The plight of Samuel Coleridge's ancient mariner is shared by many a skipper. Onboard water conservation can be critical to those who cruise to remote destinations for extended periods. But it also matters to any captain who disconnects the dockside hose bib while carrying crew members inclined to overly-long showers. And so, for most any boat smaller than a cruise ship, water management matters.
So how much onboard water is enough? A human can survive on a bit more than a quart of water a day, but the average American landlubber uses up to 100 gallons every 24 hours. Clearly, we shouldn't bring these thirsty habits aboard, but we also don't want to evoke aquatic austerity measures that present challenges to personal comfort and hygiene. A survey of various blogs and forums reveals that some water-frugal sailors get by on as little as two to three gallons per person, per day. Of course, such routines usually involve saltwater supplies for sinks and toilets, cursory or sporadic personal rinses and deck washdowns only when rain showers arrive. A more realistic number for those who enjoy reasonable showers, the odor-free advantages of a freshwater-flushing toilet and some regular hand washing would likely be closer to 15 or 20 gallons daily per passenger.
Great Harbour owners don't typically need to engage in draconian water rationing, as their N and GH series trawlers carry anywhere from 300 to 600 gallons of water—plenty for a week or more away from a water hose. At eight pounds per gallon, filling these onboard tanks adds 2,400 to 4,800 pounds to the boat's total displacement. Fortunately, that extra weight isn't really felt when traveling at the 7 or 8 knot hull speeds these boats provide.
The same won't hold true for our new TT35, which is designed to deliver exemplary fuel efficiency when operating in the 12 to 15 knot range. Weight control is key to obtaining this performance, and at these higher, lift-generating speeds, carrying a literal ton of water would result in a noticeable decrease in performance.
We will fit the TT35 with sufficient capacity to get a water-conscious family of four through a long weekend, or sustain a couple for a week or more. For those seeking extended self sufficiency, we are also working on a system that will provide virtually unlimited freshwater supplies without the need to install large tanks.
Onboard watermakers are nothing new, and most mariners familiar with these systems develop a sort of love-hate relationship. On the one hand, the ability to create a steady supply of fresh water is extremely liberating. But these systems don't come cheap, and repairs and replacement parts can be equally costly, and sometimes difficult to obtain. This complexity and expense isn't due to the basic technology involved—which is actually fairly straightforward—but to the use of proprietary parts and complex add ons.
To provide the TT35 with the pleasures of a watermaker without the pain, we are now working on an “open source” design that employs readily-available industrial parts and fittings. In addition to cost savings, this will result in a system that is much easier to maintain and repair. This device many not sport all the bells, whistles and chrome-plated knobs of the name brands, but it will provide plenty of pure, fresh water reliably and cost effectively. And that's exactly what's needed when you are hanging at a favorite anchorage far from civilization, with no plans to return anytime soon.