A Thought About Heat

[Dockhead]

I've thinking about heating systems for my hypothetical new boat.

I sail in cold places and plan to sail in even colder places, so heat is mission-critical and even a life safety issue.

In my opinion diesel-fired hydronic systems are functionally superior to other types of heat, but they have a big disadvantage in that the furnaces are not easily user serviceable, and they do need service from time to time.

So I thought to back up the hydronic system with a pot-type heater with coils, maybe in the pilot house. Something which would allow you to see the flames, which would be cozy.

One reason why the hydronic furnaces coke up and require service is running with light loads. It occurred to me that two birds might be killed with one stone by installing TWO of them in series, a small one and a larger one. You could run both when you need max heat -- initial warming of the boat, or really cold weather. Then shut one down and continue on the small one for maintenance heat. There would be two of them, so if one stopped working while cruising in a remote place, you'd still have the other. No special control system would be required. Just have two control panels and do it manually. I wish you could get a readout of what heat stage each furnace is using -- they do Low, Medium, High, and Power, and I wish to hades that I could see which at any given time.

If complexity were not object (it always is an object, so this is purely hypothetical), other things on my dream wish list:

1. Engine and generator cooling circuits spliced in with plate-type heat exchangers.

2. Some kind of heat storage so that the engine or generator waste heat could be stored.

3. Separate kerosene (paraffin) tank to supply the heaters periodically, to burn off carbon and extend the service interval.

4. Radiators instead of fan coils wherever possible for zero power consumption and noise. Maybe supplemented with fan coils for when high output is needed.


I would think that this would be robust enough for remote area polar cruising. You could carry parts, diagnostic harness, and even a complete spare furnace, if you wanted to.

[Hanksy]

Great idea putting in 2. Wouldn't be zero noise though. You'd hear the water being pumped through the rads but alot quieter than air.
Radiators are standard practice on inland liveaboards in the UK. Usually heated by an solid fuel stove because firewood is easy to find.
I've been doing some thinking on this for a boat I'm working on now and I've figured an Diesel heater + radiators is the way to go.
Have you read Amyr Kilinks book about circumnavigating are Antarctica? He had a diesel heater that had coking problems and it caught fire when he was ashore. Can't remember what caused the fire but he explains it in the book

Sent from my HUAWEI SCL-L01 using Cruisers Sailing Forum mobile app

[hpeer]

I would go with 2 diesel forced air heaters. Besides providing redundant heat it also keeps the air hose runs down. Then carry a third for spare. If you got the pockets.

[Dockhead]

Originally Posted by Hanksy

Great idea putting in 2. Wouldn't be zero noise though. You'd hear the water being pumped through the rads but alot quieter than air.
Radiators are standard practice on inland liveaboards in the UK. Usually heated by an solid fuel stove because firewood is easy to find.
I've been doing some thinking on this for a boat I'm working on now and I've figured an Diesel heater + radiators is the way to go.
Have you read Amyr Kilinks book about circumnavigating are Antarctica? He had a diesel heater that had coking problems and it caught fire when he was ashore. Can't remember what caused the fire but he explains it in the book

Sent from my HUAWEI SCL-L01 using Cruisers Sailing Forum mobile app

Thanks; hot tip! So to speak

[Dockhead]

Originally Posted by hpeer

I would go with 2 diesel forced air heaters. Besides providing redundant heat it also keeps the air hose runs down. Then carry a third for spare. If you got the pockets.

Forced air is ok on smaller boats, but it's really hard to distribute heat around a 65' boat with it. You can run a hydronic pipe anywhere, but an air duct -- not so much.

Plus you can't use waste heat nor can you heat water.

I have hydronic now and wouldn't go back to forced air.

[atoll]

first thing to do if you are building the boat from scratch is to plan to have 3-4 inches of insulation throughout,including under the floors,with double glazed hatches and windscreens.

2nd is to place your radiators at the lowest level possible,ie floor level if using a hydronic system with passive radiators.

this system should also include a loop in to the engines cooling system,so you can heat the boat when running the engine.

this I would back up with a blown air system in the pilot house for instant heat,and a 4kw woodburner in the main living area or gravity fed diesel with a loop into the radiators.

you also need to plan to have ventilation otherwise condensation can be a problem

[TJ D]

I think that you are on precisely the right track with the 2 units. We are using a 30,000 btu Webasto hydronic system, and it definitely does not like moderately chilly nights. Too many cycles on and off and short burn times equals a fouled burner from time to time.

I think that a 40k and a 10k unit would be about perfect for a well-insulated boat in the 60's.

Either that or do a single larger hydronic and then a conventional diesel stove with a coil or two. I had one of these on a previous boat, with a coil built in, and also a heat exchanger in the stack ducted to another part of the boat, and it was pretty good for a 44 footer.

You would have the added bonus of having a heating system not dependent on the boat's electrical system with this arrangement. .

For my part, I definitely did not like the open flame effect out in the salon. I just couldn't help waking up in the aft cabin and being briefly alarmed by the flickering of flames up forward. I never fully got over it.

I would also note that most of the certifiable high-latitude types have gone to gravity fed stoves, just because they mostly were having a hard time keeping the hydronic units running.

I paid 'Sauvage' (one of the Ushuaia/Antarcic charter boats) a visit in Dutch Harbor a few years ago, and they were heating with just a Reflex heater with 2 coil setups let to radiatiors forward, and they were quite happy and comfortable with it. Their advice was to install 2 stacks, as tall on the exhaust as you could make it. I followed this guidance with my stove, and found the results to be dramatic. Much better, more consistent burn. I used to get a lot of backdraft when sailing on one tack, and this was eliminated by the intake stack.

Sorry if I did nothing but muddy the waters. No single answer, I guess.

Good sailing. Thanks for the advice a couple of weeks ago, too.

TJ

[Dockhead]

Originally Posted by atoll

first thing to do if you are building the boat from scratch is to plan to have 3-4 inches of insulation throughout,including under the floors,with double glazed hatches and windscreens.

2nd is to place your radiators at the lowest level possible,ie floor level if using a hydronic system with passive radiators.

this system should also include a loop in to the engines cooling system,so you can heat the boat when running the engine.

this I would back up with a blown air system in the pilot house for instant heat,and a 4kw woodburner in the main living area or gravity fed diesel with a loop into the radiators.

you also need to plan to have ventilation otherwise condensation can be a problem

Thanks -- all very good thoughts.

I will definitely have a ton of insulation (will probably be a metal boat, so this is not optional). For ventilation I will have something like what I have now -- a lot of oversize dorades, plus lots of opening hatches and windows above deck.

For hatches, I love the ones Noelex and SWL picked out when specifying their new boat. tempered glass, double-glazed, and gorgeous. A far cry from the plastic Lewmar hatches our boats have (although I must say the plastic Lewmar hatches are excellent for waterproofness).

What about heat storage, to maximize the value of engine/generator waste heat?

[Dockhead]

Originally Posted by TJ D

I think that you are on precisely the right track with the 2 units. We are using a 30,000 btu Webasto hydronic system, and it definitely does not like moderately chilly nights. Too many cycles on and off and short burn times equals a fouled burner from time to time.

I think that a 40k and a 10k unit would be about perfect for a well-insulated boat in the 60's.

Either that or do a single larger hydronic and then a conventional diesel stove with a coil or two. I had one of these on a previous boat, with a coil built in, and also a heat exchanger in the stack ducted to another part of the boat, and it was pretty good for a 44 footer.

You would have the added bonus of having a heating system not dependent on the boat's electrical system with this arrangement. .

For my part, I definitely did not like the open flame effect out in the salon. I just couldn't help waking up in the aft cabin and being briefly alarmed by the flickering of flames up forward. I never fully got over it.

I would also note that most of the certifiable high-latitude types have gone to gravity fed stoves, just because they mostly were having a hard time keeping the hydronic units running.

I paid 'Sauvage' (one of the Ushuaia/Antarcic charter boats) a visit in Dutch Harbor a few years ago, and they were heating with just a Reflex heater with 2 coil setups let to radiatiors forward, and they were quite happy and comfortable with it. Their advice was to install 2 stacks, as tall on the exhaust as you could make it. I followed this guidance with my stove, and found the results to be dramatic. Much better, more consistent burn. I used to get a lot of backdraft when sailing on one tack, and this was eliminated by the intake stack.

Sorry if I did nothing but muddy the waters. No single answer, I guess.

Good sailing. Thanks for the advice a couple of weeks ago, too.

TJ

Muddying the waters is kind of what I was hoping -- more information, more points of view. Thanks for that.

I found this alarming:

"I would also note that most of the certifiable high-latitude types have gone to gravity fed stoves, just because they mostly were having a hard time keeping the hydronic units running. "


Practical experience is better than theory.

I have looked at Reflex stoves, but really don't like the fact that you can't modulate the heat output. Also, the stack is a PITA and in the way. I haven't definitely crossed it off my list, however.

[minaret]

I'll just mention Olympia one more time. Just serviced my OL60, it doesn't coke at all. Maintenance involves replacing the filter and nozzle, and exchanging the antifreeze followed by burping the system. Super low maintenance. These systems get less calls for maintenance than any other. Just ask the guys at Sure Marine. It's a 110V system built for big boats, the 60k BTU is their smallest unit. Super low draw, mine runs over night on inverter without pulling much juice at all. 110V means it's a much more robust system. Many components in a 12V system are constantly working near capacity. These things are made with Riello burners. They are basically custom made from high end house furnace parts. Blows the competition away. Have worked on all major brands, and it's night and day between performance and maintenance. Olympia is also by far the quietest system I have ever been around.

[atoll]

Originally Posted by Dockhead

Thanks -- all very good thoughts.

I will definitely have a ton of insulation (will probably be a metal boat, so this is not optional). For ventilation I will have something like what I have now -- a lot of oversize dorades, plus lots of opening hatches and windows above deck.

For hatches, I love the ones Noelex and SWL picked out when specifying their new boat. tempered glass, double-glazed, and gorgeous. A far cry from the plastic Lewmar hatches our boats have (although I must say the plastic Lewmar hatches are excellent for waterproofness).

What about heat storage, to maximize the value of engine/generator waste heat?

once you stop running the engine if it has a loop through the cooling system it will cool very quickly,so heat storage would be negligiable,but you would be able to continue using the residual heat until you close the loop,and switch to the gravity fed heater or hydronic heater loops,simple 3way valves in the piping circuit would allow you to do this.

this would allow 3 switchable alternate sources of heat for your radiator system.

in our pilot house we have quite large windscreens which always drip condensation from the frames (120x80cm x2 and 60x200cmx2) a real pita! double glazing with 4mm acrylic on the inside would go a long way to alleviating this problem, plus stop a great deal of heat loss.

this I would put high on the list when designing the boat

if the boat is well sealed and insulated you will be surprised how little heat it requires to keep warm.

on the other side of the river we have a few friends with large wooden boats most are in the 60 ft range and open plan with 3inch wood planking, a 4kw morso woodburner keeps them toasty due to the great insulation properties of wood .

[Dockhead]

Originally Posted by atoll

once you stop running the engine if it has a loop through the cooling system it will cool very quickly,so heat storage would be negligiable,but you would be able to continue using the residual heat until you close the loop,and switch to the gravity fed heater or hydronic heater loops,simple 3way valves in the piping circuit would allow you to do this.

this would allow 3 switchable alternate sources of heat for your radiator system.

in our pilot house we have quite large windscreens which always drip condensation from the frames (120x80cm x2 and 60x200cmx2) a real pita! double glazing with 4mm acrylic on the inside would go a long way to alleviating this problem, plus stop a great deal of heat loss.

this I would put high on the list when designing the boat

if the boat is well sealed and insulated you will be surprised how little heat it requires to keep warm.

on the other side of the river we have a few friends with large wooden boats most are in the 60 ft range and open plan with 3inch wood planking, a 4kw morso woodburner keeps them toasty due to the great insulation properties of wood .

For heat storage, I was thinking something like a large hot water tank.

1 liter of water can hold 60 watt/hours of energy over 40C range of temperature (say 80 to 40), so 100 liters is 6kW/h. 200 liters would be 12kW/h which seems to me like maybe a useful amount of heat.

So if you had an extra-large domestic hot water tank, well insulated, and ran your hydronic loop through it, it seems to me like you could get 3 or 4 hours of moderate heat out of it, after you shut the main engine down.

It would be even more useful with the generator. In moderate weather where you need just a bit of heat, it seems to me that you might be able to largely avoid using the diesel furnace at all.

I wonder if anyone has tried something like this.

As a bonus you would have super deluxe inexhaustible domestic hot water. We do love our hot showers.


As to how much heat is required to stay warm -- a lot, notwithstanding your friends' experience. My boat is pretty well insulated and doesn't suffer from much condensation, but I'm using 3.5kW of electrical heat (100% efficient) right now, and it barely keeps the salon and aft cabin at 18C in this weather (2 to 8C, not that cold). One probably I have is really good ventilation, which sucks the heat right out of the boat when the wind blows.

I have a 10kW Eber and it cannot get the boat to 20C when the temperature is below freezing. That might be a limitation of my distribution capacity, however, as I have rather crappy fan coils, but I think I would want about 15kW of total capacity on the new boat.

[witzgall]

Here is my take.

1. Carry a spare complete heater. If you need to service the unit, just swap them out. When we install hydronic systems, we put valves to isolate the heater, and each fan unit.
2. Bring spare axial fans, fuel pump, and any other critical component.

3. Install a single "Emergency" cabin heater that works off of the engine cooling circuit.

Some of the heaters have multiple heat settings, so get one of these. The Espar Mii-12 have five settings. One power, that only applies for the 1st 30 minutes, and four lower ones. You can install a small kerosene tank with a valve so that you can use kero to keep it clean. run the heater once a month, off of this tank.

Chris

Originally Posted by Dockhead

I've thinking about heating systems for my hypothetical new boat.

I sail in cold places and plan to sail in even colder places, so heat is mission-critical and even a life safety issue.

In my opinion diesel-fired hydronic systems are functionally superior to other types of heat, but they have a big disadvantage in that the furnaces are not easily user serviceable, and they do need service from time to time.

So I thought to back up the hydronic system with a pot-type heater with coils, maybe in the pilot house. Something which would allow you to see the flames, which would be cozy.

One reason why the hydronic furnaces coke up and require service is running with light loads. It occurred to me that two birds might be killed with one stone by installing TWO of them in series, a small one and a larger one. You could run both when you need max heat -- initial warming of the boat, or really cold weather. Then shut one down and continue on the small one for maintenance heat. There would be two of them, so if one stopped working while cruising in a remote place, you'd still have the other. No special control system would be required. Just have two control panels and do it manually. I wish you could get a readout of what heat stage each furnace is using -- they do Low, Medium, High, and Power, and I wish to hades that I could see which at any given time.

If complexity were not object (it always is an object, so this is purely hypothetical), other things on my dream wish list:

1. Engine and generator cooling circuits spliced in with plate-type heat exchangers.

2. Some kind of heat storage so that the engine or generator waste heat could be stored.

3. Separate kerosene (paraffin) tank to supply the heaters periodically, to burn off carbon and extend the service interval.

4. Radiators instead of fan coils wherever possible for zero power consumption and noise. Maybe supplemented with fan coils for when high output is needed.


I would think that this would be robust enough for remote area polar cruising. You could carry parts, diagnostic harness, and even a complete spare furnace, if you wanted to.

[Terra Nova]

Originally Posted by atoll

first thing to do if you are building the boat from scratch is to plan to have 3-4 inches of insulation throughout,including under the floors,with double glazed hatches and windscreens.

2nd is to place your radiators at the lowest level possible,ie floor level if using a hydronic system with passive radiators.

this system should also include a loop in to the engines cooling system,so you can heat the boat when running the engine.

this I would back up with a blown air system in the pilot house for instant heat,and a 4kw woodburner in the main living area or gravity fed diesel with a loop into the radiators.

you also need to plan to have ventilation otherwise condensation can be a problem

Good post.

[Dockhead]

Originally Posted by minaret

I'll just mention Olympia one more time. Just serviced my OL60, it doesn't coke at all. Maintenance involves replacing the filter and nozzle, and exchanging the antifreeze followed by burping the system. Super low maintenance. These systems get less calls for maintenance than any other. Just ask the guys at Sure Marine. It's a 110V system built for big boats, the 60k BTU is their smallest unit. Super low draw, mine runs over night on inverter without pulling much juice at all. 110V means it's a much more robust system. Many components in a 12V system are constantly working near capacity. These things are made with Riello burners. They are basically custom made from high end house furnace parts. Blows the competition away. Have worked on all major brands, and it's night and day between performance and maintenance. Olympia is also by far the quietest system I have ever been around.

Thanks for reminding me; I'll have another look.

The most obvious disadvantage of this furnace is that it is HUGE compared to the ordinary marine hydronic furnaces. It weighs 100kg! It's the size of a small generator. I guess it would be much easier to service, however -- just like what you have at home.