I am considering a propane refrigerator on my 40' catamaran.
These propane fridges don't work well with monohulls
unless gimballed but cats do quite well with them. Gemini
cats use them as standard equipment (and they seem to
require little maintenance). My priorities are lightest
weight and reliability. I kept hearing "we've had a propane
fridge for 10+ years with no problems" on the Gemini owners
list.

If I went this route, it would be installed on the
bridgedeck cabin, venting into the cockpit and installed in
a gas tight box, separate from the rest of the boat.

I thought I would just take a stab at rough costs and weight
of two options. The results surprised me:

PROPANE

Weights: (lb)
1 extra 20 lb tank (aluminum) 13
full of propane 20
Norcold 5 ft^3 fridge 99
extra insulation 10
hose, fittings 4
Total weight 146 lbs

Costs:
20 lb tank 125
Norcold fridge 1000
extra insulation 50
hose/fittings 50
Total $1405

(I would already have regulator, alarm, solenoid because I
will have a propane stove)

ELECTRIC FRIDGE

Weights: (lb)
Home made box 50 lb
Ice box conversion kit 20 lb
extra solar panels 2x75 watt 35 lb
extra battery capacity ~120 lb
(say 2x60 lb golf cart batteries)
Total weight 225 lbs

Costs:
Home made box 100
Ice box conversion kit 850 (through careful shopping)
solar panels 650
extra battery 120
Total costs: $1720

I started this exercise convinced that a propane fridge
would be too heavy but now I'm leaning the other way! The
only variable I have left out of the cost side of things is
the cost of propane. But say the 20# tank lasts 1 month;
that's $150-200/year in extra propane. Probably the
increased reliability and lack of maintenance vs. an
electric fridge would offset this to some degree.

Now all I have to do is put some heating coils in the back
of the fridge to heat hot water and I'm set. No need for a
propane on demand hot water heater because the fridge is
doing the work for you. (o.k. I'm kidding about this)

Somebody tell me where I'm missing something on the
cost/weight comparison please!

Evan Gatehouse

Evan Gatehouse writes:

Somebody tell me where I'm missing something on the
cost/weight comparison please!

Your analysis purports to show propane being a better store of energy than
batteries.

If hydrocarbon fuels had better energy density than lead-acid batteries,
then we'd all be driving those extinct gasoline automobiles of yesteryear
instead of the electric cars we all drive these days.

Hi Evan,

Don't forget that costs of propane are only while underway/on anchor.
While at the dock almost all of these units switch to A/C.

I don't know the efficience of the model you mention, but I've had
Dometic propane refer for over 20 years on my mono-hull and it has
always worked just fine including long passages and once crossing the
Gulf Stream on our ear.

BTW, Dometic no longer produces the exact model we built into our
interior. It was their smallest unit but operates on propane or AC/DC
(DC draws too many amps to be practical). If they have a fault it is
their tendency to quit being efficient on propane after about five
years(we are on our fourth unit)despite working just fine on AC. Maybe
it has to do with living aboard full time in the tropics and salt air.

Also, so far as costs go, I've never run into anyone who has propane
who has ever had a repair problem....they simply don't seem to break
(sometimes require a cleaning of the burner orifice every couple of
years).

Good luck, hope you get out there soon

On Mon, 02 May 2005 23:14:25 -0700, Evan Gatehouse
wrote:


No expert info here, although I have lived in vans that used gas
fridges and they work fine. They would not get the rocking that sea
would cause, but get a fair battering from road travel.

You need to look at the cost of fuel, or an extra bit on the wind
turbine/solar panel to generate electricity to run an electric fridge
as well. I don't know if you're looking at a eutectic style, but even
they draw pretty fair current to work well.

rant on...........
Mind you, that may be hard to find out. Don't ya love the following
specs and the terms? Current in amp-hours and energy in amps.
(astrerisks are mine)

http://old.cruisingworld.com/joecold/coltest5.htm

"12-VOLT COOLING SYSTEM: Time to cool refrigerator from 65°: 38 min.
**Current used: 25.5 amp-hrs**. Time to cool freezer from 65°: 1:34
min. **Current used: 52.5 amp-hrs**. Refrigerator perfomance: Time to
freeze refrigerator plate: 30 min. Current used to freeze refr. plate:
16.9 amp-hrs. Daily (24-hr.) current required: 12.2 amp-hrs. Freezer
performance: Time to freeze freezer plate: 35 min. Current used to
freeze freezer plate: 19.3 amp-hrs. Daily (24-hr.) current required:
44.9 amp-hrs."

and then the real killer.....

"DAILY **ENERGY REQ: 57.1 amps.**"

If they mean the daily energy required is 57 amp-hours, that's quite a
drain on a battery. You need about 2 amps 24 hours per day to keep up.

And then there is this, just in case you need to know how well solar
works
http://www.quirks.com.au/autofrdg.htm
"**SOLAR-PORT* Large: 2 x 50 watt solar modules in suitcase
configuration. Output from these modules would be approximately
**5.8 amps per hour** of peak sunlight (for a location such as Sydney,
the average daily output during summer months would be **~35 amps per
day** to a 12 Volt storage battery). "

rrgghhrrgh!

rant over

I am considering a propane refrigerator on my 40' catamaran.
These propane fridges don't work well with monohulls
unless gimballed but cats do quite well with them. Gemini
cats use them as standard equipment (and they seem to
require little maintenance). My priorities are lightest
weight and reliability. I kept hearing "we've had a propane
fridge for 10+ years with no problems" on the Gemini owners
list.

We had a small Electrolux on our last cat, and it worked well, at least
after I corrected the installation errors of the boat builder (this seems to
be quite common). Follow the dictates in the installation manual.
It is very important to have plenty of cooling air. I installed a small
radio Shack fan to pull more air through, and that really made a difference.
The burner wasn't on as long.
I learned from someone at an RV dealer to "burp" the unit by laying it on
each side for a day or so. IIRC this was at the start of the season, or when
it had been shut down for a while.
I wa told that they do need to stay reasonably level, but that the motion of
a boat aids the circulation of the ammonia.
They really were not designed for marine use, and have parts that do rust,
so you will need to wire brush, and spray paint some parts.
Lastly, you need to be careful about keeping gasoline fumes away from the
pilot light.

"Evan Gatehouse" wrote in message
...
I am considering a propane refrigerator on my 40' catamaran.
These propane fridges don't work well with monohulls
unless gimballed but cats do quite well with them. Gemini
cats use them as standard equipment (and they seem to
require little maintenance). My priorities are lightest
weight and reliability. I kept hearing "we've had a propane
fridge for 10+ years with no problems" on the Gemini owners
list.

If I went this route, it would be installed on the
bridgedeck cabin, venting into the cockpit and installed in
a gas tight box, separate from the rest of the boat.

I thought I would just take a stab at rough costs and weight
of two options. The results surprised me:

PROPANE

Weights: (lb)
1 extra 20 lb tank (aluminum) 13
full of propane 20
Norcold 5 ft^3 fridge 99
extra insulation 10
hose, fittings 4
Total weight 146 lbs

Costs:
20 lb tank 125
Norcold fridge 1000
extra insulation 50
hose/fittings 50
Total $1405

(I would already have regulator, alarm, solenoid because I
will have a propane stove)

ELECTRIC FRIDGE

Weights: (lb)
Home made box 50 lb
Ice box conversion kit 20 lb
extra solar panels 2x75 watt 35 lb
extra battery capacity ~120 lb
(say 2x60 lb golf cart batteries)
Total weight 225 lbs

Costs:
Home made box 100
Ice box conversion kit 850 (through careful shopping)
solar panels 650
extra battery 120
Total costs: $1720

I started this exercise convinced that a propane fridge
would be too heavy but now I'm leaning the other way! The
only variable I have left out of the cost side of things is
the cost of propane. But say the 20# tank lasts 1 month;
that's $150-200/year in extra propane. Probably the
increased reliability and lack of maintenance vs. an
electric fridge would offset this to some degree.

Now all I have to do is put some heating coils in the back
of the fridge to heat hot water and I'm set. No need for a
propane on demand hot water heater because the fridge is
doing the work for you. (o.k. I'm kidding about this)

Somebody tell me where I'm missing something on the
cost/weight comparison please!

Evan Gatehouse

Somewhere I have the owner's manual for a home Electrolux refrigerator, ca
1948. Part of the delivery regimen was to roll the unit -- upright, side,
top, other side upright. This apparently put the vital fluids in the proper
place in the circulatory system. No electricity for that unit except for
the light bulb. Just a little gas flame.

Roger

http://home.earthlink.net/~derbyrm

"Garland Gray II" wrote in message
newskVde.2337$cf5.441@lakeread07...
We had a small Electrolux on our last cat, and it worked well, at least
after I corrected the installation errors of the boat builder (this seems
to
be quite common). Follow the dictates in the installation manual.
It is very important to have plenty of cooling air. I installed a small
radio Shack fan to pull more air through, and that really made a
difference.
The burner wasn't on as long.
I learned from someone at an RV dealer to "burp" the unit by laying it on
each side for a day or so. IIRC this was at the start of the season, or
when
it had been shut down for a while.
I wa told that they do need to stay reasonably level, but that the motion
of
a boat aids the circulation of the ammonia.
They really were not designed for marine use, and have parts that do rust,
so you will need to wire brush, and spray paint some parts.
Lastly, you need to be careful about keeping gasoline fumes away from the
pilot light.

"Evan Gatehouse" wrote in message
...
I am considering a propane refrigerator on my 40' catamaran.
These propane fridges don't work well with monohulls
unless gimballed but cats do quite well with them. Gemini
cats use them as standard equipment (and they seem to
require little maintenance). My priorities are lightest
weight and reliability. I kept hearing "we've had a propane
fridge for 10+ years with no problems" on the Gemini owners
list.

If I went this route, it would be installed on the
bridgedeck cabin, venting into the cockpit and installed in
a gas tight box, separate from the rest of the boat.

I thought I would just take a stab at rough costs and weight
of two options. The results surprised me:

PROPANE

Weights: (lb)
1 extra 20 lb tank (aluminum) 13
full of propane 20
Norcold 5 ft^3 fridge 99
extra insulation 10
hose, fittings 4
Total weight 146 lbs

Costs:
20 lb tank 125
Norcold fridge 1000
extra insulation 50
hose/fittings 50
Total $1405

(I would already have regulator, alarm, solenoid because I
will have a propane stove)

ELECTRIC FRIDGE

Weights: (lb)
Home made box 50 lb
Ice box conversion kit 20 lb
extra solar panels 2x75 watt 35 lb
extra battery capacity ~120 lb
(say 2x60 lb golf cart batteries)
Total weight 225 lbs

Costs:
Home made box 100
Ice box conversion kit 850 (through careful shopping)
solar panels 650
extra battery 120
Total costs: $1720

I started this exercise convinced that a propane fridge
would be too heavy but now I'm leaning the other way! The
only variable I have left out of the cost side of things is
the cost of propane. But say the 20# tank lasts 1 month;
that's $150-200/year in extra propane. Probably the
increased reliability and lack of maintenance vs. an
electric fridge would offset this to some degree.

Now all I have to do is put some heating coils in the back
of the fridge to heat hot water and I'm set. No need for a
propane on demand hot water heater because the fridge is
doing the work for you. (o.k. I'm kidding about this)

Somebody tell me where I'm missing something on the
cost/weight comparison please!

Evan Gatehouse