A Watermaker Upgrade

Share this post on:
Low-lying atolls like this one are beautiful and surprisingly dry, making a watermaker essential

Low-lying atolls like this one are beautiful and surprisingly dry, making a watermaker essential

As a classic-boat sailor, I’ve long held that simpler is the better. I still think this is true: a simpler boat is cheaper, she has less gadgets to break down and there’s a certain satisfaction in knowing you’re able to handle a bit of discomfort.

Thus, for a long time, I sailed boats most cruising sailors today would consider downright primitive. My current boat, Celeste, a cold-molded wooden sloop with a waterline of only 28ft, would probably also be considered fairly rudimentary by modern standards. And yet she has a key piece of kit that has made life aboard significantly more luxurious. A watermaker.

Desalinators appeared in my life when I was planning a voyage to the Arctic. The Alaskan North Slope might have plenty of oil, but it doesn’t have much freshwater. Celeste has acceptable freshwater storage, but nothing like the 150 gallons I’d grown used to carrying when my husband, Seth, and I sailed around the world on our first boat, Heretic. So I investigated emergency watermakers—small, hand-powered ones made by Katadyn—the sort to go in the abandon ship bag. This led me, in the end, to go with both a ditch-bag unit and the smallest electrical desalinator that made sense for our kind of sailing, the Katadyn 40E.

The author enjoys the ambrosia of the sea: a drink of clean freshwater!

The author enjoys the ambrosia of the sea: a drink of clean freshwater!

Drawing only about 4 amps and providing 1.5 gal-per-hour (gph), the Katadyn 40E was a godsend. Not once did we have to ask for water ashore, and as we had plenty of wind throughout, neither did we have to purchase fuel. I got the impression the local people we met along the way appreciated this, and we consequently made quite a few good friends.

The Katadyn 40E continued to purr away on our subsequent trip down to the Baja peninsula, making pure, sweet water for us in a place where shore water must be treated. In the Arctic, the 40E had been sufficient for our needs, which mostly amounted to drinking and cooking. But once in the tropics, and especially after we’d crossed the Pacific and were regularly scuba diving from aboard Celeste in French Polynesia, we began to wish for a slightly bigger one, to generate enough water to rinse our dive gear (essential for maintaining acceptable safety standards) and even maybe rinse ourselves. This wasn’t an issue in the Marquesas, high islands with plenty of delicious ground water. But a larger watermaker soon went to the top of our wish list in the Tuamotu islands, coral atolls with only brackish ground water, if that. Maybe a Spectra Ventura 150, we thought, something just a little bigger (the inevitable curse whenever one chooses to go down the road of creature comforts).

Fortunately, watermakers are not really as complicated as many think, at least not for those sailors willing to install them themselves. We acquired a Ventura 150 Rowboat model, formerly used by a woman trying to break the ocean rowing record between California and Hawaii. It’s very similar to the standard Spectra Ventura 150, generates 6 gph and draws 9 amps. For us this draw is significant—the watermaker is our biggest power draw on Celeste—but we accounted for the new power need by installing two new solar panels. Thus we can run the watermaker strictly on solar power.

The hardest part of installing the Ventura 150 was getting it into the same spot where we had the Katadyn 40E, despite the fact of it being somewhat bigger. Fortunately, by removing a shelf in the locker and then fitting the shelf back in again later, we made it work.

The rest of the installation was fairly simple. We could use the same ¾in through-hull and seacock as we had formerly with the 40E, and this same through-hull was already fitted with a strainer. On the 40E, the intake hose had led directly to the watermaker’s pre-filter. But for our new Ventura 150, we cut the hose and installed a valve that could be turned to let in either seawater during normal operation or desalinated water for cleanings. The Katadyn 40E does not require routine flushing due to the fact it does not generate enough water to justify doing so. However, the Ventura processes four times the amount of water, and flushing after each use lengthens the membrane’s lifespan, making it a good practice. This in turn requires using pure water—because treated water usually includes chlorine and damages the membrane. We, therefore, have our flush hose coiled and ready to run to a clean bucket filled with desalinated water. This has the additional benefit of allowing us to measure exactly how much rinse water we use. Two gallons is recommended.

From the valve, we ran the intake hose to the feed pump. This is simply a regular water pressure pump, which makes for easy maintenance. If it ever malfunctions, it can be replaced with a pump found at any chandlery. It’s good to mount the pump as low as possible, so that it has less gravity to fight against. From the pump, we led a hose to the accumulator (which comes with a pressure gauge), then the 5-micron pre-filter.

From there, the installation was almost an exact repetition of how we did things with the Katadyn. To start out, we led a hose from the filter to the intake for the Spectra Clark Pump and membrane. These are both part of a single unit, with the Clark Pump providing the high pressure needed for the membrane to filter out all the salt and impurities necessary to produce drinking water. By combining the two, Spectra makes it so that installers never need to plumb any kinds of high-pressure hardware, only low pressure hoses and fittings. After that, it’s just a matter of attaching the correct hoses to the membrane for the fresh product water and briny discharge. You can either have a dedicated through-hull for the waste or T the line into an existing drain, which is what we did.

It’s a good idea to run the product water hose to a valve that will allow you to either run it to a testing hose or directly into the tank. This way you can test the water and make sure it’s pure before adding it to your existing freshwater supply. We also use the testing hose to fill one-gallon jugs, which we then use as our drinking water whenever we’re not happy with the quality of our stored shore water.

Once we’d finished mounting and plumbing the Ventura 150, all that was left was the wiring. Once again, we were able to use the same wires we had fitted for the Katadyn 40E. These included a pair of heavy-gauge wires from our main DC circuit breaker to a terminal bar near the watermaker. Remember when you run wires that the length is the sum of both positive and negative wires and that you will need a heavier gauge for longer runs to prevent voltage drops.

After installation, we followed the instructions for new-system startup and testing to purge the chemicals that were preserving the membrane and get it operational. So far—and we’ve had the unit 3 years now—it has been easy to use and maintain. The flushing appears to work well, and we’ve only had to store the membrane with chemicals one time while we were away.

Overall, the Ventura 150’s output has been perfect for our needs, supplying plenty of water to drink, cook, rinse our dive gear and even take some quick showers. In all the time we sailed in the Tuamotu archipelago last summer, we never once had to buy water ashore and were always able to run the unit off our solar panels. This is definitely a bit of luxury to which I’ve now happily grown accustomed. 

Photos by Ellen Massey Leonard

March 2022

Leave a Reply

Your email address will not be published. Required fields are marked *