Just a little more about water makers. They’re heavy and take up space, and higher than design temperatures can contribute early failure of system components, perhaps most often membranes. We can buy a Dow 40” membrane from CruiseRO for around $200, but the same part in Papeete was about $600. Consider the ambient temperature of your installation space, and if you think you’re going to install the water maker in an engine compartment, understand that temperature environment while running the engine hard in a warm tropical environment. Maybe that space won’t harm the water maker components, or maybe you need to add a couple of bilge fans to actively move hot air out of the compartment while motoring. Maybe all you need to do is run the water maker only when the compartment is cool. The only component of an energy recovery water maker that makes noise is the feed pump – perhaps that component can live in the engine compartment and the rest in somewhere in the cabin interior. A high volume unit like the CruiseRO used a large AC electric motor spinning a high pressure pump common to pressure washers, and not only is that assembly noisy, but the pump’s vibration energy is transmitted through the high pressure hoses and the membrane pressure vessels, so everything becomes a loudspeaker. Installation in the cabin will likely guarantee that you will be keenly aware the water maker is running, and if your name is Isabel it’ll be a source of great irritation and the occasional headache. I did my best with our installation, ultimately shoehorning the entire machine into the aft cabin hanging locker and I did a lot of reduce the noise. Given my education and work background is in the field of noise and vibrations for both automobile and aerospace manufacturers, my efforts were reasonably effective yet even I am tired of hearing that thing run. Still, we love having abundant potable water.
We do have to be considerate of the energy the system uses, and generally run it on excellent solar days after the house batteries have reached 90% SOC, or while we’re having to motor underway in lousy sailing conditions. Always find a way to use excess electricity for something useful. If you want to minimize energy use and the size of your battery bank and solar array and minimize or eliminate burning fossil fuel to make water, throw down the bucks for the most reliable and supported energy recovery system you can buy. Running a lower production rate unit for more hours a day is generally the best way to save money and the water maker likely won’t care. Generally it’s better to run that sort of machinery more often, and the membranes should last for xx years or xx liters of water produced, so find the best water make to fit your budget. That said, you will anchor in some icky places where you just don’t want to produce water, either because of filth in the water or high turbidity due to organic life or sediment. Show up with full tanks and plan to go for the occasional day sail if you want to linger there.
Depending upon the environment you intend to cruise in, getting a good night’s sleep may involve an airconditioned master cabin. Cooling the entire boat isn’t practical unless you’re willing to run a generator full time or plugged in at a marina. Aircon equipment is expensive, heavy, and eats up valuable real estate in the boat. It’s also a real electricity pig.
Given your cruising environment, solar array effectiveness and useable capacity of your house battery bank, at some point you may have to convince your sailing companion(s) to austerely at times or cave in and have a generator aboard. We’ll think about that next time.
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