Water is essential to living, cruising, showering, washing dishes, laundry, and a seemingly endless supply of leaks.  Voyage furnished a 400 liter (approximately 100 gallons - except ours never took over 80) stainless tank that was sufficient for a week or so with the two of us or about 8 hours with a guest family and two teenagers.  We felt it insufficient for our ocean crossing from Cape Town to Barbados so . . .

We purchased a PUR 40 gallon per day water maker from West Marine.  It was professionally installed by Ricardo using Voyage-supplied salt water fittings and 6 mm wire we strung through the Voyage-provided wire races.  It worked well for the first part of the crossing (although it always leaked).  The PUR water maker began to admit salt into the fresh water tank in the Virgin Islands although we were not absolutely sure it had failed until about two days from Florida.

We had a sufficient supply of reserve drinking water to reduce our dependence on the PUR until we arrived in Florida and had the unit repaired.  The water never became to salty for dish washing or showers.

Important Lesson:  If you have a water maker, be prepared with sufficient emergency drinking water to reach port from any place in your planned trip.

We concluded the membrane had failed and called PUR.  They said there was a minimum three-month backlog for warranty service.  We had the unit repaired locally a total of four times - with West Marine intervening to get the necessary parts from PUR - they were reluctant to ship them to us.

The third time we shipped the unit to them.  They promised us four day turnaround - but it took over two weeks for them to tell us the unit was not economically repairable.  It was still within the two year warranty.  Eventually, we negotiated a replacement unit, a PUR 80 that had been reconditioned, for the list price difference between the PUR 40 and PUR 80 at West Marine, about $1900.  We were all satisfied and they shipped the unit.

Then came the Annapolis Boat Show. 

We learned that both PUR and Spectra use custom high pressure pumps to generate the 800 PSI (or more) required for operation of all water makers.   These units are highly efficient but are in limited use-restricted to a single company.  We began to hunt for a unit that used standard parts to see if one was available within our money, power, space, and water need budgets.

The SK AC/DC Model 150 met our needs.  Produced by SK Watermakers in Ft. Pierce, FL (561-489-0852), our water maker uses a standard size DC motor that is interchangeable with a standard size AC motor in about 5 minutes.  It uses a CAT high pressure pump - widely available and easily replaceable.  The pressure cylinder and hoses are standard and carry a warranty for the life of the unit.  The entire unit is warranted for two years.

Best part was the price.  I explained my problem and budget and - with me reusing the filters and pre-filter pump - they nearly met the exchange price offered by PUR.  The extra $50 for the SK unit was paid back in the first day:  the unit works - right from the box, it produces the advertised amount of water (5 to 6 gallons per hour depending on the state of the pre-filters and the salt content of the water), and - best of all - it is very quite, hardly louder than a cabin fan and much quieter than the engine fans.

I installed the unit on the SK-provided base (powered coated aluminum), by relocating the control panel to the edge of the base.  I used the SK-provided sound deadening mounts and threw out all the stuff I had added trying to make the PUR quieter.

The blue rag in the photo covers two pre-filters and one chlorine filter (used when flushing the water maker with tank water).  These are covered to keep off excess light and control algae growth.

The top left of the control panel has the intake pressure (or vacuum) and the high pressure.  The black knob controls the high pressure and indirectly controls the product water flow rate - shown by the right thermometer-style gauge.  I put lines in the approximate center the recommended settings on each gauge.  The unit never varies from the settings by more than the width of the line until the pre-filters start to clog.  We have two sets - drag one behind while we use the other.  We interchange filters every two weeks in the Chesapeake Bay and about every six weeks in the Virgin Islands.

The water is always excellent - tastes better than bottled.

The SK unit, as configured, draws somewhat under 20 amps in our configuration.  SK will upgrade the motor and the membrane if you need more water or convert from DC to AC operation if you require that.  Both changes can be installed in the field in minutes - once the wiring is complete.

In February, 2004, our watermaker began to produce slightly salty water.  After cleaning and washing the unit, we concluded the membrane had failed and needed replacement.  SK had just reduced the price so we were able to order a new membrane and a meter to see how salty the resultant water really was.  It has arrived and will be installed soon.  Stay tuned.

Water Maker Wiring

We had a unique wiring opportunity since we were converting from the PUR (about 6 amps) to the SK units.  The original installation was done with 6 mm wire from our switch panel to the water maker - approximately 40 feet round trip.  While this wire would have safely carried the new load - there would have been substantial voltage drop, an unacceptable situation for a motor device that runs a lot.  Our choices were to upgrade the 6 mm wire or install a relay so the original switch could control the power from a heavy gauge wire.  Since the wire races were already crowded, we were reluctant to replace the 6 mm wire with 8 AWG needed to produce an acceptable voltage drop.

Fortunately, the water maker was located within a few feet of one of two large alternators installed to meet our electrical needs.  We priced a 25 Amp relay and found that for not much more we could purchase a Flexcharge NC25A charge controller (available from Jack Rabbit Marine at 203-961-8133, that was designed to divert surplus power to loads that could run only occasionally.

The NC25A didn't quite meet our requirement - we wanted the water maker to run whenever the engine was effectively charging the house battery bank - about 12.8 volts or above - and to stop running within a short time after the engine was stopped - say 12.6 volts.  Its minimum was somewhat higher.  After some thought and discussion with Flexcharge, I decided to put a 1.5 volt battery in series with the panel switch so the Flexcharge would sense a voltage somewhat higher than "true" and perform the task we needed.

It works perfectly.  The water maker goes on and off when we motor and keeps our supply of water about right with little attention.  Occasionally we overflow the tank - and turn off the console switch for a day or so.  Sometimes we use so much water we must run the unit overnight to catch up.  There is a switch on the panel (supplied by JK) that is wired to override the NC25A and make water whenever there is power above about 11.5 volts.  We don't do this often.

We are working with Flexcharge to custom make a controller that will work perfectly in a water maker environment.  Stay tuned for the cost (probably just over $100) and ordering information.