Recommend me best heating method

[GHA]

There's really no better solution than a blown air eber type heater and, though some of the drip feed and solid fuel stoves are very effective and attractive, they can't be used while underway.

Reflex works underway.
Far better solution imho than blown air to liveaboard away from mains power. No amps needed, mine would stay on for weeks on end in a northern winter. No noise either. Toasty dry cabin with a pot of stew on the reflecks

 

[JumbleDuck]

Plenty of previous threads on this topic but I must say our charcoal hampshire heater , which I fitted 2 seasons ago for w coast scotland has been one of the best jobs we've ever done on our 29' er. Carry easy to pop in charcoal parcels , a little piece of fire lighter in flue first (like a cardboard eco type) , just brilliant. Look for previous postings for other charcoal success stories. Dont think hampshire heaters still operating but its very unfair not to mention our positive experience.

Is yours a Hampshire Heater too, then? Mine is absolutely lovely when it gets going, and I like the way I can adjust the heat from "firebox glowing red" to "gentle warmth" with the air control. It's just lighting the thing which is a pain. Here's what I have tried:

• The official instructions (half fill with charcoal, pour meths on wick). Never worked for me because I could never get the wick to absorb more than a tiny quantity of meths and it went out after ten to fifteen seconds.
  
  
• Barbecue lighter block impaled on a match and stuck onto the top of the wick. Works about one time in three.
  
  
• Variant: squirt some barbecue lighter fluid on the charcoal, then as above. Worked once, exploded once. Method shelved.
  
  
• Barbecue lighter blocks laid on the grate and lit from below with a gas match. Works about one time in two.

All using nice big bits of lumpwood charcoal, so as not to block air flow. The good news is that the effort of digging out warm but stubbornly non-inflamed charcoal keeps me warm, but as I plan to leave the boat in this winter a recipe for reliable lighting would be very welcome. Do you give it a full charge of charcoal at the start or light just a bit and then add more?

 

[srm]

What source of heat were you using, and where do you think the water was coming from (including, of course, humans/wet clothing)?

Since my first boat l always used heaters with a flue: Taylor pressurised paraffin on a 29ft; Taylor diesel drip feed superceded by Wallas paraffin heat exchanger heater on my 42ftsteel boat; Wallas again on 32 ft catamaran and 35 ft mono. I also fitted internal insulation above the bilges, carpet glued to the hull inside lockers was sufficient.
Moisture comes from humans, cooking, and recirculating the external atmosphere. Heating air drys it, then cooling causes the moisture to condense out again. If the external atmosphere is very cold it will be dry to start with so heating and cooling that will not produce much condensation. However, North Atlantic coastal atmosphere tends to have a high humidity wherever you are so plenty of potential for condensation.
If the sea temperature or external air temperature is below the internal air's dew point you will get condensation on un-insulated hull structures. Dew point is a function of the air temperature and its moisture content. Its basic physics.

Regarding Reflex heaters, when I was in Shetland in the 70's and 80's they were standard fit on all the inshore fishing boats I came across, running all the time in the cabin, often with the tea pot on top. If I had a boat with the space I would fit one for northern waters.

 

[BabaYaga]

Refleks suggests up to 10° of lean. That might be a plus for a pumped system for some.

I'm a bit surprised by that figure, a 10 degree heel is not much. I'm sure mine works well at far greater heel.
Also surprised by the instructions regarding the installation with respect to orientation. As I read it, they would place the regulator athwartships to the burner pot. That is contradictory, by 90 degrees, to the advice I had from my manufacturer.
(I don't think a pumped system would make much difference, this is not about how the fuel reaches the regulator but how it flows between regulator and burner).

 

[JumbleDuck]

Moisture comes from humans, cooking, and recirculating the external atmosphere. Heating air drys it, then cooling causes the moisture to condense out again. If the external atmosphere is very cold it will be dry to start with so heating and cooling that will not produce much condensation. However, North Atlantic coastal atmosphere tends to have a high humidity wherever you are so plenty of potential for condensation.
If the sea temperature or external air temperature is below the internal air's dew point you will get condensation on un-insulated hull structures. Dew point is a function of the air temperature and its moisture content. Its basic physics.

Three minor quibbles. First, heating air doesn't dry it. It reduces the relative humidity because warm air can carry more water than cold air, but any water in it doesn't go away. Second, cooling heated air can only cause moisture in it to condense if you cool it below its original temperature. If the water didn't condense out on a surface before the air was heated it won't condense out afterwards either. Third, dew point depends only on the moisture content of the air - technically it's the saturation temperature corresponding to a saturation pressure equal to the partial pressure of the water vapour.

Can you tell that I am an academic ("Nitpickers 'R' Us") currently proofreading material on atmospheric fluids?

 

[srm]

Can you tell that I am an academic ("Nitpickers 'R' Us") currently proofreading material on atmospheric fluids?

I was trying to avoid a lecture on absolute and relative humidity and concentrate on the practical effects of living on and heating a sailing boat in cold climates. In these situations it is a fairly safe assumption that humidity will be added to atmospheric levels inside the boat.
My background is lecturer in Maritime Studies, part of which involved teaching met to MN deck officer candidates. I did start to mention 'ship sweat' in cargo holds, but thought better of that and deleted it. There are always problems in trying to simplify a complex subject and we are both capable of coming up with exceptions and variations.

 

[Scomber]

Is yours a Hampshire Heater too, then? Mine is absolutely lovely when it gets going, and I like the way I can adjust the heat from "firebox glowing red" to "gentle warmth" with the air control. It's just lighting the thing which is a pain. Here's what I have tried:

• The official instructions (half fill with charcoal, pour meths on wick). Never worked for me because I could never get the wick to absorb more than a tiny quantity of meths and it went out after ten to fifteen seconds.
  
  
• Barbecue lighter block impaled on a match and stuck onto the top of the wick. Works about one time in three.
  
  
• Variant: squirt some barbecue lighter fluid on the charcoal, then as above. Worked once, exploded once. Method shelved.
  
  
• Barbecue lighter blocks laid on the grate and lit from below with a gas match. Works about one time in two.

All using nice big bits of lumpwood charcoal, so as not to block air flow. The good news is that the effort of digging out warm but stubbornly non-inflamed charcoal keeps me warm, but as I plan to leave the boat in this winter a recipe for reliable lighting would be very welcome. Do you give it a full charge of charcoal at the start or light just a bit and then add more?

Yep its hampshire,,
1, small wafer of bbq starter , eco stuff from factory shop , in flue , use a match
2, maybe couple handfuls charcoal placed in stove
3, fill burner with meths , now and again loosen wick so meths soaks in easily
4, by then Ive checked flue is warm
5, attach burner with open airflow , leave maybe 5 mins till lid hottish
6, sharpish ,, lift lid and pop in a premade sealed parcel of lumpwood , (paper bag filled with correct dia full of charcoal, part of a tree shelter as a filler works for us)
7, maybe vent open a few more mins , see flame flickering on burner and by then lid real hot
8, shut down air control ,,, depending on wind strength ,,,can get up to 7 hrs or so,
for longer , while still hot pop another parcel in sharpish after say 4-5 hrs
Strong leather gloves essential. We buy huge bags of catering charcoal and make up parcels at home , although on long trips easy to buy more. Got a wry smile in plockton 2 yrs ago , buying charcoal,,, it was absolutely pi**ing it down!!!
The benefits of that cosy quiet cabin , far outweigh a small amount of methodical effort.
On a more general pt ,, the flue size is very tidy ,,about an inch and a quarter, I think.

 

[Plum]

There's really no better solution than a blown air eber type heater and, though some of the drip feed and solid fuel stoves are very effective and attractive, they can't be used while underway.

Why do yo say diesel drip feed stoves can't be used underway? Mine (a Taylors) works perfectly well underway.

www.solocoastalsailing.co.uk

 

[JumbleDuck]

I was trying to avoid a lecture on absolute and relative humidity and concentrate on the practical effects of living on and heating a sailing boat in cold climates. In these situations it is a fairly safe assumption that humidity will be added to atmospheric levels inside the boat.
My background is lecturer in Maritime Studies, part of which involved teaching met to MN deck officer candidates. I did start to mention 'ship sweat' in cargo holds, but thought better of that and deleted it. There are always problems in trying to simplify a complex subject and we are both capable of coming up with exceptions and variations.

Fair enough. My main point was that heating the air doesn't increase the condensation when it cools - though from personal observation I think it may generate draughts which move air into cold places it wouldn't normally get to.

On my last boat I used a Tilley lamp for light and heat in winter. Boy, does that teach you about condensation ...

 

[JumbleDuck]

Yep its hampshire,,
1, small wafer of bbq starter , eco stuff from factory shop , in flue , use a match
2, maybe couple handfuls charcoal placed in stove
3, fill burner with meths , now and again loosen wick so meths soaks in easily
4, by then Ive checked flue is warm

Ah, right, so you're using the bbq starter in the flue to suck air though. Neat.

I think I need to look at my wick (oo-er missus). Even when new it was so tightly packed that I could hardly get it to absorb any meths.

Many thanks.

 

[srm]

My main point was that heating the air doesn't increase the condensation when it cools

You are perfectly correct, provided that the composition of the air does not change. However, put a group of people in a room, (or one or two people in a boat cabin) and both the humidity and dew point will increase over time. This is something I have observed a number of times when getting a group of students to take wet and dry bulb readings to obtain dew point without taking the thermometers outside (as one should).

 

[convey]

I'm interested in their oxygen consumption, and where they are getting it from (I realise that second half sounds dumb, but stick with me on this, I am thinking things through for myself).

A few of the systems used closed or balance systems, actually dual flues. They suck outside air in, combust it, and let the mixed gas exhaust out. Cabin air remains the same.

Most of the diesel and the charcoal burners, draw air in from the cabin and exhaust most of the gases out of the flue. I'd suspect the unsealed Refleks, the ones with stove hobs, and the charcoal burners give out slightly more noxious gases in comparison to the sealed Refleks (non-hob) types, that give out practical none. That air has to be replenished from somewhere. In most cases, this will come from loose hatches and boards. Although, I know some guys that are able to close up their hatches quite tightly, and ventilate in poor weather through routes via cockpit lockers etc.

Bear in mind getting it wrong, burning hydrocarbons in a small enclose space is a reliable way to commit suicide. A charcoal burner in a small sealed car became very fashionable in the far east.

Taken to their northerly extremes, you have examples such a Roger Taylor's full submersible, sealed cabins. From what I remember reading, he depends mainly on good insulation and body/stove heat. Again from memory, I think the body gives out about 1kw in heat, which is not bad really. (There is also a trend in architecture right now for highly insulated, highly sealed housing that requires little to no heating and often there advice if a small amount more heat is required ... is to get a dog! Just how effective the calorific exchange rather between pet food and heat is, I have no idea).

How do the eberspacher types work, do they have an external intake and external exhaust and then just recycle cabin air?

Where I am going with this is to ask if there is a low tech way to dehumidify intake air?

I like the concept of high seal/high insulation approach but obviously you still need new air, especially if your heater is drawing in cabin air. I was wondering if there was a way to dry it on the way in as, obviously, it will be as wet as the outside air.

Thanks.

Obviously, the calorifier/water heater types have none of these problems. I did read recently of a terribly tragic case where a husband killed his wife and daughter through using a suitcase generator to run an inboard electrical heater (he left it running all night and the exhaust was neither sealed nor designed to cope with how it was used) but I can't say I've heard of many cases, or indeed any cases, of people killing themselves with these kinds of heaters.

 

[Scomber]

Ah, right, so you're using the bbq starter in the flue to suck air though. Neat.

I think I need to look at my wick (oo-er missus). Even when new it was so tightly packed that I could hardly get it to absorb any meths.

Many thanks.

Nearly mentioned previously,,keep your wick, ash free ,,, and a thin metal skewer will loosen your wick thereby allowing the meths to.......
penetrate more effectively!!

 

[MarkCX]

I made the stupid mistake of running my small portable generator on a cockpit seat. Even with all hatches closed, it wasn’t long before my CO2 alarm told me I was an idiot. Could have turned out much worse. Needless to say, I’ve never done that since.

 

[peteK]

The op was asking about a heater for a 26ft boat a blown air heater can be tucked away in a stern locker,which most of the others cant.

 

[BabaYaga]

Where I am going with this is to ask if there is a low tech way to dehumidify intake air?

I like the concept of high seal/high insulation approach but obviously you still need new air, especially if your heater is drawing in cabin air. I was wondering if there was a way to dry it on the way in as, obviously, it will be as wet as the outside air.

The classic method is to lead the incoming air through the bilges or past an uninsulated section of the hull below the water line, so that the humidity can condensate on the cooler surface before the air enters the cabin.

 

[Rappey]

it. Has anyone ever tried double glazing fixed portlights with a second piece of acrylic on the inside? Would it make a difference?

It would make a difference but the frame would be the weakest link as it has no thermal break within it.
Aluminium double glazing frame usually has hollow chambers and some sort of resin strip right through the centre to stop internal condensation.
I was quite surprised that 10mm acrylic is the area of the greatest heat loss on my boat.
This is a gebo portlight from the outside, 21c inside. The rigging is the coldest at -4 and the acrylic is heating the outside at 15c.
The eberspachers can suck heating and combustion air from the outside and exhaust to outside

 

[Goldie]

the drip feed and solid fuel stoves are very effective and attractive, they can't be used while underway.

My old Pansy heater used to get lit at the start of an Autumn/Winter cruise and shut down at the end.

 

[JumbleDuck]

I'm interested in their oxygen consumption, and where they are getting it from ... Bear in mind getting it wrong, burning hydrocarbons in a small enclose space is a reliable way to commit suicide.

In my case the air comes from the vent in the washboards, which is non-closeable. [/quote]

It takes about 12kg air to burn 1kg charcoal. When I can get the damn thing to light, 1kg of charcoal gives me about 6 hours' running, so 2kg of air per hour, which is about 500cc per second. The opening in my washboard vent is about 350cm^2, so I need a draft coming on of about 1.5cm/s, which isn't enough to register on the Beaufort Scale.

Again from memory, I think the body gives out about 1kw in heat, which is not bad really.

About 100W steady-state.

 

[JumbleDuck]

Nearly mentioned previously,,keep your wick, ash free ,,, and a thin metal skewer will loosen your wick thereby allowing the meths to.......
penetrate more effectively!!

Thank you. I shall take a skewer with me and ram it firmly up my wick whenever I start feeling cold.