Adapting your gas cooker into a heater?

I am no expert on cabin heating. However I liked the device in the link.
Small computer type fans are cheap low current and available in all different sizes. So you need a vent tube about 50 mm in diameter with a suitable sized fan in the top (cool) end of it to suck out the CO etc.
This needs to collect air from immediately above the flame which is hot.
You need to transfer the heat from the hot exhaust gas to the cabin.

An Aluminium or copper tube that ran about 2 metres horizontally from above the stove to a hole in the rear cabin bulkhead would transfer this heat to the cabin area around the tube. Pity it will be at ceiling height but surely it will still be usefull.
If you cut slots in copper and fitted (soldered) fins through the hot air stream and protruding out into the cabin air then more heat would be transfered.
The device in the link seems to have a heat exchanger from the exhaust gases out into a box above the flame from whence I imagine a tiny fan will move air through the heat exchanger into the cabin. This would facilitate a vertical flue to immediately above the cooker while still extracting the heat from the exhaust gas.

If you had a suitable concertina or telescopic tube for the exhaust it could be raised up for cooking to the ceiling where it could function as an exhaust fan.

Sorry all this comes from thinking about the problem. Me I don't even have the cooker on the boat and certainly don't need heating. So I won't be trying it.
olewill
 
fill a tray with volcanic rock and whilst useing cooker put on bottom tray or steel pan on ring heat turn off go to bed, will give off heat for about an hour, This method was described in PBO many years ago. Or leave a candle butning in the oven with door open this will keep a faily large space above freezing (Old lorry drivers trick)
 
Cooking up a curry will provide additional subtle cues for the need for a bit of ventilation! It's the tootsies that are the problem in a boat - heat rises and it's hard to get ventilation without selectively dumping all the lovely heat that's making your head too hot!!
 
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Yes, my thought too. If the cooker hasn't poisoned you with CO, why should the cooker plus a brick or a flowerpot, unless you sealed every opening perfectly and ran the cooker for hours? There are so many examples of things that people have been doing for centuries suddenly becoming hazardous. Not that I am suggesting that some commonsense is not required, of course. The one safety rule we have always had is that we would never leave any form of flame heating on all night - a good sleeping bag nowadays is so cheap that it just isn't worth the risk.


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Yes people have been heating themselves in such ways for a long time, but equally some who have not followed sensible rules have killed themselves. The ammounts of CO required to give you CO poisoning are relatively small so you don't have to make that much to put yourself at risk. There have been cases of people sunbathing on the decks of boats who have been poisened by the CO from the exhaust of boats beside them charging batteries etc on very still days.

I have happily used gas heaters in boats before and would do so again, but you need to ensure good ventilation, one of the key problems being good ventialation wastes some of that valuable heat you have made, so people have a tendency to restrict the ventialtion leading to disastrous consequences
 
Way back, I worked briefly for a crop-dusting outfit. Up by Lockerbie we were doing some forestry work, the strip up a hill at Eskdailmuir (sp?) It was really brassmonkeys and when it was too claggy to fly we waited in a caravan. The Finnish pilots subscribed to the brick on the flame heating idea,but when the gas (butane) stopped because of the cold, one would go out, drain a cup of avgas, chuck it on the ground, light it and put the bottle on the fire. It lasted about an hour, then repeat. I said something about it, they replied that " It´s OK as long as there isn´t a leak"
Of course the CO was not a prob as the door was opened frequently and we were all well awake. These guys were excellent company BTW.
Andrew
 
The great terracotta pot debate

I live on a Hartley Ferro ketch on Lake Macquarie Australia. It is currently our winter and where my previous yacht was lined with a type of carpet inside and stayed relatively snug the floating footpath is cold. I have done a lot of research on cheap ways to heat my main cabin. Finally I found that the best system is 3 unglazed terracotta pots. 8" 6" 4" Each sits inside the other with a 6" bolt holding each pot apart with nuts and washers. Turn the whole lot upside down and set on secure legs then a small tea candle is lit underneath. The metal takes up the heat from the candle and disipates it to the pots which radiate a cosy heat. Enough candles for winter (use one every two nights) costs about $10 and the pots were around $25 with the bolt etc. I will never go to bed and leave a naked flame! Incidently the temperature here gets to around 5 deg centigrade and the cabin warms to around 18 deg centigrade with just a candle. I just add some soxs and a wooly jumper.
 
Both propane and butane when burned produce water and carbon dioxide (CO2). If there is a shortage of oxygen (O2) they can also produce carbon monoxide (CO)…..but you'd probably be worried by the shortage of oxygen before CO is produced by a stove.

CO is lighter than air and CO2 is heavier than air.

CO binds to the O2 carrying molecule in blood (haemoglobin) preferentially so no O2 gets your brain. Carbon dioxide will displace air in an enclosed space from the bottom up thus depriving you of O2 to breathe.

Both situations can kill you and there are many cases where Darwin prevailed. Essentially one should not burn an open flame in an enclosed space without adequate ventilation.
 
The trouble with using the cooker to heat a boat is the condensation.
You wake up next morning to a colder, damper boat.
You will need a washboard out for ventilation.
Even so, your boat will become a mouldy, smelly boat.

Also gas is expensive in bottled form.

Have a good sleeping bag to go back to and go to the pub.
Or get an Eberbasto.

The engine is a better way of warming the boat if you have no smelly fuel or oil leaks, but diesels don't produce much heat at idle. Arrive late with a hot engine!

Statistics always lie, but I would be more scared of CO than gas explosions personally.
 
Smut

Relax said:
Anybody have experience of using a paraffin lamp in the cabin?

Was thinking of getting one for this reason - if I have the stove on for even a few minutes to make tea the heat builds astonishingly - so I wondered if a hurricane lamp would be enough to keep snug?
Click to expand...

I fell asleep then the lamp decided to start making smut. By the morning the entire upper 18" of the boat was black and I was coughing up black stuff for days...
 
lw395 said:
You were lucky!
Click to expand...

We have used an unvented parrafin heater for three years now, a Corona turbo. It is quite large, but fits under our stowed table when not in use. We have a good quality co alarm and the heater has a built in shutdown that measures low oxygen levels. During cold winter evenings when its on for five hours, the co alarm stays quiet and it does not shut down. Despite this, there is no way we would use it when asleep. Our boat is very well ventilated and we are aware of the symptoms of the deadly menace of co poisoning. The first one up on a cold morning puts it on and within half an hour its toasty. Corona, heaters are worth a look, as long as you use sensible precautions.
 
It's only really to snug the boat down, I cannot see that there is much difference between cooking a tinned FB pie for 30 minutes in the oven and cooking a fire brick for 30 minutes. Of course you could do both, a fire brick on the top shelf and a pie on the bottom. Fire brick will keep the heat for a long time. I used to have one of the bricks out of a night storage heater, for just such a purpose. It does tend to bend the shelves though, but you could bolt it to a more substantial piece of steel.
 
I'd have thought we'd be sensible enough to know not to leave unventilated gas burners running and go to sleep or something, and not all gas cookers have flame failure devices either. How about an Origo Heatpal or Contoure Heatmate 5200, meths heater/cookers £150 or so. Also a reserve cooker if you do run out of gas. Same applies about ventilating and producing moisture though...
 
portvasgo said:
A long time ago I dimly remember reading an article about someone who placed an inverted clay plant pot over the flame of their gas cooker to heat the cabin. The idea is that the terracotta heated up and then radiated out heat. I have also seen proprietary sold adaptors (metal towers that sit on top of a Coleman stove) that are based on the same theory. I was wondering if there was some way of doing something similar on my Plastimo stove. I don’t want much heat, I would rather wrap myself in a sleeping bag if it came to it, and I am aware of the condensation problems etc. But I was wondering if there was such an adaptation that anyone knew about that would take the chill off the cabin from time to time. I am trying to find out whether the metal towers that fit the Coleman stove will fit others, but I am doubtful.
The thought occurred to me to perhaps use some of the heating bricks that you get in electric storage heaters, I actually have some of those in the shed. My worry, which was my first thought when reading the article on using a terracotta flower pot, was the risk of the thing exploding! The blocks from storage heaters, are of course high density and designed to be heated up, but would they be ok when heated on a naked gas flame?
Any thoughts or ideas would be most welcome.
Click to expand...

I tried out the plant pot on an absolutely minimal gas flame at home - it exploded - well broke in pieces!
 
mawm said:
Both propane and butane when burned produce water and carbon dioxide (CO2). If there is a shortage of oxygen (O2) they can also produce carbon monoxide (CO)…..but you'd probably be worried by the shortage of oxygen before CO is produced by a stove.

CO is lighter than air and CO2 is heavier than air.

CO binds to the O2 carrying molecule in blood (haemoglobin) preferentially so no O2 gets your brain. Carbon dioxide will displace air in an enclosed space from the bottom up thus depriving you of O2 to breathe.

Both situations can kill you and there are many cases where Darwin prevailed. Essentially one should not burn an open flame in an enclosed space without adequate ventilation.
Click to expand...

It isn't just shortage of oxygen that causes CO emissions; in fact this is an unlikely cause as you point out.

The problem with putting things over the flame is that potentially they cool the flame so that incomplete combustion results. The chemistry of a flame (A-level!) is rather more complex than simply

CnH2n+1 + 1.5nO2 -> nCO2 + nH2O (not quite right, but near enough; I can't be bothered to make the stoichiometry exactly right!)

There are parts of the flame where it is more like:

CnH2n+1 + nO2 -> nCO + nH2O

The CO then oxidizes in another part of the flame.

It is actually even more complex; there may be parts of the flame where CO2 is reduced to CO, and then the CO oxidizes back to CO2.

So, if you cool the flame prematurely, you can get CO rather than CO2.

This is a known problem for people melting snow for drinking water over paraffin stoves; because the mixing of air and gas occurs before burning it is much less of a problem for gas, but is still a potential hazard.
 
djbreeze said:
I'd have thought we'd be sensible enough to know not to leave unventilated gas burners running and go to sleep or something, a.........
Click to expand...

The problem is carbon mon dulls your 'sensible' sensibility without you noticing.
You fall asleep without intending to and do not wake up.

It is popular for suicide for a reason.
The safe level of carbon monoxide is very small, 9 parts per million for 8 hours.
 
Gas???

I don't know if you read my post through? I didn't say I used gas I use candles. Yes they eat away oxygen too but I do remain ventilated in my cabin. I only expect my little heater to lift the temperature by a few degrees to take the chill (read cold) off the air.
If I do decide to use gas it would be so little that the cost would be negligible compared to being alongside a dock and paying their fees for electricity use. If my stove or oven were in use cooking dinner for a few hours I might kill myself with fumes as well, if I didn't ventilate.
We all should be aware of the danger and yes we should all take care. I thought I made that clear in my post?
Never mind, thank you for reading and responding just the same.:)
 
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