Which Type of Watermaker Is Right for Your Sailboat?

When we first added a watermaker to our liveaboard setup, we didn’t realize how much it would change our cruising rhythm. The ability to stay off-grid longer, to shower guilt-free after a salty dinghy ride, and to avoid the logistical stress of finding potable water in unfamiliar harbors—it was a game changer.

In this week’s Tech Talk, marine electrical systems expert Doruk Kocuk breaks down the key differences between DC, AC, and belt-driven watermakers, and shares insights that go beyond the specs. If you’ve ever wondered whether a watermaker is worth it—or which kind fits your sailing lifestyle—this one’s for you.

Watermakers – Which Type Is Right for You?

Using the force of the wind to sail to your next destination.

Generating your own energy from the sun.

Turning the endless sea into drinking water.

Welcome to the world of sustainable boating.

It’s not just about comfort and independence anymore—it’s about minimizing your footprint while exploring the planet.

In this episode, we dive into the world of watermakers. These are fabulous machines that let you fill your tank from the ocean. Over the years, they’ve become more affordable, easier to maintain, and significantly more efficient. You’ll now find technicians who can service them in almost any marina. Noise levels have dropped, connectivity options have improved (some even talk NMEA2000 now), and there’s a type for nearly every kind of cruiser.

But not all watermakers are created equal.

Depending on how you generate power, how often you're underway, and how much fresh water you need—the type of watermaker you choose really matters.

🔌 DC Watermakers

Ideal for solar-powered boats without a genset.

DC-powered watermakers run on battery power—usually 12V or 24V. That makes them perfect for cruisers who rely on solar panels and care about every watt.Because your stored energy is limited and precious, DC watermakers are designed to be extremely efficient. Freshwater production typically ranges from 15 to 100 liters per hour, which might not sound like much—but they’re made to run longer and quieter, sometimes 4–5 hours a day.

The DC option also tends to be compact, making it easier to install in tight spaces. They're a favorite for couples and families who value silence at anchor and want something that plays nicely with solar setups.

Maintenance-wise, regular servicing is DIY-friendly. Heavy servicing (every 4–5 years) requires some tools and know-how.

How They Work: They use a single feed pump to supply a steady flow of seawater into the system. Inside, a hydraulic amplifier boosts the pressure via a piston-driven mechanism. This high-pressure seawater is then forced through a reverse osmosis membrane, filtering out salt, minerals, and impurities.Freshwater goes to your tank. Brine goes back to the sea. That’s it.

⚡ AC Watermakers

For boats with a generator and high daily demand.

AC-powered watermakers are designed to operate while the generator is running. They’re generally louder (though the genset drowns most of it), and can produce 100 to 400 liters per hour. The idea here is to run them for short periods but fill your tanks fast. Efficiency is less of a priority since the energy comes from a generator.

There are two pumps:

1. A low-pressure pump that supplies volume

2. A high-pressure pump that boosts seawater to RO pressure

   
   

Maintenance is fairly similar to DC systems. The heavy stuff is a bit more accessible due to the system’s larger, modular design.

If your boat has a reliable genset and you’re regularly cruising with guests, kids, or long showers—AC might be your best friend.

🦾 Belt-Driven Watermakers

Once a smart solution—now slowly fading away.

Belt-driven systems use the main engine’s shaft to power a pump mechanically. It’s the same basic principle as the AC version: seawater is pressurized and pushed through an RO membrane. But instead of electric pumps, it’s the diesel engine doing the heavy lifting.

These systems made a lot of sense back when solar and lithium setups were expensive and bulky. They were especially popular among motorsailers who could make water while motor-sailing long passages.

But today, with the rise of efficient and affordable energy storage and generation, belt-driven systems are approaching the end of their run. They still work, but they’re harder to install, harder to maintain, and not very flexible unless you’re motoring regularly.

💭 So... Which One’s for You?

• No generator, but solid solar and lithium? → Go for a DC system.

• Big crew, big water needs, running genset daily? → You’ll want an AC model.

• Motor a lot, rarely at anchor, and already have a belt drive system? → You might keep it running a bit longer... but consider a backup plan.

🧭 Final Word

A watermaker can change the way you cruise—letting you stay off-grid longer, anchor in remote spots, and forget about the next fuel dock or marina. Especially when exploring islands, finding clean, drinkable water can be surprisingly inconvenient—or downright impossible. With a watermaker onboard, that stress simply disappears.

Choosing the right one isn’t just about liters per hour or brand. It’s about how you live on your boat, how you generate energy, and how much you value silence, space, and autonomy. And as you gain more autonomy with onboard systems like watermakers, there’s a new frontier reshaping how we manage life at sea: connectivity. From batteries that ping your phone when they’re low to watermakers that send service alerts, your boat is learning to talk.

In the next episode of Tech Talk, we’ll explore how marine equipment is becoming more connected—and what that means for your time on the water. Stay tuned.

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Watermakers are one of those upgrades that few cruisers regret—but finding the right one can take some research. I’m grateful to Doruk for making this decision easier with solid, no-nonsense advice from real-world installs. If you’ve been considering going watermaker-equipped, this guide is a great place to start.

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