Future Sailing – Wind Assisted Ferries
By Kimball Livingston Posted April 21, 2014
Eventually, someone is going to get “wind assisted” transport right.
Don’t bet against Richard Jenkins.
The same Richard Jenkins who spent his first ten adult years figuring out how to set a wing-powered landsailing speed record of 126.2 mph.
The same Richard Jenkins who recently, remotely, sailed a 19-foot, wing-and-solar-powered prototype drone from San Francisco Bay to Kaneohe Bay, Oahu, then to the South Pacific, and back, and who is now neck deep in developing his next generation Saildrone, capable of carrying a complete array of oceanographic research instrumentation to any coordinates on the blue reaches of the Blue Planet. Never putting humans in harm’s way. With none of the fuel burn or
accumulated costs of, say, a 200-foot diesel-powered research vessel. And there just might be a circumnavigation . . .
And all of this is tied together by the control mechanism that Jenkins developed when he realized that his landsailer was hitting speeds too fast to be controlled by pulling on stuff, the way people sail a boat. Even a “stable” breeze had too much fluctuation for human response. But, a tiny trim tab, trailing behind the wing, set to maintain a constant angle of attack, could turn the trick.
Jenkins projects an impish enthusiasm, an infectious enthusiasm and a raw, boyish enthusiasm from beneath a halo of curly hair that shifts in the breeze. He sails. He flies. He innovates. He hits his marks. It’s easy to understand how, given the success of the prototype Saildrone, Google’s executive chairman, Eric Schmidt, would say yes to a proposal to fund a fleet. With his wife, Wendy, Schmidt funds the 11th Hour Project, putting juice into many environmental, climate, and oceans-related undertakings. But for Jenkins, it’s been a long road to get to this point. He will tell you, when he was building his fourth record-hunting landsailer, which turned out to be the right one, “I had no idea there was any practical application. I spent years thinking I would eventually take the speed record, and beyond that, what I had on my hands was a totally useless technology. It’s funny how one thing leads to another.”
Or he might quip about how he has turned an engineering career into an adventure in “double-down or quits.” Jenkins was a student in England, earning some money on the side at Green Marine, when he inquired about a curious contraption abandoned in a dark corner. It was, he was told, one of those record-hunter dreams, never finished, and in a flash he said something like, “Can I have it?”
So innocently did this begin.
On his landsailing record holder Greenbird, and on Saildrone in prototype and in its production form to be, the wing that powers the craft is high-aspect ratio. Tall and thin. On the prototype “ferry wing” that Wind + Wing Technologies now has in trials on San Francisco Bay, the control system stays the same, but the wing becomes something very different. Robust. Something that could be built for use on large ferries, no sailing talent needed, with a working lifespan of decades and near-zero maintenance.
That’s a lot to take in, but the more you learn, the more it makes sense, seven years into development.
I’ve been aboard for two demo rides (sandwiches, chips and—hot damn—Odwalla!) and one ride included representatives from the ferry industry whose curiosity, at least, has been piqued. Those are perhaps the only two occasions when I have been under sail with no intent, even given an opportunity, to turn off the motor. Not because you couldn’t, but, to prove the viability for a scheduled daily ferry service, the point is to demonstrate that the wing generates enough drive to allow the fuel burn to be throttled back for significant savings while maintaining a target speed. That is, demonstrate viability and potential ROI without sounding moon-eyed. Should a commercial ferry service someday find that there are certain runs and certain times when they can safely and responsibly shut down the diesels completely, let them discover that on their own and then explain this newfangled thing called “sailing” to the relevant authorities.
San Francisco Bay sailors have been sighting and wondering about this contraption for a while . . .
Another key player here is Jay Gardner, who has been operating the Adventure Cat ride and charter service on San Francisco Bay for 23 years. They’re kinda-sorta heroes to me, because they’ve taken more people sailing hereabouts than anybody else, ever, ever, ever. Jay and his wife, Pam Simonson, also built the 42-foot trimaran that is being used as the demo platform. One telling fact is that the wing can freewheel—it has survived a night at the dock in a sixty-knot storm; sans America’s Cup-catamaran dramas—and it creates only one-tenth the wind resistance of the mast and rigging that were removed to make way for it. When the demo project is complete, Pam gets her boat back, and a hatch will be installed where the wing spar now penetrates the cabin top through a 16-inch steel bearing, landing on a smaller bearing on the cabin sole.
The wing, 40 feet high and 10 feet wide, is powered by a 14-inch X 14-inch photocell on each side and has its own battery pack and actuator. Combine computer logic with the trim tab set about 15 degrees off the angle of the wing, and you get the somewhat eerie effect of a wing that is forever in motion as it responds to changes in the breeze, but doesn’t really seem to be working, because the boat continues on a steady course, and there is no noticeable heeling. For a sailing-type sailor, the lesson here is how variable a “stable” breeze can be, even for a boat moving at only 7 knots through the water.
Looking at the wing, don’t be fooled by the bright green area of what might appear to be the working trim tab. The actual working part is almost invisible at the back of that element, slightly offset because we were under way, on the trailing edge. As a great American once said, click to enlarge.
In a breeze in the teens, figuring a normal motoring speed of 7 knots at 1800 rpm, the demo tri burns a carefully-monitored .55 to .66 gallons per hour. Turn the wing on (and that’s really all there is for the operator to do, a key fob does the trick) and you can see the boat maintaining 7 knots as the throttle is pulled back to 1200 rpm and the fuel burn drops by half, to the range of .3 gallons per hour. Do the math on an 11-mile ferry run from San Francisco to Sausalito, with an annual fuel burn of 450-500,000 gallons, and you’re into serious reductions in costs and emissions. True savings, however, would fall in the range of 20 percent, allowing for calm winter days or early summer mornings when the famously-strong San Francisco seabreeze is not cranked up. In light-wind regions, you would need a completely new analysis of ROI.
Regular readers will know that I like to describe the Golden Gate wind slot as the world’s greatest Venturi tube. We have a seabreeze and a half, and that is what Jay Gardner likes to describe (quote approximate) as, “the closest thing to a perpetual motion machine.”
It is imaginable but not likely that existing catamaran ferries could be retrofitted. Considering the bureaucracy involved in proving the safety of such a thing, a new build makes a better picture. Jenkins and Gardner figure that for, say, a new $20 million ferry, two wings could be added for another $4-5 million. “You would pay that off in two to five years,” Gardner says. “There’s no reason why a wing built to be strong and simple can’t have a service life of 30 years, and there are ferries operating now that are 40 years old. The potential long-term savings are huge.”
And the way the numbers play out, the faster the boat, the better the wing works.
Fuel burn on the demo boat is calculated by measuring the amounts going into the injectors and also coming out. The data is relayed to the Berkeley laboratory of Dr. Timothy Lipman, Co-Director for the Transportation Sustainability Research Center at the University of California. There is nothing haphazard about this attempt to redefine the future. Funding for the demo project has come from the Air Quality Improvement Program, California Air Resources Board, and the Bay Area Air Quality Management District, plus Gardner’s Venture Cat company and Jenkins’ Photon Composites.
The rendering here comes from the office of Morrelli & Melvin, which has done the conceptual engineering for the ferry project. You may have heard of them. And if not, you should try harder. Clicking the link is the easy part. I note that M&M shows a two-element wing, while Jenkins’ prototype has a single element and is aimed at ultimate simplicity and durability. I suggest we let those details sort themselves out in the fullness of time because I really do believe that, someday, someone is going to get “sail assisted” right. Probably well ahead of any clean-energy magic bullet.
In other wing-powered sailing craft, you turn the rudder and the wing turns along with the boat. Jenkins’ wing is free-rotating, governed independently by its relationship to the wind and to the boat and always assuming its correct angle. Adding or subtracting wing thrust is as simple as dialing in an off-wing-center angle for the trim tab.
Thus my sensation that the wing doesn’t seem to be working, when it is.
And it was.
It was working as Richard, at right in the photo, talked sailing with Adventure Cat skipper Michael, and we made target speed ahead, throttle-back, burn-low.