Conference unifix::sailing

re .1: 

Nigel Calder wrote a nice little book on marine refrigeration systems.
Having just read it, I'd strongly suggest you read it also. It is
basically a design manual. Refrigeration is considerably more complex
than I'd imagined, and the choice of what type of system to use isn't at
all simple. 

The unpleasant bottom line is that an adequate refrigeration system is
very, very expensive unless you have more or less continuous shore
power. Even then it ain't cheap. You're talking a major investment here 
that will likely not be recoverable when you sell the boat, but that may 
not be a concern for you.

A Sea Frost engine-driven holding plate system (perhaps the best
available) is about $1800 without the engine drive pulley and compressor
mounting bracket. A shore power assist adds additional complexity and
much additional cost. Without shore power the daily engine running time
to keep the holding plate frozen is 30 to 60 minutes depending on
ambient temperature and insulation. (Were we to install refrigeration, 
we'd get a Sea Frost, but for our weekend and vacation sailing we can 
buy a lifetime supply of ice for much less than the cost of a Sea 
Frost.)

An electrically-driven holding plate (eg, Adler-Barbour) uses really a 
lot of electricity. Our ice box is rather well insulated. My estimate is 
that an Adler-Barbour would use at least 50 amp-hours per day on our 
boat in Maine and 75 to 100 amp-hours per day in really hot weather. 
Calder strongly recommends at high-tech electrical system, eg, 
high-output alternator (100 amps or more) with a special regulator (such
as Ample Power or Cruising Equipment) and big batteries (see other
notes). Alternator, regulator, isolator, voltmeter, ammeter shunts, wiring, etc,
will be in the range of $600 to $1200 or more depending on how fancy you
want to be. 50 amp-hours per day from solar panels (see other notes), or
a wind generator is a lot and solar panels require much space, to say
nothing of the cost. Add another $700 or $800 for a couple of big solar
panels (which won't be enough anyway). A wind generator is $500 to $1000
and they tend to be noisy, don't provide all that much electricity, and
have other drawbacks like mounting problems. The wind generator owned by
some friends is unpleasantly noisy and would generate many complaints
from marina neighbors. For dockside power you'll need a big battery
charger -- $250 and up. 

You might even want to think about a new engine for all these new 
accessories. If you live aboard, you'll want to upgrade the electrical 
system anyway.

Calder also discussed building an icebox in detail. 6" of insulation 
seems about right. Building one, especially retrofitting one, looks like 
a major project to do right. Calder recommends rigid insulation (it is 
easier to work with) but foam is also possible.

Propane stoves: We have one and wouldn't have anything else. Propane is 
discussed in some detail elsewhere in SAILING. A good stove is $700 to 
$1000 or so. Add $300 for aluminum propane tanks and a solenoid valve. 
Building a vented well for the propane tanks isn't a trivial undertaking 
either, nor is finding the space for the tanks. 

    A consideration on liveaboard.  Is it pierside, if so a cheap fridge
    on shore power.
    
    Friends of our retired to the Caribbean on a 38ft sail boat a few years
    back.  They considered refrigeration (the owner is an engineer of
    considerable skill) but decided to go without.  We cruised with them
    down around St Vincent and found you can adapt very well to life
    without mechanical refrigeration.  
    
    They had a similar problem older boat, atomic 4 ,but the 3 1/2 years
    they cruised the area worked out fine for them.  (John was a good
    spearfisherman, so that helped).    Life without ice seemed ok.
    
    Frank
    

re .2:

Heck, life with ice isn't so bad either! We have some liveaboard friends
who make do with ice. Admittedly, it isn't as convenient as refrigeration, 
but it is cheap and reliable. 

Another not immediately obvious cost of non-shorepower refrigeration is
the extra wear on the engine from running either an engine-driven
compressor or recharging the refrigerator battery bank. When at anchor
we need to run our engine only every third day for less than an hour to
recharge our batteries. Adding a Sea Frost would require probably half
an hour of engine running per day. A small diesel has a life of maybe
2000 to 5000 hours and costs maybe $6000. That's roughly $1.20 to $3.00
per hour of running plus fuel, filters, and oil. (This summer in Maine
ice cost us about $1.50 per day.) This engine-running cost tends to make
alternative energy (solar and wind) look more attractive as at least a
supplement to engine running. Deeply discharging batteries, as
electrically-driven refrigeration system will tend to do, shortens
battery life to as little as a couple of hundred discharge/recharge
cycles. Hence the refrigerator battery or battery bank might need yearly
replacement if you're living aboard away from shore power. 

There just isn't a simple answer here. I guess the best one can do is
recognize the pluses and minuses of the various options and make the
choice that seems best. After reading Calder's book my interest in
refrigeration is considerably less. Living aboard would make the
decision much harder, I agree. 

Alan

    Less can definitely be more.   I'm always amazed at how long ice stays
    ice in a top-quality ice box or cooler, even on a hot day.
    

    
    	At least until the crew comes aboard with beer out of a hot car
    	interior!
    
    	We try to make blocks at home- good for the weekend anyway. A 
    	solar fridge at the rental place would be nice...

    On your question of the stove.  Propane is very nice.  It is clean and
    readily available in the United States.  When we cruised in the Bahamas
    we knew of several people who ran out and had difficulty getting
    refills.  The other issue is safety.  Propane is heavier than air and
    will collect in the bilge.  
    
    For these reasons, we choose kerosene.  It is avaiable anywhere in the
    world.  It is very cheap to purchase and relatively safe.  We find that
    for weekend cruising we use about a gallon a year around here.  It has
    only two drawbacks.  It is dirty.  It blackens yours pots and is
    difficult to clean off.  Also you have to prime the burner with alcohol
    before ignition.  
    
    Everything is a compromise.  But I would go with keorosene again.

    I know I'm not known in this conference as a cruiser, but I HAVE
    cruised extensively.  My opinion of the newer alcohol stoves is very
    high.  The safety factor is well known and the trade off in BTU's
    doesn't seem to be too bad.  
    
    Fat Tuesday had an Adler Barbour (sp?) refridgerator.  We could make
    ice cubes!  We almost never used it.  Insulation and good design make
    an ice box preferable (in my humble opinion) if you sail where ice is
    available.  One less thing to break!
    
    Dave (who is thinking of getting back into cruise mode)

re .7:

>>> My opinion of the newer alcohol stoves is very high.  The safety 
>>> factor is well known and the trade off in BTU's doesn't seem to 
>>> be too bad.  
    
I once tried to heat a large pot of water to the boiling point on an
alcohol stove. The lobsters died of laughter while watching this futile
exercise. 

:-)

    Alan, are you talking about the old, pressurized stoves or the newer
    ones.  We used a new one on the Mackinac race to boil water (all our
    food was sealed in boiling bags) and had little trouble.  I was
    impressed.  Granted, propane is hotter (a lot hotter) but the safety
    trade off doesn't thrill me.
    
    Dave

re .9:

Right, Dave, it was one of the old, pressurized, prone-to-disaster 
alcohol stoves. It heated small amounts of water adequately, like might 
be used to make coffee or boil pouches. My impression is that the new
style alcohol stoves are a good bit safer than the old ones, but not
particularly faster. The only way the new ones could be faster is to
burn more alcohol per unit time. 

I suppose I could be deluding myself, but I think that a proper propane
system is quite safe. As long as the tanks are in a well sealed from the
interior of the boat and adequately vented overboard, as long as the
hoses/piping are well-secured, and as long as a fail-safe solenoid value
is used, the system should be safe. We have a pressure gauge in the 
system, which makes leak detection fairly easy. It may be and probably is 
not as ultimately safe as kerosene or CNG, but I think the risk is 
acceptably low given the positive aspects. I'd much, much rather have a 
propane stove than a gasoline engine! 

Cheers,

Alan

    I have an Origo 4000 non-pressurized alcohol stove and am very pleased
    with it also. It is now two years old. It heats large pots of water for
    boiling dungeness crabs in my case just fine. All those folks out there
    who rap alcohol are thinking of those old pump models. I had one of
    those a long time ago also and the difference between those and the new
    ones is like night and day.

    
    	Personal tastes.... I've been woken up by the stink of trying to
    	get one of the old alky stoves going, and breakfast became the last
    	thought! Keeping dinner was the challenge....
    	So anyway, Dave, using the new type, how big was the pot of water,
    	and how long from cabin temp to boiling? Was the stink less?
    	My boat came with propane also. Pretty small bilge, fairly wisely
    	placed vents, enough practical fear to turn off the tank between
    	uses... no explosions yet! Has anyone seen a boat go up for this
    	reason? As someone mentioned before, gasoline makes the much better
    	bomb- so the outboard hangs on the pushpit. I notice these
    	`sniffer' systems for quite a few bucks- anybody know the MTBF on
    	these?
    	Also, do the new alky stoves kill the flow if there's no flame? I'm
    	always surprised when such thermo-mechanical things work so good
    	for so long in the salt air- I test `em pretty much every use- 5
    	years and still ticking.
    	One latest toy of consideration is a combination water heater/cabin
    	heater. Propane fired. Anybody out there used one?
    
    	Scott_who_totes_ice_blocks_or_hangs_beercans_off_the_back

    Scott, the time to boil a pretty big pot was about 10 minutes, or about
    what I'd expect a regular stove to heat.  Maybe a little slower.  The
    alcohol doesn't "flow" at all.  It is absorbed by a porous stone and
    burned in a container with a sliding lid to control the size of the
    flame.  Much like a sterno burner.  Sounds too simple to work, but I
    was impressed!  Much less stink than a pressurized stove.
    
    Now all that said, I'd be VERY surprised if propane didn't heat faster.
    
    Dave

    Another vote here for the Origo.
    
    We have a double burner, which heats water easily in very large
    quantities, albeit not with blazing speed.  We will frequently steam
    four 1 1/4 - 1 1/2 lb lobsters in one large (10 qt?) pot, although that
    still requires only 3/4 in. water in the bottom.  To heat the full pot
    to boiling for dish washing takes about 15 min., which is just about
    enough time for digestion and/or recovery from gorging oneself on
    seafood.
    
    I wouldn't mind if the lobsters laughed, Alan, but their screams drive
    the boss crazy!
    
    Their occasional escape attempts are a pain as well.
    
    BTW, my brother has an Origo double burner with oven and swears he will
    never own another stove.
    
    R.
    

I've had some experience with an Origo stove, going to Bermuda with Jeff
Gardiner.

The stove is idiotically simple. There are no valves, no fittings to leak,
no gas or liquid under pressure anywhere at any time. We used the stove several
times a day to make dinner, heat water for coffee, etc. The stove puts out
plenty of heat. It's extremely easy to light, since it's basically just a big
sterno can. 

I have a pressure alcohol stove on my current boat, and I hate it. I'm planning
to switch to an Origo, as soon as I have time to deal with the inevitable
installation hassles.

--RS

Last year we installed a Norcold AC/DC refrigerator (either model DE-250 
or DE-251) in our Catalina 34.  We placed additional foam insulation 
around it and changed the trim moulding to flush mount it under the 
chart table.

Overall, we are very happy with this solution to our refrigeration 
problem.  First of all since it is AC/DC, while we are in port it is 
always on but not drawing power from the battery.  Second, we still have 
the ice box which we can use for additional storage.  This last weekend 
we sailed to Block Island and we had lots of food for three adults for 4 
days.  We put in the refrigerator the things that we were going to be 
looking for often (drinks, cold cuts, condiments, etc.) and placed in 
the ice box those items that we were only going to access before cooking 
dinner.  So we can store a lot of food for trips lasting up to a week.  

Last, we don't find that the refrigerator puts too much of a drain on 
the battery.  During our trip, while we were moored, we ran the boat off 
battery #1, and we never ran it down so low that we couldn't start the 
engine with it.  We are currently considering adding a wind generator, 
but this would be so that we could be more liberal in the use of our 
power, not because the refrigerator has taxed the power of one of our 
batteries.

	Jacqueline

      re .11 and others.  I vote Origo.    We find it to be much better
    than the old alcohol stove.  Faster and safer.   Not propane BTU's
    but more than adequate.
    
      We cruise with kids, no way would they be able to use the old
    pressurized stove.  (at the start of each season, I had to give the
    light-off some thought)
    
      Just one drawback on the Origo, if its near the compass (as mine
    is on top of the ice chest in a Pearson Triton) is that is made of
    *magnetic* stainless.   I had to move the compass up after the
    new stove went in, and recompensate it.
    

Back to refrigeration again ......

According to some advertising I have, a system similar to if not exactly 
the same as an Adler-Barbour Cold Machine removes 225 BTU/hour from the 
refrigerator and uses 5 amps of electrical current. Being a suspicious 
sort, I turned on my HP calculator and began pushing buttons .....

A BTU is a measure of heat energy. 1 BTU = 1054.35 joules and 
1 joule/sec = 1 watt. So, 225 BTU/hr = 65.90 watts. Assume that your 
battery voltage is 12.6 volts (a fully charged conventional wet deep 
cycle battery). 12.6 volts x 5 amp = 63 watts. Wow, something for 
nothing! You're putting in 63 watts and taking out 65.9 watts. Sorry, 
this just isn't possible with today's physics. So, two possibilities:
One, the refrigeration system removes less than 225 BTU/hr. Two, the 
battery current is greater than 5 amps. I don't know the efficiency of a 
refrigeration system, but I'd be very surprised if it exceeds 80%. 
Assuming 80% efficiency, it will require just over 1 amp-hr from the 
battery to cool a six-pack (12 oz cans) from 80 deg F to 40 deg F. 
Alternatively, 1.3 pounds of ice would melt providing the same cooling 
(melting a pound of ice requires 144 BTU).

Our icebox melts 10 to 15 pounds of ice per day depending on how much 
ice is in it, ambient temperature, how much the engine is run (one wall 
of the icebox is also a wall of the engine room), etc. Thus this system 
would, at best, use 40 to 60 amp-hours per day in Maine. 

The efficiency of a refrigeration system depends on, among other things, 
the temperature of the condenser, which liquifies the hot, high pressure 
refrigeration gas. The higher the condenser temperature, the lower the 
efficiency. If the condenser temperature is high enough, the system 
won't work well enough to provide any useful refrigeration. 

Re .16 and an earlier reply about an Adler-Barbour: These systems use an
air-cooled condenser. As long as the ambient air temperature is low,
they should work fine. But, mounting the condenser in a hot engine room
(where summer temperatures with the engine running may exceed 100 to 120
deg F) or mounting it under a chart table could well result in a very
substantial loss of efficiency and greatly increased electrical
consumption in hot weather. (Water-cooled condensers are much better
since sea water temperature usually doesn't exceed 85 def F even in the
tropics. In colder waters a flow restricter may be needed with a
water-cooled condenser -- too much cooling is also a problem.) So be
careful about drawing conclusions about a system based on its
performance in coolish weather, most especially if you are planning
cruising in hot climates. A friend of ours has a large Norcold AC/DC
refrigerator (with no additional insulation) on his powerboat. It pretty
well discharges a 180 amp-hr battery in 24 hours in summer. 

Calder's book is "Refrigeration for Pleasureboats: Installation, 
Maintenance, and Repair", published by International Marine Publishing, 
Camden, ME, 1991. 

Alan

RE:.18 by MSCSSE::BERENS "Alan Berens"

> Wow, something for nothing!  You're putting in 63 watts and taking out 
> 65.9 watts. Sorry,  this just isn't possible with today's physics. 

It is possible.  The second law of thermodynamics requires that the best
efficiency of a refrigeration system is:

             T_in             Heat
Eff_max = --------------  = ----------
           T_in - T_Amb       Work

(temperatures must be in an absolute scale (degrees K,  where 273 K = 0C))


        +---------------+
	|		|
	|		|
	|		|          (Work)
	|	T_in	| (Heat) =>      => (Waste heat)  => T_Amb
	|		|
        +---------------+

So for your six-pack example,  best efficiency would be 

277 K / (300 K -277 K),  12 times or 1200%

I don't know about the practical efficiencies of a small refrigerator,  but
large ones will do 300+ % on a temperature difference similar to that.

It isn't something for nothing,  as disorder in the waste heat will be larger
that the disorder in the input heat.  Entropy increases.


Phil

    As I recall the 3 laws of thermodynamics go soemthing like this:
    
    Law 1:	You can't win
    Law 2:	You can't break even
    Law 3:	You can't get out of the game
    
    Did anyone else study "Thermo" from Prof. E. Howard Stolworthy?
    (You wouldn't forget him)
    
    Bill
    

re .19:

Well, I did not understand the three thermodynamics courses I took in 
college all that well (most especially the quantum thermodynamics 
course), and I took them over 25 years ago (which is a depressing
thought in itself). I won't argue with your definition of the efficiency
of a refrigeration system, but ...... somewhere in the laws of physics
(and I suppose thermodynamics) the hypothesis is that you don't get
something for nothing. 

What we have here is a system that uses 63 watts of input energy 
(electricity) to produce 65.9 watts of output (heat). To say that this 
is possible seems to contradict the principle of conservation of energy
-- energy in equals energy out (neglecting any conversion of mass into
energy or energy into mass). It is no doubt true that the disorder 
(entropy) in my head is continuously increasing.

:-)

    Nothing quite like hot food/water at sea.  I've sailed/worked on boats
    with diesel, alcohol, kerosene, and propane stoves.  Different problems
    with each one- some caused by the fuel, some by installation, some by
    stupidity.  Lots of stories about lots of great meals.  And then there
    are the (more interesting) stories about the meals that didn't quite
    make it to the table.  After some of these experiences, with perfect
    20/20 hindsight, I pompously think that playing with fire has inherent
    dangers and must always be respected.
    
    Diesel: Memories of a winter spent lobster fishing in southern New
    Zealand.  Snow on the shore, pre-dawn, me as breakfast cook, struggling
    to light the diesel stove.  Heaping up paper, lighting it and carefully
    letting fuel onto the flame, shaking in my gum-boots.  Dirty, smelly
    fuel.
    
    Alcohol: Running a charter club in San Diego with about 20 different
    alcohol stoves.  Until we set up a regular maintenance program that
    included testing all stoves, we regularly encountered clogged fuel
    jets, and subsequent customer complaints of mal-functioning equipment.
    We did have occasional flare-ups during pre-heating, and learned to
    spend considerable time instructing people in the safe use of alcohol
    stoves.
    
    Kerosene: Sailing along in the Newport-Ensenada race surfing at 9+
    knots, in the middle of the fleet, chutes all around, beautiful sunset. 
    Time for dinner.  My wife was along as cook.  One of the owners went
    down to light the kerosene stove for her. All of a sudden, she came
    flying up out of the companionway.  My wife is normally pretty calm, so
    I thought I should have a look.  The cabin sole was aflame and the
    owner was trying to stamp out the rapidly spreading flames.  I grabbed
    a fire extinguisher and after a brief discussion, we concluded that we
    faced less damage from the fire extinguisher than we did from the
    flames. It turned out that the pre-heating flame had nearly gone out,
    and hadn't done enough pre-heating.  The owner grabbed a pint bottle of
    alcohol to pour a bit more in.  It flared up pretty quickly and the
    bottle got dropped onto the flame.  Fortunately the only damage was to
    the cabin liner and (somehow) to my wife's sleeping bag.  Oh yeah,
    there was the mercilous ribbing the owner took every time he went to
    light his stove.
    
    Propane: I commissioned a 45 ft Airex-core boat in Bangkok for a rich
    New York banker back in 1975.  Our banker had been sent to Thailand for
    three years to run the local branch of Farmer's Trust.  His plan may
    have been to sail triumphantly past the Farmer's main offices in his
    new yacht.  Unfortunately, he had a tight schedule, a long way to go,
    and he was in Thailand where schedules tend to slip.  He decided to
    finish commissioning the boat in Singapore, before setting off across
    the Indian Ocean.  Among unfinished work was stove installation.  We
    were motoring down the Gulf of Siam on our way to Singapore.  It was a
    beautiful moonlit night.  The air was still and hot, so sweet you could
    taste it.  I was on the 0200 - 0600 watch.  About 0300 I decided to
    have a cup of coffee.  Down to the stove, no fuel.  Hmm, I thought, the
    fuel must be turned off at the tank.  I went back to the mizzen where
    two tanks were safely secured in a well-ventilated teak box.  Sure
    enough, the valves were off.  I turned one on, and went down to
    complete my task.  I was trying to light the stove when the RPM's on
    the Westerbeke diesel engine took off.  I went on deck to see what was
    up.  Sure enough the engine was revving at over 4000 RPM, an increase
    of more than 1200 from it's normal maximum.  I tried the fuel cut-off
    with no success.  Down to the engine room:  sounded like a ship's
    engine.  It was loud!  Everyone was still sleeping (How could anyone
    sleep through that racket??).  I was pretty concerned by this time, but
    had not figured out what was wrong- only that I had to stop that
    engine.  I crawled into the engine room and tried the fuel cut-off
    there.  No luck.   What could be wrong?  I gave up and went back on
    deck.  The engine gradually returned to its normal RPM.  Chalking it
    up to spooks, I went down to finish making my cup of coffee.  Still no
    fuel at the stove.  At this point, I realized what had happened and
    went back into the engine room.  Sure enough, the fuel hose had been
    disconnected. At 0600, when the banker came up for his watch, I asked
    him about the hose.  He told me that he had disconnected it in the
    engine room to make sure that no one would use the stove.  We had a
    rather serious and emotional discussion about the power of propane and
    the need to communicate.
    
    Dave 

RE:.21 by MSCSSE::BERENS "Alan Berens"


> What we have here is a system that uses 63 watts of input energy 
> (electricity) to produce 65.9 watts of output (heat). To say that this 
> is possible seems to contradict the principle of conservation of energy
> -- energy in equals energy out (neglecting any conversion of mass into
> energy or energy into mass). It is no doubt true that the disorder 
> (entropy) in my head is continuously increasing.

There are three energy terms to balance.

E_1) the heat leaving the cold space.
E_2) the work running the system.
E_3) the waste heat expelled by the system.

First law is that

E_1 + E_2 = E_3

Now,  in this case E_1 is 66 watts,  E_2 is 63 watts,  so E_3 must be 129
watts.

If we used this device as a heater ("heat pump") to pump heat out of cold
winter water and warm the interior,  for just 63 watts of electric work we
could get 129 watts of heating....  Ever hear of a heat pump?


Phil

    
    Magic. Just add thermo- mirrors.
    
    Quantum Thermo? What a concept Mr. Watt.
    
    The "5 amps" was probably a somewhat average, or maybe quiescent,
    number, I'd suspect. Like the home fridge, it turns on/off with the
    thermostat, right? Now filling it with hot beercans is not the same as
    the 6th day out, when the `box is more full of air.
    
    Unless that IS the Max... everything running....?
    
    I'll bet the Clippers never had these problems....

re .24:

I believe that the 5 amps is the compressor running current. An 
Adler-Barbour switches on and off as needed just like a home (er, land) 
refrigerator. In a holding-plate system the refrigeration is used to 
freeze a solution, making, in effect, a block of ice. The compressor in 
an engine-driven holding-plate system might require something like 2 hp 
to run. A 2 hp 12 volt electic motor would have a running current on the 
order of 100 amps.

    re: .22
    This is great! I have just learned how to pseudo turbo charge a diesel
    enging with very little effort! Just think, if it doesn't make the boat
    go forward through the water much more quickly, it will decide to
    elevate itself and go up and over the water instead!

My original idea was to go with an Origo with oven. I have heard, though, 
from sources outside this conference, therefore of questionable 
character, that alcohol is not as easy to get outside of the US, like 
down in the islands. Thus propane came about as the better alternative. I 
have one of those good ol' pressurized alcohol stoves now and am able to 
cook just fine with it. Anyway, when you're sitting at anchor in some 
nice cove, what's the rush? Its not like you have to go somewhere, you're 
already there. Time to cook has not been an issue. Fuel availability is.

Back to insulation. The stuff in my boat is standard urethane foam 
sheets. About five days is all 15 lbs of block will last. I know 
Frigidaire et al can handle 100+ DEG F temperature drops across their 
freezer units without getting cool enough to create condensate on the 
outside walls. Even when relative humidity is near 90%. It would seem to 
me, they got something different than the lumberyard carries. 

Alan B. Thanks for the name and title of the refrigeration book.

Tom