Is it better to fit large water holding tanks, or make your own water as you go?  The answer will depend on your boat and how you intend to operate her.  Solar Navigator may benefit by making her own water.  It all depends on how much energy a desalination plant might consume in contrast to the energy used to purify seawater.  This will be a subject for later examination.  For now have a look at the technology, what is available, from who, and where:- 



Sea Water Desalination Reverse Osmosis Technology


There are significant differences in the equipment used for removing most of the dissolved solids from seawater and from most surface or well waters.  Seawater units are referred to as desalinators and surface/well water units are called reverse osmosis (RO) units as a general rule.  At the current state of technology, approximately 1 psi driving force is required for each 100 mg/l of solids dissolved in the water to be treated.  Seawater has about 35,000 mg/l of dissolved solids, hence to obtain the first drop of permeate water a pressure of 350 psi is required.  


Reverse osmosis units on the other hand normally treat water where the dissolved solids content is in the area of 6,000 mg/l or less.  The required pressure for that first drop of water for 6,000 mg/l is 60 psi.  To insure an adequate flow of water from the respective devices seawater units usually operate in the area of 1,000 psi and RO units in a range of 150 to 250 psi.  The additional pressure requirement for seawater increases the required strength of almost all components and requires much larger pumps.  Also, seawater is extremely corrosive so the materials of construction for seawater units must be non-corrosive.  All of these differences cause the cost of seawater units to be much higher than the cost of an equivalent RO unit per gallon of treated liquid.



Evaporation technology


Evaporation is a third method of treating salt water.  Unlike the process of reverse osmosis, in which salt water is filtered through a membrane to produce fresh water, evaporation technology produces distilled water.  A titanium evaporator and condenser are mounted in a vacuum chamber so that seawater can boil at 45 degrees Celsius instead of 100 degrees. The condensed water is then moved from the chamber by a fresh water pump into a holding tank. One such manufacturer using this technology to provide water on oil rigs, is Alfa Laval.







The need for fresh water on an oil platform is really no different than whatís usually needed at home or work. It is just that on an oil platform there is no public utility to provide a steady supply of potable water. For this reason oil rigs usually make their own water.


Alfa Laval has a long-standing reputation as the leading supplier of desalination equipment based on plate heat exchangers for offshore platforms and marine vessels.

Alfa Laval's entry into the desalination market for land-based processing industries in the mid-1990s was based on a major breakthrough: a new type of thermal desalination system called Pressed Plate using Falling Film. This system requires smaller space for installation and minimizing scaling.





Sales contact: Hans Jacob Svensen
Email: hansjacob.svensen@alfalaval.com

Technology: SÝren Jensen
Email: soren.jensen@alfalaval.com








Sea Recovery - Ultra Whisper



In 1985, Sea Recovery became the first reverse osmosis desalinator manufacturer to gain full product line Type Acceptance by ABS-American Bureau of Shipping.  Today, they still hold that certification. ABS Type Approval is recognized by clients throughout the world in the marine industry as a mark of high quality.  Sea Recovery also holds European CE Conformity Declarations issued by private testing laboratories. Additionally, they have full support and approval from The National Marine Manufacturers Association (NMMA) while maintaining our active and outstanding membership for 20 years.


Sea Recovery's new Ultra Whisper Series with its unique energy transfer device eliminates the need for a high pressure pump, reducing the electricity consumption of the RO system by as much as 75%. This is efficient for small and midsize sail or power boats. The Ultra Whisper reverse osmosis systems are available in a compact or modular configuration producing from 200 to 600 U.S. gallons (758 to 2,271 litres) per day or 8 to 25 gallons (32 to 95 litres) per hour of pure, fresh potable water.  These models have been engineered with state-of-the-art marine technology and have been successfully tested in sea water conditions. They feature intelligent design, marine-grade materials, and attention to detail. The result is a reliable water maker trusted by boat owners all over the world.



Ultra Whisper Compact

8, 17, 25 U.S. gallons per hour


32, 63, 95 litres per hour



Ultra Whisper Modular

8, 17, 25 U.S. gallons per hour


32, 63, 95 litres per hour



Ultra Whisper Compact with EfficientSea Technology200 to 600 U.S. gal. (757 to 2,271 litres) per day
8 to 25 U.S. gal. (30 to 95 litres) per hour

To see the various accessories available for the UWC, click on Accessories.




Rated Performance / Product Water Produced:
+-15% 841 PSI / 58 BAR, 77oF / 25oC & 35,000 PPM TDS typical sea water


Model #

Per Hour

Per Day

Weight of System

UWC 200-1

UWC 400-1

UWC 600-1

8 gal/30 lit

17 gal/64 lit

25 gal/95 lit

200 gal/757 lit

400 gal /1,514 lit

600 gal/2,271 lit

130 lbs/59 Kg

145 lbs/66 Kg

155 lbs/70 Kg



Salt Rejection (Chloride Ion): Minimum 99.2%, Average 99.4%
Product Water Temperature: Ambient to feed water temperature. A slight increase in the product water temperature occur due to the heat transfer from the engine room and feed pump.
Salinity Monitorings: The system monitors the salinity of the product water continuously and compensates for temperature variations. Only potable product water is directed to the ship's potable water tanks. The product water quality is continuously displayed on the system touch pad.
Salinity Range: Designed for Seawater use up to 50,000 PPM TDS (NaCl) (typical seawater salinity is 35,000 ppm)

Temperature Range: Max. 91oF / 33oC, Min. 33oF / .5oC

System Feed Water:
Flow: 50Hz, 1 - 3 gpm / 5 - 11 lpm; 60Hz, 2 - 4 gpm / 6 - 13 lpm

Reverse Osmosis Membrane: High Rejection/High Yield aromatic tri-polyamid, thin film composite, spiral wound, single pass, high rejection reverse osmosis membrane element.

Chlorine Tolerance: 0.01 PPM

pH Range: 3-11 (typical seawater pH is 8)

System Pressure:  
80 - 185 psi / 6 - 13 bar / 6 - 13 Kg/cm2  (Minimum)

Feed Water:   
125 - 220 psi / 9 - 15 bar / 9 - 15 Kg/cm2     (Maximum)


System Operation: Typical seawater has a salinity of 35,000 ppm TDS and an average temperature of 77oF / 25oC. Under these conditions, the system operating pressure is approximately 700 psi.

External Installation Water Connections: Pipe sizes to be supplied by the installer for connection of the Sea Recovery supplied components.





GET custom desalinator



GET manufactures state-of-the-art water makers (seawater & brackish water desalination systems) for every application and in every size from 1 ton to 1,500,000 tons (about 200 gallons to several hundred million gallons) per day. These reasonably priced watermakers are energy efficient, produce high quality, tasty, soft, healthful drinking water, and offer reliable operation, low maintenance and low operating costs. GET offers standard watermaker models which we gladly customize for you and custom water maker systems designed especially for your application. 

  GET, Inc. has over 26 years experience in designing, manufacturing, installing & servicing water makers (sea and brackish water purification equipment).

Why choose GET, Inc.?    


GET water makers can be customized to fit in your available space and can be set up to operate from any standard A/C power source. GET can also help by providing a source of power if needed. Water makers are used to provide a dependable, high quality, safe source of good-tasting, healthful drinking water from available seawater, brackish or polluted water.

GET equipment features Reverse Osmosis (R/O) technology. GET designs are state-of-the-art, optimizing efficiency, reliability, product water quality, and overall low cost per unit of water. GET advanced designs recover higher percentages of the feed water as good quality product water. Boiler feed quality may be obtained by using specialized GET equipment designed for that purpose, even from seawater feed containing up to 55,000 PPM TDS.



GET, Inc.

Global EnviroScience Technologies

Mail: PO Box 90756, Long Beach, CA 90809-0756, USA

Factory: 3286 E. Willow Street, Signal Hill, CA 90755, USA

Tel: 1-562-989-5400; Fax 1-562-989-5405  

Toll-Free Tel: 1-800-600-8482 (US Only)
E-Mail us now! : info@get-inc.com






SEM, 200 to 600 gpd


Seafari Escape Modular



Seafari Escape Modular
200 to 600 U.S. Gallons Per Day
(757 to 2,271 Liters)
8 to 25 U.S. Gallons Per Hour
(30 to 95 Liters)


The new Seafari Escape Modular (SEM) with its unique EfficientSea energy transfer technology brings efficient, compact, extraordinarily quiet watermaking to small and midsize power or sail boats. The unit's energy transfer device eliminates the need for a power-hungry high pressure pump, reducing the electricity consumption of the RO system by as much as 75%. The SEM is ideal for sail and power boats with very limited onboard power, and even less onboard space. The system easily adapts to various boat designs and installation locations. The flexibility of this modular system provides a quiet, efficient watermaking system that will fit your boat perfectly.








Thomas Desalination

        24851 Big Valley Blvd., Poulsbo, WA 98370
        Contact: *Dana Thomas
        Tel: (360) 598-4481
        Fax: (360) 598-2274
        Email: Aguadana@Aol.Com
        Web:         www.thomasdesalination.com


Thomas Desalination has been servicing and installing reverse osmosis desalinators for over twenty years to the pleasure boat market from San Diego, California to Anacortes, Washington.



Sunburst Boat Company

        18316 41st Place West, Lynnwood, WA 98037
        Contact: *Len & Jackie Dickinson
        Tel: (425) 697-3700
        Fax: (425) 697-3737
        Email: Sunburstboat@Att.Net
        Web: Www.Sunburstboatcompany.Com

Sunburst Boat Company was established in 1985. Our experienced staff specializes in service and installation of reverse osmosis desalinators suitable for use on 25 feet pleasure crafts to cruise ships.

Solent Yacht Services

        Bldg. 13 Shamrock Quay, William Street, Northam
        Southampton England S014 5ql
        Contact: *Ray Bryan / Chris
        Tel: 011-44-2380-335294
        Fax: 011-44-2380-637337
        Email: Solent.Yachtservices@Talk21.Com
        Web: www.solentyachtservices.com


Solent Yacht Services sell, service, and install reverse osmosis desalinators for pleasure boats in Great Britian. We have the experience of more than two decades in the marine and boating industry.

AER Marine Supply

2301 NASA Road # 1
Seabrook, TX 77586
Contact:  Richard Miller
(281) 474-3276                          Phone
(281) 474-2714                          Fax
sales@aersupply.com                Email

AER Supply was founded in 1977. A family business started by Dick and Lou Miller is now owned and operated by Richard Miller (son) and Judy Johnstone (daughter). AER has evolved into a technical or added value distributor specializing in providing products and support in all large pleasure craft and light commercial applications including Water Purification, HVAC, Refrigeration, Filtration, Sanitation, Electrical, Plumbing, Generators, and Propulsion.



Bates Unlimited

1544 Sawdust Rd #602
The Woodlands, TX  77380
Contact:  Lyle Bates
(281) 367-4312                          Phone
(281) 367-4326                          Fax
(800) 367-9048                          Toll-Free
bates@batesunlimited.com      Email

Bates Unlimited was established by Lyle Bates in 1983 as a part-time side business to meet the need for reverse osmosis membrane cleaning in the Houston area. In October 1990, Bates committed his efforts full-time to develop Bates Unlimited as a service and distributing company to the marine/offshore water treatment market.


Ocean Options, Inc

        95 Riverside Dr., Tiverton, RI 02878
        Contact: Mike Bowden; Ed Hamilton
        Web:  www.oceanoptions.com
        Tel: (800) 832-3905; (401) 624-7334
        Fax: (401) 624-8050

Ocean Options specializes in refrigeration, air conditioning, reverse osmosis desalinization and heat for yachts and commercial vessels.

Sea Recovery

Sea Recovery
P.O. Box 5288, Carson, CA 90745
310-637-3430 Fax
Tom Ginnetti, Sales Manager

Sea Recovery was established in 1981 and conceived with the vision of manufacturing small Sea Water Reverse Osmosis Desalination Systems for marine applications. The company's initial product line turned Sea Water into Drinking Water for the Marine Industry, and remains the company's focus today.


HRO Systems

P.O. Box 5463, Carson, CA 90745
310-631-6395 fax
Toni Chavez, Dealer Development


HRO System      www.hrosystems.com


Established in 1976, HRO Systems is the pioneer of marine reverse osmosis desalination systems (commonly referred to as watermakers). HRO Systems is the leader specializing in sea water desalination systems from 170 to 44,000 U.S. gallons per day (644 to 166,558 liters)






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