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Subject: RE: [worldcruising] water maker
From: A0884958, Dave (wdr@XXX.XXX)
Date: Mon Jan 08 2001 - 05:17:11 EST
Practical Sailor has evaluated the common 12V watermakers. You can ask for
a copy of their eval from the archives.
Before we can make recommendations a few questions;
1. where will you be sailing (maintenance and spare part considerations)?
2. what is your power source (110V/220V, 12V/24V or main engine/gen set
driven)?
3. what is your expected water consumption?
IMHO the Spectra and the Village Marine of the best of the 12V watermakers.
The Clark pump on the Spectra is the most efficient and using a standard 40
PSI source pump is brilliant but the Village Marine is the most common and
therefor can be repaired just about anywhere. However, all 12V systems have
limited output and must run several hours a day, gobbling amps from the
battery bank to output just a few gallons of water. Don't get me wrong, I
too have had one (a PUR 180 which I would have gladly thrown overboard would
it not be polluting). Their chief advantage is their compact size and the
common availability of 12V on board.
On our new boat, with a dedicated engine/mechanical space where I can walk
around (this was one of 3 key criteria in our boat selection) we have
selected a 120V AC powered unit that runs off the gen set. Clearly it is
larger with a 1 HP motor and 2 large membranes but it also puts out about
3200 liters per day depending on salinity and temp. The pump is the
industry standard "CAT" pump which over 50% of the makers use. Likewise
membranes, sensors and valves are all standard so I believe I will be able
to obtain parts just about anywhere in the world. We have a 8.5 KW 120V 60
Hz generator going on board which runs about 1 hour per day anyway so making
water is a side benefit. One hour will produce about 125 liters or 30 US
gallons per day again depending on salinity. We run it daily and often
jerry the extra output to friends around us. Our consumption has been
something around 6 gallons per day but I am sure this will increase over
time with increased capacity and availability. Read this as we will waste
more water.
Water makers like to be run. Daily is best. Green beasties grow in the
residual salt water left in the system virtually overnight. If you are
leaving the system idle for more than a week you will have to pickle it. In
other words add a preservative to the system. Formaldahyde (yes the same
stuff that you embalm a human body with) is the common preservative. Really
ugly stuff to work with and a task watermaker owners hate. When they didn't
have formaldahyde available at the battel of Trafalgar they used rum to
pickle Nelson's body. The sailors siphoned it off thus the term "Nelson's
blodd". I don't think Rum will work in the watermaker. If you don't pickle
the system look forward to buying new membranes which seem to be about the
same price as replacing the system (close anyway). Also, another warning,
when installing put a large charcoal filter with a 99% chlorine removal spec
in line with the flush water source. Chlorine degrades those expensive
membranes and as the flush water source is your tanks they often have
chlorine in the water either from shoreside or what you added.
Efficiency; with a DC driven unit you will go from generator or alternator
or battery charger, to batteries, to DC pump each dropping something like
50% of output along the way. Well battery chargers are about 80%,
alternators 60% but batteries are horrible at about 50%. With AC driven you
are going from alternator directly to the AC motor. Direct engine shaft
drive is even better. Balmar makes a combination genset and watermaker but
the design looks clugey to me.
So in my opinion to answer your question, if there is a convenient location
and you have a generator, and you plan on using lots of water or run it for
only short periods the AC version (either 110V or 230V) is the way to go.
Simply put it is more efficient. Space is however usually the driving
criterion.
Regards
Dave Richardson
SY OverStreet currently lying in Secret Harbour Grenada W.I.
-----Original Message-----
From: Gennaro Sammarco [mailto:gigiopil@XXX.XXX]
Sent: Sunday, January 07, 2001 6:27 AM
To: Worldcruising
Subject: [worldcruising] water maker
Hello everybody!
I' considering to upgrade my sailboat with a water maker, so I'd like to
have informations on its power consumption, maintenance, troubles and
troubleshooting, and if it is really worth the expense along with
suggestions about the type and make.
Thank you very much,
Gennaro
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