Gear Review: The Watermaker

Water is one of the hard limits on how long a boat can genuinely stay out and self-sufficient — tankage is finite, and once it's gone, the only options are cutting a passage short or finding somewhere to fill up. A watermaker turns seawater into fresh water underway or at anchor, removing that limit entirely, which matters enormously for the longer ARC+ and Caribbean legs where the next marina might be a week or more away.

The complete system installed in its locker, with the pre-filter and product water filter housings alongside.

Without a watermaker, tank capacity effectively sets the length of a passage or the size of the crew you can carry comfortably — whichever runs out first. With one, the boat can make its own fresh water from the sea it's floating on, for as long as there's power to run it, and the low-energy design here means that's rarely a constraint. That changes the calculation for longer legs entirely: the ARC+ crossing and the winter Caribbean season both depend on exactly this kind of self-sufficiency, rather than planning every passage around the next place to refill tanks.

Worth noting for guests: the system is designed and tested for typical seawater use specifically — it isn't something to run in harbour water, oily water, or fresh water without proper sterilisation first, and the membrane itself is a genuinely delicate, expensive component that a fair few careless operating habits can quietly ruin.

Installed in December 2025, in good time for the 2026 season, by Marc at Enàutica — the same trusted electrician behind the TITAN lithium bank and Mastervolt charging system. Keeping the watermaker's DC installation with the same person who wired the rest of the boat's power system means the whole electrical side of the boat, not just the individual units, is specified and wired by someone who already knows exactly what the battery bank and charging sources can support.

The whole system was built up as a single skid-mounted unit before it went in — twin feed pumps, the Clark Pump and pressure vessel, and a compact two-button control panel with its own indicator lights, all pre-plumbed on one stainless frame and tucked into a dedicated locker rather than scattered around the boat. The spare tubing and fittings came bundled and colour-coded in the box, which made routing feed, product and brine lines to the right place straightforward rather than guesswork.

The twin feed pumps and control panel, installed in their dedicated cupboard.

The through-hull sits above the waterline, and the plumbing run was made noticeably easier by the system's location on the port side — a genuinely convenient spot rather than one that fights the rest of the boat's layout. A new Marco UP6/E 12/24V electronic gear pump was fitted into the fresh water system at the same time, giving constant pressure at the taps and shower even as demand increases with more people drawing water at once, rather than the pressure dropping off under load the way a simpler pump can.

The Marco UP6/E pump, giving constant water pressure regardless of demand.

The through-hull position, above the waterline on the port side.

We sailed extensively through 2026 to the Balearic Islands and Sardinia, often with four or five crew aboard, and the watermaker changed the trip completely: we never once topped up at a marina, and never went without a daily shower, even with that many people aboard drawing water every day. It's genuinely one of the best upgrades made to Gran Blau — the kind of change that doesn't show up on a spec sheet but reshapes how a season is actually run, freeing up route planning from chasing the next tap and letting the crew live properly rather than rationing.