Heading south for the winter? Life's great under the swaying palms—until you get thirsty. Too often the drinking water in tropical paradises tastes funky. (Maybe that's why so many folks in the Caribbean drink Mount Gay rum for breakfast.) Protect yourself by turning bad water into something you'll actually enjoy swallowing with an onboard water-treatment system.
In the United States, most drinking water is safe, but it still might not taste good. While EPA regulations require all public water systems to reduce concentrations of the most dangerous contaminants, removing other impurities is recommended but not mandated by federal law. High concentrations of these secondary contaminants, including aluminum, copper, fluoride, and sulfates, "may cause cosmetic or aesthetic effects," according to the EPA. (For detailed info on water quality, see the EPA's SafeWater program.)
Even if the water coming from the dockside tap is fine, your fiberglass tanks can turn it sour. The problem is exacerbated by algae and other nasties, especially if the water isn't used and replenished frequently. So step one on the path to pure water is to clean the tanks. Add a cleaner/treatment, like Starbrite's Aqua Clean, take the boat for a ride to slosh it around, then pump the tank dry through the galley and head faucets. Refill the tank, adding Starbrite's Water Conditioner to keep it and the plumbing sweet.
Atlantic Ultraviolet Corporation
Here's a cross-section of a typical ultraviolet water purifier.
Now add a filter system. Large yachts with many freshwater outlets usually install a large-capacity industrial charcoal filter at the water pump. Boats with dockside pressure-water should have a filter at the inlet, too. In either case a flow meter will be handy for determining when to change the filter cartridge; a dirty filter is worse than no filter at all.
A simpler way is to install a filter at each faucet, or maybe just one in the galley and one for the ice maker. This is a do-it-yourself job requiring only basic skills and tools: Mount the filter under the sink, where it's easy to reach for changing the cartridge. Turn off the freshwater pump, disconnect the supply hose from the cold-water faucet, connect it to the filter, then connect the filter to the faucet. Let the water run for five minutes to flush away loose charcoal. Have a drink.
Many systems include dedicated faucets so you filter only the water you want to drink, extending the life of the cartridge but making installation more complex and often taking up work space around the sink.
Shurflo makes good, reasonably priced filters. If you want to spend more for something fancier, check General Ecology's NaturePure and Seagull IV systems. And check West Marine for a selection of filters.
If you want the ultimate in water purifying, how about ultraviolet disinfection? Used in conjunction with standard water filters to remove solids and chemicals, a UV water purifier uses the germicidal band of the UV spectrum to kill microorganisms; the filtered water runs through a clear tube, where it's zapped with UV light. The Water Fixer and Atlantic Ultraviolet make UV purifier for both 12- and 120-volt systems. The cost is less than $500 for a high-flow purifier. How can you afford not to have one?
Ask the Experts: Pat Peterson
Question: I wash down my sportfisherman scrupulously after every trip offshore, but I always end up with water spots the next day, especially on the brightwork and metal. Is there any way to prevent this, short of spending an hour drying the boat with a chamois and towels?
Answer: Any captain will tell you drying the boat is as important as washing and rinsing her if you want to avoid streaks and water spots. But folks can free themselves from chamois tyranny, says Pat Peterson of Peterson Marine in Oldsmar, Florida. Peterson sells, installs, and services water, electrical, sanitation, and air-conditioning products aboard power and sailboats. Many of his customers own large sportfishermen and are water-spot-phobic.
"We didn't invent the solution," says Peterson, "but we—Harry McNally, my head service technician and I—perfected it." The answer, he says, is not to use dockside water straight, but to run it through your watermaker first. "Who knows what's in your water?" he asks. The reverse-osmosis membrane will remove almost all impurities, producing water that's "micro-pure, nearly lab quality," says Peterson. You can forget wipedowns, and there won't be any water spots when the boat dries.
The modification is fairly simple, although installation should be left to an expert. Step one is to plumb a dockside water inlet to the watermaker boost pump. Add a 20-inch charcoal-block filter in the line to remove chlorine—"There's a lot of chlorine in city water," he says—and a three-way valve at the pump. The valve lets you switch between usual watermaker function, i.e., desalinating sea water, and producing micro-pure water from dockside. The watermaker works normally in either case; the difference is only in the water source.
Peterson recommends adding a flow meter and a pressure gauge to the inlet plumbing, too. The meter measures water usage; a pressure drop indicates the filter needs changing. Along with a charcoal filter, these are worthwhile additions to any dockside water system, he says. Otherwise, some captains tend to change the filters too frequently, others not often enough.
So far, all the systems Peterson has installed have directed output water into the freshwater tank, just like when the watermaker is desalinating; the washdown pump pulls from the water tank. "Most of the boats have been new, with nice, clean tanks," he says; by using this system from day one, the fresh water is micro-pure.
This article originally appeared in the September 2008 issue of Power & Motoryacht magazine.