Sizing calculator
What size watermaker does your boat need?
Seven quick questions about your crew, your water habits and your power. You'll get one system that fits, with the run time and battery use behind it.
- 3-year warranty
- 7-day support, weekends included
- Australian owned
Your result goes to a real person
Send your result to Kalim from the calculator and he'll check it against your boat, your power and the way you cruise before you order.
I handle most of the technical support and sales advice myself, so when you reach out, you'll be talking with me directly, not a call centre and not a script.
Kalim, Owner · +61 2 8317 1755
How we size a watermaker
We start with your daily water. Allow at least 40 litres per person per day, and more if you like long showers, run a washing machine or wash the boat down with fresh water. Add about 15 litres for the freshwater flush after each run.
Then we allow for the water you cruise in. Every system is rated in 25°C seawater, and cooler water makes less. Expect about 85% of the rating in NSW waters, 70% in Victoria and northern New Zealand, and 60% in Tasmania. We size for the coolest water you cruise in regularly.
Divide your daily litres by what the system makes in your waters and you have an estimated daily run time. Most owners run once a day, while the generator or engine is on or the sun is high.
Last comes power, and 12 volts isn't really the question. What matters is whether your setup can start and run the pump, and how much energy each litre costs. Our Low Power systems run on a quality 2 kVA inverter or a Honda EU22i class generator. High Output systems need a quality 3 kVA inverter or a 4 kVA class generator. On batteries, a second membrane nearly doubles the water from the same pump, so each litre costs far less battery.
Common sizing questions
How many litres of water per person per day on a boat?
At least 40 litres for careful use, around 50 for a daily shower each, and 70 or more if you're generous with water.
Can I run a watermaker from my batteries?
Yes, through a quality inverter. A Low Power system needs a quality 2 kVA inverter and a High Output system a quality 3 kVA. The calculator checks your bank and solar can carry the daily run.
Does cold water reduce watermaker output?
Yes. Our ratings are at 25°C, and water of 10 to 15°C can cut output by 25 to 40%. Size for the coolest water you cruise in regularly.
What if I'm not sure about my power setup?
Choose "not sure" and you'll still get a result. Kalim will check your power setup with you before you order.