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Thinking of Adding a Watermaker? Different Facts, But the Same Conclusion, From a Power Boater and a Sailor

October 1, 2011

Thinking of Adding a Watermaker?

Different Facts, But the Same Conclusion, From a Power Boater and a Sailor

As technology improves, the cost and size of “high-tech” boating items, like

This Spectra watermaker fits nicely into M/V Cachibache's engine compartment

watermakers, has come down. As a result, more boaters are in a position to afford a watermaker. Whether or not to consider adding a watermaker depends on you, your boat and the type of cruising you do. We spoke with two readers with very different vessels, different fresh water needs, and different boating plans. Both are satisfied, for different reasons, with their recently installed watermakers. Gavin Ashworth cruises aboard his Sabreline 36 trawler Cachibache. John Brundage currently sails his Catalina 310 Euphoric between New Jersey and Massachusetts. John plans to retire and live aboard in the Bahamas. We present their perspectives on choosing a watermaker in the hope that their different experiences and suggestions will be helpful to you.

A Power Boater’s Perspective

Gavin Ashworth aboard M/V Cachibache

I’ve heard unfavorable rumors about watermakers that included the following:

  • They need to run constantly in order to be reliable
  • They are at times unreliable
  • Membranes are expensive to replace
  • Someone has to be on board every five days to perform a fresh water flush
  • They are time consuming to winterize
  • They are noisy

A visit to the Newport Boat Show last year, and exposure to a friend’s boat, changed my perception of watermakers. I’ve found that the truth is:

  • They do like to be used, but need not be run often to remain reliable
  • Routine flushes can be performed automatically
  • Winterization is as easy as winterizing your fresh water tank
  • They are very quite to run
  • They are smaller than expected

After considerable research I chose to install a Spectra Newport Mark 400 MPC-5000 Mk2. watermaker. It easily fits into my trawler’s engine room, supplies all of my water needs, and is relatively simple to maintain.

Some may ask, “Why would a trawler owner, with two 75 gallon and one 50 gallon water tank (total 205 gallons) aboard install a watermaker”? Allow me to explain. What follows are my seven top reasons for adding a watermaker to a powerboat:

1)    My wife and daughter don’t understand that a boat at anchor, or at a mooring, is different from a boat attached to a dock. Before adding the watermaker I was constantly monitoring the washing of food, or showering, and saying “Please, please, I’m going to need to make another visit to the dock with my collapsible water bottles to fill the tank”. I needed to do this even though we can carry over 200 gallons of fresh water aboard.  The problem I had would only be compounded on a smaller powerboat that might have a tank holding 35-70 gallons. With a family of 3 aboard, a few days at anchor empties water tanks pretty quickly. We simply needed a larger fresh water supply when away from our dock.

2)    Cachibache spends a good part of her cruising time at anchor. Once I had set the anchor, and had gone through 20 kt. winds, and the anchor had dug in and set well, I was reluctant to lift the anchor and move the boat to a dock for water…only to come back and discover someone has taken my spot.  After visiting a dock for water I would then need to re-anchor and wait aboard to be certain of another good anchor set. I can now stay for a week at anchor in one area without needing to pull up and re-anchor. This saves time and improves anchor related safety.

3)    My boat is a fast trawler with a semi-planing hull. Carrying 205 gallons of water, at 8.3 pounds/gallon, means full tanks add 1700 pounds to the boat.  Now, when I depart, I carry only 25-50 gallons of water in my center tank. The boat planes and cruises faster at the same RPM as in the past. This results in a significant fuel saving. Also, the boat is always balanced because I cruise with only the center tank full.

4)    Supplying your own water reduces hassles at the fuel dock.  If you go to a fuel dock and ask only for water, staff is often reluctant to do so. If you fill with fuel and ask for water, there is often a rush to get off the dock because other boats are waiting. Having a watermaker ends the hassle.

5)    A few years ago I had the hull painted with Awlgrip. In order to keep salt water from drying and staining the paint, I routinely rinse the hull after each cruise. At an anchorage without a watermaker, I reluctantly used fresh water from my tanks, knowing this would mean a trip to the dock to refill tanks. Now I can wash and rinse the entire boat at anchor, or at a mooring, without water concerns.

6)    My watermaker requires 110-volt power. Because I run the generator and watermaker at the same time, there is an unlimited amount of hot water aboard.  A near unlimited water supply has made life at anchor, or on a mooring, far more enjoyable.

7)    Having a watermaker facilitates living on anchor. A lot of boaters either have had a bad experience anchoring, or have heard anchor-dragging stories.  If you study anchoring, read NFTB (See Principles of Anchoring, June 2011), and read Happy Hooking by Alex and Daria Blackwell (White Seahorse, Inc. 2008), you can learn a lot about anchoring. Anchoring can in some circumstances be safer than being at a mooring or at a dock. When you attach yourself to a mooring in bad weather, you never know the exact condition of the tackle under the mooring ball. Has the chain degraded? Is the anchor properly weighted and set? With anchor chain you know that your ground tackle is in good shape.  If you use an anchor appropriate for your boat, and have a good anchor like a Rocna, and you set the anchor properly, you can be as safe, or safer, at anchor than at a mooring.  Besides, being at a dock for me is similar to being in a crowded campsite. At anchor you can choose quiet spots “out there”. As the boat swings in the wind you will have a breeze through the hatches and keep your aft cockpit protected from the wind. Being at anchor, for me, is extremely pleasurable. A proper anchorage may even be safer than being at a dock. Neighboring docked boats may not be properly secured; some call it dental floss as lines, and can place nearby boats in jeopardy.

Choosing a Watermaker

If someone has an interest in, and is considering installing a watermaker, I feel the

NorEast Marine Services of Fairhaven MA advised the author and installed his Spectra system. Scott Manchester (L) and his partner Steve Rebello own the company

best approach is to first obtain “local knowledge”. What I mean by this is talking with boaters who use various types of units. Also very helpful is asking questions at boat show and on boating blogs. I was fortunate enough to be referred to NorEast Marine Services of Fairhaven, Massachusetts. NorEast’s co-owners Scott Manchester, and his partner Steve, advised me on the type of units that would best suit my needs, quoted a fair price, and deliver and installed the watermaker on budget and on time. When I had a small problem associated with the systems in my boat, not caused by the watermaker or the installation, Scott took a day out of his busy schedule to travel to my location and trouble shoot and fix the problem. Now that’s what I call service.

Maintianing a Watermaker

Winterizing my watermaker is as easy as winterizing the fresh water tanks, and even uses the same chemicals. While filters can cost nearly $20 each, I have used the same two filters throughout the entire past summer.


Now, with a push of a button on a remote panel I can make 17 gallons of fresh water per hour, which makes my wife and daughter happy, my hull and decks spotless, lowers my fuel consumption underway, and makes hanging on a hook for extended periods of time a whole new experience.

A Sailor’s Perspective

S/V Euphoric's 12 volt Katadyn watermaker

By John Brundage, aboard S/V Euphoric


NFTB contributor John Brundage sails his 31-foot Catalina throughout the Northeast US, and usually does so single-handed. John’s concerns and reasons for installing a watermaker were as follows:

I chose to install a watermaker in large part because I plan to retire on the boat, and winter in the Bahamas. Water at a dock in the Bahamas can cost $1.50 per gallon or more. The cost/benefit analysis, therefore, suggested that adding a watermaker was a very practical decision. As I do not have a generator aboard, I was interested in a 12-volt system. The Katadyn unit I chose produces a bit more than one gallon per hour. For my purposes that is sufficient. I use approximately 7-8 gallons daily, which includes showering, making the watermaker’s output acceptable.  The unit draws an acceptable amount of current, and the watermaker was affordable and relatively easy for me to install. I supply the watermaker’s 5 amps power requirement primarily with either my wind generator or solar panels.

Katadyn currently recommends a filter combination that includes a 35-micron filter and a 10-micron filter. Filters need only be changed annually. This may in part be due to the fact that I do not run the unit unless the seawater is relatively clean. Basically this means avoiding making water in New York Harbor, Raritan Bay, and some local harbors…depending on conditions. I’ve used the watermaker for four years without difficulty. I need to wait about one minute before diverting the water product into my fresh water tank, as the water salinity is high during the first minute or so of operation.

I installed the unit myself. Maintenance and deconditioning is easy. I am basically happy with the unit, although sometimes I wish it would produce more water. The cost of the unit, including installation, was just over $1000.

Editor’s Note:

We trust that Gavin’s and John’s experiences with watermakers have piqued your interest in having one aboard. If you have experiences with watermakers and wish to share them with fellow readers, please pass along your comments.

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