Insulate for ceiling drips?

[Wavewacker]

I bother people on other boating sites too, but have reserved this question for you guys!

How do you, if at all, insulate a wood cabin on your boat? Maybe a better question, since most are not insulated, do you need to in a cabin about 600 cubic feet?

Is there a condensation issue running a heater in zero degree weather or where the tempature and dew point are close to the same? (foggy)

I can see insulating an aluminum boat, a glass boat, and I realize that wood has some insulating qualities, but is not that great. But say you were not so concerned with efficiency of heating a small space as you are taking a shower from the ceiling.

Should you insulate or not and why? Thanks...

[Brian Palmer]

If you ventilate the cabin well enough to remove the moisture from people breathing in the cabin and cooking, etc., then you will not have a condensation problem.

[Wavewacker]

Yes, kinda like driving down the road with the window open keeping the temp outside about the same as the inside,that works.

The problem exists when the air movement does not replace the humid air fast enough which allows you to retain heated air. You could also plug in a dehumidifier and suck up the batteries or fuel the gen set.

I was wondering if a computer fan would help in that much space....would you want to run it 24/7 in winter weather? Seems the best way is to inulate it keeping the moist heated air from being in contact with a colder surface....

Those with wooden boats and sizable cabins, is your cabin insulated or is it not that much of an issue?

[wizbang 13]

A heater with a chimney(wood,coal,charcoal,diese,promisect,will take the waterville,up said chimney.It is,in a way ,self ventilating.
Non vented heaters make lots of "water"
Water vapor. Not Waterville,dam apple thingy

[Ian McColgin]

In my thirty years of living aboard one boat that had an insulated overhead and three that did not, I've not had a problem with condensation. I have used electric, coal and oil heat. The combustion systems are probably best since they draw air in and have a stack to carry off not just the CO and smoke but also the vapor that are byproducts of combustion.

It also helps to have a winter cover so that you don't have such extreme thermal difference between the air in the boat and the inside surface of the hull and overhead.

I've been on glass boats where condensation was a huge problem, but not wood.

G'luck

[skipper68]

Ours was insulated, with the perforated white headliner from the factory. Being up north, the condensation was being caught in the underside of it. It started to mildew. We removed it and put in heavier insulation, and mahogany luan to cover it. The boat was under cover, and it happened with electric heat and Kero heat. No problem since. In the Bow cabin, just body heat and breathing can cause it. Ours is insulated as well. Bomar makes a hatch with a solar fan built in, to keep air circulating, if that info will help.

[Wavewacker]

Thanks Ian, that's kinda what I was getting at, my glass boat dripped like a watermaker (hmmm, is that a survival technique..LOL) and I have been in wood campers that didn't have the problem.

I was hoping to use a propane heater vented out the back. I see your point of the chemeny.

I was thinking of using 3/8 ply on the cabin with 1" foam insulation board and 1/4" insde. Or, 1 by lumber.
There is also that cedar lining for closets that smells nice (with a light sanding ever so often), T&G, but would not cover the entire interior. Seems cedar would be good for some critters too.

Wondered if such woods would keep well.

Might as well ask while I'm here, I have some 15# felt for a roof, the stuff use to be used for walls in construction before vapor wrap. Since there are two layers for the cabin, inner and outer skins, would felt be OK to keep vapor transfer down and minimize temp. transfers? If glued in, I can see it as a water proof membrane as well.....is this done?

[Lew Barrett]

Propane is the absolute last choice for heat in your circumstances.

[Wavewacker]

Hey, thanks wizbang and skipper, I didn't even see your post when I posted...

Lew, why is propane the last choice? I will have an OB on gas, no diesel on board. I think a drip diesel would be good, but don't need two fuel tanks.

Wood and coal, very messy and dirty, but a fireplace would be nice, and room is at a premium.

I had a gasoline heater years ago in a VW bug, it went boom and was a good thing I was not in the car.

The heater I'm thinking of would be mounted on the aft cabin wall with the tank outside with about 2' of line to it.

What else would there be?

[Soundbounder]

There is a product called Armaflex which is a black rubbery material used in commercial insulation on ductwork where sweating is an issue. It is available in sheets of various thickness.

It's pricey, and you aren't going to find it at Home Depot or West Marine, but if you know anyone in the commercial construction trades, they might be able to get you some leftover scraps. It works very well.


Edit: what is that icon 1678 thingy?

[Mad Scientist]

Your icon thingy is up to 2137 now. Strange...

Tom

[skipper68]

It said:http://whos.amung.us/widget/acpggfze6cku.pnh Here's a link http://www.bing.com/search?q=http%3A...=0-0&sp=-1&sk=

[Lew Barrett]

WW:
Propane releases water when it burns. A catalytic heater of the type I'm thinking of will claim to push all the combustion products up the chimney but in practice that is much harder to accomplish with a fuel that releases water all by itself in the very act of burning.

We lived with a propane range on board for many years and while they are by far the funnest and most familiar appliances to cook with, they always release water to the boat. Making coffee on any but a nice morning was always a very.....steamy affair. It's the day to day weakness of that approach to fueling.


Nature of the beast.

[Soundman67]

I have been looking into what is going to be the best method of insulating a wooden boat cabin. and above the waterline I cant find anything that is going to work as well as a properly applied spray foam insulation. I should give the best thermal break and it will create its own vapour barrier on the inside surface of the foam. My walls and cabin roof are 1.5" thick and I am going to put in 1" of foam. unless I can find a diy kit to fill the void after both sides of the wall have been sheathed. then I want to have a full void and no airspace. Also if you can set up a fan to pull cold air off the floor or from the bilge and out of the boat and let fresh air come in from the various air leaks will help to keep the air dry . In winter here in Vancouver I run a dehumidifier too so that the humidity doesnt get too high during all that rain.

[wizbang 13]

I used simple 1 inch white styrofoam, but I made a one inch airspace between the foam and the deck with broken pieces of the same foam.After 15years and a lot changes of latitude,I easily pulled it down and showed my PNWBOAT friends what a cochroach egg peerolked like,cuz there were a thousand of them up there

[Wavewacker]

I'm somewhat familiar with armaflex and hear it works, I think there is a spray on type....I'm retired from the real estate arena. I also thought of using PDM roofing, a rubber roofing material, but it is heavy, but in a hull, I doub't you'd ever get holed as it would give and stretch some and would be water tight.

Ahh, the right fuel question....? I think I will be stuck with propane,

I would think trying to get spay foam to completely fill gaps would be hard to do,, you can spray it on and shave it to contour to fit the wall/ceiling cover, but there would be gaps. Spraying inside a wall is tricky as it expands and can push the wall covering out if there is too much, it can crack/break a 2x4 stud in a wall that has a lumber wall, as in older houses! Wiring in walls can also be a problem. But it sure is good stuff!

And, maybe I'm thinking I should go thicker for the cabin roof too, after hearing what you guys have.

[Lew Barrett]

Is the furnace already on the boat? If not, a small day tank will work just fine with any of the Diesel heaters on the market, the smallest of which are an easy match against say, a propane bulkhead mounted job.

. I know a lot of people who have pulled propane heaters off of boats and replaced them with something else. Mind, I really like cooking with gas and carried it without concern but that's another story. I do understand that these things have a way of defining themselves that sometimes requires compromise.

[Wavewacker]

Did I fail to mention the boat ain't built yet? I need to make up my mind what goes where.....

Maybe I should consider room for alternatives....hmmmm!

I'm sure cooking will be propane, makes sence tome to carry more propane, but I guess that could change in the future

[willmarsh3]

Have you looked at a heater that circulates off the diesel engine coolant? That would be completely dry heat with none of the risks of CO poisoning.

[Canoeyawl]

Cutting a simple bead on the bottom of the deck beams and the bottom edge of the carlin will "funnel" the condensation drips to the bilge.
(Old School)

exhibit A

[wizbang 13]

Cutting a simple bead on the bottom of the deck beams and the bottom edge of the carlin will "funnel" the condensation drips to the bilge.
(Old School)

exhibit A

gonna funnel those drips right onto your pillow

[Soundman67]

just revisiting this thread. I ended up going with a little bit of tech to solve the condensation problem. my roof is framed with 2x6 and cut to give a curved deck above. I put in 2" of closed cell foam and left a gap above. The underside of the frames are sheathed with 1/2" MDO. At the very top of the curved roof; or in the center of the deck I drilled a series of 3/4" holes through the frames to allow air to travel and then at one end I put in a small fan to exhaust the air out of that space to the outdoors. At the other end there is a small vent to allow air in. So far it seems to work.

[chas]

"but I guess that could change in the future"

I would make that change. You will want dry heat on your boat, when it's "in zero degree weather or where the tempature and dew point are close to the same? (foggy)". I'd design it in somewhere. / Jim

[Phil Y]

just revisiting this thread. I ended up going with a little bit of tech to solve the condensation problem. my roof is framed with 2x6 and cut to give a curved deck above. I put in 2" of closed cell foam and left a gap above. The underside of the frames are sheathed with 1/2" MDO. At the very top of the curved roof; or in the center of the deck I drilled a series of 3/4" holes through the frames to allow air to travel and then at one end I put in a small fan to exhaust the air out of that space to the outdoors. At the other end there is a small vent to allow air in. So far it seems to work.

Sounds like progress. We need pictures, its a forum rule. personally i suspect that insulation in cavities just creates little places whwere moisture will gather and rot will thrive, but it sounds like you have given attention to active ventilation. I certailnly have seen non-vented propane heaters work as great watermakers. I also just don't like the idea of a propane heater exhausting into such a small and enclosed space as the inside of a boat-you could easily wake up dead one morning. I want to put a drip diesel heater in my boat, with a chimney/flue to the outside-and will one day.