Watermakers for boats 46 to 52 feet.
At this size the boat usually carries a generator, a 24 volt bank and enough crew that consumption climbs faster than length does. The question shifts from whether you can power a watermaker to whether you want to run the genset to do it.
The electrical reality at 46–52 ft. Typically 24 V, usually with a generator. A genset is common at this size, which opens the mains systems. Whether you want to run it daily for water is the actual question.
What matters at 46–52 ft
Consumption climbs with crew, not metres
Five aboard at 28 litres each is 140 litres a day, and that is before a swim rinse or a load of washing. Be honest about the number before sizing anything.
Genset hours have a cost too
Diesel, servicing and noise at anchor. An efficient DC system that runs off the array while the genset stays quiet is worth more here than the specification difference suggests.
Two hulls means two options
On a catamaran the install can split across hulls, which solves space problems monohulls of the same length do not have — and catamaran deck space usually means a genuinely large array.
Redundancy starts to matter
At this size and this crew, a failed watermaker ends a trip. Ask what fails first, whether spares are stocked in Australia, and whether the pump is rebuildable.
Shortlist for 46–52 ft boats
The 10 best matches of 32 that suit a boat this size, ordered by balance of both. Run time and energy are for 140 litres a day.
| System | Power | Output L/hr | Draw W | Wh per litre | Price |
|---|---|---|---|---|---|
| Zen 100 Schenker | 12/24/48V DC or AC | 100 | 400 | 4.0 | $9,600 |
| D100 DUO Dessalatorreported | 12/24V DC | 100 | 700 | 7.0 | on request |
| Newport 400C Spectra | 12/24/48V DC | 64 | 288 | 4.5 | $14,500 |
| Modular 48VDC 140L Rainman | 48V DC | 100–140 | 1,250 | 10.4 | $6,421 |
| Portable AC 140L Rainman | AC 240V | 100–154 | 1,250 | 9.8 | $5,329 |
| 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 50 foot catamaran?
- Five aboard at 28 litres each is 140 litres a day. Something making 60 to 100 litres an hour covers it in a comfortable run. Catamarans usually have the deck space for a serious array, which makes an efficient DC system practical where a monohull of the same length might need the genset.
- Is a 240 V watermaker better on a boat with a generator?
- Better in one way only: output per dollar. It ties water-making to genset hours, which is fine when the genset runs anyway and expensive when it does not. Compare the Wh/L figures before assuming the mains unit is the obvious choice.
Not your size?
Before you shortlist
Length is a proxy, not a measurement. 140 litres a day is 5 aboard at 28 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 balance of both. Watt-hours per litre is rated draw divided by rated output. Methodology.