Watermakers for boats over 65 feet.
Above twenty metres water stops being a cruising constraint and becomes a service level. There is mains power, there is redundancy, and the crew is expected to keep tanks full without anyone noticing. The systems in our table reach the bottom of this class; above it you are into commercial plant we do not rank.
The electrical reality at over 65 ft. Typically 240 V from a generator, as standard. Mains power from a generator. Output and reliability decide it; the energy per litre matters to the diesel bill rather than to whether the system can run at all.
What matters at over 65 ft
Guests do not ration
Eight aboard at 35 litres each is 280 litres a day, and charter experience says plan higher. Size for the busy week, because running out is a refund conversation rather than an inconvenience.
Downtime is the real cost
At this scale the question is not what the unit costs but what a failed trip costs. Automatic operation, stocked spares and a serviceable layout are worth more than a specification advantage.
Our table reaches the bottom of this class
The largest systems we rank suit the lower end of this band. Above that, commercial desalination plant is the right answer and it is outside what this site covers — we would rather say so than pretend otherwise.
Log everything
Hours, pressures, TDS and filter changes. On a boat with paid crew and rotating hands, the log is what keeps a membrane alive across a handover.
Shortlist for over 65 ft boats
The 10 best matches of 14 that suit a boat this size, ordered by litres per hour. Run time and energy are for 280 litres a day.
| System | Power | Output L/hr | Draw W | Wh per litre | Price |
|---|---|---|---|---|---|
| Frame AC 240L Torrent, auto Rainman | AC 240V | 180–264 | 2,800 | 12.6 | $15,089 |
| Frame AC 240L Torrent, manual Rainman | AC 240V | 180–264 | 2,800 | 12.6 | $12,089 |
| Zen 150 Schenker · spec unconfirmed | 12/24/48V DC or AC | 150 | — | not published | on request |
| Portable AC 140L Rainman | AC 240V | 100–154 | 1,250 | 9.8 | $5,329 |
| Portable Petrol 140L Rainman | Petrol | 100–154 | — | petrol | $6,731 |
| Portable 48VDC 140L Rainman | 48V DC | 100–154 | 1,250 | 9.8 | $6,240 |
| Modular AC 140L Rainman | AC 240V | 100–154 | 1,250 | 9.8 | $5,460 |
| Frame AC 140L, auto Rainman | AC 240V | 100–154 | 1,250 | 9.8 | $11,168 |
| Frame AC 140L, manual Rainman | AC 240V | 100–154 | 1,250 | 9.8 | $7,685 |
| Frame 48VDC 140L, auto Rainman | 48V DC | 100–154 | 1,250 | 9.8 | $12,115 |
Common questions
- What size watermaker for a superyacht?
- Larger than the systems we rank, in most cases. Eight aboard at 35 litres each is 280 litres a day and charter operations plan well above that. The biggest units in our table suit the bottom of this class; beyond it, commercial plant is the right category and we do not cover it.
- How many litres per hour does a large yacht need?
- Enough to cover the day inside one generator run, plus margin for guests. For 280 litres a day that means something from about 150 litres an hour, which puts you at the top of our table or above it.
Not your size?
Before you shortlist
Length is a proxy, not a measurement. 280 litres a day is 8 aboard at 35 litres each — a planning figure for boats of this size, not a claim about yours. Two people cruising frugally on a 45-footer use less than a family of four on a 38. The shortlist is filtered to systems whose power source and output suit a boat this size and ordered by litres per hour. Watt-hours per litre is rated draw divided by rated output. Methodology.