Marine Watermakers & Boat Desalination Systems
Build true self-sufficiency at sea with dependable reverse osmosis (RO) watermakers, expert guidance, and an in-stock selection from Fisheries Supply.
Key Takeaways
- Systems & Brands: Reverse osmosis and manual desalination options from Katadyn, FCI WaterMakers, and US Watermaker.
- Sizing: Match output (GPH/GPD) to your daily water need, power budget (12/24 V DC or AC), and install space.
- Reliability: Protect membranes with strainers and pre-filters; flush after use; monitor with inline TDS (Total Dissolved Solids).
- Support: Talk to our marine systems team for model selection, install planning, and parts lifecycle.
What a Marine Watermaker Does
A marine watermaker converts seawater to potable freshwater using reverse osmosis: high-pressure pumps push seawater through semi-permeable membranes to remove salts and contaminants. Reverse osmosis is the world’s dominant desalination method and underpins most onboard systems for cruisers and commercial craft.
Choose the Right System
Reverse Osmosis Systems (Primary Choice)
Best for: full-time cruisers, passagemakers, and liveaboards who need consistent daily output.
- How they work: High-pressure pump ? pre-filters ? RO membranes ? product water (fresh) + brine (reject).
- Advantages: Highest water quality; scalable output; wide parts availability.
- Consider: Power draw (DC or AC), noise isolation, membrane care (flush/pickle), and access for service.
Manual & Low-Power Watermakers (Backup & Minimalist)
Best for: emergency redundancy, liferafts, and minimalist boats without ample electrical capacity.
- Hand- or belt-driven units provide small, survival-grade output.
- Keep stowed as a backup even if your primary system is electric RO.
Critical Accessories & Parts
- Raw-water strainers and pre-filters to protect pumps and membranes.
- RO membranes and carbon/sediment filter replacements.
- Inline TDS meters for live water-quality monitoring.
Sizing & Specification Factors
- Daily Water Need (GPD): Crew count × use (drinking, cooking, showering). Offshore crews typically require higher output.
- Power: 12/24 V DC for small/efficient installs; AC for higher-output systems (generator or inverter).
- Space & Layout: Modular systems fit tight bilges; framed/enclosed units simplify mounting and service.
- Cruising Profile: Ocean crossings vs. coastal hopping; refuel/refill frequency; tank capacity.
Featured & Best-Selling Systems
- FCI WaterMakers Atlas+ / Aquamiser+ — high-output, automated RO with marine-grade controls; popular for long-range yachts and light commercial use.
- US Watermaker Clearwater / Island Explorer — flexible modular builds for recreational and semi-commercial applications.
- Katadyn PowerSurvivor 40E — compact 12 V DC unit for small boats and minimalist crews.
Installation & Maintenance Essentials
- Flush routinely: Freshwater flush after each run; pickle for lay-ups per manufacturer guidance.
- Filter discipline: Replace pre-filters on schedule; never run with clogged elements.
- Membrane care: Clean or replace based on water quality and hours; avoid running high-pressure freshwater through standard RO membranes.
- Quality checks: Use an inline TDS meter; confirm taste/odor before tanking.
For a deeper dive, see our article: Choosing a Watermaker.
Why Buy from Fisheries Supply?
- Trusted brands, in stock: Proven RO systems, parts, and membranes ready to ship.
- Expert help: Our marine systems team can size output, advise on DC vs. AC, and plan installs.
- Replacement parts: Strainers, filters, seals, and service kits for long-term maintenance.
Need help choosing? Call our representatives at (800) 426-6930.
Frequently Asked Questions
Do I need a generator to power a marine watermaker?
Not necessarily. Many compact RO systems run on 12 V or 24 V DC, ideal for solar-supported boats or boats without a generator. Larger, higher-output systems often use AC via inverter or genset.
How often should I service my watermaker?
Flush after each use and replace pre-filters regularly. Follow your manufacturer’s membrane cleaning/replacement schedule based on hours and feed-water quality.
Can I install a watermaker system myself?
Modular systems are DIY-friendly if you’re comfortable with marine plumbing and DC/AC wiring. Complex framed or integrated systems may warrant a professional installer.
What output range should I consider?
Small units produce ~1 GPH (survival/compact cruising), while yacht-class systems exceed 1,000 GPD. Select output to match your true daily consumption and tank capacity.