Watermakers for sailing boats
A sailing boat makes its own electricity slowly and stores it in a bank you would rather not flatten. That single fact reorders the whole market: the cheapest system to buy is frequently the most expensive to own, because you pay for it again in the panels and battery it needs.
The power reality. Sailboats are DC boats with a finite daily surplus. The question is never just "does it make enough water" but "does it make enough water inside the energy I have".
What matters on sailing boats
Run it in the middle of the day
Making water straight off the panels avoids the round-trip losses of charging the bank and discharging it again. It roughly halves the effective cost of a litre.
Tanks are the cheap buffer
Tankage is passive and costs nothing to run. Let it absorb the cloudy day rather than oversizing the watermaker for your worst case.
Regular short runs beat occasional long ones
Membranes prefer being used. A system sized to run most days needs pickling far less often than one that sits between passages.
Noise carries below
A high-pressure pump running for six hours in a hull you are living in is a different experience from one running for ninety minutes.
Shortlist for sailing boats
The 8 best matches of 20 that suit sailing boats, ordered by energy per litre. Run time and energy below are for 66 litres a day.
| System | Power | Output L/hr | Draw W | Wh per litre | Price |
|---|---|---|---|---|---|
| Zen 30 Schenker | 12/24V DC | 30 | 110 | 3.7 | $6,300 |
| Zen 100 Schenker | 12/24/48V DC or AC | 100 | 400 | 4.0 | $9,600 |
| Ventura 150 Deluxe Spectra | 12/24V DC | 24 | 108 | 4.5 | $6,000 |
| Ventura 150 Connect Spectra | 12/24V DC | 24 | 108 | 4.5 | $7,400 |
| Newport 400C Spectra | 12/24/48V DC | 64 | 288 | 4.5 | $14,500 |
| Zen 50 Schenker | 12/24V DC | 50 | 240 | 4.8 | $7,800 |
| D100 DUO Dessalatorreported | 12/24V DC | 100 | 700 | 7.0 | on request |
| D60 Freedom Dessalatorreported | 12/24V DC | 60 | 550 | 9.2 | on request |
Common questions
- What is the best watermaker for a sailboat?
- On a sailboat without a generator, an energy-recovery system in the sub-6 watt-hours per litre band, because it makes a day's water on a few hundred watt-hours. The premium buys energy efficiency, and on a solar-only boat the alternative is fitting the panels and battery a thirsty system needs.
- Do I need a generator to run a watermaker on a sailboat?
- No, if you choose a DC system sized to your solar surplus. You do need one for the 240 V AC systems, which draw over a kilowatt and are designed around a genset or shore power.
- How much power does a sailboat watermaker use?
- It ranges enormously. In our table the most efficient system uses about 3.7 watt-hours per litre and the least efficient 19.7. For 100 litres a day that is the difference between roughly 370 Wh and nearly 2,000 Wh.
Guides that go deeper
Not quite your boat?
How the shortlist is built. 66 litres a day is 3 aboard at 22 litres each — a planning figure for this kind of boat, not a measurement of yours. The list is filtered to systems whose power source suits sailing boats and ordered by energy per litre. Every figure is the manufacturer’s rated output and draw; Wh per litre is one divided by the other. Methodology.