Air district unveils new wind-powered ferry

Brian McMahon

San Francisco, the city with the highest concentration of hybrid cars, may soon be the first city to boast a hybrid ferry as well. Officials today at Pier 1 ½ unveiled a vessel that runs on both wind and engine power, significantly reducing fuel use and air pollution.

The design, called the WingSail, involves a carbon fiber sail that resembles an airplane wing standing up vertically. The sail uses wind to efficiently propel the boat when available, but also works with the engine to keep the vessel moving if gusts die down, much like how a hybrid car switches between fuel and electricity. 

“The idea with wind technology is that we could use this every day, with more or less the same propulsion power [as an engine], depending on where you are,” said Damian Breen of the Bay Area Air Quality Management District. “Literally with the flick of a switch, you can go between wind power and fuel power.”

Already existing ferries that are retrofitted to include the WingSail can save up to 40 percent on fuel costs, and ferries that are designed and built with windpower in mind would be even more efficient. Currently, a motorized ferry that travels between San Francisco and Sausalito spends $250 million annually on fuel, according to Jay Gardner, president of Wind+Wing Technologies.

“My vision is to see a bay full of wind-powered ferries,” Gardner said. “I think that could be as iconic as the San Francisco cable cars.”

The trimaran on display today -- a smaller scale model of would might eventually be full-sized ferries -- just completed three months of test voyages around the Bay Area. Researchers at UC Berkeley will now begin to analyze that data to find the potential improvements in air quality and fuel cost savings. That study will be an important factor in how this technology is implemented in the future, and the results should be published sometime this summer.

The WindSail technology is already being used in racing for both land and water events -- most prominently in the America’s Cup sailing championships here on the bay last summer -- but this would be the first use of hybrid wind power in a passenger boat. The Wind+Wing Technologies webpage already shows designs for ferries that can hold either 149 or 400 travelers.

All of the builders and officials there today emphasized that the Bay Area is the perfect place to roll out this technology. Not only is it one of the most environmentally conscious regions in the world, but the bay is also windy enough to power the WindSail without relying too heavily on the engine.

One of the attendees asked when you would want to use wind power over fuel, and Breen immediately stepped forward to answer the question.

“Wind is zero emissions,” he said. “Wind is always better.”


...though to tell the truth I'm not sold on the wing sail idea.

Philip C. Bolger's "100 small boat rigs" touched on the possibility of having an impeller (whose effective sail area is the area swept by the fast-moving blades) driving a propellor through a gearbox; the driving propellor can be oriented in any direction as like a tractor tug.

The idea of wind driven transit can happen on land too. For instance, a wind-powered MUNI line running north-south on the Great Highway. The benefit of the above mentioned impeller system is that batteries can be charged while the machine is at a standstill.

Posted by lillipublicans on May. 01, 2014 @ 8:22 pm

By the way, a glaring drawback of wing sail technology (which is answered by my seagull chopper described above) is the inability to go directly up wind. No fixed foil can drive a boat upwind closer than about 30 degrees to the true wind and the angle gets worse the faster a boat is moving because the speed is a vector which causes the apparent wind to move forward, forcing the boat to bear off.

Fast-moving multihulls are famous for "not being able to point" but making up for their far longer zig-zag courses through higher speed, but this is less appealing when you are motorsailing a longer course trying to keep some schedule.

Also, a hard wing cannot be furled when the wind is too strong for its use, so the prototype in the story, while outwardly clever and appealing based on recent Americas Cup fame, doesn't seem a likely pattern for future development.

Is this boat going to be kept at the public dock for some length of time? My understanding is the normal limit is 4 hours.

Posted by lillipubicans on May. 02, 2014 @ 3:17 am

Just hook a few tubes at City Hall and there will plenty of wind to fuel the ferry.

Posted by Guest on May. 02, 2014 @ 3:27 pm

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