So how does this impact us living on a sailboat?  Well even though we are surrounded by water, most of the time it is not potable.  Even in places like the Rio Dulce where we are on a body of fresh water we are still not in drinking water heaven.   Are you going to buy water at every stop?  How do you know the quality of the water going in to your tanks from a water source you only pulled up to in the last 24 hours?  You are making some big assumptions.  Where is their water coming from?  If it is processed, who monitors the process and how often is it checked for quality? 

The cost of water

Bottled water is pricey and not practical to supply your day to day needs.   Dock water in many places in the Bahamas and Caribbean comes at a price.  Here is our experience with acquiring water;

In some marinas dock water is included as part of the slip price,  as you can see the cost of water is not to be ignored.  At one time we paid $70 US to fill up the SeaYeti, and it was the worst tasting water we had experienced.   Regardless,  if you are traveling in the Bahamas, without a water maker, you can easily spend $10/ day to meet your water needs.  We spent from from January to March in the Bahamas.  Without the water maker that could have equated to $1,200.00 just for water.   In comparison we spent about $400.00 on fuel at $3.50 a gallon.

What is in the water? 

Water from an unknown source is always a risk.  Without sophisticated tools it is almost impossible to determine what is in the water.  Unimproved areas of the world will sometimes vent raw sewage in to the river, run off from agricultural areas can contain a cocktail of microbes and sediments.  If the river recently went through a flood stage there may be additional effects from run off.

Well Water - The Hazards

The marinas here use a variety of methods to produce potable water.  Most pull their water from a well some distance from the river.  The water is then passed through a container exposed to Ultraviolet (UV) source of light.   The UV sterilization process is good, but has limitations.  The water must be clear of sediments, a condition that may not be present during floods or heavy rains.

Treatment of water

So what does UV treated water do for you.  It kills living organisms. The UV treatment of the water will kill bacteria, viruses, and parasites.  The UV radiation actually sterilizes the organism preventing them from reproducing.   The clarity of the water before it is treated is very important.  Cloudy water tends to absorb the UV radiation creating a virtual shadow in which some of the living organisms may still pass through the system.     Notice I said it sterilizes the organism, not kill it, nor remove it.  The process is still considered very safe, but is designed to work within specific limitations.

How to remove it?

Most cruisers use at a minimum a cartridge filter assembly that contains a replaceable 30 micron filter assembly that was acquired on sale at the nearest home supply store.   This is usually the only line of defense in the cruiser's lazaret for maintaining the purity of the water in their tanks.   Many cruisers carry a far better weapon for defending themselves but rarely employ it - the water maker.    Reverse Osmosis water makers have a pore size in the membranes that is .001 micron.   The same properties of the membrane that filter out salt, can also filter out the bacteria, viruses and parasites since they are larger than the .001 micron pore of the membrane.  A 30 micron filter cartridge will not remove bacteria.    Using a 5 micron pre-filter, and the membrane allows us to make fresh water on the river.  I felt the following passage from Gary's book, best describes the filtering properties of a RO membrane.

It seems obvious that a quality RO membrane in

good working condition will not only reject a very

high percentage of sea salt (i.e., sodium chloride)

and larger ions and molecules, but it will surely

prevent passage of viruses and bacteria. The size of

pathogenic bacteria is on the order of 0.5 microns

(500 times larger than the membrane pores). Small

viruses are about 0.004 microns in size.* As small

as bacteria and viruses seem to us, they are megamolecules  on an atomic scale. Trying to push bacteria (or viruses) through an RO membrane seems a lot like trying to squeeze an elephant (or cat) through a chain-link fence.

Selecting our water maker

There are many different brands of water makers,  and many variations on the technology used to purify the water.  Most all water makers found in cruising applications produce similar amounts of water for similar amounts of electrical energy.  When we equipped the SeaYeti, we found our water maker on the SSCA discussion board.    If we were the analytical type we would have looked at initial cost, amperage to operate, size of the unit so we could start to envision where it would fit.  

After having the unit for one year, the items I would look at now include; amperage to operate, size of the unit, and the ease of use and ease of maintenance.   Notice the last two entries there.    Our water maker is a used PowerSurvivor 80E,  which is an enclosed system that by the technical manuals would produce 80 gallons a day.   It had been in storage for a year, the membranes had been pickled (preserved).   It had all the parts, and was available for $1600 (US).  Sold!   Nice logic eh?

Given two water makers that produce equal amounts of water.  I want one that is simple, easy to rebuild with a minimum of tools and operates reliably over a long period of time.    I had no idea how important that was to become,  and after enjoying a few sessions with Gary Alders the self proclaimed PUR Evangelist,  I found out how easy it was to be proficient in servicing and maintaining the system. 

I want to take this moment to introduce Gary who travels on board his 34 foot Aloha Sloop Ishi.  Gary has a long history with the PUR/Katadyn water makers using them for over 12 years.    After a session with Gary, I found the complexity of my water maker was in my head.  The simplicity of it was frankly,  eye opening.  I have since had Gary educate me on the PowerSurvivor 35, and the PowerSurvivor 40.   Gary has authored a book on maintaining the PowerSurvivor series of water makers.  During the years he has been cruising the Pacific coast of the US he has been instrumental in providing feedback to Katadyn from the field.  Now it is the Caribbean's turn.   For those of you traveling to the Caribbean in the 2006-2008 years, be sure to attend one of his seminars if you hear about one.  It is well worth the effort.

After reading and educating myself on water quality, how to measure it, the risks associated with unpurified water, water purification and the processes involved, I have come to the conclusion that we should be using our water maker on a full time basis for all our water needs.  

I am also taking the opportunity to equip ourselves to assist other cruisers who may need assistance with their water makers.   So if you see the SeaYeti in your anchorage and have a Kaytadyn or PUR system, give us a shout!   We are very happy with our system, and find that most cruisers know about as much as we did.   If you see us, we have available copies of Gary's CD with a ton of reference material on it.   I have posted his book, and links for the reference manuals on this site.

If you see me, ask for Gary's full CD, it contains a huge quantity of reference material and it is free for the asking.

Jim