Courtney Thomas wrote:
How do the forced air units compare with the hot water ?


The water units are more efficient in terms of amount of fuel burned per
BTU transferred to the cabin air, but they are more expensive and a bit
more demanding to install in most boats. Maybe a wash, unless you want
to put a heater in a space distant from the furnace. Then the hot water
makes sense.


Dennis Pogson wrote:
I would guess that pumping hot water at low pressure through radiators and
associated piping requires a lot less power than forced-air blowing.

Partly that, and partly that water-cooling a combustion chamber picks up
more heat over a smaller area.

... At
least, that is our experience, and the heat is much more evenly distributed.
Also, those areas which didn't need heat were simply turned off, or the
radiator stat was turned low to suit the environment/occupants. The system
is silent, which makes for peace and quiet. Drilling through bulkheads etc.
is a darned sight easier when the holes are merely 1" dia. or less, against
the 3"-4" holes required for air tubing.

True, but you have to provide routing both ways, and insulat the lines.
In our boat, I ended up drilling two 1 1/4" holes thru each space for
the heater lines. Still, that's less area and a bit easier to place, and
can carry more heat than a 4" air duct.



The heating unit is very quick to achieve operating temperature, and for
cold the system started to be effective in about 15 minutes. If an en-suite
radiator is inadvertently left full on, the heads would become a sauna!


That agrees with our experience. Between 10 ~ 15 minutes and the heaters
are hot. Takes a bit longer to warm up the space, but it's marvelous to
be able to warm your hands or feet at the radiator.


Although diesel-fired, our boat seemed to survive the winter on very little
fuel, admittedly, we had 2 * 60 gallon tanks, but the guage never seemed to
move much over winter.


We kept our boat (36' tug) toasty warm thru a NC winter, admittedly not
as cold as some but last winter was long & wet, for about 30 gallons of
diesel... actually that included a few short trips underway, too.

I am completely sold on this form of heating against the forced-air systems.


My wife loves our heater, and that makes it worth everything. IMHO the
forced air ones are easier to install with regard to the main unit and
if routing the ducts isn't a big problem. They pump out the heat pretty
quick. But the fans are noisier (our Webasto heater is totally silent
except for the clicking of the fuel pump, and maybe an occasional
whooshing in the furnace exhaust) and it's most often a problem to route
ducting to say a fore cabin. With the water heater, you can put the
radiators in series and heat several spaces from one loop. With air, you
need ducts to every space. And I've known several boats with toy 2"
ducting for both heat & A/C... not worth the bother, can't get enough
air thru it.

Fresh Breezes- Doug King

On Thu, 06 Oct 2005 08:42:21 -0300, Terry Spragg wrote:


At dockside, absolutely no question, electric heaters, with hot water tank
and a wood stove for back up in the event of power failure. I would burn
commercial firelogs in the stove when neccessary, and keep my rear wheel
drive cargo van back end full of them for ballast on slippery roads. I
would want a tiny woodstove, and would cut up the firelogs to suit it's
capacity using a coping saw.

Be careful on which fire logs. Some, ones with wax for instance, are not
suitable for woodstoves.

We have a small heater that works off of our propane tank. Don't have
heated water. This is our second year living aboard. The litttle
heater works great. And as a bonus people say that it and it's little
chimney look cute as hell

In my house boating days I used two oil filled wall mounted
electric heaters with built in fans and they worked great. I
had 60amp service to the boat
"Jim Richardson" wrote in message
...
On Sat, 08 Oct 2005 18:03:13 GMT,
Brian Whatcott wrote:
On Sat, 08 Oct 2005 09:55:54 GMT, "Dennis Pogson"
wrote:

Courtney Thomas wrote:
How do the forced air units compare with the hot water ?

Thank you,
Courtney

I would guess that pumping hot water at low pressure
through radiators and
associated piping requires a lot less power than
forced-air blowing. At
least, that is our experience, and the heat is much more
evenly distributed.
Also, those areas which didn't need heat were simply
turned off, or the
radiator stat was turned low to suit the
environment/occupants. The system
is silent, which makes for peace and quiet. Drilling
through bulkheads etc.
is a darned sight easier when the holes are merely 1" dia.
or less, against
the 3"-4" holes required for air tubing. Quickly drying
wet clothing and
washed items is an absolute godsend, and this alone makes
up for any
disadvantages of hot water heating.

The heating unit is very quick to achieve operating
temperature, and for
cold the system started to be effective in about 15
minutes. If an en-suite
radiator is inadvertently left full on, the heads would
become a sauna!

Although diesel-fired, our boat seemed to survive the
winter on very little
fuel, admittedly, we had 2 * 60 gallon tanks, but the
guage never seemed to
move much over winter.

I am completely sold on this form of heating against the
forced-air systems.


Dennis.

Interesting observations. In countries where the need is
for heating
only, nobody uses blown air. It's noisy, and its dirty.

But when the need is for cooling, circulating water
systems are not so
popular.

As soon as I typed this I realised that when computer
suites need
cooling, the system chosen is often circulating water
chillers.
So even where cooling/heating systems are needed, there is
room for
circulating water, seems to me.

Brian Whatcott Altus OK



Forced air also has some advantages. If your recirculating
water heating
system springs a leak, it's a mess, and may even damage
other systems.
If the forced air system leaks, then all it takes is a bit
of duct tape
to fix, if you want to bother. No need to bleed air out of
it either,
although that can also be avoided with a decent design in
the water circ
system.

--
Jim Richardson http://www.eskimo.com/~warlock
Strip Mining Prevents Forest Fires.

"Boots" wrote in news:1128978635_132625@spool6-
east.superfeed.net:

In my house boating days I used two oil filled wall mounted
electric heaters with built in fans and they worked great. I
had 60amp service to the boat


How'd ya keep the cord from getting wrapped around the prop??

--
Larry

wrote:
Interested in a discussion oriented towards people who are looking to
live aboard, of ways to safely heat a cruising sailboat at dockside.

SH


For the last two winters I have been using a Pelonius oil-filled
radiator-type heater. The one I have includes a timer so this allows me to
set 2 on-off cycles. I set it to turn on around 6AM to warm the boat up a
bit and then off at 8AM. It comes on again around 2PM to warm things up for
my return. It is a 1500 watt unit and I run it at full power instead of
lower settings. I find it adds about 10C to whatever temperature is
outdoors. I also have a small fan sitting behind it to blow air through the
radiator assembly. The thermostat for the unit is in the housing so I figure
it may shut off prematurely when the unit gets warm rather than the interior
air. The fan is an attempt to lessen this possibility and also distributes
the warm air. Last winter I didn't bother with the timers, just ran the unit
continuously at Medium and I noticed an increase in my electric bill. Just
going to set it up today for the first time this winter.

The boat, C&C 37, came with an Espar and I use this in the evening if it
gets particularly cold.