Water Maker Installation on a Catalina 400 Sailboat

The following was sent in by Tim, the owner of SV Magic a Catalina 400 Sailboat after returning from their first season of cruising the Bahamas.  Not every client sends such a detailed water maker installation write-up to us.  So when this one came in we had to share it!


In the spring of 2012, in preparation for extended trips to the Bahamas from the Chesapeake Bay, we decided to add a watermaker to our inventory. After an exhaustive search, we decided on the 110-volt SM20 by Cruise RO Water Maker.  This decision was based on several factors:

•    Modular design. I could put the components basically where I had the most space and where it was most convenient. The Catalina 400 doesn’t have a lot of excess storage space and it was important I use wasted space whenever possible:

•    High output (20 gph) using a Honda 2000i to power the high-pressure pump. Since we already had the generator that saved us money.
•    Price. This unit was almost ½ the price of almost every other system I found and had a higher output than any.
•    Customer support. I had no idea how much I would wind up relying on these guys during the design and installation of my system. Even though Rich was on his boat in Mexico, I never had to wait more than a couple hours for a response to either an e-mail or phone question.
•    Easy of operation. While not as automatic as other systems, the instructions were very clear and it was quickly apparent it would be easy to operate.


Once we made the decision to buy the system, my biggest priority was to find locations on the boat where the watermaker would take up the least amount of usable storage space. That space wound up being one of our huge aft cockpit lockers. I was able to put all components of the system in this locker except the saltwater intake and associated lines.

I wanted to place the relatively heavy high pressure pump relatively low and near the centerline and since the bottom of this locker is curved, had to construct a shelf that provided a flat mounting surface but also fit the contours of the hull. The photo at left shows the platform, which is tucked up under an overhang in the aft cockpit locker, painted and glassed to the hull structure itself. This was unused space before. If you look closely you can see a separate plate directly under the pump. Between that and the platform is a piece of rubber that I included to reduce vibration noise. The pump was already relatively quiet, but the rubber shock-absorber did help.

I found space for mounting the Valving/ Cleaning Assembly, Boost Pump and dual Pre-Filter assembly along a transom locker wall that intrudes into the aft cockpit locker. Minor modifications to how the assemblies were put together were made to reduce water line runs. Rich Boren at Cruise RO was extremely helpful here, helping ensure these mods would work for our application. Note: In the photo the valve assembly has been reversed. The line leading in from the left is the freshwater flush that comes from a connection in the cockpit shower. The second photo shows where saltwater flows into the valving assembly and then to the boost pump. Barely visible at the bottom right of the photo (around a corner) is the dual filter assembly. While sailing the boat, all these assemblies are covered and protected by a line bag that hangs from the top opening of the locker.

After leaving the dual pre-filter assembly, saltwater then goes to the high-pressure pump which (in my case), is AC powered. At anchor, I accomplish that by running my Honda generator, plugging it into the shore power receptacle and then plugging the AC pump into the 110-volt receptacle shown in the lower photograph.  Two major components still needed to be installed, the membrane (where the magic happens!) and the Remote Panel. In my case, the membrane fit nicely (if snugly) right against the forward bulkhead of the cockpit locker and can be seen in the photo to the left. This blue “tube-like” membrane runs athwartship and is well protected. Note: Slipping slightly larger reinforced water lines over the watermaker plastic lines in strategic spots protected them from chafing. The people at Cruise RO were extremely helpful here in helping me locate potential weak spots.

The last major component, the Remote Panel may have provided me the most head scratching of the install. I kept moving that unit around and checking both fit and utility until I found a location where it was both accessible and secure. I wound up hanging the panel directly below a couple of shore power circuit breaker plates at the outboard side (port) of the locker which allowed fairly good viewing, was protected from the elements and made water line runs pretty easy. To ensure “stiffness” I attached the panel to a couple aluminum bars that I then used to attach to the circuit breaker plates. The piece of aluminum seen at the bottom right of the photo stiffened the bottom of the panel nicely. Note:  At the bottom of the Remote Panel are two rocker switches, one for the boost pump, and the other for the high-pressure pump. You will note just above the boost pump switch (left), I installed a 15-amp circuit breaker. I think it is a nifty location.

The only remaining installation challenge was how to plumb saltwater to the watermaker and discharge the brine. I tapped off one of my head intake lines to bring seawater to the system and all brine discharge lines were connected to existing cockpit deck drain lines.


During our 6 months in the Bahamas, I had absolutely no problems as all with the watermaker. We did continue to take “Navy” showers and otherwise conserve our fresh water, but I only found it necessary to make water every 3-4 days for about 1 ½-2 hours at a time. I only plumbed the RO water into my aft tank (to avoid a long water line run to a bow tank) and we used it almost exclusively. We had enough water that I even allowed myself to give the boat an occasional freshwater bath!


Bottom line is that I couldn’t have been happier with our Cruise RO SM20 watermaker. Yes, it did fall into the “want” list rather than the “need” one, but I viewed it as a quality of life benefit. While other cruisers stood in long lines waiting for questionable island water, we pretty much made as much as we needed! My hats off to Rich and Charlie of Cruise RO Water!