How to Choose a Watermaker For Your Next Boat Upgrade

Understanding Your Needs

Before you make any decisions about manufacturers or models, it’s important to decide what kinds of trips you will be primarily using your watermaker for and how much water you’re actually going to require. If you’re a weekend sailor who spends most of their time no more than a day from the nearest harbour, you may only be considering a watermaker for the convenience of onboard water and the reduced space requirements compared to storing water aboard or paying to fill up dockside. However, if you’re planning to spend a significant amount of time at sea, either living on your vessel or conducting long passages, a watermaker is essential.

The first step is determining how much water you actually need. Watermakers generally range from 30 of clean drinking water per hour upwards, with their price scaling accordingly.

Your water needs can vary wildly depending on your lifestyle at sea but for cruising a good average is anywhere from 30-75L per person per day. Once you have your average, work out how much water you must produce to meet your needs and have some in reserve, and aim for a watermaker that will do so with only a few hours of operation per day.

Know Your Space

As well as calculating your freshwater needs, you will need to work out how much space you have aboard for a watermaker. Watermakers come in two basic configurations, modular or skid. In a modular system, the machine’s components are independent of each other and can be arranged and connected around your vessel as you please. In a skid unit, the components are pre-assembled and contained within a housing which you then mount, usually on a shelf.

Skid units can be faster to install but take up more space as a result of the housing, whereas modular watermakers can be fitted where space allows. The adaptability of modular systems makes them extremely popular with cruisers on smaller craft, where space is at a premium.

Working out not only how much space you have available for your watermaker but where the components will be routed and ultimately connect is an important factor. Once you know how much space you’ve got to work with and where everything will go, you can move on to the final decision.

Power Requirements

Another important aspect to consider in choosing a watermaker is its power usage. Many vessels will still utilise an onboard generator for power-hungry appliances but as more cruisers move away from gensets and instead rely on solar panels and battery banks for their energy needs, different watermakers may not be suitable.

Your choice of power supply will more or less determine your choice of watermaker. If you get your power from solar panels and batteries, you will want to choose a watermaker that draws less power. Watermakers that utilise an Energy Recovery System (ERS) have power consumptions from as little as 3.7 watts per litre of drinking water produced compared to 14 watts per litre for units that do not have an ERS. You will also want to consider whether you want a DC or AC powered unit.

Lower capacity watermakers and watermakers with an ERS require less power to operate and are available in 12/24VDC. Larger capacity models tend to favour AC configurations.

Making the Choice

Watermakers are an investment for any vessel and just like any other addition to your boat, they need to be considered carefully before you make a decision. Cost and availability will inevitably factor into your choice of watermaker but the most important aspects will always be how much water you need, how much space you have, and how you plan on powering it. Once these three questions have been answered, your decision will be made much easier.