Alcohol Heater

[Tedd]

I have a Mac 26S that I occasionally use for overnight trips. Now that we're getting into cooler weather (I'm in the south of British Columbia), I've been thinking about getting an alcohol heater, such as this one from West Marine. I already have a propane camp stove on board, for cooking. I'm wondering if the alcohol heater is a significant advantage over the propane stove, for warming up the interior on cold mornings? What experience do other people have with these?

Both are reputed to only produce CO2 and water vapour (when properly operated). And, yes, I do have a CO monitor in the cabin.

 

[dlochner]

The alcohol is probably an advantage in the safety area. Propane is heavier than air and will slowly fill the boat from the bottom up. I think alcohol will create more vapor and condensation.

 

[LeslieTroyer]

I wouldn’t have alcohol on board (other than medicinal that is half water) It burns invisible. Propane may be heavy but there are alarms that detect its presence before its explosive. Get alcohol on you and lit it’s hard to put out and almost guaranteed to be second if not third degree burns.

 

[Rick D]

Leslie has a good point, but I have one of these aboard and have had it for over 15 years. I have also used it as a back up stove when I had a bad tank of CNG. It puts out quite a bit of heat. I do not run it all night and keep a port cracked when using it. I have used it in the cockpit when having a bunch of people over on a cool night. I totally endorse it. BTW, it nests, so it is only half as large to store.

 

[Captain Larry-DH]

I have a Coleman Black Cat catalytic propane heater. Works well. Coleman doesn’t make them anymore but search (for propane catalytic heater) online and you can find other brands.

 

[Tedd]

Captain Larry:

Great idea! Catalytic heaters make even less CO than alcohol, I think. If I can find one that works with the same propane fittings as my stove that would be a really simple solution.

 

[Tally Ho]

I have used the Coleman Catalytic heater in tents and on my boat. Worked well.

Greg

 

[LeslieTroyer]

The real problem is when they run out of fuel. You can’t refill them because they are hot, but your tired and cold so you do it anyway. You become the human torch.

 

[thinwater]

a. Propane and ethanol create similar ratios of heat to water vapor. High school chemistry, count the moles.
b. Propane detectors alert to any flammable gas. That is what they are based on.
c. Any unvented heater produces and unhealthy level of carbon dioxide in less than an hour in a small, ventilated space. OSHA limits CO2 to 5000 ppm, but 1500 ppm is consider the limit for investigation in homes.
d. Refilling is not really a problem, for me. I don't turn the heater on until dark, at which time I fill the tank. It will last until 10-11, at which time I turn in and crawl into a thick sleeping bag. I would not leave ANY simple heater running at night. But NEVER refill a hot stove. I also prefer to remove the can and put it on a lipped tray on the counter to refill; in that way I can see what I am doing and spills are contained. Easy.

Really, the most you should run an un-vented heater is cooking a meal, and not a really long one. Carbon monoxide is NOT the only hazard. Oxygen depletion is another issue. Mostly, you may just feel muddled an loggy.

Unfortunately, there is no such things as a simple vented heater on the market. I've designed a simple vented stove top heater that can be put together for lunch money in an hour. It will be in a magazine, but it's not hard to figure out; just look at the Sig Cozy Cabin and see how little there is to it, other than the burner. No fan, no thermostat, no sealed air intake, just a can and a vent. The key is that the exhaust must go outside.Every portable heater has a warning about leaving a window cracked, but there goes your heat, and how much do you crack it? Makes no sense unless you live in a barn.

[I had a fancy sealed heater on my cruising cat. Very nice for the 4-season cruising I was doing. But my F-24 suggested something much simpler.]

 

[Captain Larry-DH]

a. Propane and ethanol create similar ratios of heat to water vapor. High school chemistry, count the moles.
b. Propane detectors alert to any flammable gas. That is what they are based on.
c. Any unvented heater produces and unhealthy level of carbon dioxide in less than an hour in a small, ventilated space. OSHA limits CO2 to 5000 ppm, but 1500 ppm is consider the limit for investigation in homes.

Really, the most you should run an un-vented heater is cooking a meal, and not a really long one. Carbon monoxide is NOT the only hazard. Oxygen depletion is another issue. Mostly, you may just feel muddled an loggy.

Unfortunatly, there is no such things as a simple vented heater on the market. I've designed a simple vented stove top heater that can be put together for lunch money in an hour. It will be in a magazine, but it's not hard to figure out; just look at the Sig Cozy Cabin and see how little there is to it, other than the burner. No fan, no thermostat, no sealed air intake, just a can and a vent. The key is that the exhaust must go outside.Every portable heater has a warning about leaving a window cracked, but there goes your heat, and how much do you crack it? Makes no sense unless you live in a barn.

I think you are fairly safe if you crack the hatch and choose a catalytic heater that has low oxygen shut down protection. I would also recommend adding a CO detector and a propane detector. Also, it should be noted that the green 1-lb disposable propane cans tend to leak after being removed from use, so partially depleted cans should be stored outside or in a locker that's vented overboard.

Schedule 40 PVC pipe with PVC end caps make a good stantion-attached storage container, with a 1/8" vent hole drilled in the bottom fitting. Add a 1/2" x 1/8" aluminum flat bar (bent into an "L" at the bottom and top ends) to enable easy top access to the propane cans, just slide them up by lifting the bar from the top.)

PS - I still wouldn't use one when the crew goes to sleep. Heavy blankets and sweatpants are a lot safer than portable heaters.

 

[Terry Cox]

I have a Mac 26S that I occasionally use for overnight trips. Now that we're getting into cooler weather (I'm in the south of British Columbia),

Hi Tedd, we had a Wallas forced air kerosene furnace on our H28 that was a wonder at keeping the boat warm during those cooler nights. No worries about venting, fumes, etc. Very efficient and uses very little fuel and electricity. I highly recommend this unit for your boat. Well worth the money. There are other dealers that sell this unit besides Scan Marine. https://www.scanmarineusa.com/wp-content/uploads/1300-2018-s.pdf

 

[Bob J.]

I'd consider a propane Buddy heater. Got one on my boat, takes the chill out & doesn't introduce a lot of water vapor like an open flame. I wouldn't sleep with it on.

Although it claims to have a low oxygen sensor, reality is it's only a thermocoupling so I woudn't gamble my life on it.

 

[thinwater]

... propane Buddy heater. Got one on my boat, takes the chill out & doesn't introduce a lot of water vapor like an open flame. I

It generates exactly the same amount of water vapor as an open flame, to the microgram. This is fundamental chemistry, not design.

"Although it claims to have a low oxygen sensor, reality is it's only a thermocoupling so I woudn't gamble my life on it."

Exactly. This is not well understood. It only triggers when the flame starts to expand due to very serious lack of oxygen.

 

[Bob J.]

It generates exactly the same amount of water vapor as an open flame, to the microgram. This is fundamental chemistry, not design.

I respectfully disagree based upon my experience. I fire up the propane stove for cooking in the evening & the moisture in the cabin is very noticeable. That's not the case when I fire up the heater.

 

[jssailem]

I wouldn’t have alcohol on board (other than medicinal that is half water)

 

[thinwater]

I respectfully disagree based upon my experience. I fire up the propane stove for cooking in the evening & the moisture in the cabin is very noticeable. That's not the case when I fire up the heater.

Opinion plays no part in this, only the math and the chemistry. Any flame emits water vapor in proportion to the amount of hydrogen in the fuel. If they are the same fuel, there can be no measurable difference, unless you have specific chemistry to suggest.

Cooking includes pots with water in them. Evaporation from the pots is greater than that emitted by the flame. Additionally, this evaporation is additive (in addition to combustion products) and could be just the difference between being above or below the dew point. Cooking will always steam the place up.