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I hope to do quite a bit of winter sailing / camping and need to heat the cabin from time to time. using my cook stove or any other open flame seems unsafe. Any ideas?


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might try a pocket rocket. burns hot at full on and will last about 15 years. simple to make from a 5 gal bucket and a couple pieces of stove pipe. 

Or solar hot water linked to a bus heater and storage tank. if properly insulated it should heat for the entire night. 

I am liking this as a topic and have been giving it much thought.  I'm even building an experimental heater that will put the cumbustion chamber outside the cabin.  To summarize some of the ideas given on this topic and to outline my current plan I've come up with the following;

1. Sail to a warmer climate - warm once you get there, cold on the way.

2. When alongside at a marina, plug in to shore power and heat the cabin with a ceramic or electric oil heater - works great!  Lived on a Westsail 28 for a winter with several feet of snow on deck.  Not so good when "off the grid"

3. Use a marine diesel stove or similar that vests to the outside - great but it takes up a lot of space.  May be able to build a small one out of a soup can that will fit on a Tiki 21 or 26.

4. Use chemical pocket warmers like www.warmers.com - awesome and feels like your on a mountaineering expedition.  Good if you like that kind of thing.  These things last 10 hours.  Put one at the bottom of your sleeping bag and you'll sleep great and be just fine.

5. Use a hurricane lantern.  I heat my Tiki 26 this way.  Works pretty well.  Smells of kerosene which some people don't like.  Needs to be well ventilated. 

6. Current plan is to build a heat exchanger with heat source outside of cabin and a radiator in the cabin.  I'm using a copper coil in a Jetboil pot full of water connected with rubber tubbing and a small electric pump to an automatic transmission fin radiator to move heat of combustion as hot water into radiant heat in hull.  With a small computer style fan and windshield fuild pump the power use will be minimal and the heat will come from the "boiler" outside of the cabin.  See the picture of all the bits and pieces required.  I'm going to build this on the bench to refine it before it moves on board.  Then in January, I will do field tests to see how it works at anchorage.

I'll be looking forward to your results!

Thomas I don't think we've ever talked but I recently read your blog and am very impressed with your T26 TSUNAMICHASER she's quite a beautiful boat. You've done excellent work! I'd love to talk boats sometime via phone or email I can be reached at ItsaGamble at Gmail.com or call or txt at 831 five six six 4154

I'm considering building a removable main hatch cabin top similar to Casey's T21 BADU. (wondering if you are still in touch with him) I think it would be very nice to sit upright while I cook breakfast and steering in the rain from inside would be cool too. 

I have two Interstate SRM-27 deep cycle marine batteries that'll be my "off the grid" power supply I'm thinking one in each hull or maybe on deck not sure where or how I'll keep them yet. I'm planning on adding the charging add-on to my outboard to gain power from there and a solar panel for each hull. That combined with charging at the dock should have me covered (I'm guessing)  

I liked the infrared aquarium heaters because they are designed for a humid environment are low wattage and don't give off any dangerous gasses that will kill me in the night. They are also cheap and easy to install and a low tech solution. I like the ceramic electric heater because it's cheap, small, and dry heat that is also not going to kill me in the night. I'm looking for something between the mountain expedition method (which I'm currently using) and the intricate wood burning stove with a chimney idea.  If anyone knows something that I don't or is seeing something that I'm missing please chime in.  I've been loving this thread and all of the crazy and awesome ideas. I'm also trying to keep with the Wharram way by keeping the system as simple as possible. I find it so easy to get carried away with intricate designs...

Currently I've been taking Element on hunting trips to the islands on my lake. Deer, Turkey, and tons of small game can be found on them and hunted with a bow. It's been a lon of fun but the cold nights and even colder mornings make these ideas all the more important.

Happy Sailing!


Well let me know what you and yours come up with Thomas. After you exhaust all the other options We'll just build you a little rocket stove for Chaser. Probably run about 30 bucks to build.

*Sigh* Wish i was out on the water now but we are in the moving to build/designing the whole boat/ setting up boat shed phase.    

Please take a look at duck works articles I think you might see something there you can like Tony

Dylan Winter from the 'keepturningleft.co.uk' blog has made a video about how he heats up his small cruising yacht and his office. The video went viral and he laughs about it.

Here it is


how about using multifoil to insulate one hull as the main sleeping / reading / living space. Although it really needs an air gap, it will still work. It's difficult to see who to attach it but it could be attached with small battens or wire. Remember the heat source needs only to balance the heat loss.

Good luck...

yes Ian heat is only half the story. Insulation is the unsung hero ! A small space is easy to heat. A hurricane lamp or similar will do it. A mantle type will burn hotter than a wick type producing less fumes / smell. The gas canister type will give both light and heat in a confined space with a minimum of smell / fumes compared to petrol or kerosene. Obviously all these need venting, preferably a through venting as in leaving opposing windows open a little on each side of an RV or fore / aft hatches or vents in a cabin.

All open flame devices can produce c.monoxide. Catalytic heaters have no open flame and therefore cannot and are much safer.

I use all these and used SENSIBLY all have their uses.

All these are unvented and need a combination of venting and insulation. Even without heating just sleeping in a cabin will produce a pint of moisture much of which will condense on the cabin head on a chilly night.

One product I have seen is sold as an underlay for timber floors - the "click" type. It is a 4mm closed cell foam with a smooth closed surface so about the same value as 12mm expanded polystyrene. It is 1m wide and light grey in colour and SELF ADHESIVE. Trimmed neatly to fit I could see this as a neat job and quite effective,

All boats for temperate climes should at a minimum have the cabin top insulated. After 20 years I can say that 90% of my re-fitting was due to condensation damage. And 10% due to not fitting a keel band to a boat on a drying mooring.

As said, this is a really interesting discussion. It's got my engineering mind spinning. How do you heat a small boat space, safely, efficiently and simply?

There is no doubt insulation is essential. It is to flip side of the heating question. It reduces the scale of the problem. Condensation is a difficult problem, reduced somewhat by insulation and by not burning gas internally (dangerous). I remember using gas mantle lamps to heat tents in -20C. You could sit in a t-shirt and read, it was so warm, but ice actually formed on the inside of the canvas. Also, over time high humidity gets into your clothes and into you sleep bag. If you can't air it, it looses comfort and insulation dramatically. I've experienced this paddling kayaks in the cold on multi day descents. Not nice.

A 60W heater on your battery might last 18hr from full charge. 60W is not much but it depend on what you radiate from the boat. This depends on the out/in temperature difference and your insulation.

To keep going for any time out in the wild, you either carry high energy content fuel (petrol, diesel, or gas etc.) or use wood which you can find. I met some Germans once on a climbing trip who heated their tent with a wood burning stove. The chimney arranged out through the door somehow. They were warmer then us and always somehow found enough scraps of wood despite the lack of trees. They lived there for weeks.

As mentioned, an external stove with heat exchanger and internal radiator would work. It would be a great engineering project. It's a shame that the stove would be above the hulls, making thermosyphoning difficult and probably working against you. The need for a pump add complexity and points of failure.

What a shame the outboard engine throws away all that heat. If you could tap it you could charge a large thermal mass and store the energy for later. On a three month trip we heated a 50 litre tank with a heat exchanger from a Land Rover engine. Living out of a vehicle in the cold was considerable improved with all that hot water.

Have a great Christmas wherever you are....

I love it... in the end I followed Ann and Nev's advice and heated my boat with lattitudes :) I now reside in Sarasota, FL and have all the warm days and nights I could want to sail and camp and explore. About to take a week or two off to sail and camp along the coast after the new year. 

Well done Brandon ! I am afraid I am too attached to my life here to follow you .. I actually enjoy living here in Ireland !

A few words on how batteries are rated might be appropriate her since the subject of battery capacity has been raised in a few posts.

The following is based on Don Dodd's book - "This Is Modern Cruising Under Sail."

The capacity of a battery is measured by slowly drawing it completely down  to destruction [ about 10 V ] From here it can never be recharged - even deep cycle types. Most appliances will not work at less than about 12 V so this is the realistic limit of how much we can draw down. Also our control panels cut off the power below this to save the battery - save in the sense of preventing damage which would prevent a re-charge.

So the point at which the control panel cuts off the power is approx. 50% of the named power. Even running down this far regularly is not good. So probably we should not draw more than about 40 ah from a 100 ah battery and in any case probably cannot draw more than 50.

Working up from that 60 watt heater - this will draw 5 Amps [ 5A X 12v = 60 W ] To run for 16 hours will draw 5 X 16 amp hours = 80ah. This is the max available from a bank of 160 ah batteries. More realistically it is 40% of a 200 ah. battery bank. This will weigh about 45 kg or 100 lb. A lot on a small boat.

To give an example of how much heat is in 60 watts - it is about what your PC puts out as waste heat. Not a lot.

Comparing this to the effort to generate it - and considering what it would take to scale up to what most of us would expect from a heater - it is easy to see why we don't see this solution about.

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