Watermaker Installation

 When we bought C Ghost, it did not have a watermaker installed. We knew we wanted to have one eventually, but decided to wait until our cruising plans dictated we’d really need one. With our intent to cruise to the Bahamas later this winter and potentially be at anchor for extended periods and away from a fresh water supply, the time had come.

There were four main factors in our watermaker decision – where to install it, power draw, capacity (how much water can it make), and cost. We knew well in advance this was going to be an expensive addition and had planned for it when we bought the boat. We also knew we wanted it to run off 12V DC so we wouldn’t need to run the generator or engine every time we needed to make water. Ideally, its power draw should be low enough so it could run off the energy from our solar panels on sunny days (for more on that topic, see Solar Panels). Having been at anchor for up to 10 days on previous cruises, we had a good idea of our consumption habits, both in “miserly’ mode and “luxury” mode. Our goal was to find a watermaker that could operate within our solar energy budget and in the process, produce enough fresh water to get us as close to “luxury” mode as possible. The last piece of the puzzle was finding a watermaker that could fit on the boat without intruding on our living space or consuming an inordinate amount of precious storage space. As it turns out, this last requirement was the hardest part of the project.

After a lot of research, it became clear we’d need a “modular” style system to meet the space requirement. Self-contained watermaker systems, while much easier and idiot-proof to install, were just too big for any available space we had. Modular units allow the individual components of the system to be spread around different parts of the boat making much more efficient use of space, but also complicating the plumbing and overall installation.

After careful measurements of the space we made available, we decided on the Spectra Ventura 200T system. This unit produces 8.3 gallons/hour with an energy draw of 10 amps @ 12V DC. In theory, running this system for 2 – 3 hours a day (daily use is actually recommended for this technology) would keep us in “luxury” mode. The Ventura 200T comes as four major components and several smaller parts. Here are pictures of the spaces we made available on the boat to install these components:

This is the compartment under the floor at the foot of the master berth where we planned to install  some of the watermaker components. The existing black hose (for the deck wash-down pump) had to be re-routed to make more room. The white electrical wire for the watermaker was run from a new breaker on the main DC panel.
This is the hanging locker in the master stateroom. We had converted it some time ago to enclose a set of “soft” shelves to store clothes instead of hanging them. There was good usable space on the floor of this locker.

The last time the boat was out of the water, we re-purposed an existing thru-hull to be the intake for a future watermaker. On the Island Packet 420, there are two thru-hulls in the underfloor compartment at the foot of the master berth. One is for the depth sounder and the other for a paddlewheel style speedo. We replaced the dedicated depth sounder unit with a combo depth sounder/speedo unit (converting it to a NMEA2000 sensor at the same time). That freed up the thru-hull previously dedicated to the speedo. We replaced the speedo’s large plastic thru-hull with a smaller diameter bronze thru-hull and backing block (some epoxy work was needed to make the original hole smaller).

A closer look in the underfloor compartment at the foot of the master berth. At the top of the photo you can see two thru-hulls. Originally, the top one was for the depth sounder and the one below it was for the speedo (paddlewheel style knot meter). We replaced the original depth sounder with a NMEA2000 sounder/speedo combo unit. We then replaced the original plastic speedo thru-hull with a traditional bronze thru-hull with valve and backing board. The green wire connected to the new bronze thru-hull is from electrical bonding circuit. Pre-existing in this compartment are the shower strainer and drain pump (left side) and parts of the Purasan system for the forward head (bottom left).

In that same compartment is where we mounted two of the four main watermaker components, the feed pump module and pre-filter, as well as a seawater strainer. Also shown is the optional Z-ion disinfectant unit  used during the “flush” cycle. Here is how they fit:

The charcoal filter (blue), control panel (white with yellow valve), and feed pump (black) were all contained on a single module from Spectra. We mounted the Z-ion control unit (white with the word Spectra visible) on top of the feed pump module. To the right is the black 5-micron pre-filter. These components had to be mounted high enough so their filter housings could be unscrewed and lowered in order to replace the filter elements. The intake thru-hull can be seen on the left.
Looking at the starboard side of the compartment shows the plumbing from the intake thru-hull. The water first goes to a sea strainer (white top metal mesh filter) mounted on the wall in the left side of the picture. From there, a hose goes down (out of the picture) and connects to the bottom of the feed pump module on the right side. Also in this picture in the upper left are the electrical connections for both the watermaker and the Purasan system (located on the port side of this  compartment) situated above all the water pathways.
On the left side of the picture is the 5 micron pre-filter (black). This pictures looks into the port side of the compartment at the foot of the master berth where in a previous project we installed modular components of a Purasan system for the forward head. The newer looking hose running from the watermaker pre-filter snakes to the underside of the hanging locker and comes up thru a hole we drilled where the membrane unit is located.
The pre-assembled feed pump module from Spectra has a charcoal filter mounted on the left side (you can only see it’s blue top in this picture). This is part of the fresh water “flush” system for the Watermaker which is required to be run after each use. The charcoal filter removes any chlorine that may be present in the flush water which could foul the membrane. For a source of fresh flush water, we had to tap into our fresh water system at some point. Very conveniently, there was a fresh water line already running along the top of this compartment (on its way to the Purasan system) just above where we mounted the feed pump module. A tee connector and short bit of hose did the trick.

Next was the installation of the largest component of the Ventura 200T system, the high pressure pump/membrane. The space we chose for this was the floor of the hanging locker in the master stateroom. We had previously converted this locker into a closet with soft shelves for clothes as you can see below:

Full view of the locker with the membrane unit placed on the floor. It just barely fit.

Locating the pump/membrane unit in this locker allowed us to “tee” into the existing shower drain thru-hull, which is also in this locker, with a very short hose run for the brine discharge.

A closer look. The white hose leading to the above-the-waterline thru-hull on the left comes from the shower drain pump (via a vented loop just above).

The last main component is the accumulator tank, pressure gauge, and flow meter combo. These gauges are mechanical, not electronic, and must have water lines plumbed to them to operate. Wanting to make these waterlines as short as possible, we decided to mount the gauges and accumulator tank on a wood “panel” fashioned to fit just inside the locker door on the aft side:

We had to make two modifications to this locker. The first was drilling a hole in the floor for the water hose coming from the pre-filter to connect to the input of the membrane unit. Second, we fabricated a wood panel on which to mount the accumulator and pressure/flow gauges. The picture shows the back of this panel before being permanently mounted. The accumulator is on the bottom of the panel and the back of the gauges just above it. The coiled thin black hose on the left of the picture is the product water hose which leads to the boat’s water tank.
The membrane/pump unit all plumbed in. here you can see how the brine discharge hose goes from the membrane unit into a tee plumbed into the shower drain hose taking advantage of the existing close by thru-hull. This picture also shows our fabricated wood panel in place with the front of the gauges showing. You can see the plumbing to the accumulator tank just behind the panel below the gauges.

Lastly, the product water needed to make its way to the water tank. This was harder than we thought it would be. The best part about using the spaces we did for the installation was that we had very short hose runs, particularly for the high pressure lines. However, the only accessible part of the top of the water tank was much further aft in the boat, under the floor panel in the main salon next to the nav station. Also, operation of the watermaker necessitated running the first few minutes of product water into a separate area/container in order to test it before diverting it into the tank. We wanted to make sure this part of the operation wouldn’t result in water possibly spilling where we didn’t want it. The answer was to run the product hose aft from the master hanging locker behind the port side settee and then make a left turn to the center of the boat toward the tank fill inlet. Our original thought was to tee into the tank inlet hose in order to get the watermaker product into the water tank. That was going to be difficult however, since the existing tank inlet hose was much larger than the watermaker output hose, and the clearance under the floor where the tank inlet hose enters the tank was minimal. We decided instead to “tap” a new hole in the top of the tank and screw in one of the supplied fittings from Spectra to connect to the tank. This was a little scary, but turned out great. It also allowed for the placement of the product water diverter valve just under the floor in that same area so that the “sample” water at the start of each cycle could drain straight into the bilge:

The aft end of the water tank under the floor panel in the main salon. In the upper part of the picture just below the yellow label, you can see the blue handle of the diverter valve mounted to the underside of the floor. The product water hose comes from the watermaker and connects to the back of the diverter valve. When the valve is in the “sample” position (which it is in this picture), the product water goes into the coiled thin black hose on the bottom left of the picture. When the watermaker is first started, the output runs thru this hose into the bilge until the salinity level drops to a drinkable level. At that point (determined via a salinity tester), the blue diverter handle is moved to the right and the product water goes into the tank. The new tank fitting we drilled and tapped is the tiny grey plastic elbow on the tank in the upper right of the picture with the thin black hose connected to it. The white stuff at the base of the fitting is teflon tape where the treads of the fitting screw into the tank.

Since we were in our marina, and the water still has a lot of sediment from hurricane Irma, we tested the watermaker with an “artificial ocean” (made with measured fresh water and sea salt) in a five-gallon bucket. We had to tighten a few hose clamps and re-tape one fitting with more Teflon tape, but all eventually worked very well with no leaks. The product water tasted good with well-below the recommended salinity.  At least with the artificial ocean, the production rate and power consumption were as advertised. We’ll report again on how it works in actual daily use once we get to the Bahamas.


5 thoughts on “Watermaker Installation”

    1. Thanks! This one was a fun challenge. It had that mystique of not knowing precisely how it would all come together once I got started. Adapt as you go…

  1. Tom & Paula: Great Job. Having witnessed the installation on our recent visit was very nice to see your clever workmanship with this clean water project. We imagine both Spectra and Island Packet must be quite pleased to learn of your handiwork on their products. Sparkling–Clean–Fresh Water–C-Ghost has it all. Luv, M & D “C”.

  2. WOW! yoy have been busy. I am not sure what happened. I have been checking your blog but many of your entries just showed up recently. Happy New Year!

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