A watermaker for passage making is not a luxury, it is water security. Once you are more than a day offshore, the marina tap is gone and your tank capacity sets a hard limit on how long you can safely stay out. A reverse osmosis watermaker removes that limit, converting seawater into clean drinking water while you are underway or at anchor. This guide covers what output you actually need, what to look for in a passage-making system, and which LEDI unit suits your boat and crew.
How Much Output Do You Need on Passage?
The starting point is daily water consumption. A conservative offshore allowance is around 2 to 3 litres per person per day for drinking alone. Add cooking, hand washing, and rinsing and a realistic figure for a passage crew is 4 to 6 litres per person per day. For a crew of two on a comfortable passage, 10 to 12 litres per day is a workable target. For a crew of four who want showers underway, you are looking at 30 to 60 litres per day or more.
Match those numbers against how long you plan to run the watermaker each day. Running a 10 LPH unit for 90 minutes gives you about 15 litres: enough for a two-person crew with a margin. A 20 LPH unit halves the run time to reach the same volume, saving battery and letting you run it in a single short session.
Portability Versus a Fixed Install: Which Suits Offshore Sailing?
Traditional fixed watermakers are plumbed into the boat permanently. They are powerful and convenient, but they add installation cost, take up locker space, and require a qualified person for major servicing. A portable unit like the LEDI Scout does none of those things. You drop the stainless intake filter over the side, connect the supplied hoses, and you are making water within minutes. When the passage is over, the unit stows in a cockpit locker or a quarter berth.
For many cruisers on boats between 20 and 50 feet, the portable approach makes more practical sense. There is no plumber, no dedicated through-hull, and no proprietary service centre. Every part on the Scout is field-replaceable, and spares post Australia-wide and internationally, usually within one business day.
If your boat is a larger liveaboard, a charter vessel, or you want the unit out of sight entirely, the LEDI Modular gives you a below-deck configured system with a remote control panel and auto freshwater flush. The LEDI Nomad sits between the two: a high-output portable unit producing 40 to 80 LPH, suited to bigger crews, longer passages, and heavier daily use.
Power Draw on Passage: Running a Watermaker off Solar and Battery
One of the most common questions about passage-making watermakers is power. The Scout draws 16 to 18 amps at 12V DC. A house bank with 200 to 400 watts of solar handles this comfortably during daylight hours. You do not need a generator. On a typical sunny offshore day you can run the Scout for an hour or two and replenish your tank without touching your battery reserves meaningfully.
If you are running a larger crew and need 40 to 80 LPH, the Nomad operates at 12V or 24V DC (with a 240V mains adapter available, and 48V BLDC as a custom premium upgrade). The integrated control panel on the Nomad includes a TDS monitor and flow meter as standard, so you can see exactly what you are producing while underway.
Water Quality: What You Get Out the Other End
A passage-making watermaker is only useful if the output is safe to drink. The Scout uses a marine-grade RO membrane with 99.4% salt rejection. Output is typically 250 to 300 ppm TDS, well under the 800 ppm upper limit, and it meets Australian drinking water standards. A built-in UV steriliser provides an additional layer of protection against biological contamination. You are not just removing salt; you are producing genuinely safe drinking water from seawater at up to 35,000 ppm, or from brackish and river water at lower salinities.
For context on how to verify water quality, the article Ensuring Safe Drinking Water: A Guide to Water Testing covers the testing methods worth knowing before a long passage.
Maintenance Underway: Keeping the System Running
Passage-making creates specific maintenance demands. You may be running the unit every day, sometimes in rough conditions or off-colour water. Here is what matters most:
- Pre-filter: The 5 micron cartridge on the Scout is the routine consumable. In clean offshore water it lasts 30 to 40 hours of running time. In silty or coastal water, change it sooner if feed pressure climbs or output drops. Replacement 2.5 x 5 inch cartridges are $25 AUD each and take minutes to swap.
- Freshwater flush: Flush the membrane with fresh water after every session. This prevents biological growth in the membrane and is the single most important habit for membrane longevity. The article Watermaker Flushing: How Often, Why It Matters covers the full process.
- Membrane pickling: If the boat is sitting at anchor for a week or more without running the watermaker, pickle the membrane to prevent fouling. See Pickling a Watermaker for guidance.
- Carry a spare pre-filter: On a long passage, pack two or three spares. They are small, light and cheap insurance.
The RO membrane is not a routine consumable. With proper flushing and pickling it lasts several years. A replacement seawater RO membrane is $330 AUD if you ever need one.
Which LEDI Unit Suits Your Passage?
Matching the right unit to your boat avoids both under-buying and over-spending:
- LEDI Scout 10 LPH, from $4,899 AUD: Suits trailer sailers, smaller cruising yachts and solo or two-person crews. Run it for 90 minutes a day and you have a comfortable water margin without touching your tanks.
- LEDI Scout 20 LPH, $5,799 AUD: Same portable format, double the output. Suits a crew of two to four, or anyone who wants to run the unit for a shorter window each day. A good choice for coastal passages with variable run times.
- LEDI Nomad, from $9,899 AUD: 40 to 80 LPH in a portable but higher-output format. Suits crews of four or more, liveaboards, and anyone planning extended offshore passages where showers and cooking use push daily demand above 40 litres. Single-membrane unit is $9,899 AUD; double-membrane is $10,899 AUD. Available to order now at lediwatermaker.com/products/nomad-watermaker.
- LEDI Modular: For boats being refitted or built new where a below-deck permanent install suits the layout better. Configurable from around 10 to 80 LPH. Contact the team for configuration and pricing.
All LEDI systems use commercial marine-grade parts and non-proprietary components. That matters on a passage: if something needs attention in a remote anchorage, you are not waiting on a proprietary part from a European supplier.
Spares and Accessories Worth Having Offshore
Carrying the right consumables and spares keeps you self-sufficient. The LEDI spares collection covers everything from pre-filters to membranes, fittings and chemicals. Practical items to consider for a passage:
- Two or three spare pre-filter cartridges ($25 AUD each)
- Maintenance chemicals for pickling and membrane storage ($12 AUD)
- A spare stainless intake filter ($20 AUD)
- The Watermaker Install Kit ($180 AUD) if you want the larger 2.5 x 10 inch pre-filter housing for extended offshore runs between filter changes
Frequently Asked Questions
Can I run a LEDI watermaker while sailing underway?
Yes. The Scout operates on 12V DC and connects to your existing house battery bank. It draws 16 to 18 amps, so you can run it off solar or battery while sailing. Many passage-making sailors run it for 60 to 90 minutes once or twice a day, typically when the solar panels have a surplus.
How long does the pre-filter last on a long offshore passage?
In clean open-ocean water, the Scout's 5 micron pre-filter lasts roughly 30 to 40 hours of run time. On a two-week passage running the unit 90 minutes daily, that is around 21 hours total, so one filter should cover the trip. Carry a spare as insurance, and swap earlier if output drops or feed pressure rises.
Does the watermaker output meet drinking water standards?
Yes. The Scout's RO membrane rejects 99.4% of dissolved salts, producing water typically between 250 and 300 ppm TDS, well under 800 ppm. The built-in UV steriliser addresses biological contamination. The system meets Australian drinking water standards.
What is the difference between the Scout and the Nomad for offshore passages?
The Scout is a 10 or 20 LPH portable unit suited to smaller crews and boats up to about 50 feet. The Nomad produces 40 to 80 LPH and suits larger crews, liveaboards, and extended passages where daily water demand exceeds 30 to 40 litres. Both are portable and require no permanent installation, but the Nomad is heavier (around 38 to 42 kg) and includes an integrated control panel with TDS monitor and flow meter as standard.
Talk to the Team Before You Depart
Choosing the right watermaker for your passage comes down to crew size, daily consumption, available power, and how long you plan to be offshore. The LEDI team, based on the Gold Coast, can help you match the right unit to your boat and make sure you carry the right spares for the trip. Contact them at info@ledi.com.au or call +61 494 562 668. You will speak with a real person, not a call centre.
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