing the problem. I have been on boats that were wet and this was often due to leaking hatches and windows. Even in summer they were wet and mouldy.
I understand that...
I have spent weeks aboard my boat as well. Each solar vent moves 700 cubic feet of air an hour. On my boat that is a total of 1400 cubic feet per hour or (mental math time) over 33,000 cubic feet a day. Assuming the ambient humidity is lower than the in-boat humidity that should be enough air movement to keep things dry(er). If it is wetter outside than inside I can close them off.
I have spent weeks aboard my boat as well. Each solar vent moves 700 cubic feet of air an hour. On my boat that is a total of 1400 cubic feet per hour or (mental math time) over 33,000 cubic feet a day. Assuming the ambient humidity is lower than the in-boat humidity that should be enough air movement to keep things dry(er). If it is wetter outside than inside I can close them off.
The CONDENSATION issue aboard our boat is:
Thanks one and all for the time and effort expended to help us expel the moisture that accumulates even during ambient temperatures that are in the 50+F range. As we and another recipient of the "Phantom of the Silent Mist", has pointed out, we are living on the vessel full time and creating large amounts of water vapor do to breathing, cooking and just everyday moisture production that may include wet clothes drying or washing ourselves. The problem was so bad that we stopped cooking with propane and used a electric skillet. The moisture accumulates at a very rapid rate because the hull, in certain places, is not insulated with either carpeting or some liner material, fiberglass or whatever. Oddly enough, the overhead is dry except for the hatches and ports, where the external cold is conducted via the aluminum framing of the hatches. This means that the overhead is not cooling to the dew point. It must have a double liner effect or be insulated somehow. We ran a small fan along with the dehumidifier and electrical heater. Much accumulation was had, but the quarter berth was so wet, we had to remove the cushions and spray them with Lysol as a preventative measure against mold and mildew. While absent from the boat for an extended period of time, the dehumidifier was placed atop the galley sink and allowed to drain directly into it while simultaneously a box fan was moving the air. Upon return, of course, every thing was dry as a bone. Obviously, it is during the onboard living that the joys of boating take on a whole other dimension. It seems to me that if a hull and top deck were so engineered and constructed as to have insulative qualities throughout, that this problem would be eliminated. The normal venting by opening hatches and ports, even during very cold days, does help remove water vapor from the air, but not enough time passes to allow evaporation and removal by this method of remedy. Leaving the dorades open didn't help and caused discomfort during the colder nights. So, if only we could be warm enough, we would be all set with swim suits! Towels anyone? We are still in good humor, but the waders have to go. Tnx.... Frank
Thanks one and all for the time and effort expended to help us expel the moisture that accumulates even during ambient temperatures that are in the 50+F range. As we and another recipient of the "Phantom of the Silent Mist", has pointed out, we are living on the vessel full time and creating large amounts of water vapor do to breathing, cooking and just everyday moisture production that may include wet clothes drying or washing ourselves. The problem was so bad that we stopped cooking with propane and used a electric skillet. The moisture accumulates at a very rapid rate because the hull, in certain places, is not insulated with either carpeting or some liner material, fiberglass or whatever. Oddly enough, the overhead is dry except for the hatches and ports, where the external cold is conducted via the aluminum framing of the hatches. This means that the overhead is not cooling to the dew point. It must have a double liner effect or be insulated somehow. We ran a small fan along with the dehumidifier and electrical heater. Much accumulation was had, but the quarter berth was so wet, we had to remove the cushions and spray them with Lysol as a preventative measure against mold and mildew. While absent from the boat for an extended period of time, the dehumidifier was placed atop the galley sink and allowed to drain directly into it while simultaneously a box fan was moving the air. Upon return, of course, every thing was dry as a bone. Obviously, it is during the onboard living that the joys of boating take on a whole other dimension. It seems to me that if a hull and top deck were so engineered and constructed as to have insulative qualities throughout, that this problem would be eliminated. The normal venting by opening hatches and ports, even during very cold days, does help remove water vapor from the air, but not enough time passes to allow evaporation and removal by this method of remedy. Leaving the dorades open didn't help and caused discomfort during the colder nights. So, if only we could be warm enough, we would be all set with swim suits! Towels anyone? We are still in good humor, but the waders have to go. Tnx.... Frank
Dry top due to wood
The dry top is probably due to wood or plastic foam. Almost all decks are cored and wood is a reasonable insulator. I would put insulation on all exposed hull!!!! Tom
The dry top is probably due to wood or plastic foam. Almost all decks are cored and wood is a reasonable insulator. I would put insulation on all exposed hull!!!! Tom
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