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
(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
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.