Building your own watermaker

Modern technology has brought us many new devices that make the cruising life much safer and easier.

- DAVE MCCAMPBELL

a water maker inlet manifold under construction.

Since we are not interested in camping out while cruising, obtaining safe and clean fresh water has always been a major priority, especially overseas. The three most common ways of obtaining fresh water on a cruising boat are: 1) an effective rain collection system, 2) from shore via a hose, or 3) a watermaker. Given reasonable storage capacity and a good filtration system, a high-capacity watermaker is the most efficient — especially if you are a boonies cruiser.

A look at putting together a unit from standard parts

A reverse-osmosis water-maker takes clean seawater and, by pushing it through a specialized membrane (special filter) at relatively high pressure, makes fresh water. This means that no longer do we have to carry hundreds of pounds of extra fresh water just to ensure we don’t run out. Also, we no longer must get up in the middle of the night to catch rainwater, or search out places ashore where we can jerry-jug water from sometimes expensive or suspect sources.

a well-laid out system like this one will make operation and troubleshooting easier.

Watermakers suitable for use on a cruising boat can be obtained from a number of sources depending on your budget and tolerance for electronics gadgetry. But they all do the same thing: make fresh water from seawater. We think that if you are going to have a watermaker aboard, it should have bulletproof — and mainly mechanical — equipment with minimal electrical and electronic parts; use commonly available (not proprietary) components; make the most water practical in the shortest time (40 gallons per hour is our choice); and be repairable with onboard spares, tools and skills.