A LOAD OF HOT AIR
I am buying a 38ft Dutch steel cruiser and looking either to put a diesel air blower or oil-filled radiator system. I am wondering which would be best. JASON SMALL, via the CB website
TONY REPLIES: Assuming you mean a hot air version of the typical Webasto / Eberspächer type heater then they seem more reliable that the wet versions, but I would have the same reservations about running them for long periods at low output. You also need to factor in heat losses through the air ducting, but hiding the ducting will be less of a problem on a wide beam boat.
If you only use it on a shore line, the easiest and probably most reliable will be some form of electric heating, but if you intend to leave it on when you are away from the boat check your insurance documents very carefully. Electric heating from batteries or generators becomes very expensive and can ruin even the best batteries within months, but it all depends upon your charging equipment, regime and battery bank size.
Although gas is expensive to run, a bulkheadmounted, gas-fired hot air blower with thermostatic control might be suitable and relatively simple to install.
How do you intend to get hot water? If from the engine then perhaps something like a wet system with radiators and a twin coil calorifier fed by a Hurricane diesel boiler might do the job.
I chose a solid fuel stove and a gas-fired wet heating boiler with a room thermostat. Gas is arguably the most expensive boat heating but it is fast and when the stove is lit it spends a lot of time not running. During recent freezing conditions (-7C) we were perfectly warm and the stove ensured the gas boiler rarely ran once the boat was warm.
Air heaters are a good solution