Boat U.S. - March 2009 - (Page 61)

much energy that the crew had to run the air conditioner constantly to avoid overcharging the large battery banks. In recent sea trials of a prototype E Motion Hybrids Lagoon 500, at nine knots under sail, the props were generating three kilowatts of energy. That’s the equivalent of a 12-volt battery charger or alternator putting out over 200 amps! Calder points out that coastal sailing in lighter breezes regenerates much less, but it may still be worth doing in conjunction with plug-in recharging dockside; that’s part of the purpose of the EU study. Imagine using electric power alone to leave the marina, then raising sails to regenerate enough power to return to the docks or motor through calms during your cruise. Multiply that by thousands of boats and you save fuel and reduce air pollution. Boats Are Not Cars The dramatic rise in fuel prices in 2008 made everybody aware of the Toyota Prius automobile, which is wonderfully economical in city driving. It’s a complex vehicle that uses a Parallel Hybrid drive train. Its small, specially tuned gasoline engine drives an electric generator and a unique planetary gear transmission, as does another electric motor/generator; both are connected to a battery bank. A computer controls the entire system, measuring loads and determining whether the little gas engine needs help from the electric motor to accelerate or climb a hill, or the car is slowing and can use regenerative braking, or is stopped and can be shut down. The Prius, and other hybrids from Honda, GM and Ford, employ regeneration. When the car is coasting downhill or stopping at an intersection, the electric motor becomes a generator that recharges the onboard battery pack. This is more complicated than a boat requires, so most marine applications are Serial Hybrids. Parallel Hybrids allow multiple inputs and outputs, which is well suited to the wide range of speeds and loads that occur in a car. Lagoon 420 hybrid-drive sailing catamaran, built by a division of the huge Beneteau group, is in full production and about 60 are reportedly in operation now. Charter one in the Caribbean to see if you like it. I tested the sixth developmental Lagoon 44 hybrid in 2006. A prototype, its control systems were not as user-friendly as they needed to be for average skippers, but it proved the concept. The twin electric motors (one in each hull) were not silent, but their rumble was barely audible at 1,000 rpm as they drove the big catamaran to its normal cruise speed. When the 22-kW diesel generator kicked in to recharge the battery bank (equivalent to 12, 8D-size batteries wired in series to produce 144 volts), I was still unable to get my sound meter to read anything above the gentle swish of water going past the hull. Shifting from forward to neutral to reverse was effortless, as that function is done by a three-position electrical switch. If you’re not looking for a sailboat, check out the DSe 12m from Island Pilot, launched in January 2008. This power catamaran carries not only a diesel generator but also a large solar panel array to charge its batteries and run the electric motors. The Island Pilot has gotten a lot of publicity recently and is capable of powering at five to six knots under solar power alone. Lots of experimental craft are out there now, many built by avid home mechanics and some by well-funded corporations. Do a Google search on “boat hybrid drive” to get the latest; the field is developing rapidly. You’ll also find dozens of electric-drive boats, using everything from portable gensets to solar panels for recharging their batteries. “There’s not a single one of these systems that I could recommend to a boatbuilder today,” Calder says, “But with what my EU project and others are doing, I believe this nut will get cracked in the next two to three years.” These are exciting times for engineers as they explore the Next Big Thing in propulsion — Hybrid Drives. Tom Dove, a former science teacher, has been boating more than 50 years. Over 1,000 of his technical, how-to, and travel articles have appeared in national and regional magazines, books, and newspapers. He divides the boating year between Crescendo, a 1976 Ranger 33 sailboat on the Chesapeake in summer, and Presto, a 17-foot Scout runabout, on Florida lakes in winter. The Hybrid Boat Experience So what’s it like to drive a hybrid boat, and how soon can you get one? The answer to the second part of this rhetorical question is, “Right now.” The

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Boat U.S. - March 2009 Contents Reader Forum Boat U.S. Reports What’s New In The Brew? The Perfect Paint Job Launch Into Spring Boats Gear Wheels One Mom, Two Teens, No Exit So, Nigel Had This Idea Ice Devices It Was A Club Of Their Own Expanding The Boating Universe Tech Connection A Case Study In Getting Results Let’s All Do This Together Classifieds Member Benefits/At Your Service

Boat U.S. - March 2009

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