I know of a number of boat that have a similar setup. Webasto sells a whole
like of hot water based cabin heaters. So does Espar. I have seen several
boats that have used regular automotive heater cores. No problem other than
having to run the engine to get heat.

Doug

"Larry W4CSC" wrote in message
...
"Ken Heaton" wrote in
news:RZE1e.114238$fc4.16211@edtnps89:

I'd
forget about the electric heater unless you can stay below 400 watts

Can I ask a silly question? Geez, don't tell any of the yacht
professionals hanging around the dock if you do this, but why can't we
simply install an ENGINE POWERED HEATER like the beast that turns my
stepvan into an oven into the boat's cooling water loop, like the water
heater??......Silly me.

http://www.rustrepair.com/stepvan_pa...v&p=wi-heater-
ht.aux

The 6x7x6" 13,000 BTU small unit puts out TWICE as much heat as a 1500
watt
AC heater many of you have now. Just mount it up under a table near the
engine compartment to keep the hoses short and you're in business.

Bigger boat? I have the 20,000 BTU unit in the back of my stepvan and at
30F it will run you out in 10 minutes! They have a 33,000 BTU model if
you
need it. They are very small....no bigger than your little electric
heater
you keep tripping over in the passageway.

You'll need a heater control valve to control the water flow....
http://www.rustrepair.com/stepvan_pa...v&p=wi-heater-
ht.val

To be really nice, get one that uses a cable control....
54-062 62" cable with knob that mounts through a simple hole.

And a fan speed control....
http://www.rustrepair.com/stepvan_pa...sv&p=wi-heater
switch and resistor....

These units are all made to run from the helm of the stepvan with the
heater in the back so controls are separate.

Sure beats the hell out of running the engine and inverter to power that
crappy little heater in the passageway.....