Heating

[flagold]

I've just returned from using the C-Dory as a "camping cabin" in N. Ga in some sub 30 degree temps. I've camped all over the Rockies in it, but that was in summer. The main problem I'd like to solve is the Wallas heats the cabin fine from waist up, but the fwd berth area tends to remain cold. I seem to remember someone lining the berth area -- was that for insulation? Did it work? When camped out on the trailer, we don't get the thermal effect of water -- so it takes more heat -- I typically had the Wallas cranked full bore at night. The terrycloth curtains definately made a difference in insulating the windows, as did putting up the camping canvas. The chill difference in standing under the camping canvas and being outside was significant at night.

The Wallas -- would start, light off, and then auto-shut down. Upon re-firing, it would run all night (did this 3 times), a minor inconvieniance, but may not holding a fuel prime. It has done this on my trips out west as well, whether I'm on battery or generator doesn't seem to matter.

Other than the above -- worked great as a "boaterhome" as it has on all trips previous.

[Alyssa Jean]

Water will suck the heat from a boat much faster than air. I found this in a search for info pertaining to this.

Thermal conductivity is the measurement of the speed at which heat travels through a material through conduction. In the US, it is commonly expressed in terms of the number of BTUs of heat which will travel through one sq. foot of material which is one inch thick when there is one degree F temperature difference across the material (ie. Delta T). This expression is often stated as btu/in/hr/sq.ft/°F. In SI units, (SI = Système Internationale d'unités) this is expressed as W/m K, (watt per meter degree kelvin) which is the energy per second conducted through the material per square meter, when a temperature gradient of 1K/m is applied to the material.

So what's the difference in thermal conductivity between air and water? About 30 times as great for water than for air. (.02 W/m K for air and .6 for water.


There are a number of C-dorys that have lined the ccutty cabin with various types of covering. Also know of one that did the same on the whole interior of the cabin, Can't remember the name right now but they are in the Pacific NW. some will come up with the names and more info for you shortly I'm sure.

I use a small 12 V fan to move the air around the cabin a bit better. Getting it into the cutty cabin is a little more complicated. I think I read of running a small insulated flex tube from the heater area along the bulkhead into the cutty along side the helm area.

[C Spray]

I believe the one you are looking for is on the Lynn Marie. You can see the installation here

Just keep clicking on the next photos and you will see the installation process, it is a nice looking project.

[Adeline]

Hi all, I spent eight nights in the South Sound from 11/8-11/16. The first week was rain free and the Wallas kept the cabin @ about 74degrees @ 80% output. While I was very comfortable moisture condensed on the sides and in the v-berth. By the time I got home water had ran under the v-berth pad and puddled there. Some even ran down into the Porta-Potty area. Fortunately, I have a Hypervent Mat http://www.hyperventmarine.com/product.htm that kept the pad off the sides and v.b. decking so it stayed dry. I would like to line the interior but wonder if it would prevent condensation or simply absorb it. Any advice appreciated. Pete

[flagold]

Thanks David -- I always thought that if water was against the hull at 40 degrees, at least that portion in contact would stay 40 degrees -- at least I'd hoped so. I do know that 26 degree air surrounding the whole boat can make for a very cold experience if the Wallas isn't kept running continuously, the curtains and camper canvas arent up, and something isn't covering the bilge opening.

Good ideal on ducting -- I'll have to look into that some more. The fwd berth wasn't unlivable, but it was markedly colder. I didn't think about it at the time, but I probably could have put some Saran Wrap or similar under the anchor rode cover to seal that better. Everything else was pretty tight.



Matt
C-Dawg-E

[Larry H]

Hi,

I insulated the berth area of my 22 cruiser. I used ethafoam(sp?) and glued in one layer of 1/4 inch. The foam on the hull sides was covered with marine carpet. This has eliminated the condensation problem. If you are going to use foam, BE SURE it is CLOSED CELL foam so it won't soak up water.

[Sea Wolf]

Hi Guys!

When installing my heater (Force 10 Cozy Cabin, propane powered) the summer before last, I went through the same questions about heat distribution. Where I live, in Northern California, about 28 degrees is usually the bottom end temperature encountered most of the time, and I usually sleep on the converted dinette berth, so insulating the v-berth wasn't a priority with me.

I did consider setting up a blower to force warm air from above the heater into the v-berth, however, and after some thought, decided it would be more difficult than another alternative.

My thinking is that to force warm air from the top of the cabin down into the v-berth would be difficult without a fairly strong (and noisy) blower unit that would not only deliver the air to the forward area, but also mix it up thoroughly, as the warm air would otherwise just rise up to the top of the forward cabin from the mouth of the tube and follow the cabin roof back to the main cabin ceiling, leaving much of the area cold. A strong fan would forcefully do the job of thoroughly mixing the warm and cold air, but I wanted to use one or two small computer CPU fan motors that could be run all night with negligible power drain.

What I decided would work more easily was to use two such fans and a tube system to pump the coldest air in the cabin from the main floor area up through the galley cabinet and onto the hot surface of the heater and become heated. As the fans progressively remove the cold air from the floor, the warm air that collects at the ceiling level gradually grows in volume, and soon the bottom boundary (a thermocline) of that warm air descends to the floor as all the air becomes heated. In this way, we're not using the fan power as a forced air furnace delivery system, but instead using it to eliminate the cold air at the bottom of the heated chamber and letting the warmed air distribute itself naturally. In the process, cold dense air in the v-berth flows outward to the cabin floor naturally and is replaced by warm air entering from the main cabin area.

It does, of course, take power to lift the cold air up to the hot surface of the heater, but not as much as to have a complete system of forced circulation. I hope this makes sense and is not overly wordy, but wanted to convey the idea thoroughly. In practice it works very well, and I seldom use the 3,000 / 6,000 btu heater on anything other than the lower setting. I also suspect that the heater used with the fan system is able to extract a considerably larger percentage of the heat produced by the flame and is therefore much more efficient.

The two fans are 0.17 amps each, and used over a 10 hour period only use 3.4 amp hours of current, which has negligible affect on two 105 amp hour deep cycle batteries.

If necessary, one could also boost the warm air flow into the v-berth area with a tube and small similar fan system, pushing warm air from the main cabin through a tubed passageway through the cabin bulkhead to assist the heat flow into this area. Another small fan would have little additional affect on electrical current consumption. A bigger problem would be where and how to route the tube, as the helm/dash/bulkhead is pretty busy already and esthetic considerations would also be important.

Hope this helps your thinking regarding installing a complete heating system. Photos of my heater installations are in the Library under Cabin Interior Photos with test explanations. Nice visiting with you. Joe.

[MOOSE]

Coincidentally, I too have been thinking recently about how to warm up the V-berth. One thing we did as soon as we bought the MOOSE was to put a Thermarest® foam pad on each side, partly for warmth and partly to cushion the old bones. They work great and are a quick fix to add extra insulation.

The other thing that we’ve just concluded is worth doing is to buy a permanently wired and mounted, fold-down 12-V fan, Guest model 902, I think. I don’t know that WM sells that model but I found it at www.Go2Marine.com ; it’s their part no. 27094. It’s about six inches square by two inches thick and folds flat when not in use. My idea is to mount it to the underside of the companionway into the V-berth and flip it down when needed. Return air would simply flow back into the cabin around the gaps between the bulkhead and the hull.

Al

[Sea Wolf]

Al-

I like the idea of having the fan fold down for use and up out of the way for storage. It would certainly provide enough air to bring the v-berth to the same temperature as the rest of the cabin. Sounds like it's basically a cooling fan to me.

You might ask the manufacturer if it can be equipped with a variable resistor in line to dial the voltage/motor speed/air supplied down in case it provideds so much air the effect is one of "cooling" because of the velocity of the air movement. It might also be advisable to be able to limit the power consumption, since the specifications on the go2marine listing say it's power consumption is just under 8 amps.

Let us know how it works out! Joe.

[MOOSE]

Once again your suggestion is a good one, Joe. I wouldn't have thought of a rheostat, but it certainly might be nice to dial the fan speed down for heating and then back up on a muggy night.
Al