On Board Watermakers

This year a lot of marinas and outstations will remain closed or only offer limited services, which means boaters will have to make alternative plans to get water on board.  One solution is to install a water maker that turns salt water into potable water. 

Today’s watermakers use a process called desalination or reverse osmosis.  The seawater goes through a filtration step to remove the particulates, and then it is pumped through a membrane at high pressure around 800 psi.  The water then passes through a salinity test to determine if it is acceptable. If it passes the test, it goes into the water tank; however, if it does not pass the test, then it is put back in the ocean as waste brine water.

Like most gear on a boat, nothing is one size fits all. What works for a small sailboat will not be the solution for a larger powerboat.  Let’s look at some of the decisions you should consider before making a purchase.

12V or 110V?  First up, decide if you want the system to run on 12V batteries or a 110V/220VAC generator or shore power.  If you do not have a generator, but you like to anchor for extended periods, have a large battery bank, or alternative charging sources like solar, wind, or a fuel cell, then the 12VDC solution will be the best for you.  If you spend most of your time at a dock or run your generator daily, then AC is the way to go.  AC will give you more liters per hour (lph) than a DC powered watermaker system.

Modular or Semi-Modular? The second decision will be whether you want a modular or a semi-modular frame-mounted system.  A modular system will allow you to install the different components like filters, pumps, and strainers throughout the boat.  This allows you to customize the install to maximize the use of inside cupboards and bulkheads and is the best solution for someone with limited real estate on board.  Just remember to put the filters in an easily accessible space as they require regular maintenance.  A frame-mounted system is self-contained, somewhat plug and play but requires much more space.

A frame-mounted system can cost more but is somewhat automated. Some modular systems can be far more manual, and you will have to adjust knobs and valves to figure out the best settings.  If you are going offshore or don’t have access to a technician, sometimes it is better to have a manual system because you will have to have a better understanding of how everything works in case something goes wrong.

Some of the most popular water maker manufacturers are Spectra, FCI, Schenker, Dometic Spot Zero, PowerSurvivor, and Sea Recovery.

For DC powered watermakers, we recommend the Spectra Ventura 150 Deluxe or 150C for small to mid-sized vessels.  Both are modular systems that are energy-efficient, lightweight, and deliver 24 liters per hour.  The 150 Deluxe is manually controlled, and you must test the water yourself.  The 150C is entirely automatic with a remote panel that runs a freshwater flush when it is done.  It can also be controlled by a smart device if you have WiFi onboard.  The unique thing with both of these watermakers is that they ship with all the parts required for the installation except for the thru-hulls.  Many watermakers are not sold as kits, and you have to purchase a lot of extra pieces to complete the installation.  Depending on the fluctuation of the US to CDN exchange rate, the Spectra 150 Deluxe retails for $9,400, and the Spectra 150C retails for $13,900.

For AC powered watermakers, we recommend the FCI Max-Q+, which is a framed water maker and can make 200 liters per hour. It is entirely automatic with a touch screen remote panel.  This is a foolproof system that requires little maintenance, has a fresh water flush, and one simple, easy to replace filter.  It is also NMEA compatible.  The manufacturer’s suggested retail price is $22,000.

Now that you have a basic idea of what is available, how do you decide how much water you want to make?  Do you simply want to have a couple of showers and do some dishes, or do you want the kids to rinse off on the back deck, or maybe even wash the boat with fresh water made from your watermaker?  On average, a 12-meter boat will have a 150-liter water tank.  Using the DC powered Spectra Ventura 150c, it would take six hours to fill the tank, whereas the FCI Aquamizer would take less than one hour.

No longer just for offshore sailors, a water maker offers boaters more independence and convenience. As water becomes more precious in our local communities, it just makes sense to be able to create your own reliable and safe water onboard. 

About the author: Jeff Cote is the owner of Pacific Yacht Systems, a full service shop delivering marine electrical and navigation solutions for recreational boats. Visit their website and blog for info and articles on marine electrical systems, projects and more: www.pysystems.ca.