Alternate heat source question
 

We have a 30' Islander sailboat that we sail all year round in the Puget
Sound. I'm fine with the weather in the right clothes while my wimpy wife
doesn't like sailing in 40 degrees. Our bulkhead doesn't have room for a
Force 10 type diesel heater. We've used an alcohol stove (wet heat), a
portable propane heater (toxic) and the propane stove oven (costly.) I was
just about out of ideas that would keep my best sailing buddy warm.
Then, a buddy of mine was out with me for the last three days and he came up
with an idea. He suggested that I pick up a car/truck heater and plumb it
into the hot water heater system. It would provide heat while we're under
way and allow us to go below and warm up once in a while.
Has anyone else installed a system like this and did it work?
Dan

Alternate heat source question
 

I would even be wimpy in 40 degrees with wind. Not all of us are easily
inspired by sailing in that type of weather.

Alternate heat source question
 

He suggested that I pick up a car/truck heater and plumb it
into the hot water heater system. It would provide heat while we're under
way and allow us to go below and warm up once in a while.


That's what small power boats have.

If you can find a stove you can live with, there is an old trick for heating
when at the dock. Put stove on low heat, invert a traditional terra cotta
ceramic plant pot and put it over the burner. It will heat up and radiate
nicely.

Henry.

Alternate heat source question
 

May be share a sleepingbag and bottle of port ;-)
--
c ya Wim
www.cruising.ca/thousand/f-index.html


"Weathered Rose" wrote in message
nk.net...
: I would even be wimpy in 40 degrees with wind. Not all of us are easily
: inspired by sailing in that type of weather.
:
:

Alternate heat source question
 

Henry:
We heard about that approach too. We subsequently heard that the potential
for carbon monoxide and other nasty gases is too likely. It would be fine
with the companion way open so it remains an option...

As far as the 40 degree temps: it keeps most of the Stink potters in their
slips and we then have the Sound to ourselves. It really is fantastic
sailing and doesn't get that cold very often. It's usually a balmy 50 or so
:)

Dan



"Henry" wrote in message news:_DhNb.96816$ts4.41405@pd7tw3no...

He suggested that I pick up a car/truck heater and plumb it
into the hot water heater system. It would provide heat while we're
under
way and allow us to go below and warm up once in a while.


That's what small power boats have.

If you can find a stove you can live with, there is an old trick for
heating
when at the dock. Put stove on low heat, invert a traditional terra cotta
ceramic plant pot and put it over the burner. It will heat up and radiate
nicely.

Henry.

Alternate heat source question
 

"DB" wrote in message
...
Henry:
We heard about that approach too. We subsequently heard that the potential
for carbon monoxide and other nasty gases is too likely. It would be fine
with the companion way open so it remains an option...


Were does the CO ( & other nasty gases ) come from in what is hot water
radiator?
Only possible source I can think of is exhaust from the engine but we are
all risk limited exposure to this when motoring.

As far as the 40 degree temps: it keeps most of the Stink potters in their
slips and we then have the Sound to ourselves. It really is fantastic
sailing and doesn't get that cold very often. It's usually a balmy 50 or
so
:)

Dan


JohnE

Alternate heat source question
 

"DB" wrote in message
...
We have a 30' Islander sailboat that we sail all year round in the Puget
Sound. I'm fine with the weather in the right clothes while my wimpy wife
doesn't like sailing in 40 degrees. Our bulkhead doesn't have room for a
Force 10 type diesel heater. We've used an alcohol stove (wet heat), a
portable propane heater (toxic) and the propane stove oven (costly.) I was
just about out of ideas that would keep my best sailing buddy warm.
Then, a buddy of mine was out with me for the last three days and he came
up
with an idea. He suggested that I pick up a car/truck heater and plumb it
into the hot water heater system. It would provide heat while we're under
way and allow us to go below and warm up once in a while.
Has anyone else installed a system like this and did it work?
Dan

Neat idea. All I do is remove the engine covers and let it radiate into the
cabin area. However, I do a VERY LITTLE boat. 18ft over the deck!

JohnE

Alternate heat source question
 

John:
I was referring to the "Flower Pot" cover over the propane burner producing
CO2. The hot water radiator would potentially avoid this problem and that's
why I'm exploring it.
We just lost a boating couple up here who turned on a propane heater and
went to sleep on the boat. They never woke up and I don't want join them
just yet.
Dan

"John.E" wrote in message
...

"DB" wrote in message
...
Henry:
We heard about that approach too. We subsequently heard that the
potential
for carbon monoxide and other nasty gases is too likely. It would be
fine
with the companion way open so it remains an option...


Were does the CO ( & other nasty gases ) come from in what is hot water
radiator?
Only possible source I can think of is exhaust from the engine but we are
all risk limited exposure to this when motoring.

As far as the 40 degree temps: it keeps most of the Stink potters in
their
slips and we then have the Sound to ourselves. It really is fantastic
sailing and doesn't get that cold very often. It's usually a balmy 50 or
so
:)

Dan


JohnE

Alternate heat source question
 

"DB" wrote in message
...
John:
I was referring to the "Flower Pot" cover over the propane burner
producing
CO2. The hot water radiator would potentially avoid this problem and
that's
why I'm exploring it.
We just lost a boating couple up here who turned on a propane heater and
went to sleep on the boat. They never woke up and I don't want join them
just yet.
Dan


I have to apologise as I missread the thread and was querying why an hot
water system would generate CO.

I am sorry to hear about your loss Dan.

JohnE

Alternate heat source question
 

My question is: what heats your hot water? Your engine cooling
system? If so, why not? You could get some useful heat out of
it, while cooling off your tank, even with the engine off. If
your engine is running, even on idle, you would have a source of
heat you could use, or even if you use a seperate fuelled system
to heat your water. Please don't tell me you use a 12v battery to
heat your water.

Terry K

DB wrote:

We have a 30' Islander sailboat that we sail all year round in the Puget
Sound. I'm fine with the weather in the right clothes while my wimpy wife
doesn't like sailing in 40 degrees. Our bulkhead doesn't have room for a
Force 10 type diesel heater. We've used an alcohol stove (wet heat), a
portable propane heater (toxic) and the propane stove oven (costly.) I was
just about out of ideas that would keep my best sailing buddy warm.
Then, a buddy of mine was out with me for the last three days and he came up
with an idea. He suggested that I pick up a car/truck heater and plumb it
into the hot water heater system. It would provide heat while we're under
way and allow us to go below and warm up once in a while.
Has anyone else installed a system like this and did it work?
Dan

--
Terry K - My email address is MY PROPERTY, and is protected by
copyright legislation. Permission to reproduce it is
specifically denied for mass mailing and unrequested
solicitations. Spamspoof salad by spamchock TM - SofDevCo ®

Alternate heat source question
 

We have one of these - it only works while the engine is running. While
there is some hot water still in the system after you shut down the engine,
it is not circulating so the water in the system cools very rapidly and is
of little use on a sailing boat.

Cheers

"DB" wrote in message
...
We have a 30' Islander sailboat that we sail all year round in the Puget
Sound. I'm fine with the weather in the right clothes while my wimpy wife
doesn't like sailing in 40 degrees. Our bulkhead doesn't have room for a
Force 10 type diesel heater. We've used an alcohol stove (wet heat), a
portable propane heater (toxic) and the propane stove oven (costly.) I was
just about out of ideas that would keep my best sailing buddy warm.
Then, a buddy of mine was out with me for the last three days and he came
up
with an idea. He suggested that I pick up a car/truck heater and plumb it
into the hot water heater system. It would provide heat while we're under
way and allow us to go below and warm up once in a while.
Has anyone else installed a system like this and did it work?
Dan

Alternate heat source question
 

Paddy:
"tis as I suspected it might be. Thanks.
Dan
"Paddy Malone" wrote in message
...
We have one of these - it only works while the engine is running. While
there is some hot water still in the system after you shut down the
engine,
it is not circulating so the water in the system cools very rapidly and is
of little use on a sailing boat.

Cheers

"DB" wrote in message
...
We have a 30' Islander sailboat that we sail all year round in the Puget
Sound. I'm fine with the weather in the right clothes while my wimpy
wife
doesn't like sailing in 40 degrees. Our bulkhead doesn't have room for a
Force 10 type diesel heater. We've used an alcohol stove (wet heat), a
portable propane heater (toxic) and the propane stove oven (costly.) I
was
just about out of ideas that would keep my best sailing buddy warm.
Then, a buddy of mine was out with me for the last three days and he
came
up
with an idea. He suggested that I pick up a car/truck heater and plumb
it
into the hot water heater system. It would provide heat while we're
under
way and allow us to go below and warm up once in a while.
Has anyone else installed a system like this and did it work?
Dan

Alternate heat source question
 

Dan--

Right off the bat let me say yes, you have to be sensible using the heating
system on my boat, a Westsail 32. It is a kerosene radiant heater. Yes, in
a tightly enclosed space it can be dangerous, even lethal. So the trick is
to make sure the heated space--the boat's cabin--is NOT tightly enclosed.
Typically we leave the hatch open, the butterfly hatch cracked, and the
forward hatch ajar, so there is plenty of air circulation. The capacity of
the heater is far more than adequate for the boat, so we can afford to
"waste" some heat with the circulating air. In fact, once the boat is
warmed up, we have to turn the heater off and on at intervals, to avoid
getting too hot in the cabin--and it's off at least half the time. Works
for us. Has for 10 years. In short, you use the heater exactly the way its
instruction manual says, and according to all the warnings on the unit--with
plenty of ventilation. We ALWAYS turn the heater off before hitting the
sack, of course.

And that clay flower pot on the cookstove burner is a good trick, too--for a
quick warmup. Same caveats about ventilation apply.

Great sailing in the winter, all right--we sail from Fisherman Bay on Lopez
Island. DON'T give that up!

Cheers, fair winds, and toasty toes to you,

Dick Behan


"DB" wrote in message
...
We have a 30' Islander sailboat that we sail all year round in the Puget
Sound. I'm fine with the weather in the right clothes while my wimpy wife
doesn't like sailing in 40 degrees. Our bulkhead doesn't have room for a
Force 10 type diesel heater. We've used an alcohol stove (wet heat), a
portable propane heater (toxic) and the propane stove oven (costly.) I was
just about out of ideas that would keep my best sailing buddy warm.
Then, a buddy of mine was out with me for the last three days and he came
up
with an idea. He suggested that I pick up a car/truck heater and plumb it
into the hot water heater system. It would provide heat while we're under
way and allow us to go below and warm up once in a while.
Has anyone else installed a system like this and did it work?
Dan

Alternate heat source question
 

Dick:
Thanks for you insights. If we didn't love our Islander so much, a Westy was
our other choice. We cruised into Fisherman Bay just last year. We draw
nearly six feet so the entrance there has a pucker factor to it. :-)
Do you know the brand name of your kerosene heater? I've been in West
Marine, Fisheries Supply, Home Depot and a few others looking for a small
footprint kerosene heater. No joy yet.

Dan

"R.W. Behan" wrote in message
...
Dan--

Right off the bat let me say yes, you have to be sensible using the
heating
system on my boat, a Westsail 32. It is a kerosene radiant heater. Yes,
in
a tightly enclosed space it can be dangerous, even lethal. So the trick is
to make sure the heated space--the boat's cabin--is NOT tightly enclosed.
Typically we leave the hatch open, the butterfly hatch cracked, and the
forward hatch ajar, so there is plenty of air circulation. The capacity
of
the heater is far more than adequate for the boat, so we can afford to
"waste" some heat with the circulating air. In fact, once the boat is
warmed up, we have to turn the heater off and on at intervals, to avoid
getting too hot in the cabin--and it's off at least half the time. Works
for us. Has for 10 years. In short, you use the heater exactly the way
its
instruction manual says, and according to all the warnings on the
unit--with
plenty of ventilation. We ALWAYS turn the heater off before hitting the
sack, of course.

And that clay flower pot on the cookstove burner is a good trick, too--for
a
quick warmup. Same caveats about ventilation apply.

Great sailing in the winter, all right--we sail from Fisherman Bay on
Lopez
Island. DON'T give that up!

Cheers, fair winds, and toasty toes to you,

Dick Behan


"DB" wrote in message
...
We have a 30' Islander sailboat that we sail all year round in the Puget
Sound. I'm fine with the weather in the right clothes while my wimpy
wife
doesn't like sailing in 40 degrees. Our bulkhead doesn't have room for a
Force 10 type diesel heater. We've used an alcohol stove (wet heat), a
portable propane heater (toxic) and the propane stove oven (costly.) I
was
just about out of ideas that would keep my best sailing buddy warm.
Then, a buddy of mine was out with me for the last three days and he
came
up
with an idea. He suggested that I pick up a car/truck heater and plumb
it
into the hot water heater system. It would provide heat while we're
under
way and allow us to go below and warm up once in a while.
Has anyone else installed a system like this and did it work?
Dan

Alternate heat source question
 

Dick:
Thanks for you insights. If we didn't love our Islander so much, a Westy was
our other choice. We cruised in and out of Fisherman Bay just last year. We
draw
nearly six feet so the entrance there has somewhat of a pucker factor to it.
:-)
Do you know the brand name of your kerosene heater? I've been in West
Marine, Fisheries Supply, Home Depot and a few others looking for a small
footprint kerosene heater. No joy yet.

Dan

"R.W. Behan" wrote in message
...
Dan--

Right off the bat let me say yes, you have to be sensible using the
heating
system on my boat, a Westsail 32. It is a kerosene radiant heater. Yes,
in
a tightly enclosed space it can be dangerous, even lethal. So the trick is
to make sure the heated space--the boat's cabin--is NOT tightly enclosed.
Typically we leave the hatch open, the butterfly hatch cracked, and the
forward hatch ajar, so there is plenty of air circulation. The capacity
of
the heater is far more than adequate for the boat, so we can afford to
"waste" some heat with the circulating air. In fact, once the boat is
warmed up, we have to turn the heater off and on at intervals, to avoid
getting too hot in the cabin--and it's off at least half the time. Works
for us. Has for 10 years. In short, you use the heater exactly the way
its
instruction manual says, and according to all the warnings on the
unit--with
plenty of ventilation. We ALWAYS turn the heater off before hitting the
sack, of course.

And that clay flower pot on the cookstove burner is a good trick, too--for
a
quick warmup. Same caveats about ventilation apply.

Great sailing in the winter, all right--we sail from Fisherman Bay on
Lopez
Island. DON'T give that up!

Cheers, fair winds, and toasty toes to you,

Dick Behan


"DB" wrote in message
...
We have a 30' Islander sailboat that we sail all year round in the Puget
Sound. I'm fine with the weather in the right clothes while my wimpy
wife
doesn't like sailing in 40 degrees. Our bulkhead doesn't have room for a
Force 10 type diesel heater. We've used an alcohol stove (wet heat), a
portable propane heater (toxic) and the propane stove oven (costly.) I
was
just about out of ideas that would keep my best sailing buddy warm.
Then, a buddy of mine was out with me for the last three days and he
came
up
with an idea. He suggested that I pick up a car/truck heater and plumb
it
into the hot water heater system. It would provide heat while we're
under
way and allow us to go below and warm up once in a while.
Has anyone else installed a system like this and did it work?
Dan

Alternate heat source question
 

Dick:
Thanks for you insights. If we didn't love our Islander so much, a Westy was
our other choice. We cruised in and out of Fisherman Bay just last year. We
draw
nearly six feet so the entrance there has somewhat of a pucker factor to it.
:-)
Do you know the brand name of your kerosene heater? I've been in West
Marine, Fisheries Supply, Home Depot and a few others looking for a small
footprint kerosene heater. No joy yet.

Dan

"R.W. Behan" wrote in message
...
Dan--

Right off the bat let me say yes, you have to be sensible using the
heating
system on my boat, a Westsail 32. It is a kerosene radiant heater. Yes,
in
a tightly enclosed space it can be dangerous, even lethal. So the trick is
to make sure the heated space--the boat's cabin--is NOT tightly enclosed.
Typically we leave the hatch open, the butterfly hatch cracked, and the
forward hatch ajar, so there is plenty of air circulation. The capacity
of
the heater is far more than adequate for the boat, so we can afford to
"waste" some heat with the circulating air. In fact, once the boat is
warmed up, we have to turn the heater off and on at intervals, to avoid
getting too hot in the cabin--and it's off at least half the time. Works
for us. Has for 10 years. In short, you use the heater exactly the way
its
instruction manual says, and according to all the warnings on the
unit--with
plenty of ventilation. We ALWAYS turn the heater off before hitting the
sack, of course.

And that clay flower pot on the cookstove burner is a good trick, too--for
a
quick warmup. Same caveats about ventilation apply.

Great sailing in the winter, all right--we sail from Fisherman Bay on
Lopez
Island. DON'T give that up!

Cheers, fair winds, and toasty toes to you,

Dick Behan


"DB" wrote in message
...
We have a 30' Islander sailboat that we sail all year round in the Puget
Sound. I'm fine with the weather in the right clothes while my wimpy
wife
doesn't like sailing in 40 degrees. Our bulkhead doesn't have room for a
Force 10 type diesel heater. We've used an alcohol stove (wet heat), a
portable propane heater (toxic) and the propane stove oven (costly.) I
was
just about out of ideas that would keep my best sailing buddy warm.
Then, a buddy of mine was out with me for the last three days and he
came
up
with an idea. He suggested that I pick up a car/truck heater and plumb
it
into the hot water heater system. It would provide heat while we're
under
way and allow us to go below and warm up once in a while.
Has anyone else installed a system like this and did it work?
Dan

Alternate heat source question
 

Dick:
Thanks for you insights. If we didn't love our Islander so much, a Westy was
our other choice. We cruised in and out of Fisherman Bay just last year. We
draw
nearly six feet so the entrance there has somewhat of a pucker factor to it.
:-)
Do you know the brand name of your kerosene heater? I've been in West
Marine, Fisheries Supply, Home Depot and a few others looking for a small
footprint kerosene heater. No joy yet.

Dan

"R.W. Behan" wrote in message
...
Dan--

Right off the bat let me say yes, you have to be sensible using the
heating
system on my boat, a Westsail 32. It is a kerosene radiant heater. Yes,
in
a tightly enclosed space it can be dangerous, even lethal. So the trick is
to make sure the heated space--the boat's cabin--is NOT tightly enclosed.
Typically we leave the hatch open, the butterfly hatch cracked, and the
forward hatch ajar, so there is plenty of air circulation. The capacity
of
the heater is far more than adequate for the boat, so we can afford to
"waste" some heat with the circulating air. In fact, once the boat is
warmed up, we have to turn the heater off and on at intervals, to avoid
getting too hot in the cabin--and it's off at least half the time. Works
for us. Has for 10 years. In short, you use the heater exactly the way
its
instruction manual says, and according to all the warnings on the
unit--with
plenty of ventilation. We ALWAYS turn the heater off before hitting the
sack, of course.

And that clay flower pot on the cookstove burner is a good trick, too--for
a
quick warmup. Same caveats about ventilation apply.

Great sailing in the winter, all right--we sail from Fisherman Bay on
Lopez
Island. DON'T give that up!

Cheers, fair winds, and toasty toes to you,

Dick Behan


"DB" wrote in message
...
We have a 30' Islander sailboat that we sail all year round in the Puget
Sound. I'm fine with the weather in the right clothes while my wimpy
wife
doesn't like sailing in 40 degrees. Our bulkhead doesn't have room for a
Force 10 type diesel heater. We've used an alcohol stove (wet heat), a
portable propane heater (toxic) and the propane stove oven (costly.) I
was
just about out of ideas that would keep my best sailing buddy warm.
Then, a buddy of mine was out with me for the last three days and he
came
up
with an idea. He suggested that I pick up a car/truck heater and plumb
it
into the hot water heater system. It would provide heat while we're
under
way and allow us to go below and warm up once in a while.
Has anyone else installed a system like this and did it work?
Dan

Alternate heat source question
 

DB wrote:

We have a 30' Islander sailboat that we sail all year round in the Puget
Sound. I'm fine with the weather in the right clothes while my wimpy wife
doesn't like sailing in 40 degrees. Our bulkhead doesn't have room for a
Force 10 type diesel heater. We've used an alcohol stove (wet heat), a
portable propane heater (toxic) and the propane stove oven (costly.) I was
just about out of ideas that would keep my best sailing buddy warm.
Then, a buddy of mine was out with me for the last three days and he came up
with an idea. He suggested that I pick up a car/truck heater and plumb it
into the hot water heater system. It would provide heat while we're under
way and allow us to go below and warm up once in a while.
Has anyone else installed a system like this and did it work?
Dan

After a little thought and reading the replies, It ocurred to me
that no one had suggested a small tent heater. You still need to
read the instructions air supply. A small vent to supply
combustion air and a small vent for exhaust is required.

External combustion devices could provide hor water for your
truck heater, for instance, a campstove full of coiled soft
copper tube inside the stove with the lid down, out on deck, with
rubber hoses and a small circulation pump?

As fas as 'alternate' energy sources goes, how about a similar
idea using a wood burner out on deck, with a hot water coil? Or a
stovepipe wrappped in copper tube with a fire log inside? You can
stop a firelog by stopping the air supply.

Now as far as electric heat is concerned, wouldn't it be nice if
we could get sails that were solar cells, or solid wing foils
with solar cells? We could use the juice to make hydrogen, and
use that to inflate a para wing sail. Smaller cells could pump up
H2 during the week, when most boats are parked. The H2 might
come to be a useful way to store energy without heavy batteries.

This raises a question: if you run an electrolysis cell, how
does the pressure in a close system affect the production of
gases? In such a system, would you need to contain the O2 in a
seperate tank from the H2? How do the pressures go, if the system
is let go on running? Would there be more H2, more H2 pressure,
and an imbalance of water heights in the collector tubes around
the electrodes? Would simply venting a little O2 restore the
levels?
--
Terry K - My email address is MY PROPERTY, and is protected by
copyright legislation. Permission to reproduce it is
specifically denied for mass mailing and unrequested
solicitations. Spamspoof salad by spamchock TM - SofDevCo ®

Alternate heat source question
 

Consider this...the coolant temp on an automobile gas engine reached 200+
degrees. Run your water heater that high and it will most likely blow up, not
to mention scald you the first time you even attempt to use it. If a water
heater produces 140F degree water, I doubt you will get more than a few degrees
rise in temperature at 40 degrees ambient temps using an automotive style
heater core.

Hoping to be on the water soon...Dennis

Alternate heat source question
 

"DDeanFountain" wrote
...... If a water heater produces 140F degree water, I doubt you will get
more than a
few degrees rise in temperature ... using an automotive style heater core.


This is true, but the rise may still be worthwhile if one keeps it cheap and
simple.

One could get a small car radiator or heater core and plumb it in series
with the water coming out of the motor going into the exhaust. It won't do
much because the water is only about 120 - 140 degrees but it's cheap,
simple safe, and should make a small cabin more comfortable - at least while
motoring. OTOH using water from a water heater is a waste. Whatever heated
that water would be better used to heat the cabin.

A small propane heater heats my whole house. It is so efficient that one
can *almost* hold one's hand on the metal chimney because the hot burned
gasses spend so much time giving up their heat in a metal labyrinth before
exiting. A 1/10 scale model would be perfect for a boat. I'm surprised
nobody makes one ... or do they?

The propane "furnace" in my motor home is little more than a foot square,
sits in a compartment that is outside the cabin for safety, and provides
forced air heat. One could mount one in a sail locker or a detachable "deck
house" like they do carry-on AC units.

A little ingenuity .....

Alternate heat source question
 

Probably a Shipmate brand, like the one I just removed from my boat.
It's not really needed given our location, but I can appreciate where
you're coming from. We just moved down from Sammamish, where we lived
for the past two years. We sure do miss cruising in the Sound.

Regards,

Louis
s/v Synergy
Westsail 32 #679
Miami, FL

"DB" wrote in message ...
Dick:
Thanks for you insights. If we didn't love our Islander so much, a Westy was
our other choice. We cruised in and out of Fisherman Bay just last year. We
draw
nearly six feet so the entrance there has somewhat of a pucker factor to it.
:-)
Do you know the brand name of your kerosene heater? I've been in West
Marine, Fisheries Supply, Home Depot and a few others looking for a small
footprint kerosene heater. No joy yet.

Dan

Alternate heat source question
 

FYI
I have a Coronado 25 and I looked at Mr. Heater "Portable Buddy" @
www.wheretofindbuddy.com
Runs on the same tank as my gas grill, that would no be being used at 40 deg
anyway.
I would need to see an ice breaker to get out any time soon, It's cold here
in Baltimore..........

Blue Skies,
JRS

"Vito" wrote in message
...

"DDeanFountain" wrote
...... If a water heater produces 140F degree water, I doubt you will
get
more than a
few degrees rise in temperature ... using an automotive style heater
core.


This is true, but the rise may still be worthwhile if one keeps it cheap
and
simple.

One could get a small car radiator or heater core and plumb it in series
with the water coming out of the motor going into the exhaust. It won't do
much because the water is only about 120 - 140 degrees but it's cheap,
simple safe, and should make a small cabin more comfortable - at least
while
motoring. OTOH using water from a water heater is a waste. Whatever
heated
that water would be better used to heat the cabin.

A small propane heater heats my whole house. It is so efficient that one
can *almost* hold one's hand on the metal chimney because the hot burned
gasses spend so much time giving up their heat in a metal labyrinth before
exiting. A 1/10 scale model would be perfect for a boat. I'm surprised
nobody makes one ... or do they?

The propane "furnace" in my motor home is little more than a foot square,
sits in a compartment that is outside the cabin for safety, and provides
forced air heat. One could mount one in a sail locker or a detachable
"deck
house" like they do carry-on AC units.

A little ingenuity .....