Skip to main content

Hybrid propulsion quietly gains steam

Showcase of an in-line diesel-electric system

Island Pilot’s DSe Hybrid and Frauscher’s St. Tropez runabout showcase in-line diesel-electric system

Capitalizing on the wave of newfound environmental consciousness and the trend to conserve fuel, the Toyota Prius hybrid car has seen a meteoric rise in popularity among consumers. Now U.S. builders are trying to bring a Prius-like experience to pleasure boating, but with technology that was developed elsewhere.

Island Pilot LLC, for instance, plans to roll out the 40-foot DSe Hybrid 12M Oct. 30-Nov. 3 at the Fort Lauderdale International Boat Show. The vessel is fitted with two 75-hp power plants that are made by the Austrian engine manufacturer Steyr Motors. Each consists of a diesel engine, an electric motor attached to the flywheel, and a hybrid control unit to supplement the DSe’s 6-kW solar-electric propulsion system.

“At a time with record-high oil prices, we are bringing to market a product that will dramatically reduce the most visible expense of a recreational motorboat — the cost of diesel,” says Reuben Trane, president of Miami-based Island Pilot, in a statement.

And Sea Ray is evaluating the Steyr hybrid concept as part of its research into alternative propulsion systems and other energy-efficient technologies. Sea Ray director of marketing Rob Noyes wasn’t ready to reveal details, only that Sea Ray has a “fully operational 240 Sundancer hybrid that will have to undergo rigorous testing” before any decisions are made.

This story originates in Austria, where gas currently is $8 a gallon and the government imposes severe restrictions on powerboat operation to reduce traffic and pollution on the pristine freshwater lakes nestled between Alpine peaks. The hybrid concept was jointly developed by Frauscher, a family-owned and operated boatbuilder that has been in business since 1927 and earned a reputation for quality and innovation, and Steyr Motors with the assistance of two colleges and a network of technology companies.

“Powerboats won’t go away just because gas prices are going up,” says Stefan Frauscher, who is in charge of sales. “Manufacturers have an obligation to provide consumers with technology that will allow them to pursue boating as a hobby while adapting to the new realities.”

And these realities forced Frauscher to get into hybrids early, because Austrian law exempts boats with electric propulsion from the restrictions that apply to pleasure craft powered by conventional gasoline and diesel engines. Being the first boatbuilder worldwide to offer a range of production models with this technology — the official debut was in January at the Düsseldorf boat show in Germany — Frauscher now hopes to make strides in the U.S. market. The North American launch of Frauscher’s 757 St. Tropez Hybrid runabout last spring in San Francisco was a big event witnessed by Austrian and U.S. politicians — but not Gov. Arnold Schwarzenegger — who came together and used the occasion to sign a “memorandum of understanding” on environmental protection.

The Steyr hybrid is different than other diesel-electric concepts, which depend on an electric drive and use generators to charge their batteries, in that it provides both the roar and speed associated with combustion power and a quiet, clean glide in electric mode. “This engine is multifunctional,” explains Frauscher during a factory visit in Gmunden, near Salzburg, Austria. “It is a conventional diesel engine and a generator that produces power for the electric drive and the house loads, so you don’t need a separate genset. The electric drive offers a silent and clean cruise mode, serves as a starter for the diesel, and acts as a booster to help the diesel during acceleration.” The electric motor, Frauscher says, generates 7 kW (about 9 hp) in cruise mode and 10 kW (about 13 hp) in boost mode.

Looking through the Plexiglas-engine cover of a Lido center console model at Frauscher’s dock, the hybrid installation reveals itself in clean complexity. The space under the sundeck is occupied by the diesel engine, an electro-mechanic in-line drive that is attached to the flywheel and is decoupled with a clutch in electric mode, and a hybrid control unit that regulates the charging of the two 48-volt battery banks with two AGM batteries each. There is also a separate starter battery for the diesel if the house batteries are drained. On the helm, the so-called Steyr Electronic Control Center informs the driver about vital engine data and relays throttle commands to the two electronic controllers for the hybrid.

Frauscher says recharging the batteries to full capacity is accomplished in one hour by the alternator when running under diesel power or in 12 hours when plugged in at the dock. Battery power, according to the company, is good for approximately one hour of electric propulsion, depending on throttle discipline. Maximum speed is about 5 knots, while the 250-hp diesel delivers top speeds between 30 and 38 knots, depending on the boat model.

Still, Frauscher thinks there is room for improvement. He’d like to see some form of energy recycling, which a Prius does through its brakes but which is challenging to implement on a pleasure boat, and the seamless transition between diesel and electric mode. Right now, changing requires turning off the ignition and flipping a switch on the helm.

Trane says Island Pilot chose Steyr hybrids with Saildrives after sea trials revealed they provided a higher top speed (13 knots) than a 36-hp generator-based hybrid electric system (9 knots). “Besides, the Steyr hybrids run on biodiesel right out of the box, and they are off-the-shelf components, which fits our OEM philosophy.”

Trane also emphasizes the peace of mind that comes from redundancy. “We have four engines — two diesels and two electric motors — that’s a lot of safety margin for a cruising vessel.”

The Steyr hybrid might be a clever combination of technology, but does it save fuel? “The engine is very light and efficient, and burns less fuel than a conventional gasoline engine of similar size,” explains Frauscher’s U.S. distributor Ralph Silverman, before he points out how the electric motor helps cut emissions and gas consumption. “To get in and out of the dock in the marina, you don’t need to run the diesel.” Near idle, especially when they are cold, diesel engines are least efficient, so running the electric motor in port also helps reduce emissions and water pollution near shore, where it matters most.

As an example, Silverman cites Emerald Bay, a popular boating destination with a 5-knot speed limit on Lake Tahoe. “It’s perfect for the electric mode of the St. Tropez, which gives you about 5 knots.”

Even though the marketing pitch doesn’t mention it, “this concept should tickle anglers, too,” says Rich Alley, product manager at Steyr Motors North America in Panama City, Fla., a subsidiary of Steyr Motors Austria. “Sport fishermen love the electric mode, since it is ideal for trolling and silent fishing.” Alley is familiar with the Frauscher boats, but his job is selling Steyr engines to other customers, who either want to repower their existing boats, or to U.S. manufacturers like Island Pilot.

At this point, it’s about finding the sweet spot in the demographic spectrum. The Island Pilot DSe Hybrid, which is built in China, targets the trawler cruising market, whereas the Frauscher 757 St. Tropez, built in Austria, is meant for the go-fast crowd that wants to look the part, but also embraces electric power to slip in and out of the harbor quietly or putter through a cove without emissions. At $600,000 (Island Pilot) and $185,000 (Frauscher), the boats might appear pricey, but as Trane puts it, “considering what you get, that’s still a good value.”

For now, the number of Steyr hybrid installations remains low. “I get several calls a day, but right now the cost is still prohibitive for many,” says Gregory Van Sickle of Channel Marine Services in Scappoose, Ore., Steyr’s West Coast distributor.

Van Sickle says it’s not just the exchange rate between the euro and the U.S. dollar, but the fact that this hybrid system works only with Steyr diesels, which also carry a rather lofty price tag. He considers the concept appealing for early adopters of new technology and those who want to make a statement.

“In that sense, it’s like the Prius,” he says. “Even if it doesn’t all compute out on paper, it sure makes you feel good about yourself.”


Island Pilot DSe Hybrid 12 M

LOA: 39 feet, 6 inches

BEAM: 17 feet

DRAFT: 2 feet, 6 inches

POWER: 6-kW solar array, twin 75-hp Steyr diesel hybrids with 5-kW generators and 7-kW electric motors

PRICE: $600,000

CONTACT: Island Pilot LLC, Miami.

Phone: (888) 443-2965.

Frauscher 757 St. Tropez

LOA: 24 feet, 10 inches

BEAM: 7 feet, 5 inches

DRAFT: 2 feet, 4 inches

POWER: 250-hp Steyr 6-cylinder diesel and 9-hp, 48-volt electric motor PRICE: $185,000

CONTACT: California Chris-Craft, Homewood, Calif.

Phone: (530) 525-0555.