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Duffy Fuel Cell Boat

30-foot Duffy

Believe It or Not!

An electric launch that runs on salt and water!

I wrote a test report some while ago about a Duffy-Herreshoff 30 (“Picnic Passage,” July 2002), a classic electric launch with an internal-combustion-type generator/battery/electric-motor powerplant roughly analogous to those found in today’s hybrid electric cars. The futuristic Herreshoff made an impressive sea-trial showing. Among other things, her battery-charging Northern Lights genset boosted her half-throttle operating range by almost 50 percent, from approximately 65 miles under electric power alone to something like 95 miles in hybrid mode. Compelling stuff from the marine-technology standpoint, for sure.

But after the trial, something truly wild happened. I discovered during a plant tour that the little company was stealthily working on a hydrogen fuel-cell-powered version of the 30, perhaps with a tank of compressed hydrogen as a fuel source—or maybe with something else, something so radical no one would even talk about it.

The source of the sodium borohydride that powered our fuel-cell test boat was borax, a substance commonly found in both the Earth’s crust and oceans. Presently, fossil fuel-powered manufacturing facilities create sodium borohydride from raw borax in small batches for bleaching paper in industrial papermaking operations—using the stuff to power fuel cells is a radically new application. Hence, production is currently low, and the price is high. Reportedly, the mixture of sodium borohydride and water (see photo above) we filled our Herreshoff’s 45-gallon fuel tank with cost approximately $50 per gallon—way more than we pay for gasoline at the pumps these days. However, Millennium Cell and U.S. Borax are working on clean, large-scale production methods they hope will significantly lower the price of sodium borohydride and replace fossil-fuel manufacturing methods with renewable energy resources like solar and hydropower.


I subsequently tracked the project with a hound dog’s diligence, and recently the folks at Duffy let me know they’d be introducing a fuel-cell-powered Herreshoff at the World Maritime Technology Exposition in San Francisco. The boat would transport attendees around the bay, thereby validating Duffy’s developmental efforts as well as the efforts of other contributors. These include Anuvu Fuel Cell Products, which had contributed an 8-hp PEM (Proton Exchange Membrane) fuel-cell “stack” to the project; Millennium Cell, which had contributed a Hydrogen-on-Demand system (the “radical something” the folks at Duffy had refused to talk about); and a host of other players and payers, including California State University at Long Beach, the Department of Defense, the Department of Transportation, and an outfit called Seaworthy Systems, noted for its expertise in marine engineering, naval architecture, and overall marine project oversight.

A week before the Herreshoff hit the road for San Francisco, I spent a day onboard, examining the powerplant and exercising it on the waterways of Newport Beach, California, Duffy’s homeport. Because I arrived extra early at Duffy’s waterfront facility, I decided to find the test boat on my own, there being nobody else around to guide me at the time. My plan shortly began to falter, though. The fuel cell Duffy was darn near impossible to locate because she looked so much like the 20 or so other Duffys on hand. Finally, however, I stumbled across a Herreshoff with two little differences: a clear Plexiglas engine hatch instead of a fiberglass one, and a VHF-size, helm-mounted touchpad.

I peered through the hatch like a sorcerer’s apprentice looking into a crystal ball, examining an array of components that resembled the parts of a souped-up, stainless steel air conditioning unit. I was scratching my head and mumbling to myself when the three guys who’d been closest to the development and construction of the boat arrived: Marshall Duffield, president of Duffy Boats; Lyn Cowgill, R&D president for Anuvu Fuel Cell; and Mike Strizki, senior lead scientist for Millennium Cell. We opened the hatch, and Cowgill began telling me about “the next generation in marine propulsion technology.”

Our test boat was equipped with four 15-pound Anuvu Power-X fuel cells, each capable of generating 1.5 kW, or the equivalent of 2 hp. They were assembled side by side into a 60-pound, 8-hp fuel-cell stack and positioned against the forward engine room bulkhead. Heavy-gauge wiring interconnected the negative terminal of the stack, the positive terminal of the stack, a 20-hp electric motor in the bottom of the boat (linked to a three-blade prop), a rheostat-type speed control (throttle), and an energy-stowage bank of eight Trojan batteries—half the number found on the hybrid version, which emphasizes batteries over internal combustion for power.

The PEM (Proton Exchange Membrane) cells in our stack worked like others of the type. Hydrogen gas entered on the anodic (negative) side, splitting into two hydrogen ions and two electrons, thanks to a platinum catalyst bonded to a special, semipermeable membrane. The ions moved through the membrane and gathered on the cathodic side, creating a positive charge there and leaving the negatively charged electrons behind. Voltage ensued due to the charge difference across the membrane.

As soon as Cowgill had finished with his exegesis, Millennium’s Strizki embarked upon another, starting with the aspect of hydrogen fuel-cell technology that’s drawn the most criticism over the years: hydrogen itself. An invisible, explosive gas, it continues to evoke hard, practical questions, not the least of them being how to compress and safely stow it, whether in a car or onboard a boat. Moreover, while systems that reform or extract hydrogen from gasoline or methanol—whether onboard or ashore—may reduce emissions and fossil-fuel dependence to some extent, they eliminate neither.

“But this device,” Strizki told me, pointing first toward an enigmatic apparatus atop the fuel-cell stack and then toward a plastic fuel tank filled with a clear, watery liquid, “is altogether different. Instead of reformed hydrogen, or compressed or cooled-liquid hydrogen in tanks, it creates hydrogen on an as-needed basis using a simple mixture of salt and water.”

“Salt and water?” I responded in disbelief.

Strizki hastened to explain that the salt the Millennium Hydrogen-on-Demand system uses is not the common table variety but sodium borohydride, a white powder manufactured from the common soap product borax (see “Salt?,” this story). When combined with water in the presence of a proprietary catalyst, it generates hydrogen on demand, together with some heat and a recyclable borate residue.

Salt and water, eh? Can you blame me for being just a tad enthusiastic about cranking up the Herreshoff’s hydrogen fuel cell powerplant? I virtually leapt onboard. Then came Cowgill, Strizki, and Duffield, who got behind the wheel and gave the helm-mounted touchpad a couple of taps. In seconds we were maneuvering away from the dock, although the process was not overtly dramatic. The powerplant emitted nothing more than a faint, refrigerator-like hum and a trickle of cooling water. “Darn near silent,” I commented in amazement.

We sea-trialed our Herreshoff for the next three hours. With an 8.6-mph top end, our test vessel ran just shy of the 9-mph top speed I’d recorded for the hybrid. Handling felt exactly the same, and so did throttle response. Sound levels were generally lower than the hybrid’s, and operating efficiencies were higher. Range at half-throttle (about 5 mph), for example, was approximately 218 miles, while range at roughly the same speed for the hybrid was only about 95 miles. And what’s more, there was no smell and no smoke!

“Cool?” inquired Duffield with an adventurous glint in his eye. The guy sees zero-emissions fuel-cell technology carving a serious niche in the marine marketplace over the next decade, first for gensets, then for high-horsepower, passenger-ferry-type applications, then finally for recreational cruisers. And he sees his little company surfing the big, fat, fun wave.

“Cool,” I replied, darn near totally convinced that Duffield’s darn near totally right.

Anuvu Fuel Cell Products Phone: (916) 921-7040.

Duffy Boats Phone: (800) 645-1044.

Millennium CellPhone: (732) 542-4000.

This article originally appeared in the January 2004 issue of Power & Motoryacht magazine.