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Watermakers—Pros and Cons
This article was originally published on SailNet in December 2000.
Reverse-osmosis technology for making freshwater out of seawater has been around for decades. Until the 1990s, however, the machinery was generally constructed on a grand scale to serve whole towns or communities or naval ships. When Recovery Engineering, now part of the PUR group, came out with a series of small, 12-volt watermakers about 10 years ago, the world changed for many cruising sailors. Over the years improvements in technology have made watermakers even more reliable and affordable.
Watermakers are one of those topics that, like anchors and who won the 2000 presidential election, raise love and hate to great levels in many sailors. We watched one couple arise each morning in the Caribbean and rinse the dew off their decks with freshwater. They said they couldn't live without their watermaker. Others we've met can't seem to use the word "watermaker" without preceding it with some invective.Part of the reason for this is that water usage is such a personal issue and each cruiser seems to draw the line at rationing water in a different place. For cooking, cleaning, and drinking, each person needs only a minimum of about six quarts of water per day—three gallons per day for a couple. Ninety gallons of tankage should last a fluidly frugal pair about one month, and we have lived on this amount year after year. It takes discipline. Under this regime, bodies, clothes, and dishes get washed in saltwater with a minimal freshwater rinse. For showers we use two quarts. There are bright spots to this way of life—drinking water can be supplemented with more beer without any need for rationalization. There are other cruisers who let the water run while brushing their teeth, take indolent showers, have a washing machines on board, or who just have no interest in rationing water. We met one couple that routinely used 200 gallons a week. For these cruisers, either an immensely huge boat with very large water tanks or a watermaker are the only logical choices.
Right here, in accordance with the SEC requirements that writers reveal their ownership conflicts of interest, I want to publicly state that I have never owned, nor do I have plans to own, a watermaker. I firmly believe that they have an absolutely essential value, but only to the right sailors under the right circumstances. I also believe that many watermakers are installed by cruisers who could find better uses for their money, time, and space on board.
Now that I've sugar-coated my feelings on the matter, let me explain why I've adopted these beliefs. Here are some good reasons to own a watermaker:
- The boat sails in an area where water is scarce. Desert areas such as Baja California, the Red Sea, or even the Bahamas have little or no natural water supply and the available water may be expensive. I have paid as much as 50 cents per gallon for RO (reverse osmosis) water in the central Bahamas, and then had to jerry-jug it nearly five miles to the boat. If I cruised in these locales exclusively, I think I'd install a watermaker.
- The boat has a large crew and small tanks. Many racing boats fall into this category and a watermaker adds less weight than adding additional tankage.
- The water supply where the boat is captive is contaminated. There are many places in the thirdworld (and a few areas in the US) where you just don't want to drink the water because of heavy metal, fecal, or other contamination. There may be plenty of water to wash the boat and dishes, but not a drop worthy of drinking.
That's it. Those are the only three reasons I have found that would convince me to have a watermaker on board. So now, let me discuss the downside to owning these masterful conveniences:
- Watermakers are expensive. Much depends on your cruising budget, of course, and this may not be a major issue to you, but the purchase and installation cost of a watermaker could keep us cruising for a long time, with a trip to Disney World thrown in on the side. Even if we doubled our water usage, those gallons would cost me about a dollar each, and that is some expensive water.
Watermakers use a lot of power. New companies and technologies have improved this situation in the past two years, but water made with 12 volts still takes an amp for every two gallons—that adds an additional solar panel and battery to the installation expense to get 10 gallons a day. Engine-driven and 120-volt systems rely on generators or the main engine, which each consume lots of fuel, filters, belts, and oil. No matter how you slice it, a lot of power has to be generated on board so that you can take that long shower. Watermakers take a lot of space. Not just the pumps themselves, but also the wiring, hoses, dump tank, valves, strainers, and a cabinet full of spare parts.
Watermakers are limited in use. You can't use a watermaker if there is too much silt in the water, or oil contamination, or a number of other substances we shouldn't discuss. Note that reason number three for having a watermaker is to avoid contaminated freshwater, but where the freshwater is contaminated, the seawater usually is too. There are some harbors where the smell is enough to make you close the seacocks.
- Watermakers are expensive and time-consuming to maintain. Pre-filters need to be cleaned. If it isn't run for a week, it needs to be drained and pickled. Expensive membranes wear out or become contaminated and spares need to be carried. If you like to spend your cruising hours back-flushing and tinkering, you'll love your watermaker.
So why do the cruisers who own a watermaker love them and put them on their list of 10 items they wouldn't sail without? Because they are so cool. Just the thought of throwing the jerry jugs away and never going to the dock for water again sends goose bumps down my spine. In all honesty, a long, hot shower at the end of a day of diving warms my heart and soul. The smell of freshly laundered clothes and sweet-smelling pillowcases at night could make me weep for joy on some days. And someday, just once, just for fun, I'd like to be the position of that conspicuously consuming sailor who rinses the dew off his decks with freshwater. Even the domestic routine of washing and drying dishes in running freshwater is a luxury we would all like.
As long as we realize that it is just that—a luxury that must be paid for with more money, more power, more space, more weight, and more time to maintain the system. Ah, the simple decisions of the cruising life. And we wonder why cruisers develop these love/hate relationships with their gear.
Suggested Reading List
Ten Things We Wouldn't Sail Without by Sue & Larry
Cruising Necessities and Luxuries by Randy Harman
Maintaining Freshwater by Kathy Barron
SailNet Store Section: Watermakers and Kits