On Wed, 14 Jan 2004 12:36:42 -0800, "Rod McInnis"
wrote:


"Larry W4CSC" wrote in message
...


For those times, perhaps what is needed is a black plastic water
heater you could haul up the mainmast to heat some medium for the
night.

What you would need is thermal mass. The key word here is "mass". It will
take a lot of it, if you intend to pull heat out of it all night long. And
it will be heavy. How much weight would you feel comfortable hauling up the
mast?

How about we transfer the heat into the thousands of pounds of lead in
the KEEL? Is that mass enough??...(c;

I was referring to a way we could heat the cabin in the DAYTIME, to
reduce the cost of load of heating it, not eliminate it. If you
pumped air from the cabin up into a black plastic bag, of sorts,
exposed to the sun, the air coming back out into the cabin would be
more than enough to heat the boat in the daytime....for free.

I know someone who has homemade panels hanging from the
sunny side window sills to the ground below.

This works great IF you have a sunny exposure BELOW the area where you use
or store the energy. I have known people who live on a steep hill with a
southern exposure (northern hemisphere, which means that the slope gets a
lot of sun). It is somewhat common to construct a solar heater out of black
ABS pipe that runs down the hill a ways. Heating swimming pools is common,
but I know one person who had copper pipes embedded in the concrete slab of
his home and ciculated the warm water to heat the slab.

Agreed, hence the FAN to overcome the problem, forcing air to
circulate against its will into and out of the bag.

The key is that warm air/water will rise, so if the source of heat is lower
you can create a natural flow of water. If the source of heat is above,
then you will need to pump the water, and you may end up using more energy
pumping than you would have heating.

Rod

Pumping air into the thing is easy. 12V muffin fans draw almost no
power and move a LOT of air.