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Cruising 300

Cruising 600, accessories, racing carbon, hydrogenerators cruising.

A good management of the energy on board is the key point to sail in total serenity, regardless the consumption of the on-board electronics or other electrical appliances. Watt&Sea’s hydrogenerators propose an energy self-sufficiency solution on board of cruise or race boats, in the respect of the environment.

Stemmed from ocean racing research, the first Watt&Sea hydrogenerator gets started in 2008 with the objective of an optimal output associated to a negligible drag, letting the boat sail with a positive energy while loading the batteries. Our hydrogenerator has since then being improved taking into account users’ comments, so that we are proposing today an even more reliable and efficient product.

Validated on all seas around the globe, they are the most powerful, reliable and lightest available on the market.

General view

Lifting bracket with cam cleat. Easy immersion and lifting

12/24V converter included. MPPT and Boost technology

Fastening on the transom…

Watt&Sea’s hydrogenerators are usually fastened on the transom of the boats thanks to the fastening kit supplied (adapted to straight and vertical transom). The lifting up and down are similar to a rudder blade’s handling. The charge power being so important, it allows to lift the hydrogenerator up when batteries are fully loaded. Handling makes it easier thanks to high quality steering : an Antal low friction ring to divide the effort plus a Harken cam cleat to maintain the unit in its position.

… or straight under the hull !

New model POD 600 to be fastened straight under the hull !

Tested since 2014 by a few privileged sailors, this version has been able to demonstrate those useful advantages :

• no complicated handling up and down
• easy start-up
• electrical output is the same compared to classic models

CRUISING Hydrogenerators range

After-sale service

Racing Hydrogenerator

Watt&Sea racing hydrogenerators   have radically modify the energy management on board and have become essential pieces of equipment in mythical offshore races like the Vendée Globe or the Route du Rhum. The VOLVO OCEAN RACE has chosen to place its confidence in   Watt&Sea , by equipping the Volvo Ocean 65 fleet present on the start line on the 22nd October 2017 !

Racing hydrogenerators are equipped with a controlled pitch propeller, functionning electronically with an independent system. The drag is minimal and the energy output is optimal on a speed range from 5 to 30 knots.

General View

Casque de relevage avec taquet coinceur. relevage et immersion faciles

Convertisseur / Régulateur 12/24 V inclus. technologie MPPT et Boost

Matereau 610 mm Carbone prépreg ou Aluminium

Hélice à pas variable À l’arrière, protégée des algues et des OFNIS. efficace sur une plage très vaste de vitesse

Alternateur brushless en prise directe. construit pour durer

Régule l’incidence de l’hélice par pression d’huile

1 entrée hydrogénérateur 1 entrée solaire de l’énergie au mouillage

Variable pitch propeller

Racing hydrogenerators are equipped with a controlled pitch propeller, such as an “aeroplane propeller”. High speed launch is possible, putting the blades in the feathered position.

Fastening on the stern…

Watt&Sea racing hydrogenerators tend to be fixed directly on the boats transom, thanks to the fixation kit included in the pack. The lifting and immersion is done like with a dinghy rudder. The effective charge power permits to lift the hydrogenerator up when the batteries are full. Operations are facilitated by premium quality equipment purchased : a low friction ring multiply the effort, and Harken clam-cleat maintains the hydro in the good position.

Racing Hydrogenerator range

Yachting Monthly

• Digital edition

Everything you need to know about hydrogenerators

• Sam Fortescue
• December 13, 2023

Design developments have made hydrogenerators the most efficient form of sustainable auxiliary energy for yachts. Sam Fortescue reviews the latest innovations

The potential of hydrogeneration has been well understood for decades, but it’s only over the past 15 years that the idea has started to become properly commercialised. In essence, it’s a very simple concept: the boat’s motion through the water turns an alternator which generates electricity to recharge the onboard batteries.

‘Every yachtsman owns a sophisticated wind energy machine in the form of the yacht itself,’ explains Peter Andersen of Eclectic Energy, which manufactures the Sail-Gen and Duogen hydrogeneration systems. ‘Hydrogeneration provides a simple way of converting a small part of the power harnessed by the yacht’s sails directly into electricity.’

Because water is a much denser medium than air, a small hydrogenerator fitted to the transom of a yacht can potentially produce a great deal more energy than if a larger wind turbine was fitted to it.

‘Kinetic energy increases proportionally to the cube of the velocity,’ adds Andersen. ‘That means producing 300 amp-hours per day or more is a realistic prospect while cruising at 7-8 knots with a hydrogenerator fitted. And it’s the reason why more and more boat owners are now opting for water generation, although it’s still not as popular as it should be.’

By contrast, a tradewind run with a wind turbine might yield just 80 amp-hours per day, because the apparent wind on a run is lighter. Good performance might see 40W output from 10 knots apparent. Similarly, solar panels only produce a fraction of their rated output for most of the day, so you’d need a large array to match the return of a modern hydrogenerator.

A blend of all three will, of course, give the best outcome for different conditions at anchor and under way – but on passage, it’s hard to beat the benefits of a good hydrogenerator.

Watt&Sea’s hydrogenerator is a flexible option

Speed v drag

The speed versus drag issue has always dogged hydrogeneration technology, mainly because hydrogenerators only put out meaningful energy once a boat reaches speeds of five knots or more. However, the increasing use of hydrogenerators on the international offshore racing circuit has started putting paid to most of those concerns, with all manufacturers now agreeing that the extra drag of the impeller in the water is negligible. It also becomes non-existent once the boat reaches hull speed.

The main issue for cruising sailors is the boat speed required to obtain meaningful energy from a hydrogenerator, which is mostly a question of the diameter and pitch of the impeller. Just as you need to ensure that an auxiliary propeller is matched to both the power of the engine and the speed of the hull, so the impeller on a hydrogenerator must be correctly sized for the speed of your boat under sail and desired power output.

The pitch also needs to be set to offer the optimum angle of attack for the boat’s likely range of speed through the water. That’s why leading manufacturers offer a choice of impeller, or at least an adjustable one.

Hydrogeneration is the most efficient form of sustainable auxiliary energy for yachts

The Watt&Sea is the most flexible in this respect. Its two models (300W and 600W maximum output) can be equipped with a 240mm diameter impeller or a 280mm unit. The difference in output is striking: at five knots boat speed, the smaller one produces 100W, while the larger one can manage 120W. Over the course of a day, that amounts to an extra 40 amp-hours on a 12V system.

The smaller impeller has a maximum boat speed of 11 knots, which will be enough for most cruising monohulls. Only sporty catamarans would need to consider the smaller 200mm impeller with its 13-knot top speed. Faster than that and you’d need to look at a race model with a variable pitch.

Charging performance

Apart from price, the factors differentiating the various brands on the market are their charging performance and mounting system.

Eclectic Energy is the only manufacturer whose generators rectify the current on board to produce a DC output that can be wired directly to the batteries. This has the benefit of simplicity, but requires beefier cables running all the way from the generator to the batteries.

The Duo Gen hydrogenerator from Eclectic Energy

Watt&Sea’s hydrogenerator puts out a three-phase, low-amperage alternating current that runs through a DC converter. The converter monitors the battery voltage to determine whether it is in the higher power absorption phase or the lighter float phase of charging. After that, an electromagnetic brake stops the impeller if it’s spinning too fast and becoming dangerous.

Swi-Tec’s charge controller funnels all the power from the generator into the batteries until they reach a predetermined voltage. At this point, the MPPT (Maximum Power Point Tracking) algorithm reduces the charge to nearly nothing, a buzzer sounds to alert the skipper and the impeller brakes itself automatically. It can then be changed to ‘freewheel’, allowing the propeller to rotate freely.

The Remoran is perhaps the most ambitious of all, with a charge controller that can automatically detect the system voltage and then apply a ‘smart charging algorithm’. It also interacts with a smartphone app via Bluetooth, allowing you to keep a close eye on its performance and power output.

A Sail Gen hydrogenerator mounted on a yacht’s transom

Mounting systems

While Watt&Sea supplies a pod-based system that can be permanently fitted under the hull, a removable transom fitting is still the most popular choice, allowing the unit to be removed and stowed when not in use. Alignment, though, will have a significant impact on a hydrogenerator’s performance, with the best results coming from a clean, clear flow of water. Manufacturers therefore recommend an offset mounting outside a direct line with the rudder.

There is a balance to be struck, however, as heeling can make one tack more productive than the other. On twin-rudder boats, a central mount works well.

Swi-Tec and Watt&Sea both offer an optional pivoting mount for fitting to a raked stern, while the Remoran has in-built pivoting as standard, using a spring-loaded knob to tab between different settings and offering a rake of up to 40 degrees. Watt&Sea also offers different leg lengths to suit different installations, while the Remoran Wave 3 has a telescopic leg that can be adjusted by over 30cm.

Watt&Sea unit with an optional pivot mounting for attaching to a raked stern

The Seagen and Duo-Gen take a very different approach to mounting, with a flexible yoke providing a single point of attachment. The alternator is attached at this end, while the impeller is at the end of a 1.6m tube which can be fastened out of the water in a vertical position when not in use. ‘It means the units are not rigidly attached to the yacht but are free to pivot,’ explains Eclectic Energy’s Peter Andersen. ‘This de-couples the impeller from the hull movement, reducing stress on the mounting.’

Main propeller regeneration

While a standalone transom-mounted unit is the most common type of hydrogenerator technology, there is another approach – using your main propeller to ‘regenerate’ electricity whilst under sail.

Oceanvolt’s HighPower ServoProp

Fully electric propulsion from the likes of Oceanvolt and Bell Marine has long had this capability built in, as do systems from Torqeedo and ePropulsion. But parallel hybrid systems are also available, where an electric motor is installed alongside the engine to both generate electricity and drive the boat electrically. Lynch Motors in Devon has been supplying its permanent magnet DC motors to the Vendée Globe boats for years, purely as a re-generator, and now produces the flexible Red Snapper motor for cruising yachts.

The only problem with a regeneration system is that the pitch required for the propeller to drive the boat efficiently through the water may not always be the same as the pitch for optimum regeneration. ‘The lift surface on a propeller is on the wrong side for efficient extraction of energy from the water,’ explains Eclectic Energy’s Andersen.

Manufacturers have tackled this in different ways. Oceanvolt has developed its ServoProp for saildrives, which electronically adjusts its pitch depending on speed and function. The latest incarnation allows total 360-degree blade mobility and faces forwards, which increases efficiency, albeit at greater risk of collision damage. At six knots, it produces an astounding 1kW of power.

Bruntons has another solution with the cleverly engineered Autoprop, which automatically pitches up to match the boat speed. Its Ecostar version of the prop can generate 200W at five knots and up to 1kW at 10 knots when connected to an electric motor.

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Hydrogenerator

Hydro generator.

The hydro generation or “creating energy while sailing” function is an automatic feature in all Oceanvolt motors. 

This feature is activated by pushing the button on the Oceanvolt displays for 5 seconds. The display will automatically switch to regeneration mode showing the current generated power, RPM and time until the batteries are fully charged. 

With a normal folding propeller the motor kicks the blades out and centrifugal force combined with the motor controller keep the blades open. The motor controllers tune the system actively at 10 Hz which prevents the blades from closing (too much braking would close the propellers). This is continuous monitoring, the system will adjust the propeller RPM depending on the boat speed. 

The system shuts itself down when the battery is fully charged or if boat speed is too low for efficient hydro generation.

OCEANVOLT SERVOPROP

The patented Oceanvolt ServoProp variable pitch sail drive combines a high efficiency sail drive with the most powerful hydro generator on the market. The unique feature of the ServoProp is the possibility to turn the propeller blades more than 180 degrees. The software controlled variable pitch sail drive adjusts the pitch of the propeller blades automatically so that the power generation and power output are optimal. Combined with uniquely designed blades it delivers optimal efficiency in both forward, reverse and hydro generation. And with the blades set to the neutral sailing position, the propeller creates extremely low drag similar to the drag of a feathering propeller. The benefits of ServoProp include an estimated +30% increase in forward propulsion, +100% in reverse and +300% increase in hydro generation effect.

A normal fixed propeller (that by nature does not have the blades ideally shaped for regeneration) generates less than half the power of ServoProp at a given boat speed. ServoProp is capable of generating more than 1 kW at 6-8 knots. The power generated can be used to power both the propulsion system as well as all the electronics on board without the need to have a separate generator. With this in mind we can definitely start talking about the possibility of a totally self-sufficient cruiser!

The ServoProp is suitable as a propulsion motor for monohulls up to 50 ft & multihulls up to 60 ft. It can also be used as a hydro generator in boats up to 100 ft.

Videos of hydro generation

power created by hydro generation

Oceanvolt systems are optimised for either 2 or 3 blade Flexofold folding propellers & Gori propellers.  Other folding propellers can also be used but they provide 30-50% less propulsion and regeneration power. 

The highest regeneration power is gained with fixed blade & adjustable pitch propellers and also with dedicated systems for hydro generator use, because they allow using a higher pitch/dimension propeller.

The regeneration feature is extremely suitable for catamarans because twin motors means double the energy generation.  Catamarans are also faster, which means that regeneration power capture is higher.

Sailboat Water Turbine Doubles Energy Production

Yachting Journal

Image credit Watt&Sea

Watt&Sea Hydrogenerators produce power with a water turbine housed in a computer-optimized hydrodynamic design. Once a sailboat has left the docks, is totally isolated from utility (grid) power. The production of energy on any boat is crucial to powering communications, navigation lighting and other energy consuming devices. Operating diesel engines and generators are costly, noisy and are environmentally unsanitary. The clean energy solution is the Watt&Sea Hydrogenerator, which easily deploys off the back of the cruising or racing vessel efficiently generating power for energy independence. The principle is simple: using the speed of the sailing boat to turn an immersed propeller and produce electricity. The high-tech sleek hydrodynamic design of the Hydrogenerator produces high output power with very low drag and noise while being lightweight and easy to deploy. Energy production begins at 3 kn of speed and the energy cost produced is a competitive solution. The energy production is typically twice that of solar panel and wind generator alternative energy solution allowing reduction in battery bank size and fuel storage reducing vessel weight and increasing performance. The unit is lightweight, compact and easy to install on the boats transom. Deployment and recovery is easy taking only seconds thanks to its unique lifting system (similar to a rudder). It is maintenance free, generating 240 amp-hours day @ 5 knots. It weighs 17.7 lbs and comes complete with an external automatic regulator. These hydrogenerators are currently available and sold through e Marine Systems , a supplier of marine renewable energy equipment.  

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The Latest in Water Generators

Previously published in BWS .

Water powered the beginning of the Industrial Revolution when inventors and entrepreneurs discovered that a turning water wheel could be used to drive the machines that can mill lumber, weave cloth and turn lathes. Water power could be transformed into economic power by harnessing the inherent energy in a flowing stream.

So, it is not much of a leap for the tinkerers and inventors in the marine world to figure out that the flow of water past the moving hull of a sailboat contains the same energy as the water flowing past a water wheel. Plus, that energy is there whenever the boat is underway so all they had to do was figure how to use its power to generate electricity.

Ampair underwater

Water generators are not new. American Hamilton Ferris has been building and selling water generators—the Water Power 200—since 1975 and this year (2015) is in the process of redesigning the unit to include the latest generating technology.  The concept then and today is to devise a generator that uses a propeller that is made to spin by the flow of the water to turn a small generator. The current created by the generator then runs through a regulator to the battery bank. The speed of the boat and thus the speed of the water flowing past it determines the spinning speed of the prop and the amount of energy created by the generator. Speed equals energy. Contact Hamilton Ferris for more information about the next generation models soon to be on the market.

The Ferris Water Power 200 can be converted into a wind generator with long blades and a tail that can be hung over the boat’s fore triangle where it will  generate electricity while the boat is at anchor. Several other water generator manufacturers have also adopted this dual use philosophy.

The Duo-Gen, from England, is a dual purpose generator that can be deployed in both wind and water modes. Now in its third generation, the generator advertises that it can produce six amps in 15 knots of wind or eight amps in the water with a boat speed of six knots. The unit mounts on the stern and has a crane for the wind mode and a swivel for water mode. It is built of enhanced aluminum castings and has a carbon fiber drive shaft. The Duo-Gens have been used on world cruises for years and have proven reliable. The all up cost of a unit and installation will run about $4,000.

Duo-Gen also produces the water only Sail-Gen that mounts on the transom and will deliver a whopping 10 amps at six knots. The impeller is held firmly under the water by an articulating dive plane and when it is time to retrieve it, you simply change the plane’s angle and the unit pops out of the water.  Simple, powerful and well made, the Sail-Gen will definitely keep the batteries topped up. For boats on passage, a speed of five knots will generate 150 amp-hours  per day while a speed of seven knots will put out up to 400 amp-hours. The Sail-Gen with the regulator will run about $3,000.

Ampair is another English company that has been building wind and water generators for cruisers for nearly 40 years. Their dual mode unit is called the Aquair 100 and is similar to the Ferris unit, being comprised of a small generator that can be adapted with a tail and blades in wind mode or connected to a gimbaled stern mount and a towed propeller in water mode. The generator can provide up to 100 watts of output at the top end, which translates to about 200 amp hours daily on passage. The Aquair with a regulator and the wind conversion kit will run about $1,800.

The most recent entry in the water generator market comes from France. Developed for cruisers and racers, the Watt & Sea water generators are not dual mode. Shaped like a very streamlined sail drive, the units fit on stern brackets and can be lowered  and raised easily on deck. Watt & Sea offers 300 and 600 watt models; the 300 watt models put out eight amps at seven knots while the 600 produces amps at six knots. Eight amps become 192 amphours daily.  The units are not inexpensive with prices for the 300 running about $3,500 and the 600 at about $4,500.

Watt & Sea generators

Watt & Sea also builds ultra light, all carbon water generators for racers  that are designed to perform in a wide range of boats speeds from two to 15 knots and more. The output from these units is 150 watts or about 12 amps.

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Test of Six 12-volt Watermakers

While at first blush all appear about the same size, we find important differences in output and current consumption. the spectra 180 is amazingly efficient but expensive. of the six, village marine tec's little wonder seems the most tried and true..

Last month we took an overview of the pros and cons of 12-volt watermakers. This month, we look at high-output machines from five manufacturers, ranging from systems from industry giants such as Village Marine to small shops such as SK Engineering. All of the watermakers we looked at were production models, although the Spectra 180 we tested had been re-configured to serve as a demonstration model.

As we began our market survey and field testing, we discovered that a number of other manufacturers are jumping into the fray, realizing that 12-volt watermakers constitute a small but growing segment of the market. Most notable among these new players is HRO-another industry giant-which has been promising a state-of-the-art, computer-controlled, self-contained 12-volt watermaker for more than a year. We saw the literature a year ago at the Miami Boat Show. We saw a non-operational mockup last fall at the Southampton, England boat show. We have yet to see a functional machine in the flesh.

With the assistance of Andy Cortvriend of Ocean Link, a knowledgable Portsmouth, Rhode Island, marine servicing company, we tested product output, water quality, and electrical consumption of all the watermakers. Electrical consumption was measured with a Cruising Equipment amp-hour meter, using gel cell batteries maintained at full capacity by a Heart inverter/charger between tests.

Saltwater was pulled from lower Narragansett Bay into a large storage tank maintained at a constant temperature during the tests. The waters at our Little Harbor test facility are not as clean as open ocean waters, but are closer to the reality of the watermaking most cruisers will experience. This was not a pure laboratory test with manufactured sea water of exactly the right total dissolved solids (TDS).

We then examined each machine carefully on the bench, looking for weak points, strong points, potential installation or maintenance hang-ups, and general quality of construction.

The quality of output water was tested with a TDS meter and all machines easily met standards for potability.

The real test of any watermaker is how it performs over time-not just months, but years. Because maintenance is a key factor in longevity and trouble-free operation, the owner/operator will bear a large portion of the responsibility for the long-term success of any watermaker installation.

Here are our findings.

Village Marine Little Wonder When Village Marine Tecs Little Wonder was introduced almost a decade ago, it was the first 12-volt watermaker that actually had the capacity to supply the water needs of a medium-sized cruising sailboat without almost continual running. More than 1,500 of these compact, well-made machines have been produced, and there have been virtually no changes to the design or components over the entire production run.

Both 12-volt and 24-volt models are available, with the higher voltage model producing slightly more product flow.

The standard model is totally self-contained in a well-designed package, with all components bolted to a heavy aluminum chassis, topped off with a removable aluminum cover. Mounting requires drilling through the chassis for suitable through-bolts.

The three plumbing connections-feed water, product water, and brine discharge-are pre-plumbed through one end of the case. The wiring junction box also contains connections for an optional feed water boost pump, and an internal 25-amp breaker to protect the electrics.

Although the package is tightly plumbed, there is reasonable space between components for service.

Power for the high-pressure pump is provided by a continuous-duty 1/4-hp. Pacific Scientific motor, rated at 21.5 amps at full power. The motor is connected to the high-pressure pump by a lightweight cogged belt.

The heart of the Little Wonder is its proprietary high-pressure pump, specially made by Village Marine for this machine. It features a titanium pump head with ceramic plunger-a combination which should be corrosion-proof for the life of the watermaker. All wetted parts in the pump are titanium, type 316 stainless steel, or ceramic. High-pressure plumbing and connectors are type 316 stainless.

Monitoring includes a high-pressure gauge and product flow gauge. System pressure can be adjusted if necessary using an open-end wrench, although the factory pre-set pressure of 800 psi should be correct for most watermaking situations. The pressure regulator is a high-quality regulator, rather than the more commonly seen needle-valve adjuster.

The fiberglass pressure vessel and the standard-sized 2521 membrane are both manufactured by Village Marine, although they are industry-standard in size.

In our tests, the Little Wonder produced a product flow of 5.8 gph at 13 volts, drawing 16.7 amps-about 37.4 watts per gallon. This does not include the 1-amp current draw of the small optional booster pump, which is required for above-the-waterline installations, long feed water runs, or installations containing multiple pre-filters.

The water produced by the machine we tested was very high quality. The noise level of 79 dB, with the cover removed, was louder than the two quietest machines tested, but was not loud enough to be objectionable.

The self-contained unit is 25.5″ long, 11″ wide, and 9.25″ high, and requires a slightly larger mounting space to accommodate plumbing connections and allow access for removal of fastenings holding the cover. For tight installations, a modular version is available, which does away with the mounting chassis and uses flexible high-pressure hoses rather than rigid stainless steel tubing. Obviously, installation of the modular unit requires slightly more time, but offers a lot of flexibility-very desirable in field installations aboard the typical cruising sailboat, in which locker or shelf space is at a premium.

Documentation is excellent, with a 35-page manual covering installation, operation and maintenance.

The warranty is somewhat complex. The membrane has a three year warranty, the pressure vessel a lifetime warranty, the high pressure pump a one-year warranty-although some of its internal components have only a 90-day warranty-and the electric motor 12 months. You need a flow chart to keep it straight.

The Little Wonder comes with pre-filter, three-way cleaning valve, basic plumbing connectors, and a membrane cleaning kit. You supply PVC hose, hose clamps, and the wiring connection. Options include the boost pump (standard with the modular version, $144 for the self-contained version), a three-way sampling valve ($38), a pre-plumbed fresh water flushing system ($150), hand-held salinity meter ($49), and spares kit for extended cruising ($199). For long-range cruising, all of these options are nearly essential for any properly installed watermaker.

List price of either the self-contained or modular 12-volt Little Wonder is $3,195. It is available at slight discounts through some mail-order catalogs, and there are periodic promotions at boat shows featuring special prices and thrown-in options.

Weight of the self-contained system is 63 lb. (The modular system weighs 48 lb.)

Village Marine will soon introduce a higher-output version of the Little Wonder, a 1/3-hp. watermaker in almost the same package size. Current draw, however, will be about 26 amps, requiring heavier wiring and perhaps a look at your battery capacity and charging capabilities.

Bottom Line: There are quieter 12-volt machines, more efficient ones, cheaper ones, and others that put out more water. The Little Wonder, however, has a combination of features-ease of installation, relatively low current draw, high quality components, and a 10-year track record-that is hard to beat. You can’t go wrong with this watermaker.

SK Engineering DC 150 SK Engineering is a small watermaker manufacturer based in Ft. Pierce, Florida. They do virtually no advertising, go to few boat shows, and have a very low-overhead operation geared to the Florida market. While most of their units are AC-powered, their DC 150 is a 12-volt model with a nominal output of 6 gallons per hour.

The DC 150 is powered by a 1/3-hp. continuous-duty Pacific Scientific motor rated at 26 amps. This is a larger version of the motor that powers the Village Marine Little Wonder.

The membrane is a standard 2521, and the pressure vessel appears identical to that used by Village Marine. All high-pressure fittings are type 316 stainless, as is the rigid high-pressure plumbing.

A Giant high-pressure pump provides pressure for the system. This is a standard industrial pump with a stainless steel pump head. A complete servicing manual for the pump is provided.

This is an open-frame system, with the components mounted on a heavy aluminum chassis. The footprint is 18.5″ x 12.5″, with a height of 8.5″. The pressure vessel is mounted on the outside of the chassis, increasing overall dimensions to about 25″ long outside the footprint of the mounting frame. Rubber vibration mounts are provided to isolate the chassis, reducing noise and vibration.

System pressure is user controllable via a knob-operated valve on the panel. Monitoring capabilities include system pressure and product water flow.

In operation, the DC 150 was one of the quietest machines tested, producing a maximum of 72 dB of noise. Product flow of the test machine was 6.5 gallons at 800 psi, with the motor drawing 21.3 amps at 13 volts. This translates into electrical consumption of 42.6 watts per gallon of water produced. As with other systems, adding a booster pump for above-waterline installations would add to total current draw. SK states that the system will operate without a booster pump in installations up to 2′ above the waterline.

One of the nicer features of this machine is the availability of a remote operating panel. This option allows routine operation of the system without direct access to the watermaker itself, which greatly increases installation flexibility.

The system is supplied with a pre-filter with a vacuum gauge, allowing you to monitor the condition of the filter without opening the housing. A freshwater flush kit-highly-desirable in any installation-is a $125 option. The 12-volt booster pump, drawing 1 amp, is a $120 option. An extensive cruising kit, including 12 pre-filters, rebuild parts for the high-pressure pump, cleaner, preservative, and other spares, costs $330.

SKs pricing is very competitive. The self-contained DC 150 has a list price of $2,740, but has a discount price-which we suspect would be available to most sailors who approach the manufacturer directly-of $2,350. The remote panel version has a discount price of $2,450, although the list price jumps to $3,140.

The system documentation is basic, but adequate. Total system weight is 74 lbs.

Being a small manufacturer, SK has a limited network of regular servicing dealers, but since all the system components are essentially off-the-shelf items, any good watermaker technician could repair the unit if necessary.

This is a quiet system with high-quality components and a great deal of installation flexibility when coupled with the optional 8″ x 8″ remote panel. Its open-frame design is easily serviced, although the package is not as neat as a totally enclosed package like the Little Wonder.

Bottom Line: With its 1/3-hp. motor, electrical installation will require careful thought, and you will need to look at your entire charging system and battery capacity a little more closely than you would with a 1/4-hp. machine.

The low price makes this system worth looking at. It is simple, soundly engineered, and utilizes good quality, standard components that are easily serviced. The only potential drawback is the small size of the manufacturer, which might limit long-term support.

PUR PowerSurvivor 160E The PowerSurvivor 160E is PURs entry into the high-output 12-volt watermaker market. It is the latest in a long line of machines that dates back to the PowerSurvivor 35, the first practical small 12-volt watermaking system.

The 160E uses a standard 2521 membrane in a proprietary housing. It is a dead-simple modular system, utilizing a Leeson 1/3-hp. motor directly coupled to a proprietary stainless steel high-pressure pump. Flexible high-pressure hose between the pump and the pressure vessel allows a great deal of mounting versatility, including bolting the entire system to a bulkhead. All high-pressure fittings are 316 stainless steel.

At 54 lbs. for the entire system, this is one of the lightest high-output watermakers we tested.

When we say dead-simple, we mean it. Other than the pressure bypass valve and the on-off switch-which you provide-there are no gauges to monitor, no product flow meter, and no means of adjusting system pressure, which is pre-set at the factory and is not intended to be user-adjusted. You would still, of course, install the product sampling valve, cleaning valve, and pre-filter, just as with all other units.

The 160E is a gravity feed system, and can only be installed below the waterline.

Our test machine produced 6.5 gallons of water per hour, drawing 17.3 amps at 13 volts-less than we would expect for a 1/3-hp. system. This yields an energy consumption of 34.6 watts per gallon of water-more efficient than average for the watermakers in our tests.

There are several drawbacks to the PowerSurvivor 160E. First, the system is the noisiest of any we tested, putting out 80 dB at our standard test distance of 1′. Furthermore, the reciprocating drive system of the high-pressure pump produces not a steady noise, but one punctuated by a loud popping sound at one stage of the piston stroke. We would recommend mounting this watermaker in a sound-insulated compartment if possible.

The reciprocating pump also produces pulsing in the systems hoses, which should be well-secured to prevent fatigue over time.

This is one of the more expensive watermakers we tested, with a list price of $4,440. Several discount marine catalogs sell the 160E for as low as $3,800. Options include a repair seal kit ($80), an extended cruise kit ($200), and an extensive preventative maintenance package ($420).

On the plus side, routine service of the system, including replacement of high-pressure pump seals-a requirement every 1,000 hours of operation-is simple and well-documented in the excellent instruction manual.

We also looked at two other units from PUR, the PowerSurvivor 80II modular and the newly-designed PowerSurvivor 40E. The 80II is very similar to the 160E, simply scaled down. We did not test it, but since all the other PUR machines met the manufacturers specifications, we expect this one to do the same. The smaller-diameter membrane of the 80II limits you to membranes from the machines manufacturer. It lists for $3,330, and is routinely discounted to about $2,950-about the same as the higher-output Little Wonder.

The PowerSurvivor 40E is the totally re-designed successor to the PowerSurvivor 35, the original high-output 12-volt watermaker. In our tests, its 1/18-hp. motor drew 4.8 amps, producing about 1.6 gallons per hour, consuming 39 watts per gallon of water. It is very compact, and like all PUR watermakers, easy to service and operate.

At 72 dB, its noise level was the equivalent of the quieter large 12-volt machines.

With its light weight (25 lbs.) and tiny footprint-about 15-1/2″ x 15″ x 6″ high-the 40E would be the most suitable watermaker for a single sailor or a couple cruising on a small or very light boat-a multihull, for example-with limited electrical generating capacities, perhaps just a few solar panels and small batteries.

In an emergency, the motor can be disconnected from the 40E, and it can be operated manually by a handle, just like its Survivor 35 predecessor. Because virtually all the parts of the 40E are proprietary, including the pressure vessel, membrane, and pump, you will only be able to service the units with parts from PUR.

List price of the 40E is $2,220/$1,900 discount, with options analogous to those available for larger PUR machines.

Bottom Line: All three of these smaller watermakers are actually the core business for PUR, and fill specific niches where there is no competition. Although the 160e is an easily serviced watermaker, and is more efficient than average, its high price and noisy operation are drawbacks. If the installation flexibility of the 160E is not essential to you, we think there are other 12-volt watermakers of similar capacity and quality of construction that offer better value.

Caribbean Technology The Caribbean Technology YM-200 DC 12 made by Great Water is the highest-capacity 12-volt watermaker we tested. Its rated output of 10.2 gph at 800 psi significantly exceeds that of most of the watermakers in our test.

In many ways, this modular system mimics both the output and sophistication levels of more mainstream engine-driven or 110-volt systems, including a direct drive high-pressure pump, high and low pressure automatic shutoff, and a sophisticated remote operating panel including power switch, pressure regulator, and gauges for system pressure, product water flow, and brine flow.

Power is provided by a 1/2-hp. continuous-duty motor directly coupled to a stainless steel Wanner Hydracell industrial pump. An instruction manual for the pump leads you through the periodic maintenance required. A new oil venting system in the pump claims to have eliminated an earlier tendency of Wanner pumps to weep oil.

A Codeline pressure vessel holds a standard 2521 membrane. Because this is a modular system, high-pressure plumbing includes flexible hose rather than rigid tubing. All fittings are 316 stainless steel.

A Flojet boost pump is standard, allowing the system to be mounted above the waterline. This pump-actually designed as a shower drain pump-adds 3.6 amps to the current draw of the system.

A product flow rate of 10.2 gph is pretty much the absolute capacity of a 2521 membrane, and our test system had no trouble achieving that rate of flow. The downside is that to achieve this flow, the electrical demands of the system are much higher than any other watermaker we tested: 38 amps at 13 volts, or 48.4 watts per gallon.

You would never run this system without running the engine at the same time. The current draw is high enough to drop system voltage down instantly. In all fairness, for maximum efficiency none of the systems drawing 15 amps or more should be operated without running the engine at the same time.

Because of the high current draw, your charging system should be equipped with a big alternator if you choose this watermaker. To take advantage of the big alternators capacity, youll want a big bank of batteries. The system will probably need a 50-amp circuit breaker separate from the main panel, as many main panels do not have service wiring that is really heavy enough for this type of load.

You will also need heavy wiring between the circuit breaker and the systems electrical relay box. The manufacturer recommends 4-gauge wiring, which is heavy and may in some cases be difficult to run.

Obviously, a great deal of planning and thought is required before installing a system of this capacity and with these electrical requirements.

On the plus side, the fully modular design allows the system to be mounted in a surprisingly small space, essentially little more space than is required by a modular 6-gph system.

Weight of the YM-200 is 83 lbs.

The manual includes excellent system schematics, and reasonably thorough instructions for installation, operation, and maintenance of the watermaker.

As you might expect, the size of the pumps and motors result in a fairly noisy system: 80 dB at a distance of 1′ from the high-pressure pump-the big noisemaker in any system. Due to its weight, electrical needs, and noise, the best location for this watermaker is a sound-insulated engine room or compartment, as close as possible to the ships electrical supply.

Bottom Line: The best application for this system is a larger boat with existing electrical capacity, and lacks a genset or a means of installing an engine-driven watermaker.

With a list price of $3,500-which is sometimes discounted through dealers-this is not an expensive system. In fact, on a dollar cost per gallon of water produced per hour basis, this is the cheapest system of the entire lot to purchase. It is not an electrically efficient system, but if the maximum output in the minimum time is your primary criterion in a 12-volt watermaker, the Caribbean Technology is definitely worth considering.

Spectra 180 The Spectra 180, and a few variations on its basic version, are the only watermakers produced by Edinger Marine Services. It is radically different from other 12-volt watermakers, extracting a lot of freshwater with astonishingly low power consumption.

When you first see the Spectra 180, your first impression is that one component-a big DC motor to power the high-pressure pump-has been left out. In fact, the entire system is powered by a small 12-volt pump and motor-about 1/8-hp.-no larger than the water pressure pump on a 35-footer. This is possible due to the unique design of the Clark pump, a remarkably energy-efficient pump created specifically to power this watermaker.

The Clark pump is totally unlike any other high-pressure pump used in watermakers. To oversimplify, the Clark uses two opposing pistons and cylinders with a single connecting rod. System pressure is created by the connecting rod driving the piston into the opposite cylinder. Without a detailed technical explanation of exactly how any why this works, it is fair to say that compared to other methods of creating adequate pressure for reverse osmosis, this is a remarkably energy-efficient system.

The Spectra 180 is also different from other watermakers in that it uses a standard full-size membrane whose pressure vessel is just over 44″ long-almost twice the length of the pressure vessel containing the 2521 membrane used by all the other high-capacity systems in out tests. Mounting this much longer pressure vessel may present problems in some boats. The Clark Pump housing itself is almost as long as the pressure vessel for a 2521 membrane.

According to the manufacturer, they have torn down Clark pumps after 3,000 hours of operation and found no significant wear. In any case, the pump is easy to overhaul in the field by a reasonably proficient owner. An overhaul manual for the pump is part of the system documentation, which is basic but adequate.

This is a modular system, with a remote control panel that can allow basic operation without direct access to the other system components. Total weight is about 51 lbs.

Our test system was a factory demonstrator, configured as a self-contained frame system with some performance compromises compared to the correct, conventional modular installation. Instead of a single large membrane, our test system utilized two 2521 membranes, similar in flux area to the larger membrane.

From a pure electrical efficiency perspective, the Spectra 180 was the most impressive watermaker we tested. With a current draw of 8.6 amps at 13 volts, our test unit pumped out fresh water at the rate of almost 9.5 gph–almost as much as the Great Water system, which draws almost five times as much power. Thats only 11.8 watts per gallon, by light years the most electrically efficient machine in our test.

In addition, at a noise level of 65 dB, this was the quietest system.

The Spectra 180 is not perfect, however. The system runs at low pressure compared to other systems-just 600 psi with our 70F water temperature-and the product water, although perfectly acceptable, had the highest total dissolved solids in our tests. Since product water quality can vary with different membranes, we are reluctant to attach much significance to this slightly lower water quality, which was still well within standards for drinking water.

We have some concerns about the relatively low feed water flow rate through the big membrane. The more water that passes over a membrane, the better it likes it, according to most manufacturers. The Spectras flow rate of about 90 gph is quite small for the large membrane, and we do not know how the longevity of the membrane might be impacted by this.

The ends of the main block of our systems Clark pump were machined from bronze, and showed some signs of surface oxidation at the interface to the Delrin main block. According to the manufacturer, future editions of the Spectra will have stainless steel components in place of bronze.

Likewise, the pressure relief needle valve on our test system dribbled when it was barely cracked open. We were told that this component has also been re-designed.

Our test system utilized brass high-pressure fittings, rather than the type 316 stainless used by every other manufacturer. Some manufacturers claim that the only reason to use brass is to save money, while others admitted to us, a bit reluctantly, that they had never seen a brass high-pressure fitting with significant corrosion, and stainless was generally used for appearance and galvanic compatibility as much as for longevity purposes.

Given the cost of the Spectra 180, we think you should get type 316 stainless fittings, and type 316 pump block components. The price of the Spectra 180 is $4,650, the highest of any machine we tested. You pay a significant premium for a major increase in electrical efficiency. Service, parts, and options prices are similar to those of other manufacturers: $350 for a long-term offshore service kit, for example. The price of the installation kit-$275-strikes us as a bit high for such parts as the three-way servicing and diverting valves that some other manufacturers include in the price of the basic system.

According to the manufacturer, although the system is fully functional and in production, they are still looking at further developments, including a composite Clark pump that would have no metal components. Relatively few of these machines are in use in the field at this time, as the product is quite new to the market.

Bottom Line: The most attractive feature of this system is its energy efficiency. We are less impressed by its price, and by the fact that it would appear to be a system with some room for refinement. However, if being able to run a watermaker without running the engine at the same time is important to you, and if price is less important than electrical efficiency, the Spectra 180 would be the choice among the systems we tested.

Conclusions/Recommendations Because virtually every cruising boat has different needs, priorities, and installation requirements, no single high-capacity 12-volt watermaker is going to fit the bill for every sailor. These are all well-designed, fully functional machines. Each has specific advantages and disadvantages, which we have described.

All meet their manufacturers performance specifications in terms of electrical consumption and product water output. Variances of +/- 10% to 15% from the manufacturers specifications for performance are normal.

The variations in product water quality we found are not significant. All the watermakers produce water that meets international standards for potability. The quality of the water will vary over time with any watermaker and with any membrane. A simple hand salinity tester-available from most watermaker manufacturers-is all that is required for routine checking of water quality. Most owners who use their watermakers daily don’t even bother testing salinity. They start the machine, let it run for a few minutes, taste the water, and if it tastes good, divert it to the tank.

All watermakers have similar maintenance requirements, and all we tested are reasonably easy to service. Your choice of a specific system will be largely the result of specific requirements for your boat and your cruising. The key questions are the amount and shape of space you have for the watermaker, the existing or planned electrical generating and battery storage capacity of your boat, and the amount of water you must make in a specific time frame.

All watermakers are maintenance-intensive. To a large extent, the long-term, hassle-free operation of a watermaker is a function of where and how it is used, and how religiously routine maintenance is performed. None of these machines will stand abuse.

A freshwater flushing system is an important component of a watermaker installation. Of the machines tested, only Village Marine and SK Engineering offer a ready-made freshwater back flush system as an option. While it is an easy system to design and build for anyone capable of installing a watermaker, it should be offered and recommended as an option by other manufacturers as well.

None of these systems is beyond the installation capabilities of a reasonably handy boat owner. If space permits, a totally self-contained system such as Village Marines Little Wonder will be slightly easier to install, but the total difference in installation time between self-contained and modular systems should not be more than a few hours unless there are vexing component mounting problems to solve. Plumbing and wiring connections are essentially the same for modular and self-contained systems, although a modular system with a remote panel will certainly take the longest time to install because of the number of individual components that must be placed.

All installations require attention to detail, particularly when it comes to wiring. We would not recommend you install a watermaker as the first major project you undertake on your boat, since it will require putting in a through-hull, installing heavy-duty wiring, and completing some plumbing that may in some boats be more difficult than it may first appear.

While all watermakers are covered by manufacturers warranties, all specifically exclude damage due to abuse in operation, poor maintenance, or improper installation.

A watermaker is not a use-it-and-forget-it product. Its for those who live aboard. If you don’t use it regularly and maintain it properly, you are wasting your money, and you shouldnt own one. On the other hand, if you are willing to accept the responsibility of maintaining a fairly demanding piece of equipment, a 12-volt watermaker can give you-particularly if you are a cruising sailor who desires long-term independence from shore-a degree of freedom you may not otherwise find.

Contacts- Edinger Marine Service, Inc., 298 Harbor Dr., Sausalito, CA 94965; 415/332-3780, fax 415/332-8527. Great Water, Inc., 5148 Peach St. Erie, PA 16509; 814/838-0786, fax 814/838-8700. Ocean Link, 52 Maritime Dr., Portsmouth, RI 02871; 401/683-4434. PUR, Recovery Engineering, 9300 75th Ave. North, Minneapolis, MN 55428; 800/845-7873, fax 312/315-5505. SK Engineering, 4256 N. US 1, Suite 1, Ft. Pierce, FL 34946; 800/489-0852, fax 561/489-0808. Village Marine Tec., 2000 West 135th St., Gardena, CA 90249; 800/421-4503, fax 310/538-3048.

RELATED ARTICLES MORE FROM AUTHOR

Excellent article, thank you for the research and detailed info.

Agree! Thank YOU

I really appreciated reading your recommendation, especially power consumption from one manufacturer to the other.

I am some how confused with Spectra manufacturing and Katadyn. I thought it was all Katadyn for some time now. When was this test done?.

Great review, except it would have been helpful to have specific TDS figures for the output in each case.

The contact information for SK engineering is wrong. Went to some health insurance company that sounded like a scam.

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Sailboat Wind Generators and Water Turbines

There's no doubt that a sailboat wind generator will make a significant contribution to the amps on call-up duty in your battery bank. And the more wind - up to a point - the greater will be the contribution.

A wind generator, or wind-charger as they're also known, senses only the apparent wind rather than the true wind, which is why they are much more effective on some points of sail than others.

On a typical tradewind Atlantic crossing for example, with the wind astern, their performance is likely to be disappointing. With say a 15 knot following wind and a boat speed of 6 knot, the resulting 9 knots blowing through the blades, your sailboat wind charger won't be earning its keep.

But having made your Caribbean landfall and cruising in the West Indies, it will be a different matter. Now beam winds and breezy anchorages will ensure that your sailboat wind generator provides generous and consistent battery charging.

Types of Sailboat Wind Generator

The power produced is generated by spinning a DC generator or a 3-phase AC alternator, with an internal rectifier to convert AC to DC.

In Europe the trend heavily favours smaller diameter, multi-bladed alternator types like the 5 bladed version shown here.

In the US large diameter, two or three-bladed versions still have some avid followers.

These types perform better at lower wind speeds - the quaintly named 'WindBugger' or the Hamilton Ferris (shown here) being good examples of the breed. Power produced is a function of swept area blade speed of rotation - and the faster the speed, the louder the noise. So it will come as no surprise that excessive noise can be an issue with some wind generators.

The slower two-bladed types producing a low frequency 'whump whump', while the high speed 3 and 5 bladed types can produce a penetrating howl that even a teenager wouldn't appreciate.

Manufacturers of the high speed, high efficiency types of sailboat wind generators are at last getting to grips with the noise problem through combining sophisticated blade design with high tech lightweight materials.

And your sailboat wind generator will be more effective in some parts of the world than others. In the Mediterranean for example, where calm conditions are frequent, other forms of green power such as solar panels may be a better option.

Towed Water Turbine Generators

The components of a towed generator, (aka water turbine) are an impellor, 20m to 30m of rotating towline coupled to a pulpit-mounted generator from which a cable delivers the charge to the batteries. Towed generators typically produce around 5A at 6 knots.

They really score over their wind driven brethren in light wind conditions or on long downwind passages where a sailboat wind generator would be seriously impaired by the lack of relative wind. In such situations a towed generator will continue to churn out the amps.

Towed water turbines have a keen following in many long-distance blue water sailors, but they do have their own problems:

• Drag. They will typically take between a third and half a knot off your speed;
• At speeds much above 7 knots they tend to skip along the surface, generating nothing but disappointment. This can be compensated to a degree by adding sinker weights to the impellor, and/or using a longer than standard towline. Some manufacturers offer an alternative coarser pitched unit which is good for speeds up to 12 knots, but at 6 knots this version will only be generating around half of what the standard unit would;
• In heavy seas they can leap out of the water, where the spinning tow rope is likely to snarl up into some impressive kinks and twists;
• Sharks have been known to consider the impellor as part of their diet.

You should forget about trolling a fishing line when you're towing one of these. The resulting tangle has to be seen to be believed.

Combined Wind/Water Turbine Generators

Towed generators are not much use at anchor, but some manufacturers have overcome this limitation by making them convertible from water to wind mode and vice-versa. The Aquair 100 water/wind turbine is a typical, much favoured example of one of these.

Just occasionally in the marine industry, someone comes up with a really neat idea. This time it was Eclectic Energy Limited, the manufacturers of the innovative DuoGen Combined Water/Wind Generator.

Unlike a towed unit this is a one piece design, which is permanently attached to the transom. Swing it down into your stern wave where it will act as a water turbine; swing it up and you've got a wind charger.

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• Digital Edition

Water for sailing: We survey the ARC fleet to find popular options

• Toby Hodges
• June 24, 2021

How to stow, conserve or generate drinking water for sailing is key for any offshore sailor. Toby Hodges surveyed the 81 skippers of the ARC 2020 fleet for tips

Water is the source of all life. For any sailor considering extended cruising or an ocean crossing , the ability to carry or produce sufficient fresh water for sailing is a top priority.

But how do you decide how much water to ship or how best to generate your own? Our survey of the Atlantic Rally for Cruisers (ARC) fleet last year focused on water.

We asked the skippers how much water they carried for sailing, in what form, how it was used and, for the majority with watermakers, detailed questions about the generation of water and how the equipment performed at sea.

Since we last ran a survey on this topic in 2014 our collective attitude towards waste has arguably changed for the better. That fleet of 193 yachts carried over 28 tonnes of bottled water with them across to the Caribbean. All sailors today should consider how every consumable item they carry aboard will be disposed of when they reach their destination.

Pogo 12.50 Rush. Photo: James Mitchell

The main decision ocean sailors face with water stowage is whether to fit a watermaker, which is both a practical and a financial decision. Generating your own water is one of the best investments cruising sailors can make towards comfort and true independence.

ARC skippers over the past two decades have consistently described watermakers as one of their most vital pieces of equipment. “To us, a watermaker is the single best thing you can have for cruising by a fair margin and fully changes the game,” thinks Rush ’s Ian Baylis.

Three-quarters of the skippers who replied to our survey had watermakers aboard. The seven yachts listed as not carrying one were all smaller entries between 35ft and 45ft and typically over 20-year-old models. They carried extra water in bottles and jerrycans and used it sparingly.

Usage and conservation of water for sailing

Being frugal with water becomes second nature to most cruisers. The majority of respondents said their crew only showered every three days, 12 every two days and 13 daily.

One of the most common pieces of advice from skippers concerning water conservation is to fit a saltwater tap and to use seawater whenever you can. “Cook with salt water when possible,” advises the crew of Montana , a Swan 48 S&S from 1973. Yet over half of the respondents did not have a saltwater tap fitted in their galley, nor even a manual freshwater pump in the galley or the heads.

“The saltwater tap in the galley is essential,” thinks Tobias Gröpper on his Sunbeam 44 Pivot . “We still have 50% of our tank capacity on arrival although we took showers etc.”

Jorn Aalefjær, the Norwegian skipper of Ticora III , and Dane Martin Nielsen aboard his Jeanneau 53 also both stressed the benefit of fitting a saltwater tap.

Suffisant , one of the smallest entrants, a Beneteau Oceanis Clipper 331 from 1990, has only small tanks, but uses a Katadyn Power Survivor 40E watermaker. They used salt water to wash with and had manual taps fitted in the galley and heads.

Swiss skipper Marina Passet says: “Salt water is no use for washing clothes, but can be used for brushing teeth, washing dishes and vegetables.”

Article continues below…

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Seasoned cruising sailors the Blacks aboard Bowman 57 Emily Morgan , say they have used their set-up for 8,500 miles and would not do anything differently. They relied on their Spectra Ventura watermaker, but advise closely monitoring the tanks: “We graph tank levels daily,” says Anna Black. “If the level is below the line then no more fresh water showers until it returns. Allow 20% extra in case of problems.”

Many other crews, including on the Sunbeam 42.1 Ibex , were happy relying on desalinated water without needing large back-up quotas of water.

The Chung family aboard Kaizen use a four-filter system to purify their water and drink everything from the tank. They have an instant hotwater tap, and “we make our own sparkling water and have reuse cannisters for emergency”, says Kean Chung. Their Oyster 49 has 1,000lt tanks and a Sea Fresh H20 watermaker, so the crew were able to shower daily and there was no need for any bottled water.

Water stowage

There should be no need to rely on single-use plastic water bottles when cruising. Reusable bottles, flexible or collapsible bladders and jerrycans are a perfectly adequate solution for storing reserve water, particularly if you have a good filtration system.

Use salt water when possible, for washing clothes, dishes or taking showers. Photo: Thomas Horgen

Recycling plastic is not possible on many islands. While in recent years IGY Rodney Bay Marina has provided a plastic recycling service for visiting yachts, run in co-operation with a local community group, due to COVID restrictions the service was suspended in 2020.

So it was disheartening to find that nearly half the fleet still shipped over 100lt of bottled water each, while seven yachts carried over 250lt of bottled water, despite five of these having a watermaker.

Many skippers still like to carry bottled water as a contamination-proof back-up or for monitoring intake. Aboard Escapado for example, a Beneteau first 40.7 with no watermaker, they carried over 250lt of bottled water.

Skipper Sophie Iona O’Neill says: “One person kept a tally and did three fills of everyone’s water each day.” She says the total daily consumption amounted to: “two litres of drinking water per person, plus one litre of tea/coffee, giving a total of 3lt of fluid per person, per day,” – a useful statistic for those planning water consumption.

Water generation

If installed correctly and serviced properly, a watermaker should perform consistently well. The majority of 2020 ARC skippers rated their watermakers most highly, with 70% giving 5/5 for reliability.

Wash-up in seawater, then just rinse in fresh. Photo: Tor Johnson

Just eight skippers reported having any issues with their equipment. Any problems were either fixed with spares or the result of another issue, such as a power source problem ( Adagio had issues with their genset and, in the case of the Malo 43 Ydalir II , the fault was traced to a leak onto the inverter).

The few who experienced any faults with their watermaker’s performance were typically those who had only installed it that season. The overriding advice is to make sure you have tested your system thoroughly at sea before embarking on an ocean passage.

With prices typically ranging from £4,000 to five figures, it is worthwhile making sure a watermaker is working smoothly and knowing how to service it properly in advance.

Have the power

The ability to harness power naturally and to store it efficiently is changing the watermaker world. “If you don’t want to use diesel to make water you need a lot of power generation,” warns Lucky Girl ’s Charlie Pank, who has a Schenker Modular 30. However, only five skippers say they increased their battery capacity when their watermaker was fitted.

Paul Lemmens was very happy with his Rainman AC 120lt per hour unit aboard his Hanse 455 Veni Vidi Vix , but advises: “You need good batteries/large inverter to function.” He fitted an extra 400Ah of lithium batteries when the watermaker was installed.

The advent of high DC power has had a marked effect on watermakers, says Mactra Marine’s Jim MacDonald, who, COVID restrictions apart, usually attends the ARC start for any last-minute watermaker problems or services. “Go for a low-energy system that will run off the batteries,” he advises. A good bank of solar panels or a hydrogenerator can really help – nearly half the fleet used solar to help charge their batteries.

Many of the crews in the ARC still carry significant amounts of bottled water.

“As lithium has become more prevalent, DC systems with energy recovery are coming into their own,” MacDonald continues. “This means that whatever your means of power generation, you can always use your watermaker – whereas with the old-fashioned AC/high-pressure pumps you had to run the genset to make it work.” He has also seen the reliability of modern watermakers improving as they increasingly use electronics where possible.

Despite its modest output of 20lt per hour, the Blacks on Emily Morgan rate their Spectra Ventura very highly. They installed it themselves in 2017 and describe it as “invaluable in the Pacific – simple and reliable”.

The German Schaals aboard their Bavaria Cruiser 42 Nikajuma say they wouldn’t change their set-up and that the Echo Tec DML260 always worked – but noting “that the test tap is very important”.

Filtering water

Whether storing water in tanks or making desalinated water from the sea, filtering out any impurities makes sense. “We added 5ml of chlorine in the tank to kill bacteria and used LaVie water purifiers to get the chlorine smell out of the tap water we drank,” says Patrice Charbon, who was sailing the new Fountaine Pajot Astrea 42 Eden Blue for LP4Y with four friends.

Bottled water is still popular on board, despite the potential environmental impact. Photo: James Mitchell

They were trialling a new form of UVA water filtration technology on their desalinated water. Charbon, an associate of the inventors Solable, explains: “The strong LED light beam generates UVAs which break the chlorine molecules. As a side effect, an advanced oxidation process flushes the water eliminating all molecules of pesticides, medicine or hormones that one can find in tap water.

“A 30-minute purification would bring fresh, pure water to our table every day,” concludes Charbon, calculating that the watermaker and filters helped them save “over 200 plastic water bottles for our crossing and over 12kg of PET since our departure”.

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Marine Energy Program

Foundational R&D

Project Name : Leveraging Co-Development for the Energy Capture Subsystem of a Small-Scale Adaptive Wave Energy Converter

Project Team :   Ocean Motion Technologies, Inc. 

Lead Recipient Location : San Diego, California

This article is part of the

WPTO 2021 – 2022 ACCOMPLISHMENTS REPORT

In This Report

Hydropower Projects

Marine Energy Projects

A project team led by Ocean Motion Technologies deployed a prototype wave energy converter that can generate power from passing waves created by boat wakes. This test, which took place off the coast of San Diego, California, successfully demonstrated that power can be harnessed from waves as small as those created by boats. By generating power from waves of this size, this test showed greater versatility and environments in which marine energy devices could be used to harness power.  

Ocean Motion Technologies worked with several commercial and strategic partners throughout this effort. The commercial end users provided regular feedback to ensure product-market fit (primarily focused on ocean-observing applications), while the National Renewable Energy Laboratory provided guidance and technical support. Ocean Motion Technologies also partnered with the Technology Career Institute at MiraCosta College to provide mentorship and hands-on experience to trade school students. 

This project was funded through the Small Business Innovation Research and Small Business Technology Transfer Programs. 

Foundational R&D Projects

WPTO's Marine Energy e-newsletter shares news and updates on tools, analysis, and emerging technologies to advance marine energy.

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5 Best Wind Generators For Sailboats (2024)

Last Updated by

Daniel Wade

January 2, 2024

Wind generators, also known as micro turbines, have come a long way since their first appearance on the cruising scene back in the 1970's. Loud, relatively low output and large bladed, these forerunners of the modern day wind generators were both a mechanical marvel and a source of constant consternation. They were basically a small automotive alternator encased in an aluminum housing, with little thought into aesthetics or longevity. Cruisers equipped with an old Windbugger or K.I.S.S. wind generators come to mind as the loud boats in the anchorage no one wanted to be around.

As we all know, there are very few, if any, automotive products that last very long in a marine environment. A large stock of spare parts had to be stored in case of breakage, and daily maintenance consisted of checking the bearings, monitoring the voltage vs. wind speed for signs of decreased output, and rotating the blades into the wind when the boat position changed.

Today's best wind generators boast such features as CAD designed, self-feathering composite blades that are whisper quiet, brushless magnetic alternators, automatic braking and over-charge protection. Boxy aluminum housings have been replaced with sleek, carbon fiber and fiberglass nacelles.

While you may spend a small fortune on a wind generator that has all of these features and more, you can also opt for more budget friendly models, readily available from Amazon, Home Depot and other on-line retailers. The best wind generators are usually the most expensive, but when you are looking at the lower cost models, remember to add in the cost of wiring, mounting hardware, remote monitoring stations and installation, should you choose not to do the work yourself. Not all wind generators are purpose-built for the marine environment. Buyer beware: a turbine designed for the hobbyist on land will not stand up to the rigors of an offshore passage.

Table of contents

As with any mechanical device you are researching, it is a good idea to learn some of the terminology associated with the product. Not all of us know the meaning of 'swept area', 'power capture' or 'yaw error'. Likewise with the electrical side of the wind generator. Learning about output wattage, amps, and microprocessors can seem like a daunting task, but it is necessary to know these terms before you shell out hard earned cash for a quality wind generator.

Some features of wind generators, such as weather-proof coatings and low-noise operation, are common to all makes and models. The use of rare earth elements like Neodymium, (Nd2FE14B, used in magnetic rotors), can add hundreds of dollars to the price of some of these wind generators, but defiantly do add to the overall dependability of the unit.

Some of the more desirable things to look for in a wind generator are:

• Ease of Operation

Also known as plug-n-play, the simpler the set-up, the better. Choose a model that has built-in controllers, that ???makes for less complicated wiring runs. A remote monitor is handy to check on the status of the charging system without crawling into the battery room, or looking up to see if the blades are still turning. If you are ordering your generator and having it shipped, ask your salesman to be sure it has detailed assembly instructions and perhaps an owner's manual in either DVD or booklet form.

• Low Cut-In Speed 

Wind generators work best when the blades are humming along in 20 knots of wind, but that's not always the case. Low cut-in speed means your batteries are getting a charge in the lightest of airs, if only a trickle charge.

If you happen to be ashore when the wind kicks up, you don't want your turbine to spin wildly out of control. Some generators feature a type of automatic speed governor that slows the blades down before they self destruct. Back in the day, you had to pull down on a cord to apply the brakes, then climb up the mast or mounting pole and manually tie off the blades.

• Over-Charge Protection

A 'brake' also kicks in when the batteries are nearing or at full capacity, to prevent overcharging. Some controllers slow the rotation of the blades, others 'dump' the excess power generated through a resistor and heat sink. Wiring an in line reset-able fuse can prevent damage to your batteries should a malfunction occur within the charging system.

• Portability

If you are one of those part-time sailors who cruises for a few months, then dry-docks your vessel for the off-season, choose a light-weight portable wind generator you can set up at home to off-set your electric bill. In case of a hurricane or other emergency when there is no power for days at a time, your wind generator can power cell phone chargers, laptops and rechargeable battery stations. Removing your wind generator and locking it away in the cabin also deters thieves. Portable wind generators that are light can be mounted on higher surfaces without worrying about upsetting the balance of your boat. The heavier the generator, the lower it should be mounted, allowing for safe passage under and around those spinning blades, of course!

It is also a good idea to know your boat's needs and desires before settling for a low cost, low output wind generator. Everything that runs off a battery, including the DC to AC inverter, should be listed, along with their amp/hour draw, to determine how much power you will need to generate. Compare your toys with your reserve amps of your house battery bank. Do you just have a few LED bulbs and a masthead light to run at anchor? Then you can get by with a low output generator. Are you keeping a keg cooler, stereo, disco ball and Netflix going all night? When underway, are you powering SSB, weatherfax, VHF and radar? Then you need a rack full of batteries, and a wind generator with the capacity to keep them topped off.

Speaking of batteries, make sure the wind generator you purchase can charge all the different batteries available. Even if you only have wet-cell lead/acid marine batteries now, you may upgrade to AGM, Gel or even LiFeMgPO4 (Lithium Iron Magnesium Phosphate) batteries in the future. Some wind generators and their controllers are not advanced enough to charge these newer power sources.

Unless you are well versed in the application of electrical theory and DC current, you probably don't know much about wire size and current loss. Even the best wind generator will not function as advertised if the power can not get from the blades to the battery. If you have a long run from your generator to the battery bank you intend to charge, make sure your wires are correctly sized to prevent line loss from resistance and over heating. Most installation manuals will have a wire chart included for DIY installations, and there is always a help line to the manufacturer.

Here are four out of the dozens of wind generators out there that have positive reviews and some of the most desirable features.

1.) Superwind 350, 353

This German manufactured turbine features their patented Auto-Feathering Overspeed-Avoidance System. This is basically the same method a helicopter uses to gain lift, and settle back down. As the wind speed reaches 25 knots, the blades 'feather', or dump air, making them less efficient, and slowing their speed. As the wind lessens, the blades re-pitch, becoming more efficient. This action delivers a steady flow of charging current to the batteries, without going into a shut-down mode to prevent overcharging, as some models do. The Superwind generators also can be combined with solar panels and conventional diesel generators. The Superwind generator family also uses a brushless A/C stator for maximum control of noise and radio interference while the unit is producing power. Two sets of bearings in the 350 make for smoother operation and overall longer bearing life. Available in 12v, 24v, or 48v outputs. At close to 30 lbs, these units are well built and dependable. With a price tag right around $2,700 for the Superwind 350 kit, you can expect German Engineering at it's finest.  https://www.superwind.com/superwind-350-353/

2.) Automaxx

The Automaxx line of wind generators comes in 12v, 24v 48v models, in outputs from 400w up to 1500w. Survival wind speeds are listed at 110mph, but we hope you would never have to put that spec to the test. With very low cut-in speeds of less than 6mph, you will get charging amps on the slightest breeze. All their models come with auto-braking and manual braking system protection, over charge and over-speed protection. The 3600 rotation of the power head keeps the unit into the wind, even when you are docked or med-moored. Simple plug and play setup with an internal MPPT (Maximum Power Point Tracking) charge controller makes the DB400 an easy to install unit, while their other models feature a remote charge controller. Works well when combined with solar chargers. At 16.75 lbs., it is lighter in weight than the Superwind, and it's seven times less expensive at around $400.00 for the DB400.

https://www.automaxxwindmill.com/

3.) MarineKinetix MK4

One look at this brand's marketing home page is like an advanced course in wind generator physics. The list of specs for it's models is truly impressive. Not only do they boast all the latest technologies featured in their product, they explain all the scientific jargon they use in terms us simple sailors can understand. They have been providing wind generators to the sailing community for 8 years now, and have a devoted following.

If you need to know the difference between $400.00 wind generators and $1,800 units, check out the product overview section of their website.

The MarineKinetix brand has the the industries best 3 year limited warranty, so they must be pretty sure about their product.

The 12v models of this brand are currently out of stock, due to parts supplier back-orders, but if you are in the market, there are plenty of 24v and 48v units in stock.  https://store.marinebeam.com/marinekinetix-mk4-marine-wind-generator/

4.) Rutland 1200

One of the quieter wind generators out there, the U.K. made Rutland has a long track record of dependability and customer satisfaction. A manual switch is used to stop the blades when high wind is expected, there is no auto-brake. The Rutland can be combined with solar panels up to 20A, and can be also be used with deep cycle gel or AGM batteries, and there is a remote digital display available. One of the Rutland's best features is it's Tri-namic Blade profile design, which achieves low start-up speeds, silent operation in any wind, and maximum power transfer from wind to rotor. Overall good performance and features for the $1,600.00 price tag. https://www.emarineinc.com/Rutland-1200-Wind-Turbine

5.) DuoGen-3

Wind generators are a fairly common sight in most anchorages, and towable generating devices have been around for some time. The DuoGen-3 combines the two into one multi-use charging system. Underway, the high strength carbon fiber mast is lowered down to submerge the blades. At anchor, the unit functions like a typical wind generator. The results are impressive. In the water mode, the DuoGen-3 generates 200 Watts @ 16 amps cruising at 8 knots. Wind generators do not do well sailing downwind, so this may just be the answer. Available in 12v and 24v versions. Charging regulators are not included, so monitors and controllers have to be matched to the unit and sourced locally. https://eclectic-energy.co.uk/

Choosing the right wind generator for your vessel should be a pretty straightforward process, once you have an idea of your needs, the area you will be cruising in, and how long you expect to be 'off the grid'. If one generator is simply not enough because of the size of your battery banks and the load you put on them, you may need to purchase a pair of turbines. Customer support and availability of parts may be the determining factor in your purchase. Talk to other wind generator owners, and get a feel for what they have experienced with their current of former wind generators.

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I've personally had thousands of questions about sailing and sailboats over the years. As I learn and experience sailing, and the community, I share the answers that work and make sense to me, here on Life of Sailing.

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Ampair UW100™

The Ampair UW100™ underwater generator has been manufactured commercially by Ampair in the UK for 20-years – Seamap acquired the intellectual property and manufacturing rights for the product in February 2015.

The Ampair UW100™ is a three-bladed turbine intended for use in fast flowing water and is ideally suited to the demands of Marine Seismic Exploration – generating a maximum of 100W of DC current at 12V or 24V to charge batteries – whilst being towed behind the seismic vessel.

The radial flux permanent magnet generator is housed within a pressure compensated oil filled cast aluminum casing. The casing is sealed with dual redundant seals throughout and there are only two transits into the generator section: one for the turbine shaft and one for the electrical cable. The turbine is bi-directional but because of flow obstruction by the body it is most efficient if facing into the water flow.

Download the product sheets here: UW100 Seismic – for use by the marine seismic industry UW100 Non-Seismic – for use on yachts and similar vessels or in fast-flowing waterways

Sailboat Wind Generators: The Ultimate Guide 2024

Sailboat wind generators are a way to capture the energy of the wind and use it to charge your batteries and power electronics aboard your vessel.

A large part of the appeal of living on a sailboat, for many people, is being more or less self-sufficient – using the wind for propulsion, and the elements to generate all the power you need.

Solar panels are a wonderful technology, literally magic, but the sun doesn’t shine every day. In fact, of the most popular cruising grounds in the world aren’t even that sunny. It rains three to four days a week in Barbados or Antigua, for example (don’t even get us started on the English Channel).

And what about night sailing – keeping critical loads like autopilots and instruments online after the sun goes down?

A marine wind generator fills in those vital gaps in the energy picture, and eliminates the need to generate or run the engines to keep your electronics online.

In this expert guide we take a deep dive into sailboat wind generators, covering everything you need to know – from how they work through to the very latest technological advances.

With thousands and thousands of miles under the keel, we have lived off-grid using technologies just like this for almost a decade now. We’ve rewired more boats than anyone should ever have to. We’re marine electronics nerds, basically, and specifically very passionate about renewables like wind and solar.

That’s why we couldn’t wait to write about this topic, and why you’ve got a good 4000 words on it! Sorry about that! But feel free to skip and just read the information you’re interested in, we don’t blame you!

So, let’s take a close look at sailboat wind generators, how they work, what makes a good one, the best sailboat wind generators that we think deserve a place on your next nautical expedition.

As an Amazon Associate, we earn from qualifying purchases. We also earn from other affiliate programs. This means we may receive a small commission on products purchased through our links at no extra cost to you.

Table of Contents

The best sailboat wind generators – best budget choice, the best sailboat wind generators – best overall, what is a sailboat wind generator, why install a wind generator on a sailboat, wind generators vs solar power.

• What is a dump load on a marine wind generator ?
• Marine wind generators vs hydro generators

Our top budget choice: Nature Power 500

If you are in the US, the choice for the best budget marine wind generator is easy – it’s this guy , the Nature Power 500, which West Marine have sold for donkey’s years with eternally solid reviews.

It’s a 500-watt turbine that is natively compatible with both 12V and 24VDC systems. It’s made from marine-grade aluminium that’s also coated in a thick, durable coating to help it withstand years at sea.

This wind generator is rated for winds up to 110mph – well into hurricane territory – and it comes as a complete kit including a charge controller using the latest MPPT technology. The controller even has an electronic brake, even though it’s a manual one.

Honestly, this is just a lot of value for the ~$700 they’re asking, and very easy to recommend for the best budget sailboat wind generator.

We don’t massively recommend most of the budget options on Amazon for extended cruising – they’re just not built for the task. But if it’s all your budget will stretch to, something like a Pikasola 400 would be the best bet for a sailboat wind generator under $500.

Readers in the UK or Europe could look at something like a Rutl and 914i . You’ll pay a little more, around £850, but a Rutland is a proper piece of kit – they’re been manufacturing marine wind generators since the 1970’s, long before solar panels were even seen on pleasure yachts.

The 914i will produce about 260 watts in 30 knots of breeze, or 20+ amps into a 12-volt battery. In a hurricane it’ll make over 400 watts.

This is a genuine marine wind turbine built from quality parts and specifically designed for the aggressive saltwater environment. It comes with very few compromises, from the bundled MPPT tracker to its extremely quiet operation.

The charge controller supports a small solar panel as well, which is sort of nice – but we’d highly recommend using a top-quality, stand-alone MPPT charge controller for any solar panels if you can possibly afford it.   

If you are in Europe, or can import, we think the Silentwind Pro is probably the best sailboat wind generator you can buy right now. This is with the caveat that while we’ve seen these installed on lots of different yachts, talked to multiple long-term owners, and even handled one out of the box, we’ve never actually owned one.

That’s because they start at about €2,100, which is a considerable sum for a 420w wind generator. But what you do get is an incredibly refined package – one that picks up and starts generating with as little as four knots of breeze, and remains whisper-quiet right up into the high RPMs.

The Silentwind Pro uses hand-laminated carbon blades that are rated to withstand hurricane-speed winds, but that are also highly efficient across the curve. This is definitely one of the most engineered solutions on the market today.

The polished package is rounded out by features like an automatic electronic brake that kicks in if the wind exceeds a certain speed. Cheaper options may have an electronic brake but it generally has to be tripped manually by the crew.

Models without an electronic brake of any kind are frankly dangerous, because you have to lasso them to stop them – which is how the gentleman broke his arm, and wind generator, in the earlier example.

Other than Silent Wind, there are a few slightly cheaper options that are still very good. For readers in the US, one option made locally is the Air Silent X made by Primus Wind Power. We don’t have as much experience with these, but we have met a couple of happy owners and have heard similar things to Silentwind.

Primus claim they have the bestselling wind turbines anywhere in the world; we’re not sure about that given that Marlec / Rutland have been around nearly two decades longer, but either way their site states they’ve sold more than 150,000 wind generators since ’95, into over a hundred countries.

Primus make six different models at different price points that are all potentially worthy of consideration, but the Air X Silent or Air Breeze are both solid choices.

Rutland wind generators also remain easy to recommend across the board, particularly to readers in the UK and Europe, and a premium option would be something like a Rutland 1200 .

At around £1,500, or $1900, the Rutland 1200 can produce up to 480W flat out, and will hit 300W in only 20 knots or so of breeze. It’s a proper marinized unit built to withstand the rigours of life at sea, and that should provide years of low-maintenance service.

A sailboat wind generator, also known as a marine wind turbine or wind charger, is a device for capturing wind energy and turning it into electricity.

Sailboat wind generators typically have 3 or more long, aerodynamic rotor blades attached to a central hub. The blades translate wind energy into rotational force and spin the hub, sometimes at near-supersonic speeds .

The hub is attached to an electrical generator – a lot like the alternator on an engine – that generates electricity as it spins.

A wind turbine is an electrical fan operating in reverse. The fan takes electricity and uses it to spin a motor, attached to a hub and some blades, creating wind.

A wind turbine takes wind energy and uses it to spin a hub attached to generator, creating electricity.

You can actually just spin any DC motor to generate electricity , but it helps a lot if you pick one that generates the flavour of electricity you’re after.

Brushed motors are appropriate for generating DC, whereas a brushless motor is better suited to AC voltage applications.

A handful of marine wind turbines, mostly older ones, do use a brushed motor set up to produce a voltage that can directly charge a 12 volt or 24-volt battery.

Brushed motors are called that because they literally have a core of metal brushes that drags along inside outer, magnetic stator. Those brushes wear out over time and need to be replaced. They’re in something like a starter motor that works intermittently, but putting them in wind generators was always a bad idea.

They’re also noisy – which is a major consideration in a device that is going to run overnight, above your head, while you sleep, every night.

Brushless motors have so many advantages over brushed, from their efficiency to their lifespan to their reduced mechanical noise. As such, most wind generators produce AC electricity and then rectify it to DC at the regulator in order to charge the battery bank.

This means you will normally have three wires leading from the wind generator on your sailboat to the charge controller. It also means you definitely don’t want to connect those wires, carrying AC electric, to your DC battery bank, without passing them through the charge controller first.

Wind generators offer a lot of advantages – notably the ability to work day and night, and in both sunny and stormy weather.

Solar panels are great, but they only work during the day – and on sunny days, at that. They’re also affected a lot by the seasons, because in winter there are both less hours of daylight, and the sun is lower in the sky, its rays have to travel further and they strike the panel at an oblique angle. And, it’s cloudy or rainy nearly every day.

Regardless of season, as we’ve explored earlier in this guide, some of the most popular sailing destinations don’t actually have reliable sunshine – but all of them have reliable wind.

Not so with sailboat wind turbines, which work just as well on sunny days as stormy. They often generate even more power in winter, on days when solar might be producing at 10% or less.

This effect makes wind generators a big enabling technology for grey-weather sailing, from extending your sailing on into the “shoulder season” and benefitting from empty bays and anchorages, to exploring unconventional cruising grounds such as the Scandinavian fjords.

Besides stormy and overcast days, wind generators will keep on producing at night. This is particularly helpful when night sailing with the radar, AIS and full nav suite running, maybe plus an autopilot, and then all your domestic loads like your fridge and freezer. Even if you’re just at anchor, it’s nice to wake up with topped-off batteries every morning.

This doesn’t apply if you have a modern boat with ample battery storage, but when we were just getting started in sailing, we would frequently have half-flat batteries by morning.

Not only does this shorten the life of the bank, it occasionally even meant we struggled to pick up the hook in the morning – which is a bit of a safety hazard. Again, this is mitigated by wind.

None of this is to say that you should ditch solar power for wind. Solar power has many wonderful properties, explored below, and the two technologies actually complement each other very well. If you have a large enough vessel, we fully recommend you try to integrate both into your power plan.

Wind and solar are both very useful technologies to the cruising sailor, each with its own set of advantages and disadvantages. Their pros and cons in fact offset each other and synergise quite nicely, compensating for each other’s weaknesses.

As such, we’d argue it’s less about deciding which is better, and more about figuring out whether you can incorporate both into your power plan somehow.

Nonetheless, let’s have a look at how solar power and wind generators compare and contrast, and some of the pros and cons of each technology.

Advantages of solar power vs wind power

Solar power’s major advantage over wind is that it’s “solid state”. This means it has no moving parts to wear out, and requires almost no maintenance.

In fact, solar panels will generally sit and faithfully do their thing decade after decade with almost zero human interaction. A common standard nowadays is for panels to retain 90% of their producing power after 20 years .  

There’s a 10kW solar array in Switzerland that’s been feeding directly into the grid since 1982; it’s over 40 years old and going strong.

Solar panels benefit from wiping down once or twice a year, but other than that, they’re a totally set-and-forget technology.

Many sailing destinations have ample sunshine, with long hours of direct sun throughout the sailing season.

Solar is also cheap and plentiful nowadays, and panels come in all shapes and sizes that can fit almost anywhere on a yacht – including a handful of solar panels you can walk on, although those are not cheap.

Overall, though, solar is much cheaper than wind watt-for-watt. You might pay $0.50 per watt for a good rigid polycrystalline solar panel and charge controller. A wind generator may well run to $2000 for 400w – that’s $5 per watt, up to ten times more expensive. And the wind generator has moving parts that can require replacement.

Another often overlooked advantage of solar panels is that their solid-state nature makes them very safe – there are no moving parts to catch a finger in, or spinning blades that could strike a member of the crew. They just sit and silently do their thing, year after year.

Disadvantages of solar power vs wind power

Solar only works when the sun shines. The sun, as we’ve pointed out earlier, doesn’t always shine. You might be surprised by how cloudy places like the Caribbean can be – some islands have rain up to 50% of the time.

Some popular sailing destinations, like the English Channel, average about two hours of sunshine per day, with rain or overcast skies on 75% of days annually ( no, seriously ).

There’s always night sailing, as well. If you’re night-sailing, you may well have tools like radar and AIS running for safety, plus other loads like an autopilot and anything like fridges and freezers running below.

If you only have solar power, and no wind, you may have to run the engine to make it through the night – or invest in a large battery bank that can keep up until morning.

Marine wind generators are an excellent way to bridge the gap. It can be windy at any time of the day or night, and very often the cloudy or stormy days are the windiest. It’s only sunny during the day, and only some days, so this is a major disadvantage of solar power when compared to wind.

Another disadvantage of solar panels is that they lose power quite dramatically when shaded, and sailboats unfortunately have a lot of tall, shade-casting objects. These include the mast, the boom, the sails and anything like radar or Starlink dishes .

Somewhat paradoxically, solar panels also lose power as they get hot in the sun, meaning the normal, everyday conditions in many exotic destinations can actually reduce their efficiency by double-digit percentages. They are happiest somewhere cold with lots of sun, like on top of a mountain – not in the tropics.

Advantages of wind power over solar power

The wind doesn’t rise and set like the sun – it can blow around the clock. Okay, technically, the sun rising and setting down does change the temperature and create all the wind on earth.

But the wind often continues after the sun goes down. In fact, when you’re on a boat, on the water next to land, the wind usually just reverses at night .  

It’s often windy on the water on sunny days because all wind is caused by pressure flowing from high to low, and the main source of those differing areas of pressure is heat from the sun – particularly, say, where the adjacent land and water heat up at different rates.

That’s how wind is made on sunny days. But it’s often windy on non-sunny days, too, because it’s just about air rushing between those areas of high and low pressure, hot and cold air. As such, cold fronts can bring wind too.

This makes wind somewhat more of an always-on technology than solar – especially in the places that sailing boats are found. There is usually wind offshore, and often in the anchorages too as it rolls off the hills . In some parts of the world, such as those affected by the Greek Meltemi , it blows straight 30’s weeks on end.

Overall, sailing boats are just usually found in places with abundant wind energy, so there’s a lot of synergy between sailing boats and wind generators. And we’ve pointed out, many exotic sailing destinations in the world have more wind than sun, and that’s before we get started on sailing somewhere like Scandinavia.

A wind generator has a small footprint compared to a solar panel, although it does need a large exclusion zone around it for safety. Wind generators are sometimes mounted up the mast, but we don’t generally advise putting a large, pendulum-like weight at the end of a 50-foot-long lever arm if you can avoid it as it may negatively impact the motion of your boat.

Disadvantages of wind vs solar power

Wind generators do have some drawbacks compared to solar. The obvious one is that they have moving parts, which both present a hazard to the crew and require replacement or regular maintenance.  

The worst-case scenario is a crewmember being struck by the blades. The tips of something like a Silentwind Pro can spin nearly a hundred times a second and get close to breaking the sound barrier.

Here’s an example of where someone accidentally clipped their arm on a sailboat wind generator and it both shattered their arm and sent the turbine blade flying across the cockpit. The author notes that they had also seen the wind generator explode a seagull prior to this incident.

Much of this is mitigated by putting the wind generator outboard and features like electronic brakes, so you don’t need to stop it with your right ulna as the gentleman above did. The upshot is that wind turbines are dangerous in a way that solar panels are not.

The constant motion also generates wear and tear. It used to be worse, back when we used brushed DC motors – but the bearings in brushless motors do eventually wear out too, and they benefit from regular greasing a bit like your winches. It’s just an extra thing to maintain.

It can be too windy for wind generators, too. It can’t be too sunny for solar panels (although it can be too hot). Many modern, top-end marine wind turbines have that electronic brake built in to compensate for this, but you still have to shut down and stop producing when it blows a gale.

Another disadvantage of wind is that it’s really expensive compared to solar on a watt-for-watt basis. Good polycrystalline panels paired with a brand-name MPPT controller might come to $0.50 a watt at the time of writing, while a leading wind generator works out at $5.00 per watt.

This is compounded by the fact that wind does often produce on quite a concave power curve. That is to say, you need a fair amount of wind to produce anything at all, and probably need gusts into the 30-knot range to start to see your rated wattage.

Another often-overlooked point is that if you’re sailing downwind, you are robbing the wind generator of air. If you are sailing downwind in 15kts of breeze, making 7kts, the apparent wind speed at the generator is only 8kts – which might not even be enough to start generating.

Finally, wind generators can be noisy. Again, brushless motors have helped with this significantly, but there is still the rushing of the air over the blades, and any eccentricity in the bearings or blades will send maddening, resonant tremors down the pole and directly into your sleeping quarters at all hours of the night.

The latest wind generators make use of things like acoustic decoupling, a fancy term for having a rubber dampener between the end of the pole and the deck, to mitigate this.

What is a dump load on a wind generator?

A dump load , also called a dummy load or diversion load, is something used in wind power to get rid of excess power when the batteries are fully charged.

One of the small downsides of a power source that runs night and day is the potential to oversupply electricity and overcharge the battery bank.

As an electrical generator supplies more and more power, it gets stiffer and stiffer to turn. The power has to come from somewhere, and it’s felt as resistance – producing a braking effect.

If you suddenly take that braking effect away by disconnecting the battery bank, the wind turbine will start spinning at very high speed, causing anything from rapid and excessive wear on the bearings through to a catastrophic failure where the blades shear off at supersonic speeds.

In order to prevent this from happening, the charge controller has the option to switch between charging the battery and supplying power to a dump load .

The dump load can simply be a big resistor. It will heat up as the wind generator spins on, and safely apply a brake to it by literally just wasting power as heat.

You can probably guess where this is going. Another option is to use an element specifically designed to heat up, and use it to heat water. You can easily buy DC immersion water heater elements for $20-30 , connect them in the place of the dump resistor and use them to make hot water with the excess power instead.   

We’ve often daydreamed about using it to make ice or run a teeny tiny aircon unit as well.

Some of the top-end sailboat wind generators will automatically apply an electronic brake and safely stop the blades when the bank is full, and it varies from model to model whether they simply have that as an option, or it replaces the dump load entirely (including useful ones, like making hot water).  

Do not be tempted to use the dump load to charge a second battery, such as a starter battery, when the first bank is full. If you do, you will encounter problems once the second battery is full and the turbine starts to freewheel.

If you do want to charge several banks at once, or one after the other, you want a split charger connected to the main charging output instead, and a highly resistive load that can run indefinitely on the dump load output.

Marine wind generators vs hydro generators  

Hydro generators are another way of capturing the energy of the wind and turning it into electricity. But instead of capturing the flow of air, a hydro generator is dragged through the water behind a boat under sail.  

The elephant in the room here is that a hydro generator is only going to work when the boat is in motion. A wind generator, on the other hand, keeps on producing while you swing around at anchor.

The average cruiser spends around 90% of their time either at anchor, on a mooring ball, on town quays, or in marinas. This is because the everyday business of cruising is not so much about sailing as it is about fixing the boat, going ashore for provisions or parts, waiting for a weather window, or exploring the place you sailed to, socialising with the other yachties you just met, barbecuing on the deck, and so forth.

The wind generator works through all of that, night and day; the hydro generator only a fraction.

So why does anyone use hydro generators at all, then?

The answer lies in the fact that a traditional trade-wind circumnavigation, by far the most popular way to “sail around the world”, is almost all downwind .

As a result, you are often “running away” from the wind when you sail around the world, which has the effect of subtracting your speed from the true wind speed and deducting that much power from your wind generator.

Thus, if you want to sail around the world on say, a performance catamaran, it might make sense to drag a generator behind the boat instead of in the air. That way, its performance is tied to your boat’s speed through the water rather than the apparent wind.

An adjacent use-case to this is people who “sail around the world” in the sense of not stopping, or stopping very little. Someone sailing non-stop downwind around the world, particularly on any kind of record attempt, would probably get a lot more of out of a hydro generator.

Another place hydro generators are seen is in the regenerative systems of systems like Oceanvolt . In these sophisticated systems, the propellors of the boat itself work as hydro generators by spinning and capturing energy as they’re dragged through the water under sail.

This feature is even starting to show up on electric outboards, such as the ePropulsion Navy series.

In summary, wind generators are the most practical choice for the average cruiser, multi-year circumnavigator or liveaboard sailor. Unless you love sailing so much that desperately want to go and tack around for four hours to charge your batteries – in which case, more power to you.

Wind generators can form an incredibly useful part of the renewable energy mix on board a sailboat.

While wind power on a sailboat works out many times more expensive than solar power, watt-for-watt, it makes up for this by generating power day and night – and often making even more power at times when solar falters, such as during storms.

Cruising sailboats that only have solar power will be forced to generate or motor if it’s cloudy for days on end, something that happens at least once or twice a month somewhere like the Caribbean.

Solar, naturally, doesn’t produce at night either, so if you have a lot of electrical loads running overnight your battery bank can take a beating.

A common example of where you might get caught out is night sailing with the autopilot, radar, AIS and instruments all running, in addition to your regular loads like the fridge.

Wind generators might usually be sized to produce less than a solar array because of cost, space and weight considerations, but they have the potential to run all day and night and in any kind of weather, and as such they often punch above their weight in terms of the overall energy generation picture.

Electrical loads might slow down a little overnight, as the crew sleep and lower temperatures mean fridges and freezers don’t work as hard, but it’s not uncommon for the overnight draw on a sailboat to be 8-10 amps or more. It adds up, by morning. 

Wind represents an excellent bridging technology for nights and extended cloudy spells, naturally producing the most when solar fails – such as during storms. 

A sailboat wind generator is most effective when paired with solar and a good lithium battery bank , allowing you to generate in all conditions. day and night; and to store and retrieve that energy efficiently even at high currents. 

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