Mailport: April 2013
Watermaker Field Notes
Having sailed my family around the world over a five-year period using an older Spectra watermaker, I can add a few thoughts to your February 2013 review of DC watermakers.
A watermaker is wonderful for long-distance cruising. Because we could run ours strictly on solar power, we essentially had as much “free” water as we could use when we were anchored in the tropics; our 500 watts of solar panels would top up the batteries by noon on most days, so we could make 30 to 40 gallons of water in the afternoons. We never needed that much, but we gave it away to other sailors and often to locals.
We also traded it for beer, chocolate, flour and other staples, fresh fruit, and seafood, and were able to make other peoples’ lives easier. And, we never worried about the quality of water we were giving our children.
That said, a watermaker is not a simple, trouble-free device; it requires a lot of “user participation.” The Clark pump is not something you can work on yourself; we had ours overhauled once in Thailand for a cracked casting and traded it in on a rebuilt one in Puerto Rico a few years later. Membranes will last three to four years, if cared for. You don’t need to buy them from Spectra; the same units are available worldwide through hardware stores and agricultural supply houses for less than half the cost. Ditto for filter cartridges; they are very standard. Pickling and cleaning chemicals are also available inexpensively and in bulk from restaurant equipment suppliers; a quick Internet search will get you the generic names and appropriate concentrations.
Our Spectra has dual feed pumps, and I replaced the heads almost annually and the motors several times. Again, basic Shurflo pumps are available everywhere.
One of the first things I did was to cut away almost all of the alloy cover on the main module, making the fittings and connections much more accessible.
Another early discovery and modification was that if your boat routinely sails at over 7 knots or so, you’ll need a sea chest or scoop on the intake; on our first ocean crossing, we had to reef down to make water, which was very frustrating!
Lastly, you need to include flushing water in your efficiency calculations. It takes three to four gallons of fresh water to adequately flush the unit after each use. Our Spectra drew about 16 amps and produced about 13 gallons per hour, but we typically made 30 to 40 gallons at a time and then used 10 percent of it to flush. In conclusion, I would never want a watermaker on a coastal cruising boat, but I wouldn’t choose to go long-distance sailing without one.
Aldora, Outremer 45
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