Sweating

[Scott Dunsworth]

Just wondering about heating a small wood boat like the Belhaven or the Princess. I read somewhere that there are small vented heaters that burn charcoal briquets. But I guess my main question is will our epoxy coated plywood boats sweat if the outside temp is 30 or 40 degrees and the inside of the cabin is at 70?

I plan on doing a lot of sailing and camping in the fall and early spring. It would be nice to heat the cabin at night. That is also another reason I was thinking of louvered doors on the companion way. There would always be some fresh air even if there is a cold rain coming down.

Scott

[capt jake]

Any boat will sweat given those conditions. The outside temp will cool the shell of the boat. When you are inside, the moisture from breathing, sweating, whatever, will condense on the inside of the cool shell.

[JeffM]

Would this be like a tiny wood stove, with a chimney to the outside? If not, I'd worry about carbon monoxide.

[capt jake]

Would this be like a tiny wood stove, with a chimney to the outside? If not, I'd worry about carbon monoxide.

Even with proper ventilation, you must provide for make up air (freash air). If ot, the risl of reucing the levels of O2 are increased. This is just as fatal as CO poisoning (in reality, they both cause death by lack of O2).

[john bowen]

Everybody is right about air flow. But, here are a few to look at without geting into high dollor. And by no means use while sleeping! :roll: Think about gimballed(safer).

http://www.coleman.com/coleman/ColemanCom/subcategory.asp?CategoryID=3000

[capt jake]

Those solar powered vents are pretty slick. They are highly efficient also.

[double 7]

hi scott i use to heat my previous sailboat 27' with origo heat pal 5100 btu alcohol heater they are safe to operate and inexpensive if you buy methyl hydrate about 6.oo gallon at your local hardware. as cap jake and ray said you will have condensation .these heater are available thru defender store and all big marine outlet fern.double7

[john bowen]

That thay do , moored at the dock or on the trailer. If coverd, just put a window in the tarp over the solor vent.

[Charlie Jones]

Unfortunately Ray, the fact that it's made of wood will have very little effect on the condensation problem, unless the wood is WAY thicker than the ply boats being talked about.

In my tri while we were living aboard, we got RAINED on every time it got cool and moist outside, until I insulated the overhead with foam. JUST as badly as Tehani with her solid glass cabin top does now.

It IS a problem and a heater the burns alcohol will only contribute to the condensation problems- they give off MUCHO water vapor when they burn. So does kerosene by the way. The ONLY source of heat the isn't going to contribute to the problem is solid fuel, such as wood, coal or charcoal. But THEN you get into the problem of needed to refresh the air inside the cabin, which can bring in cold air, thus requiring more heat, and around we go

And I think it's worse down here because we always have much higher humidity than does the area further north, even if you do get colder in degrees. 40 degrees, misting rain and 98 % humidty is COLD and very hard to overcome inside a small boat.

Of course, vented solid fuel heaters work very well, but installing one on a boat the size of the Princess 22 would be a problem. There are few solid fuel boat quality heaters being built any more sadly.

One thing I have done, and it works well, is using a clay flower pot inverted over a kerosene burner. I guess an alcohol burner would work too- never tried that since I refuse to have an alcohol stove onboard. The flower pot radiates a relatively ( Relatively!!) dry heat once it heats up. Of course, you need a safe place to put the pot when you aren't using it, or while it's hot and you need the stove. I used the stainless sink and a little wire hook to pick it up with via the hole in the bottom.

Insulation is the real answer. We are searching for some form of insulation to install in Tehani's cabin top and sides, that is A) worth having reasonably attractive and C) doesn't eat up a bunch of head room. So far we are searching. On the Princess, you could do as I did on my tri- I cut Blue styrofoam to fit between the roof beams and covered that with a fabric- they wwere press fit in between the beams and instantly stopped the condensation. The cabins sides were still a problem but mostly that was liveable. Although once coming down the ICW in Novemeber I spent 2 weeks with the blanket on my bunk frozen to the cabin side. I simply rolled up another blanket and stuck it between me and the frozen part.

[john bowen]

Charlie, what do you thing of this heater?

http://store.hamiltonmarine.com/browse.cfm/4,3112.htm

[Scott Dunsworth]

:wink: I guess the only easy remedy would to buy a wool or down blanket.

When I visited Graham and we talked about the Princess and Belhaven he mentioned using foam sandwiched between two layers of 1/8 ply for the roof. It sounded to complicated for me so I just forgot about it. But I guess it would be a good Idea.

Scott

[john bowen]

Scott, they make a sandwich ply (not cheap). But, like Charlie say's you could go with a liner. Would help even in the summer time.

[Guest]

I know this sounds a bit funky. But in the many times of dealing with a lot of composite hulls, both with headliners and without them, a considerable and noticable difference in the hull temperatures would occur when I would deliver many new hulls with furnishings and without them in the fall seasons, especically. Even with bunk mattresss to obsorb and maintain some warmth during the day, they gave off a bit of stabilizing heat in the evening to actually keep sweating down to a minimum in the evening. Wood is an amazing product unlike straight fiberglass. You can still insolate the roof top, [this I speak with some reserve thoughts, not knowing the interior make up for your boat] but with any cabin framing, you can use some form of blue board and some vinyl headliner material, or even some painted pegboard added and this will still give you some form of barrier coat.

[Charlie Jones]

John I've seen those in use. Some live-aboard friends of mine had one, by a different company.

They work very well, but they do take a bit of room- it says 9.5 inches deep, but that may not include distance off the bulkhead. Plus you need a stack leading out, with a Charlie Noble on it to keep water from running down. You also need a deck pipe that is designed to keep the hot stack away from the deck. If you can find the space and are willing to have the pipe out the cabin top, it should be great. I think if I were sailing in a colder climate, I'd for sure have something like that- I'd FIND a place for it

[Greg Luckett]

I found this at BoatUS. It looks promising. In the climate here it would be really nice to have a heater in the boat.

http://www.boatus-store.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=20002&langId=-1&catalogId=20002&productId=72981

[Frank Hagan]

I tried to find some stats on the amount of CO an alcohol burner would give off, and wasn't successful. Burning any carbon based fuel will give off CO, and its a big concern in any enclosed area. But nearly all the deaths on boats from CO are due to internal combustion engines, not from the stoves. There are a few every now and then when a sailor dies due to a faulty heater, but it is relatively rare.

Know how they make water for the astronauts? They combine hydrogen and oxygen ... the old H2O thing. Burning nearly any fuel also produces water vapor, as Charlie said, because in the process of combustion you are breaking up the gas molecues into different compounds and generating heat. Two of the most undesireable compounds you get are H20 and carbon monoxide, or CO. It is unavoidable. So you should size your heater large enough to heat the place with plenty of fresh air. The fresh air does three things: the movement of air from inside to outside will help send the water vapor outside, the air provides "combustion air" for the burning of the fuel so it is the most efficient and produces the least amount of CO possible, and the CO itself can be escourted out of the boat by the airflow.

The flowerpot idea seems to work well, and the clay won't give off a lot of CO by itself (the fire under it does, though!) Cast iron pots are not a good substitute, as any oil in cast iron will give off CO (and the cast iron itself gives off minute amounts). The location of the galley on most boats ... by the companionway ... helps us here, because if we are in the v-berth with the hatch cracked open, and the flower pot is on the burner near the companionway which is also cracked open, the flow of air should be over our heads and then out the companionway. The flower pot radiates warmth out, and the air takes the bad stuff out. The trick is finding the optimum amount of air being let in to be safe and the right amount of fuel being burned to stay warm.

It might be a good idea to invest in a marine CO detector to see if you can measure the actual amount of CO you are accumulating in the boat.

[Greg Luckett]

:wink: I guess the only easy remedy would to buy a wool or down blanket.

When I visited Graham and we talked about the Princess and Belhaven he mentioned using foam sandwiched between two layers of 1/8 ply for the roof. It sounded to complicated for me so I just forgot about it. But I guess it would be a good Idea.

Scott

I started getting the Navy wool blankets from surplus stores. After spending so many years sleeping under them, I find them very comfortable and WARM, even when wet. They make excellent blankets for a boat.

[Charlie Jones]

I MUST point out here that I would NEVER even consider going to sleep with that stove going, with a flower pot on it. Several wool blankets and a wool watch cap on my bald (ing?) head would have to suffice once we went to bed. I would only use it while awake. For one thing, the stove wouldn't run all night without someone pumping the pressure back up, and I just DON"T go to sleep with something burning on the boat. We didn't even do that the time we got caught in north Florida when the outside temps hit 11 degrees and it was 22 inside the boat when we got up. Believe me I got that stove going and put the pot on as quickly as I could!!!

[Greg Luckett]

I tend to agree with Charlie. To me, heating the inside of the boat is like tent camping. The heater is only on when someone is on watch. I have used an electric heater, which had tip over safety switch, while tied to the dock. The water temperature was about 45, which meant the interior temperature was close to the same. That electric heater made it very comfortable.

[capt jake]

have used an electric heater,

Hook it to a pedal powered generator and then you won't have to worry about heat. That or take a really long cord with ya.