Air heater experience in cats.

[Ostinato]

Does anyone with a 12m (40ft) or so cat have any experience heating their boat with either a Webasto Air Top 2000 or Eberspacher Airtronic D2 and are they powerful enough to keep you warm?

I am considering replacing my two Wallas 30DTs for simpler systems. I am sure the Webasto Air Top 40 will do the job but would like to know if anyone has used one or more of these less powerful heaters. When the Wallas units worked they more than kept up with our heating needs and were never run flat out so I suspect the smaller units would suffice but am not sure. My previous system used two heaters – one each hull with the ducting going to the cabins. The return came from the saloon. I expect to keep that same air circulation with the Webastos.

[atoll]

how long is a piece of string!
there are too many variables ,like what is the outside temp,how well insulated is the boat location of heater outlets etc

a cored hull will have much better thermal insulation than fiberglass or plywood single skin as will covers on the windows etc.
heating vents at floor level in both hulls will distribute heat better than a single vent in the saloon.
winter in northern europe is not the same beast as winter in the med.
humidity levels and ventilation to combat condensation also need to be considered.

on my well insulated 37ft cat a 1000w fan heater soon heats up the boat when it is 5c outside.
on a 50ft cored FP with a 2-4kw engine blower fan in each hull,a single fan at the lower 2kw setting was enough to heat the boat on passage in 7c temps, with both fans running it was too hot on the lower setting!

running 1 heater unit your problem may be distribution to both hulls.
hence the boat having 2 units.

dr david lewis on Ice bird circumnavigating the antarctic found that a single candle was enough to make sufficient temperature difference between inside and outside temps to survive in below zero temps!

[rabbi]

Originally Posted by Ostinato

Does anyone with a 12m (40ft) or so cat have any experience heating their boat with either a Webasto Air Top 2000 or Eberspacher Airtronic D2 and are they powerful enough to keep you warm?

I am considering replacing my two Wallas 30DTs for simpler systems. I am sure the Webasto Air Top 40 will do the job but would like to know if anyone has used one or more of these less powerful heaters. When the Wallas units worked they more than kept up with our heating needs and were never run flat out so I suspect the smaller units would suffice but am not sure. My previous system used two heaters – one each hull with the ducting going to the cabins. The return came from the saloon. I expect to keep that same air circulation with the Webastos.

We had a FP Mahe 36 that we equipped it with a D2. This heated the saloon area maybe 8 degree Celsius above outside temp, or the smaller cabins even warmer (but not both).
That was good enough for off season cruising in the Med.

The new owner OTOH is crusing Dutch waters, and sail there even in winter around freezing temps. So he is looking for upgrade options


So beside the differences in insulation its depending on your needs.

[Ostinato]

Rabbi - thanks for your observations. Very helpful. That's only about 14F which would not be enough in higher latitudes for sure. We are leaving the Med this coming winter for higher latitudes so we'd better go with the bigger units.