Watermakers for boats
"Which watermaker for my boat" has no single answer, because the deciding factor is not the boat — it is how much water your crew uses and what power you have to make it with. This page is the general version; the pages below narrow it to your kind of vessel.
The power reality. Every boat sits somewhere between two poles: a generator that runs daily, where output per dollar is what matters, and solar only, where energy per litre decides everything.
What matters on boats
Start with litres, not boat length
Two people cruising frugally on a 45-footer need less water than a family of four on a 38. Multiply crew by litres per person per day and size from that.
Then check it against your power
Multiply your daily litres by a candidate's watt-hours per litre. That is what it takes out of your day. If it exceeds what your solar and alternator can spare, the system only runs when the engine does.
Installed or portable
A portable unit avoids through-hulls and an installation bill but has to be set up and stowed each time, which quietly discourages the short, regular runs membranes prefer.
Where the filters end up
Prefilters get changed often. If they finish behind permanent joinery, they will not get changed often enough.
Shortlist for boats
The 8 best matches of 35 that suit boats, ordered by balance of both. Run time and energy below are for 66 litres a day.
| System | Power | Output L/hr | Draw W | Wh per litre | Price |
|---|---|---|---|---|---|
| Zen 50 Schenker | 12/24V DC | 50 | 240 | 4.8 | $7,800 |
| Newport 400C Spectra | 12/24/48V DC | 64 | 288 | 4.5 | $14,500 |
| 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 |
| D60 Freedom Dessalatorreported | 12/24V DC | 60 | 550 | 9.2 | on request |
| D60 DUO Dessalatorreported | 12/24V DC | 60 | 550 | 9.2 | on request |
| Portable 24VDC 55L Rainman | 24V DC | 45–61 | 600 | 11.3 | $4,898 |
| Modular 24VDC 55L Rainman | 24V DC | 45–61 | 600 | 11.3 | $5,053 |
Common questions
- What size watermaker do I need for my boat?
- Work from daily litres. Frugal cruising is 10 to 15 litres per person per day; normal cruising with short showers is 20 to 30; liveaboard comfort can be 35 to 60. Size so the system makes your daily total in one to two hours, then check the energy that costs against what you can spare.
- How much does a boat watermaker cost in Australia?
- Indicative unit pricing in our table runs from about $4,400 to $15,000, excluding freight, duty and installation. Installation is entirely boat-specific and has to be quoted separately.
- Can I fit a watermaker myself?
- A portable unit needs no installation at all. An installed system involves a seawater intake, a brine discharge, high-pressure plumbing and electrical work sized correctly — most owners use an installer for at least the through-hulls and the wiring.
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 boats and ordered by balance of both. Every figure is the manufacturer’s rated output and draw; Wh per litre is one divided by the other. Methodology.