Boat Heating—Part II

When the snow is still on the hills…

When I used to teach sailing many years ago, the season generally began in March—a month that could be bitterly cold in Britain’s wonderful climate. So it wasn’t surprising that when supper was cooking the crew were cheered up a little by the additional warmth.

The only propane-powered heater option at that time was the truly nasty catalytic heater that also vented the products of combustion directly into the cabin. As burning one gallon of propane produces around 0.8 gallons of water, these sources of heat inevitably turned the cabin into a dripping crypt streaming rivers of condensation, with the added threat of death from carbon monoxide poisoning. So you ended up opening the hatches to stay alive and, in doing so, let the cold right back in—ahh, the good old days!

Happily they don’t make those things anymore and new, safer propane heaters are on the market:

Colin, European Correspondent here at AAC, is a deeply experienced offshore sailor who holds a Yachtmaster licence, and a gifted photographer and talented writer who has added a whole new dimension to Attainable Adventure Cruising. In addition, since Colin and Louise are from England and had their OVNI 435, Pèlerin built in France, they bring a European perspective to our site. You can read more about Colin and Louise and their business at their website.

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Dick Stevenson

Hi Colin,
Another very nice review.
A couple of thoughts:
For the Eberspracher (as well as others like it I would guess), your suggestion of closing off outlets might generate enough back pressure to give the unit trouble. I would check with the manufacturer. My 40 foot boat has 3 outlets and the installation had louvers which cut down the free flow of air even when fully open. In one episode of trouble shooting, the company had me working out the area actually unobstructed for air to flow freely into the cabin and suggested it was too little. Since then, I have removed the louvers on the 2 main outlets and usually leave the third open. Heat is so fast that we notice little difference.
I have both Eberspracher (which came with the boat almost 20 years ago now and a Refleks, which we have lived with now for 1+ years. I like having both, but would choose Refleks hands down if restricted to one heater. Your evaluations of the pros & cons was right on.
Friends who have a “bus” type automotive heater all love it for its simplicity after installation and feel the amount of heat output is impressive. They are also quite inexpensive overall. For a power boat, this type of heat seems like a no-brainer and those sailboats who like redundancy (and basically free heat while underway under power) might consider this as well.
My best, Dick Stevenson, s/v Alchemy

Colin Speedie

Hi Dick
Hmm, that’s an odd one, as I’ve never encountered that before with any Webasto or Eberspacher installation. And certainly (for example) when we are planning for bed we’ll close down the aft vents so that more heat is diverted to the fore cabin to warm it up – always works fine. Same with the heads in the morning. We always leave the main saloon vent open, so we’ll have a minimum of two open at any one time, but as I say, that’s a new one on me.
And I like the ‘waste heat’ idea, too, although someone did warn me not to overdo the number of those heaters as it can cool the engine too efficiently, especially if linked to an existing calorifier etc.
Best wishes
Colin

Dick Stevenson

Hi Colin,
I suspect that all forced hot air heaters are concerned about back pressure, but, from your experience, some sound more flexible than others. I was never sure that back-pressure played any part in the troubles I experienced, but I was clear that the installation was not up to Eberspracher’s specs.
To quote from my installation manual, “Each model of heater has a maximum back pressure rating that can not be exceeded” (underlining in the manual). They go on to say that this is related to keeping the furnace cool enough and preventing overheating. They then elaborate with more details and admonitions, but the above is the gist of it. The instruction manual continues with a multi-page “Ducting system back pressure guide and work sheet” where it has you work out how many right angle corners etc. are in your ducting as well as other contributions to back pressure which leads to a “rating” for your particular installation.
The above is from “Supplemental” instructions for the D5L and are for a unit at least 10 years old.
That said, this morning we are at anchor in Wreck Bay, West Kyle in the Clyde area of Scotland, it was (for recent weather) a balmy 8C/46F this morning and 14C in the cabin. The Reflex alone had the cabin at 16.5 in an hour or so and the whole boat comfortable in a couple of hours. If the cabin had been much colder I might have opted for an hour of the Eberspracher working at full output (what it likes best) and also the Refleks on low which we are likely to leave going all day.
My best, Dick Stevenson, s/v Alchemy

Dick Stevenson

Hi All,
The underlining referred to in the above comment did not make it through the copy and paste and into the comments. In the manual “can not be exceeded” was underlined for emphasis. Dick

Colin Speedie

Hi Dick

yes, that makes sense. I have seen problems with collapsed ducting due to heavy kit being stowed on it that choked a heater. And I totally agree, these heaters like to be run hot otherwise trouble will soon ensue. Thanks!
Best wishes
Colin

Grenville Byford

Dear Colin,

THE CAR HEATER TYPE….. I think you are selling this bit of kit rather short. Evidently, it cannot be the only form of heat as (like a car) the heater only works when the main engine is running. On the other hand is relatively cheap to buy and install, and the heat it produces is essentially free while the engine is running anyway. In any area, the high Arctic for example, where motoring is a regular feature of life, this is a huge bonus. I have one installed at the bottom of the companion way on the Revenge (37ft, Steel Construction). It keeps the main cabin too warm if anything….. If anyone is interested, I can look up the brand I have installed.

Best regards,

Grenville

Colin Speedie

Hi Grenvile
no, I like them and recommend them. But I’m aware that they have a limited use for general heating – when at anchor for long periods, for example. And (see my comment to Dick above) it’s as well to make sure that they do not work too well!
But, in moderation, yes – why not?
Best wishes
Colin

Chris

Hi Colin,
Well researched and balanced article, you writing never disappoint us!
We have a Webasto water/ air heater on our boat and so far it has worked well ( touch wood!), when in warmer climate we use it to heat up the water balloon at anchor, so it is used on a semi regular basis, which in theory should help keeping it functional for when we really need it ( I hope).

When we ordered our Garcia exploration 45 we did not specify the refleks type stove because there was no obvious place to fit it, unlike on the Boreal. I hope we will not come to regret this decision as we are in the process of heading south towards Patagonia and even in Southern Brazil’a Rio Grande where we are weathering a cold front right now it starts to get coolish at night. I will order a spare combustion chamber as per your recommandation.

As a side note, on paper at least, our genset consumes about as much fuel as the heather. So worse come to worse we can run electrical heater off the genset.

Finally on the topic of car type heater, while it is a good idea I am always a bit concerned to hang off some non critical gear on one of the most critical system : the engine cooling system. Do you think this could work by using the hot water from the water balloon instead of the engine coolant circuit and would it require a circulation pump?
Many thanks
Best regards
Chris de Veyrac

Colin Speedie

Hi Chris
The water/air heaters, I am told, are more reliable than the air heaters although I’m not sure exactly why! If it’s working well, then all being well it should continue to do so.
Yes, it’s always a good idea to carry a spare burner assembly, which, when swapped out, leaves you the time to clean up the old one at your leisure.
I have no experience of running car heaters off a calorifier, but imagine that you might need to (a) fit a small circulating pump (no big deal – that’s what Boreal have in the Refleks/radiator system) and it might be better to have valves that would isolate the engine when it’s not in use. But – it might all get a little complicated!
Webasto do supply their water heaters to work radiators I believe, so maybe they could advise and/or supply a proprietary kit.
Thanks of the kind words, too.
Best wishes
Colin

John Harries

Hi Colin and Chris,

Our car/bus heater is plumed in series with the water heater heat exchanger coil (calorifier) and it works fine without a pump.

Some worry that such a system will rob too much heat from the engine, but I don’t think this is really a problem since, as I understand it, the thermostat on the engine will stay shut until the engine reaches operating temperature preventing much water from circulating to the heater and calorifier.

And yes, I think it’s a very good idea to have valves to isolate the engine in case a leak develops, which we do, although we have never used them.

Colin Speedie

Hi John and Chris
I was assuming that Chris was intending to heat the water in the calorifier via the Webasto, not from the engine, e.g. when at anchor. If that’s the case, then surely a circulation pump would be an advantage if not a necessity?
And the comments I’ve heard from engineers about the risks of overcooling have been more to do with not allowing the engine to reach full operating temperature after the thermostat has opened – but – this is a grey area I’m sure and (as always) there must be ways to ensure this is not a risk.
Best wishes
Colin

John Harries

Hi Colin,

Oops I misunderstood. As you say, in that case a pump will nearly always be required.

On the worry of about too much heat being robbed by a bus type heater, I guess I’m still sceptical because my thinking is that if that were the case the thermostat would never open. Or to put it another way, once it’s open the engine is at temperature and all is good anyway.

That said, I have to admit that I’m a long way from totally sure about this.

Eric Klem

Hi Colin,

Your posts on this subject have me thinking about heat again but hopefully I will be able to resist the temptation. Here in New England, we tend to only sail in relatively warm weather and I gather that people in Britain and other places regularly push the season quite a bit more. We launch in a week and will be the first boat in the water where we are if that says anything about fair weather sailing.

I started thinking about how long we could run a propane heater on the 22 lbs of propane we carry. Using Dickinson’s numbers for high heat, we could run for 86 hours and get a total of 470,000 BTU. If we used their small diesel stove, it would use 3.9 gallons for the same amount of heat and could deliver it a lot more quickly if desired. While the fuel weighs about 5 lbs more (I suspect net it will be less due to storage requirements), you can carry a heck of a lot more diesel due to density and it is so much easier to refill. Given this, I guess that I could see using propane if it were for occasional overnights at the ends of a season but I can’t see using it for a whole lot more than that.

Thanks for the series.

Eric

Colin Speedie

Hi Eric
absolutely correct, I think, and I drew the same conclusion into my recommendations. You carry an awful lot of diesel, it’s cheap and fairly straightforward to hook up a supply to a heater.
But for your local, intermittent use, propane, which burns very cleanly and so doesn’t need such regular servicing might well be a better bet than diesel.
Best wishes
Colin

Dick Stevenson

Hi Eric,
I sailed Long Island Sound for decades and some of the best sailing is April/May and Oct/Nov so enjoy being on the water early. This is, perhaps, the only time you will have your favorite anchorages to yourself.
A friend with a propane heater on board felt like he went through way more propane than he wished to keep his 40 foot boat warm on trips up and down the ICW in the US. This was in part as he needed to find propane in many locations without a car. This was in the US where propane refills are relatively easy to find. In many parts of the world, this becomes even more problematic. Also, does the heater run on butane or a propane/butane mix. Some stoves/burners seem to care and sometimes that is all you can get and/or you do not know what you are getting.
As a reference, on my moderately well insulated boat, I use about a liter/quart of diesel running my Refleks on its lowest setting for 8-10 hours. The lowest setting, after initial warming, is sufficient heat for my 40 footer on an average day of 8-10C/45-50F. Any warmer and we crack open the hatches a bit more.
BTW, I wrote a field report on installation, use, maintenance on my Refleks for these pages a year or so ago.
Let us know what you find about the amount of propane needed for boat heating as I believe you are correct in evaluating propane as best for weekend or occasional usage. The figures you quoted sounded unrealistic to me.
My best, Dick Stevenson, s/v Alchemy

Colin Speedie

Hi Dick
you raise a very pertinent point about heaters that burn butane or propane or are happy with both. From my experience I’ve seldom seen butane outside northern Europe, but certainly there you often have the choice. But as you suggest, not all stoves are happy with both and you should stick with the fuel that the heater was designed for. Not only that the regulators are set at different pressures and the bottles are different.
And actually, butane isn’t the best bet for really cold climes anyway, as the regulators tend to ‘freeze’ when the ambient temperature drops towards 0C, which necessitates warming it up. I’ve been told that German RV’ers use electrically warmed butane regulators, but that all seems to be entering an over-complicated world to me – at least for boats.
Thanks for a very helpful comment.
Best wishes
Colin

Eric Klem

Hi Dick and Colin,

Thanks for the thoughts. Dick, your fuel burn rate experience mirrors my own with a Refleks and is low enough that it is dwarfed by engine fuel consumption if you motor regularly.

Eric

James Bitondo

Colin,
I’m referencing the article, Boat Heating—Part II, After I read each article I normally print it as a pdf to be retained in my library. This time however, the resulting pdf was only small character size squares. This was true thru out the entire text. I even noticed two of these squares in the original copy that was emailed to me, right in front of your name. I’m unable to select or copy the small square. I believe this is an indication there is a non-ASCII character with in the text and the display generator simply puts a small square to indicate it. Anyway my pdf tool (Mac) fails to convert and because the result is all little squares and no text, this gives me the idea that there are a number of non-ASCII characters and one of them has come thru as a command character and thus the entire pdf conversion has failed. I’m not sure if there is anything that can be done to fix this oddity, but I at least wanted you to know.

Colin Speedie

Hi James
I’m really not sure what may have caused this – I’m the least tech person with computers you could meet, but I’m sure there will be an answer.
Thanks for the alert
Best wishes
Colin

John Harries

Hi James,

Thanks for the heads up. I’m reasonable sure that everything we are outputting is straight ASCII in that it all displays fine on our three macs and ipad.

I have also run our feed through a validator, and it is valid, which it would not be with an unexpected special character.

Has anyone else experienced this problem?

Interestingly, Phyllis experienced an intermittent problem much like yours on her Mac. We never did find out the exact cause, but clearing the browser cache, followed by rebooting the computer, seemed to solve it, so that’s what I would recommend.

Incidentally, all of this begs the question of why you would want to file these articles in the first place given that we keep them carefully categorized and searchable here on the web site? Also, we often update them as new information becomes available, which you would miss out on by storing them on your computer.

Petter ;-)

James,
I have from time to time pdf’ed articles for offline reading and experienced similar issues to the ones you describe. My experience is that the problems lies on the Mac side not at mc.com. Try a different browser and print to pdf in Preview. Normally works for me.

Greetings!

Peter de Boer

Hi Colin

Great article and good timing (for us), thanks

We are in Australia and planning a trip, Sydney (our home port) to New Zealand, on our triple diagonal kauri, Paul Whiting 40

I am interested in the picture of the Espar exhaust on Morgans Cloud
Is it possible to get some details?

Cheers
Peter

Colin Speedie

Hi Peter
John will be the one to comment on this, especially as it looks like a one-off. The standard exhaust looks like the Webasto one on our boat (and in the pic above) and it works fine for us. But there are certain installations that need extra thought – e.g. where for some reason the exhaust gases can find there way back in to the accommodation, which can be worse than just unpleasant because CO is involved.
Best wishes
Colin

Peter de Boer

Thanks Colin
I can’t tell from the photo exactly where the exhaust is situated?
Cheers
Peter

John Harries

Hi Peter,

It’s right aft and on the centre line. This position seems to work well in that we have never had any water get down it.

(We do have a low point with a drain valve in the exhaust line before it gets to the heater, but have never used it.)

John Harries

Hi Peter,

On the exhaust. It was supplied custom by Ocean Options as part of the package they supplied us. We then had a collar machined to go around the tube at the same hight as the pushpit railing and then braced to it with standard boat cover fittings and tube.

Probably worth contacting Ocean Options to see if they will do you one like it. Of course shipping to Australia will be a bit expensive, but maybe no more than the cost of a complete custom fabrication there: http://www.oceanoptions.com

We were dealing directly with Mike, the owner of the company. I suspect he will remember the project and where he sourced the pieces.

Peter de Boer

Thanks for the lead John
Cheers
Peter

Drew Frye

Your evaluation of the Dickenson Fireplace P9000 is just about dead on. I’ve had one since 2009 (8 years), and I believe it is a good answer for smaller boats that already have propane. A few thoughts:

The heat is based on input, not output, so the actual heating is a bit less, though it is about 85% efficient (I did flue gas analysis). It will occasionally blow out above 25 knots apparent, depending on the wind direction, but this could be remedied with a better wind guard; I’m sure this is the case with all stoves. It has never blown out at anchor, even in very strong winds, because the wind guard is properly oriented for that. I never did enough long winter passages to bother fixing it. There is a sensor that cut the gas if it flames out, and being sealed from the cabin should provide some back-up protection–I could never smell gas after a flame out, even inside the unit (open the door). Motion itself has no effect. It keeps my 34′ catamaran at 70F down to about 35F at night, after which it starts cooling down. I placed a cabin fan very near it, which blasts down on it and does a nice job of distributing the heat. I do let the sleeping cabins stay cool, because I like it that way.

Very easy to use. Obviously, careful installation is a must with propane (continuous hose run to locker, good locker, fume detectors).

My recommendation for anyone considering heat is to use electric heaters for a few nights first, to accurately estimate the size; boats vary in insulation and drafts. 1000 watts = 3450 BTU.

A blog post about the installation:
http://sail-delmarva.blogspot.com/2016/10/let-there-be-heat.html

Colin Speedie

Thanks Drew, for a valuable insight into a heater I haven’t had the chance to try, and I’m glad my take on it chiefs with your own experience.
You raise an interesting point, though, that heaters of all types can blow out – a reminder that it’s worth experimenting with the flue until it it is virtually impossible for this to happen. I know it took me quite a few attempts to achieve this with a number of stoves, but always got there in the end.
Also, a reminder that gas and CO alarms should be fitted always, just in case the ‘flame-out sensor’ lets you down.
Best wishes
Colin

JCFlander

Hi, thank you for a good article. Brought to mind one tip on how to lengthen the diesel heater burner service (cleaning) interval: use lamp oil on it from time to time.
Lamp oil burns very clean, so it pretty much cleans (burns) out the soot deposits also.
And, if boat is left on dry on cold winters, using the last weeks only lamp oil leaves the fuel lines and heater regulator full of non-crystallizing fuel.
If heater daytank (or similar) is not installed, this ‘alternate feed’ might require additional t-valve and small-ish tank where to feed another fuel instead of diesel, but it should be quite simple to add. Also works as a backup tank…

btw: Perhaps this is already mentioned, but couldn’t hurt to say again 🙂 – If accident has already happened and fuel lines are full of paraffine goo after winter, isopropyl alcohol is the recommended remedy. It dissolves paraffin crystals quickly and diesel heaters don’t mind burning it. (at least Webasto/Eber/Espar/Planar or Wallas/Safire)

btw2: there is nowadays air/fan diesel heaters with variable fans and fuel feeds that are designed to consume very little electricity, quite like refleks with circulating pump. And, yes, these units are a bit more complicated than refleks, but could fit very well into some boats where Refleks or similar unit is not so easy to install. Like:
http://www.wallas.fi/index.php?id=19
and, another unit:
http://safire.fi/index.php?id=50
Cheers!

Colin Speedie

Hi JC
I have heard of people running kerosene/paraffin through blown air heaters to clean the burner chamber, although I am also aware that this is a controversial issue, with some experts suggesting it can run too hot and so cause damage. But lamp oil is new to me.
Thanks for the tip on cleaning lines out.
I haven’t tried as Wallas heater myself, but have heard good reports about them and they do seem to have low power draw. And it looks like they have a wide range of products for boats of different sizes.
Best wishes
Colin

JCFlander

Oh well :d I forgot that common names for “lamp oil” are very different abroad… :d It’s likely we are talking about the same thing here. If paraffin and kerosene mean no-soot fuels good for oil lamps, then they’re the same.

Aprops…. if you ask kerosene here, they advice you to airport where you will find a JET A-1 pump 🙂 and when asking for paraffine they advice you to pharmacy where they bring you some solid, candle-like stuff 🙂

I’ll ask about what aforementioned manufacturers say about this officially and get back if I get some response. Cheers.

Colin Speedie

Hi JC
yes, the language thing – when I first wrote this piece I used the word ‘gas’ for propane, when of course in the USA it’s something else entirely….
Paraffin (as in the UK) is an alternative that is sometimes used, and it’s possible to buy this a dyed fuel or as what’s sometimes called ‘pharmaceutical paraffin’ which is clear – but much more expensive.
In every case it’s wise to check with the manufacturer whether it’s safe to run paraffin through a diesel heater.
Best wishes
Colin

Best wishes
Colin

Francisco Moreno

We installed the Eberspächer Airtronic D5 in summer 2015 in France and have used it two winters. Installation was easy as our boat comes pre-ducted for this type of heating. It starts every time, so far.

Colin points out that timers, etc., may make the system unreliable. This is not our experience, but there is good reason. We installed the default bulkhead controller that comes in the box (it is now a small, orange-backlighted, 3-button affair). It can only do start/stop/timer/ambient temp/target temp and fan-only operation. Simple. This sits in the main saloon, close to other, pre-existing HVAC controls.

In addition to this, we ordered the key-fob-sized EasyStart Remote+ radio remote. This can do everything the basic bulkhead control does, plus daily or weekly automated starts, plus on-the-fly easy to use timers. We keep this on its own pocket in the main sleeping cabin, so heating can be dialed from bed at any time. Also, we have often set a timer to start at 4:00am, so one does not wake up to a meat locker fridge.

Why no electronic problems? Simple. The remote’s clock/calendar/timer, etc., are all inside the remote itself, self-contained. And the remote’s wired interface to the heater’s controller is essentially an external ON/OFF input. So there is very little complexity that the remote adds to the stock Airtronic itself.

Worth noting that in 2015 these new-generation orange-backlight controllers were only available in the Euro market. In the States, they still sold the old blue-backlight and analog controls, which I understand were a different animal. I recommend the orange-backlight stuff.

Colin Speedie

Hi Francisco
well that’s a new development that I haven’t seen before, but it sounds like a step in the right direction – thanks for the heads-up.
Best wishes
Colin

Tobias

Hi Everybody,
I have been cooking with paraffin (sometimes also called kerosene and in German Petroleum) for ages on my boats. On Rode Zora v. Amsterdam, a Koopmans 39, we have a Taylor model 030 which works beautifully and, when properly maintained and operated, beats any other means of cooking in terms of power. Now my concern: Two years ago when in Norway we ran out of the good stuff that we buy in Germany called Esso Blue — highly refined paraffin) We were not able to obtain any suitable fuel for the Taylor. So we ended up shipping 10l of fuel for an astronomical amount of money from Germany to Norway.
This summer we want to leave on a 1 year tour of the Atlantic with stops in England, Spain, Portugal etc… Does anybody know about the availability of fuel for a Taylor stove in places like the Southern Europe, the Caribbean, the US, or the Azores? We might end up with 100l on board. With about 2-3l needed per week, this should go a long way, but it would be good to know if there are places where we could replenish.
Tobias

P. S. We heat with a Kabola Old Dutch Diesel Stove. Same principle as a Reflex. It runs off the main Diesel day tank which we replenish, as the name says, once per day via hand pump from a 900l diesel tank in the keel. This is great for places in Northern Europe but I don’t suspect we shall need it a lot south of the 30th parallel…

Colin Speedie

Hi Tobias
Esso Blue – that takes me back to the sixties, when it was the fuel of choice for small heaters!
If you can’t get fuel grade paraffin from hardware stores or the like, maybe try a chemists shop where they sometimes stock what is called ‘pharmaceutical’ or ‘medicinal liquid’ paraffin.
I’ve seen paraffin in Spain, I’m sure and it may also be available in Portugal.
And no, I doubt you’ll need your heater down S of 30 degrees Latitude….
Best wishes
Colin

Henning

I have quite some experience with Webasto hydronic, about 8,000 hours over 10 years with two successive “Thermo 90” models.

The short story is:
I’m dreaming of a Refleks diesel stove, the type that is discussed above and is installed in Boreals.

The long story is:

What we had before:
Our used 1997 Jeanneau 45.2 bought in 2006 was factory fitted with a Webasto forced air heater installed in a cockpit locker. We found this to be completely inadequate as the main sleeping cabin an bath with shower is in the front of the boat. Hot air ducting was factory installed, before the interior furnishing, with quite large diameter and no sharp turns but still there was next to no heat arriving where it was most needed (there was no ducting into the bath/shower at all and one outlet in the forward cabin). This is by design. When you talk to experts alone, they will tell you that ducting runs over 3 meters/10 feet will “eat up” most of the air flow and heat. I don’t know where the energy in the heat goes. I know physicists claim that energy can’t just vanish but they must not have heard about forced air heating with long ducting.
In the first week that we owned the boat I decided to replace the entire installation. The install was done over the following winter.

What I installed:
I installed a Thermo 90 9.8 Kilowatt max output and 7.5 Kilowatt continuous output hydronic (water) heater in the place of the old 5 Kilowatt forced air heater. The old one was still serviceable and I sold it for a quite respectable EUR 400, about half of what the heater alone would have cost at that time (do not spend that much money on such an old and inadequate heater).
I used plastic water piping of 21mm, 15mm and 12mm outside diameter with push-on fittings by Hep2O, similar to what Whale sells now, only they don’t have the two larger sizes. The different sizes are important, as any water heating installer will tell you. A rule says that at every tee you must reduce the diameter of the pipe going straight in order to create additional back-pressure which will persuade some of the water to make a 90 degree turn at the tee. If you don’t, then inertia will cause 98% of the water to go straight, leaving the radiator that is tee’d off cold. As there are only 3 different diameters in existence, and even these are hard to find, the above cannot be fully implemented, but at least partially.
I replaced the hot water reservoir (calorifier) with one having two independent heating coils. The first one is inserted into the heating system, the second one is for the generator. The main engine’s heat is transferred to the heating water circuit with an additional heat exchanger. The engine coolant does not circulate in the heating circuit (never do this). The engine heat is transferred via this additional foot-long heat exchanger of much smaller capacity than the main engine heat exchanger.
To my knowledge, most or all water cooled engines have a main duct going through the thermostat and radiator (car) or heat exchanger (marine) and a much smaller “side” duct feeding the cabin heater. This last duct is not routed via the thermostat to allow cars to heat and defrost windows before the engine reaches full operating temperature. In my car in winter in city traffic, I can keep the engine from reaching operating temperature with the cabin heater circuit alone but on the boat, with the above setup, that has never been a problem. My 62hp Yanmar has always reached operating temperature normally, even when supplying considerable interior heat plus the calorifier.
There are 2 good-sized radiators, one by the feet inside the U-shaped sofa in the salon and one at the foot of the forward berth (we sleep head forward).
There are 4 heat exchangers with electric blowers. Three of these take the air from inside, one is connected to some remaining hot air duct from the previous forced air heater and so takes fresh air from inside the cockpit locker. This last one blows hot air into the port aft cabin and the aft head which makes the aft head a good place to dry wet foul weather gear (or laundry).
The blowers in these 4 heat exchangers can be adjusted to any speed with a knob.
There are also valves at several places in the circuit allowing to balance the pressure and a valve shutting off the main circuit so that the heater will only make hot water.
What this install does is:
– combined with an air dehumidifier heats the boat sufficiently even in mid-winter at strong freezing temperatures
– provide adjustable heat to each individual space in the boat
– makes the bottom of the U-shaped sofa a very cozy place
– dries the shower quickly
– provide all the hot water we can use and heat up the hot water tank in 20 or so minutes
– heat the boat all around to comfortable temperatures and heat water when motoring (the waste heat from the engine is enough for all this while allowing the engine to reach operating temperature)

What I learned:
Webasto states that these heaters are not intended for “permanently occupied spaces” (meaning primary residences). Following our sabbatical my wife, daughter and me spent two northern winters living on the boat as we found, bought and waited for completion of a condo. I would be ready for another winter but in that case I would add a Refleks or Dickinson drip diesel stove into the existing install. The Webastos are highly computerized, meaning they can and do suffer from software bugs in addition to the fragile method of combustion. For example, my heater once suddenly stopped dead in mid-operation, something it is never supposed to do as this will cause a dangerous overheat situation. The CPU may have tripped over a bug. It restarted with no problem and when I had it in the shop next time, they installed a software upgrade addressing this issue.
They use an extremely fine wire mesh (like felt) into which the fuel is pumped by an impulse-driven dosage pump and onto which combustion air is blown. The metal “felt” is heated white-hot. It must be made from some very advanced metal but still will not live more than about 3,000 hours. The main motor is DC so it uses carbon brushes which will only live so long, either. The first of our two heaters reached 5,800 hours, according to its computer. Webasto technicians tell me this may be a record-breaking number, so don’t expect this much.
This is from the report of the final readout of its memory:
Glow-cycles (startup): 1,100
Hours of operation in
– low output: 2,100
– medium output: 3,100
– high output: 180
– max (boost) output: 140
The high number of glow cycles are in part due to a fault at one time with a temperature sensor that caused it to cycle between emergency overtemperature shutoff and warm restart. It had to suffer this endless cycle for days on end before I had a chance to take it to the shop.
I have unmounted the first and second heater from their space in the cockpit locker and taken it to a repair shop at least 10 times so far, each time draining part of the water. It’s gotten to the point where I know by heart each tool I will need for this and have the wooden plugs handy to seal the water hoses while the heater is gone.
I was strongly discouraged from attempting self service on the water heater models from Webasto as it is supposedly hard to re-seal the water chamber from the combustion chamber after it was opened. One friendly service technician that regularly does Webasto forced air heaters declined to service my water heater for this reason.
Webasto offers a service software to install on Windows computers plus a USB adapter to connect to the heater for about EUR 800 combined. I have seen this software in operation a few times on my heater. It kind of looks like a nuclear power plant command center with the heater continuously measuring and the software graphing about 10 operational parameters and driving impulse rate of the fuel feed pump, electric preheat, the continuously variable rpms of the combustion air blower, the water pump and probably more.
If you like simple an reliable, I think you will have drawn your conclusions at this point.
While I have not yet bought the software and adapter, I consider them essential if you plan to venture away from the shop. Various different operational errors, e.g. exhaust gas overtemperature from a plugged exhaust, will cause the heater to lock-up, meaning it will not restart to check if the error condition still exists. In this state (and I have been in this state probably 10 times), you need the software to unlock it.
2 years ago at the Düsseldorf boat fair I toured a Garica Exploration 50something equipped with the next size up heater from mine (a nozzle and spray-burner type, like a home furnace, but of similar size than mine). There were large radiators throughout the boat but no other source of heat. If this boat was bound for the Arctic and if I were offered a trip on it, I would have the boat captain show me at least 2 brandnew spare heaters plus the above mentioned software and adapter before I would step aboard.

What I would do differently:
I would install ball valves immediately before and after the heater and otherwise make it as simple as possible a job to unmount and remount it. You will do this regularly.
I would install two smaller 5kw models instead of one 9.8kw if I wanted to depend on this type of heater alone. As you can see from the operating hours above, even though I have a considerable number of radiators and blowers, they still can’t take more than about 3.5kw of heat from the heater after the calorifier is warmed up. I was told they can be mounted in series.
I would and maybe will add a Refleks or Dickinson drip type diesel stove with into the water circuit. If I do and my Webasto again reaches end of life, I will replace with a smaller 5kw. This can be run underway or for quick warm-up and it will operate nearer its max output more of the time, which I have learned is important for its health.

Colin Speedie

Hi Henning
thanks very much for the detailed analysis. I agree with your comments about getting heat to the extremities of the boat with blown air heaters, which can be assisted by closing the flaps on the vents in cabins that are not in use, but that will only help, not cure. And I fully accept your comments about complexity and reliability, something that both John and I reinforce at every opportunity. I’d rather have a simple, mechanical system that I could fix myself every time, and whilst I like the instant heat from our Webasto, would swop it for a Refleks or similar if I could.
Best wishes
Colin

Petter ;-)

Hoping some will benefit from my experience with heater systems, I will add some comments;

Iris came with a Webasto coolant heating and piped radiator system from new. After 15 years of service, she underwent a not exactly minor refit. At the time of the refit, I ditched the original heater, which was still serviceable and in working order, thinking I would avoid the hassle of a breakdown in a remote area. Toward the very end of the refit I also bit the bullet and decided to the smallest Refleks heater, with no heating coils, but a nice hot plate on top for heating a kettle or melting snow for water – if need be. Hence I have a dual system, one highly complex and one dead simple.

1. First off the Refleks; the heater is drip fed from a 12 litre plastic tank. The tank is filled by the diesel return line from the main engine, and when full the diesel flows back into the pain tank. Hence the fuel is double filtered before entering the heater. I mostly run the heater at low level and the tanks last me for 3-4 days, given that I do not run the engine in between. If I need to fill the tank, I run the main engine for 15 minutes a idle speed.

Having spent a fair bit of the cold season in the arctic north of Norway, I light the Refleks stove when I board the vessel, and shut it down when I leave, i.e. it runs 24/7 when possible. When I motor or sail in light winds I leave running as it works at angles up to 10 degree heel.

I have in addition procured a small Ecofan (http://www.caframolifestylesolutions.com/ecofan/) that I put on the hotplate of the Refleks, and in this way spread the heat a bit around.

Am I happy with the unit? Yes! What would I have done differently with experience? Probably added a heating coil in the Refleks and piped it into the existing radiator system.

2. Next the Webasto 90ST. (https://www.webasto.com/gb/markets-products/motorhomes/heating-solutions/coolant-water-heaters/thermo-90-st/)
It produced a lovely distributed heat – silently. I have a water boiler with a dual coil and have piped the Webasto into the boiler with a three-way valve; allowing me to select between, heating only hot water, heating only the radiators or both. In warmer areas than the arctic north, I set it to hot water only and after running the heater for 15 minutes in the morning, there is hot water for clearing up the party last night or a shower. All nice, but there are downsides, so here we go;

It produced a lot of heat, 10kW on full speed, which is too much for a 43ft vessel, hence it runs on low speed, leading to build up of coke in the burner. In the end it will not fire and needs to be cleaned. Luckily the heater is located where the burner may be extracted without dismantling the whole heater unit from its mounts. Cleaning is not to difficult, but in the end the coke will ruin the burner, so I carry a spare just in case. Not cheap.

Since new, I have also blown a main circuit board on the heater. That was exchanged under warranty.

I have heard of the trick with running the unit on paraffin from time to time. Ran it with a litre of paraffin a month ago and will run it with a litre of paraffin every month, to see if that burns away the coke, and resolves that issue. Somebody above mentioned using lamp oil. According to the recommendations I found, using lamp oil is not advisable, as lamp oil contains some c13-c14 components (Greek to me) that may clog the burner. To run it on paraffin, I simply detach the fuel supply in front of the feed pump and add secondary fuel line that goes through an appropriately drilled hole in the paraffin bottle, which I place next to the heater. Probably not the ideal setup, but I keep the process under close observation. When done the normal fuel supply is reattached and the unit primed.

What would I do if I we outfitting a vessel from new. I would have skipped the Webasto coolant heater, because of its complexity. Instead I would have added a forced air heater and a defroster unit connected to the main engine. These are relatively cheap, rugged and easy to install. There are more types and suppliers, and here is one example https://www.svb24.com/en/isotherm-air-heater-12v-and-24v.html

Secondly, I would have considered adding a Refleks heater with a heating coil, a small circulation pump and radiators. This unit just works, and with radiators, silently distributes the heat where you want it. If in really cold areas, under-floor heating might also be added. Downside is all the piping that a system like this requires to work well.

A concluding note on selecting a supplier of the system. The dual coil water heater comes from Webasto and was installed in a Dutch yard.

Knowing the boat would move around on the globe, as boats normally does, I trusted a supplier with an international brand.
https://www.webasto.com/gb/markets-products/motorhomes/heating-solutions/boiler-calorifier/isotemp-electric-boilers/

This winter it looks like the coolant heater coil in the water boiler has ripped. I have tested the coolant, which is secure down to -46 degrees centigrade, so frost did not rip the pipe. To me it hence looks like the reason for the problem is related to a manufacturing issue. I have contacted the local Webasto supplier, which btw is fully owned by Webasto itself. They will not assume any responsibility, and is sending me back to the yard in the Netherlands. So much for working with companies that pride them self as being international – or even global. So maybe a copy product supplied by a Chinese at eBay at 30% of the price is a better choice.

Greetings!

Colin Speedie

Hi Petter
and yet again, the issues related to complexity.
You (and others above) have confirmed one thing for me – just like their blown air brothers, the hydro heaters must be run hot and hard of they are not to coke up and quit. And that’s not ideal for living with.
One more vote for a simple drip fed heater, it seems.
Thanks for a great comment.
Colin

Victor Raymond

Hello Colin
As usual great post and lots of thought provoking concepts here.

Our Rajah Laut came equipped with a Taylor drip. Quite reliable and simple but no coils to a heat exchanger in the calorifier. The tank is filled from the two diesel tanks thus scours the tanks for water. An occasional hiss in the combustion chamber confirms this.

Three years ago I installed a large 30K BTU boiler that feeds electric fan heat exchangers which are temperature activated i.e. The fans only work when the circulating coolant is above 90° F. I have another heat exchanger that heats this coolant from engine excess heat which means I can also preheat the engine with the coolant.

Finally this past winter I have replaced our ancient paraffin cook stove with a Wallas diesel cook top. There are no open burners and the cabin air is dried as the exhaust is vented to the port hull two feet above the waterline.

Having a variety of heating options is only mentally complex. I reality all three systems are independent except for the fact that they all run on diesel which until something better is invented is the safest and most cost effected fuel available world wide.

All the best

Victor

Colin Speedie

Hi Victor
belt and braces -and then another belt! I presume your large boiler is AC powered?
And I’ve often admired those Wallas (type) diesel stoves, but wondered what they met be like to live with in a less cold climate?
But I totally agree about diesel as the best fuel – cheap, plentiful and easily managed, it has to be the most cost-effective and practical option available.
Best wishes
Colin

Victor Raymond

Hello Colin

Actually the boiler is diesel fired with 24v for ignition and pumps. As much as possible I have reduced our electrical dependence to D.C. only since I have 880 watts of solar panels as the cockpit Bimini roof. Our sole AC requirements are for the coffee grinder in the AM because I am too lazy to grind by hand and the electric kettle which heats a liter of water so fast nothing else comes close. Again too anxious for the Espresso fix to wait for the Wallas to heat up.

As for the Wallas, so far we have found it nothing but a delight in in its operation. We occasionally leave it on all night in which case the boiler which is on a day/night programmable thermostat rarely kicks on.

We are headed to Alaska again this year and will report on the Wallas performance.

Best regards

Victor

Colin Speedie

Hi Victor
sounds like an interesting set-up, proof yet again that there’s always something new to learn.
Do let us know how the Wallas performs after this season in Alaska. I’ve heard good things about them and it would be good to have that confirmed after a season’s use ‘in anger’.
Best wishes
Colin

Peter Mannerstråle

Coming from the other side of the spectrum regarding fuel.
On my cat I only have petrol and propane. What heaters to use?
Living in Sweden it’s cold but we don’t sail during winter but early spring and late autum. For the moment we have propane heaters.

Colin Speedie

Hi Peter
you don’t say what type of heaters you use, but if they’re anything like the Dickinson I’d have thought they might be the best bet. Maybe one in each hull?
Best wishes
Colin

Peter

Hello Colin,
Air propan heaters 2kW one in each hull.
Heating is very pore but that can be due to each hull is 42 feet but narrow.
No bridgedeck house.

Best Regards,
Peter

Dick Stevenson

Hi Colin,
Another word about the Refleks stoves for heating that have a flat cook-plate type top. It has been mentioned how nice it is to place an Eco fan on top (works by heat and is quiet) and it very much is a lovely and efficient method of moving the warm air around. I believe also the cook-plate design are easier to light. But I am thinking of another attribute, ill-considered to date.
In the way of things, I sometimes contemplate what would happen if we lost propane cooking stove service. More recently, there have been times when I worried I might run out of gas. I could have solved this with a time-honored response of throwing money at it (usually meaning the need to buy proprietorial bottles and fittings at the country I am in and re-doing my US end terminal fittings: an expensive PITA as the next month I will be in another country which is likely to have their own bottles/fittings, the EU has standardized a lot, but not gas fittings).
We have devised a number of work-arounds, but my point is that with the Reflex stove, there is always a cooktop plenty hot (in these northern lats) for all cooking needs. I would suspect that the percentage of our propane that just goes for tea is pushing 50% (4-5 mugs a day times 2 people). Then there is the water for pasta etc. We have started to use the Refleks more and more for this heating of water as it is heating the boat anyway. It is not quite as fast as the stove, but close (Refleks is set at low burn usually). Not only are we saving gas, but this method is immensely satisfying in a charming old-school kind of way. I can remember in my youth wood stoves with a kettle on 24/7, sometimes for humidifying, but also providing hot water always available.
Although we have not done it, there is no reason stews and other one pot meals could not be produced in this fashion. I did not opt for my cook-top version with this in mind, but it would be enough at this point to do so now. I know of boats who lost their ability to cook at sea, and not being able to heat water/food made their trip a misery and was close to being dangerous as they were relying on a lot of beans & rice.
My best, Dick Stevenson, s/v Alchemy

Colin Speedie

Hi Dick
as you say, using hobs in that manner was standard use in years gone by, and there’s absolutely no reason why slow cooking stews, soups etc shouldn’t be carried out in that way when at rest. And if you leave a kettle on the plate, then a cup of tea is never more than a few moments away.
I agree with you about gas fittings and bottles, and it was our impression that it’s getting ever harder to find people who will fill ‘foreign’ bottles, which means having to change them all the time. The US ones we are using now have stood us well since the Caribbean, so we’ll hopefully be OK for a while yet!
Best wishes
Colin

Marc Dacey

My only concern with the otherwise delightful idea of cooking on a hob (an uncommon term for some) would be doing so while underway, due to the non-gimballing nature of the Refleks stove. Is this countered by some sort of wire to keep the cookpot secured from above? (I realize the hob has retaining rails, but there’s a limit to that).

Forespar used to make a gimballed “bulkhead cooker” that addressed this; I have a salvaged one. They run on small butane containers, still widely available from camping gear stores. Nesting pots made for camping equipment likely fit the Forespar unit, if you can find one. Keeping a quart/litre of stew or soup or coffee hot strikes me as a very good thing for the watchstanders, and I’m sure the vicinity of the the gimballed stove makes its surroundings a little warmer. I’m not sure why they are no longer made. In the tropics, that “less heat” thing would be a benefit for morning coffee when compared to lighting up the stove.

Dick Stevenson

Hi Marc,
Yes, for sure you could not cook underway, hove to perhaps and motoring. I would also run my stove downwind sailing in moderate seas. I suspect a few rolls past the 10 degree heeling limit would be no problem. After all, the Refleks were designed for fishing boats where they run 24/7 in all conditions as I understand it and they certainly roll a bit.
The more I think about it, the more I wonder whether there has not been enough attention paid to alternative ways of preparing food on passage. We have more than once exchanged and gotten an empty gas tank. All sorts of things can happen to make the stove system to make it inoperable. With back up parts, one is likely to cobble together something but a passage without the ability to heat food would be a misery and possibly dangerous.
We used to have one of the Forespar gimbaling one pot cookers: in fact it was our only cooker on our first boat. You are right that it is a nice piece of kit but after a decade or 2 where it was never used, we sold it.
My best, Dick

Davide Zerbinati

Please remember that the heaters are not electrical insulated, so you if you have a metal hull, you have to install them insulated, especially the exhaust outlet.
In our 54′, the air heather can use cold air from the outside or air from the inside. This drop down the consume to 50% less. Off course we do it with max attention for CO2 problem and only for limited hours (we have dorade and main door open). The boat is insulated and this help a lot.
The hose is thermal insulated too. This reduce the heat dispersion in the lockers.

John Harries

Hi Davide,

Good point on the need to isolate heaters from the hull on metals boat. Our Espar, but it was quite a job requiring custom machined isolation rings for the exhaust where it passes through the deck and a break in the struts holding the chimney bridged with Delrin rods.

Dick Stevenson

Hi Colin,
I thought this field report might be of interest.
We just completed an overnight from Stornoway, Scotland, to Suduroy, a southern island in The Faroe chain. It started out mostly downwind and we sailed either DDW or broad reach in sloppy seas (are seas ever not sloppy in these parts?). It was cool/cold so we fired up the Refleks for the first time under way under sail for Alchemy.
Pretty soon it was pleasant below while the watch area (somewhat protected) was getting some benefit. The wind backed so the wing and wing went to a broad reach and then to a beam reach/broad reach in 12-20 knots.
Our average heel seemed to be 5-8 degrees, but the rolling was constant and took us up to 15 degrees regularly and certainly 20 degrees often. The Refleks seemed not to blink an eye. An added bonus was having hot water always at hand as the kettle was on the hob.
There were no drips in the drip pan nor any signs that the gravity feed to the burner was unhappy.
My best, Dick Stevenson, s/v Alchemy
Ps. Since we are talking about sailing in colder climes, and for those with a research inclination: . I have noticed that a 10 knot wind speed in 5C/40F is a far different animal than it is 20C/70F. I am continually impressed by how much more “weight” on the sails there is in colder air, but I do not have a clue where the equivalencies reside. Does 10 kn 10C wind = 20 kn 20 degree air/? Is there an easy formula?

Colin Speedie

Thanks, Dick, for this ‘on the road’ test.
my assumption (!) has always been that as the Refleks was designed for fishing boat use it would probably work OK if the boat was not staying in one plane constantly, i.e. downwind. Upwind or on a reach when the boat is always held in one plane I’d guess would be more of an issue as the fuel would tend to pour to one side in the burner. But I’ve never tried it…..
Your experience seems to suggest that a limited amount of heel is not necessarily an issue, but I’d still guess that any further amount of heel (constantly) might throw a spanner in the works.
Best wishes
Colin

Marc Dacey

I wouldn’t call it an easy formula (it’s known as Boyle’s Law and is quite venerable) but “ten percent more for cold air” seems to be a rule of thumb. I know my sail changes in May are quite different from those of August even on Lake Ontario. This (from Frank Singleton!) covers the idea: http://www.yachtingmonthly.com/sailing-skills/weird-weather-is-cold-wind-heavier-than-warm-wind-30897

Dick Stevenson

Hi Colin, Agree on all points. best, Dick