How Do Folks Heat Their Multihulls

[ImaginaryNumber]

Although I don't know any details, I understand that one multi in northern Europe used a central heater with radiators in each hull. They didn't like forced-air. Too noisy. They also hung a sail or tarp in front of and behind the deck bridge, between the hulls, to reduce the cold air flow between the hulls and underneath the deck. Obviously, this would only work while at anchor.

John

[Nordic cat]

There is an older 37 ft FP cat here in Denmark that has been used as a liveaboard by a family. They plumbed in a hot water central heating system from a small oil fired boiler.

I just spoke to a guy on a liveaboard steel motorboat here, he has installed an extra internal "window" on all hatches etc.

He uses a plumbed hot water system as well, as the air based ones are don't offer good temperature control in the different parts of the boat, you can only have 1 control place. He uses a dutch built boiler, can't remember the name..

Alan

[Captain Bill]

The Cruiseair heat pumps in my endeavourcat work well at the dock, but you have to run the genset on the hook. They work fairly well until the water temp gets below 5 C. Of course as the water gets colder they become less efficient. Below 4 C you are in danger of ice forming in the heat exchanger, so if water gets colder than that where you live they won't work for you. Water temps here in NC tend to bottom out at about 6, but on rare occasions they will get lower for short periods. I personally don't like to have sea cocks open when I'm away from the boat so I have a pair of forced air heaters from West Marine that I use at the dock to prvent stuff from freezing. They have a no freeze setting which turns them on when the temp gets below 38F. I'm thinking of adding a small hydronics unit to the engine cooling loop. I hate that when I'm motoring in the winter that I have to dump all that heat overboard without warming my cabin.

[Rvrratt]

Try an econo-heat panel in areas where you sleep. Works in Minnesota quite well. Uses 400 watts and has an option for a thermostat. Their cheap, efficent, noiseless and no moving parts. (radiant heat) You would need a couple for a boat that size to do the whole boat. If you only need it for mild nights (20's to 40's) in your sleeping area, you could perhaps run it off an inverter if your batt bank is large enough as it would not be "on" all the time.

[cat man do]

Originally Posted by capcook

Other than taking them south for the winter.

What about taking them North?

[YOGAO]

Use a hydronic heating system. Install the boiler in an engine compartment so you can vent the Carbon MONOXIDE out of the boat. Cover the hatches with plastic wrap. Get a shammy or two and police the areas where condensation occurs.

Hydronic heating is great since it blows hot air unlike a reverse cycle heating system. The boiler uses diesel and its fairly efficient (of course the boat is not very well insulated). You can also set it up to heat your hot water (great when you are not able to plug into shore power). Finally, you can run the hot water tubes through the other engine compartment and then you do not have to winterize either engine.

Fair Winds,
Mike

[kiapa]

unless you're full-time in the tropics, heat is really nice to have!!!
we've used webasto diesel heaters on our last three boats, one forced air and two hydronic. they're great systems, and because they're diesel... you don't have to carry anything extra around. due to the incredible volume of the boat, we opted for a hydronic system on our cat. we went with webasto's 2010 furnace and 5 fan-radiator units -- two small ones in each hull and one big one on the bridgedeck. we also thru in a small exchanger so we could have diesel-fired hot water for showers in cold places.

we've got a crude systems diagram @ http://www.kiapa.com/the2ndgoing/des...derations.html

[DRS]

Espar diesel fired furnace mounted in the stb engine compartment. Ducted hot air vents throughout the boat. Furnce combustion air taken from and exhaust exits to extrerior of boat. Cold air return to furnace ducted from low point in stb cabin. Small amount of 12V draw while fan is working. Toasty warm