Heating a Catamaran

[Nordic cat]

I have a friend who lives on his boat year round, and he uses a diesel based heater from Kabola, and has for several years. He loves it, and hasn't had a problem in 5-6 winters. Even at -10 C no problems.

See here: http://www.kabola.nl/kabolaEN.swf

Regards

Alan

[ssullivan]

Originally Posted by Nordic cat

I have a friend who lives on his boat year round, and he uses a diesel based heater from Kabola, and has for several years. He loves it, and hasn't had a problem in 5-6 winters. Even at -10 C no problems.

See here: http://www.kabola.nl/kabolaEN.swf

Regards

Alan

Thank you, Alan. Is it the Kabola "Old Dutch" model? Because that seems to be the only one that is a single poit source of heat. And he lives on a catamaran?

BTW: The coldest it got this winter where I'll be is -30C. It was a very low temperature, but I like to be prepared!

[David M]

Originally Posted by Southern Star

Sean, Philips suggestion makes some sense. I have read of people using a used car heater core from the heat-exchanger on the diesel - this would certainly be an effective and inexpensive way to get some additional heat when underway.

It not necessary to do that. There are heat exchangers that use waste heat from the generator or engine and use the engines coolant to run out to the heat exchanger. The heat exchanger has a small fan that blows air through the vanes. You could put a heat exchanger in each hull.

The downside is that it requires a 12v fan to work plus either the generator or main engine must be running.

I have one on my work boat and it works great. But then it is a powerboat.

[Nordic cat]

Originally Posted by ssullivan

Thank you, Alan. Is it the Kabola "Old Dutch" model? Because that seems to be the only one that is a single poit source of heat. And he lives on a catamaran?

BTW: The coldest it got this winter where I'll be is -30C. It was a very low temperature, but I like to be prepared!

He has a monohull, and it just heats the water that circulates to heaters in the cabin.

There was a family living on a 37 ft cat, who also used a hot water circulation system, but I never saw their boiler

[kevinmac]

I researched how to heat and provide hot water on a catamaran very thoroughly in the last few months. I bought a Maine Cat 30, and it is going into charter in the Pacific Northwest, and the charter company requires heat and hot water on the boat.

Diesel fired heat seems to be the most accepted way to go. Propane heat is no longer acceptable to many insurance companies. Electric (for dockside use only) is not efficient enough, and cannot be used at anchor. Wood is too heavy. (You probably are already aware that weight is more critical on cat than a mono, right?)

Diesel fired heat is available from three companies in the U.S. (for the most part, there are smaller outfits that I missed I imagine). Espar and Webasto compete for most of the business. Both of these have good parts support across the U.S., and internationally I am told. ITR also offers heating systems - indeed, Maine Cat installs ITR heating systems on Maine Cat 41s when requested. But support for ITR in terms of parts and service is weaker in the particular port where my boat will be (Bellingham), so I stopped investigating ITR.

Webasto and Espar make both forced air and hydronic (anti-freeze type liquid piped around the boat) systems.

The advantage of forced air is that it is instant on, and requires less maintenance. The disadvantage is that it requires ducting from your furnace, and the ducts are large (3 inches or so in diameter I am told). An advantage is that it uses less 12V electricity to run the furnace fan.

For many catamarans (or monohulls) forced air may be the best choice for heat. For hot water, most folks can use a heat exchanger off of their engine(s).

For boats where finding room for the ducting is a problem, or smaller boats like mine that use gasoline powered engines (twin outboards in wells) that cannot provide heat for hot water, hydronic is a better solution.

With hydronic, you can move the heat from the furnace in the back of the boat to anywhere you want it, and put a heat exchanger (radiator) with fan, theromstatically controlled. You can also use a heat exchanger to heat hot water.

Hydronic is not cheap though. The labor to install it is significantly more, and the furnaces are more.

The weak dollar has made both Espar and Webasto furnaces significantly more expensive recently. Last summer it looked like I could put a complete hydronic system in my 30' boat, parts and labor, for about $6000 US. Now just the furnace/pump is $3500 or so, and the complete 4 radiator installation with labor is in the $8000 to $10,000 range.

I had to tell the charter company I could not provide heat the first year. I will buy the parts myself this summer, and install it myself to save the larger labor costs.

Oh, one more thing. Heating, especially hydronic, uses a non-trivial amount of DC power. We sized the battery requirements for running the heat a couple of hours in the evening, and maybe an hour in the morning, but not continuously all night for example, and I still will have to add battery capacity to my boat.

I hope all that is useful to you in some way.

Kevin

[ssullivan]

Hmmm.... I hope to try and keep this thread focused. We have already had (ad nauseum) threads debating the different fuels and different heating systems.

Each person has their own personal preferences. Personally, I won't use fossil fuels. That's just my choice though.

My question was:

Has anyone heated a catamaran using a *point source* of heat?

My thoughts are currently to use a Little Cod in one hull, and an efficient fan to blow the hot air in the salon down into the other hull. If not the open fan up high, maybe I'll use a single air duct to blow hot air from hotter spot to a place down low in the unheated hull.

[Morgan Paul]

My thoughts are currently to use a Little Cod in one hull, and an efficient fan to blow the hot air in the salon down into the other hull

I don't have a catamaran or a wood stove in my boat yet. But I have used a small cast iron wood stove in my house. The stove is in the living room, and it is imposible for me to heat the bed rooms down the hall with fans. The reason for this is the stove heats by radiation. I am not saying it will not work for you, but in my situation I had very poor rusults. Another example is : My father heated the lower level of his house (on Block Island) with coal and driftwood. The 2nd floor never realy got comfortable even though he had an open set of circular stairs and many registers on the floor. You would think that heat rises, but no good, never worked. It heats by radiation.

[ssullivan]

Originally Posted by Morgan Paul

I don't have a catamaran or a wood stove in my boat yet. But I have used a small cast iron wood stove in my house. The stove is in the living room, and it is imposible for me to heat the bed rooms down the hall with fans. The reason for this is the stove heats by radiation. I am not saying it will not work for you, but in my situation I had very poor rusults. Another example is : My father heated the lower level of his house (on Block Island) with coal and driftwood. The 2nd floor never realy got comfortable even though he had an open set of circular stairs and many registers on the floor. You would think that heat rises, but no good, never worked. It heats by radiation.

Yeah, I do tend to agree. The true heat (read like sitting in the sunshine in the summer) comes from the stove radiating at you. Too far across the room, and it gets a little drafty. I guess once I get this cat, I'll have to work on this problem. It sure will be a lot more tricky than in a mono.

One important thing if you are relying on the rising heat is to have very good insuation. In my land boat, I started without any insulation other than the ceiling. We put in the heater and it was so-so. As it got colder, I insulated the walls and floor. What a difference!

Where the heat used to radiate only, it now lingered for a long time, and the top bunk bed got way too hot. The hot air rose in this case because it didn't have time to go out the walls before rising up, and didn't go out the ceiling once up high.

I think some experimentation on this boat is definitely in order.

Odd part is... the interior volume is FAR larger than my old 45' mono.

My wife was thinking maybe we could just section off a hull and reduce the area we need to heat when the real winter sets in. Another possibility...

[imagine2frolic]

This is just an example of heat rising. We use an ceramic heater in our head. That way in the morning the shower is comfortable, and not freezing. Last night being 33 degrees.

The head is located just before the port motor compartment. Leaving the door open it fills the head, and the warm air trickles out into the walkway at the foot of our bed. Now the warm air rises reaching our bed keeping us warm at night. Leaving the floor of the same walkway chilly. Once our bed is filled with warm air it spills out into the salon. This leaves the head toasty, our bed warm, and the salon keeps from freezing.

If heat didn't rise. Hot air ballons would never leave the ground. Maybe there wasn't enough heat to warm the 2nd floor.

[rick p]

Originally Posted by philip van praag

we use a wet system from a single point desil heater.

Yup - we have a Kabola on our boat which is a great source of heat and hot water. Maybe too heavy for a cat though.

Rick

[Morgan Paul]

My wife was thinking maybe we could just section off a hull and reduce the area we need to heat when the real winter sets in. Another possibility...

Sean, your wife sounds like a practical lady. I have no idea of the layout of the boat but that could work.

Last night being 33 degrees.

Sean bring your wife to Florida this way you don't have to worry about heating your boat.

[Pelagic]

Dickinson Marine plus some forced air venting

[ssullivan]

Originally Posted by Pelagic

Dickinson Marine plus some forced air venting

Thanks, Pelagic.

I like the forced air idea for venting, I think I'll give it a shot.

But I had one of those Dickinsons. They only put out less than half the heat my wood stoves do (as officially measured in BTUs on both websites - Dickenson: 12,000Btu, Little Cod: 29,000Btu). They aren't capable of heating a boat with the interior volume I am looking at, in the climates I live in, to an extent I like. Plus, if I don't keep my wife warm, I'm dead! ha ha

Also, I didn't like babysitting the flame so much or reliance on fossil fuel, or the staggering cost of operating it (diesel costs run something like $300/mo).

As a matter of fact, I have the Dickinson Lofoten with me right now and I'll be installing it for a temporary heater while I'm bringing the boat back up. There are bound to be some chilly nights... down in the 30's on my way up.

For clarity, the lowest it got where we are this winter was -24 deg F. It was quite a cold snap, but it happened. I need real heat to deal with that.

Those heaters just aren't capable of true heat you need for winter (in Maine) liveaboard situations in a volume the size that we're talking in a cat.

Great for warmer climates like VA, CA, etc...

[Pelagic]

I think Sean, the secret of having a economical heating plan in your type of winter conditions is to also look at ways of improving insulation to keep the heat in.

Then the BTU’s you make will last much longer

[ssullivan]

Originally Posted by Pelagic

I think Sean, the secret of having a economical heating plan in your type of winter conditions is to also look at ways of improving insulation to keep the heat in.

Then the BTU’s you make will last much longer

Absolutey. No question about it. It's vital to put in a ton of insulation, or even the 29K BTUs isn't enough.