Boat Review September 2011 Issue

Can New Hydrogens Serve Cruisers?

It will be hard to replicate Le Pingouin’s twin water-generator setup on a cruising boat, but the technology looks promising.

If the recent Velux 5 Oceans Race yielded one breakthrough, it would have to be the hydrogenerators from Watt & Sea. Racers Brad Van Liew and Zbigniew Gutkowski both used these devices. The sailors not only found themselves reliant upon the units, but were impressed by their capability and reliability as well.

Based in La Rochelle, France, Watt & Sea ( was founded by Yannick Besthaven, a former long-distance solo sailor who developed the product for his participation in the 2008 Vendee Globe race. Besthaven’s company currently manufactures two models: a carbon-fiber racing version that retails for $19,700 and an anodized aluminum cruising version that lists for $7,200 (a pair runs $12,455).

According to the maker’s specs, the cruising version begins generating power at just 3 knots of boatspeed. At 5 knots, the hydrogenerator reportedly produces enough juice to run all of the electronics (computer, instruments, autopilot, etc.) on a typical cruising boat. At 6 knots, the company claims, users can switch on water pressure and refrigeration. At 8 knots and above, the device reportedly generates 500 watts.

Gutkowski said his experience with Watt & Sea’s 17.6-pound cruising model was entirely positive. He noticed negligible drag from it and said: “When the boat goes over 10 knots, that thing runs all of the electrical equipment on board: radar, navigation gear, electronics, and autopilots.”

The racing version that Van Liew tested is even more efficient because it’s slightly lighter (14.6 pounds) and its variable-pitch propeller blades cause less drag. This model requires a minimum of 7 knots of boatspeed to begin generating power, and Watt & Sea’s literature claims that it will generate 500 watts at 12 knots.

The company claims that the cruising model will recharge a 200-amp, 12-volt battery to 50 percent of its capacity after 10 hours with a 5-knot boatspeed, and after only three hours at 8 knots. Van Liew experienced some overcharging problems with the prototypes he initially tested, but ultimately learned to extract the units from the water after his battery bank had been sufficiently charged. (The manufacturer said it has added a freewheeling feature to the system, which engages once the batteries are fully charged.)

Once Watt & Sea assembles the units, they’re pressurized with oil to prevent water seepage. The alternator is encased in resin, and ceramic-carbon gaskets are used between the main housing and the propeller unit. Each model is sold with a lifting bracket (intended to be mounted on the transom) and comes with a one-year warranty. The company also sells replacement props, converter units, and brackets.

Comments (2)

Roger, thanks for calling this out. This reminds me of an article in Sailing a few years back that reported a boat's tankage in "cubic liters". You know, for nine dimensional water.

Posted by: JUSTIN R | February 27, 2012 1:47 PM    Report this comment

This special report was fatally flawed for me by your repeated use of "amperes per hour." For an engineer/physicist/computer systems type, this is as bad as "knots per hour."

Amperes (amps) are a rate of charge flow; specifically, one ampere is defined as one coulomb per second.

One ampere-hour represents a charge transfer of 3600 coulombs.

Just as one knot per hour could be seen as a painfully slow rate of acceleration, one ampere per hour would represent a rate of change in current flow and would not normally be of interest to anyone.

Your normal article is so good, this report represented a serious anomaly.

Posted by: Roger D | October 27, 2011 12:37 PM    Report this comment

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