Australia's Solar Sailor
A strange new boat sails on gusts of wind, rays of light, and the passion of an inventor from Down Under.
Skimming across a man-made lake 300 kilometers southwest of Sydney, the twin-hulled Marjorie K looked like an exotic, overgrown waterbug. The resemblance grew as her crew manipulated the 7-meter boat’s “wings” – long, broad, lightweight modules covered with waterproofed solar cells. Each cell generated electricity just as a solar cell in an everyday pocket calculator does; by adjusting the wings’ angle to the sun, the crew gathered more energy for their craft’s electric motor.
But these wings weren’t just solar collectors. Raised perpendicular to the water, they caught the breeze like a sail, allowing the catamaran to use the combined power of sun and wind to leave competitors behind at the 1997 Second International Solar and Advanced Technology Boat Race in Canberra, Australia’s capital. As the boat’s lead widened, however, the wind died down and the Marjorie K was forced to rely solely on its solar cells and batteries. The boat’s support team was nervous – it was the first trial under race conditions. But to spectators on the shore, the Marjorie K appeared to pick up the pace.
A couple of human, rather than technological, errors earned the Marjorie K an extra lap and cost her first place at the finish line. (The captain was penalized for tacking too close to a race buoy and banging into another boat.) But despite these glitches, the Marjorie K – one of more than 40 participants in the all-solar regatta – won the $10,000 prize for Most Innovative Vessel (currently worth about $6,300 US). David Gaul, one of the race’s judges, was impressed with the boat’s unusual combination of wind and solar power. “The movable wing design allows you to do two things simultaneously: take advantage of the wind, and get the absolute best alignment of the panels to the sun. Just look at her,” he adds. “She’s easily the most innovative boat. You don’t see too many Marjorie Ks running around the world.”
If this unusual vessel’s inventor has his way, however, that will soon change. The Marjorie K is the contrivance, passion and obsession of Australian physician Robert Dane – she is also the prototype for a fleet of “Solar Sailors” Dane hopes to build. He envisions a number of incarnations of the environmentally friendly vessel: ferries and sightseeing boats for busy urban rivers and harbors, pleasure cruisers for ecologically fragile reefs and bays. By combining new designs, off-the-shelf technologies and cutting-edge research from labs Down Under, Dane hopes to have his first commercial Solar Sailor afloat in Sydney Harbor in time to ferry tourists during the 2000 Olympics.
Unlike most Olympic aspirants, Dane hasn’t been training all his life for his moment of glory in Sydney. Far from it. At 39, he has no formal education in engineering or boat design, and until a couple of years ago he was the local doctor in the coastal village of Ulladulla, 230 kilometers south of Sydney. But Dane’s imagination has been captivated since childhood by the idea of siphoning electricity from the sun’s rays. He first glimpsed a solar cell in a magazine article about the National Aeronautics and Space Administration’s space satellites. “I was fascinated,” he recalls. “The idea of solar panels was absolutely miraculous. I became obsessed.” Today, almost all conversations with him inevitably double back to the subject of solar power.
Dane has even found inspiration in his biomedical training and practice. He based his design for the hinge-and-pivot mechanism of the boat’s wings, for example, on his observations of the human shoulder. The idea of solar-paneled wings hatched when Dane learned the evolutionary theory that insects’ wings evolved from solar collectors. And his years in medical school at Sydney University primed him to see the advantage of coupling wind and solar energy. A longtime sailor and windsurfer, Dane knew that even a small increase in wind speed can dramatically increase a boat’s energy. Like a car speeding down the interstate, a boat creates its own breeze. Proper positioning of the sails can add this so-called “relative wind” to the true wind and boost the sailing speed. Growing weary of the late hours of a country doctor, Dane began to dream of building a sailboat equipped with a solar-powered electric motor that would create more relative wind. “From med school, I knew that anytime you see that kind of positive feedback loop in nature, you should take advantage of it,” he explains.
The idea is an old one. Early steamboats operated under a combination of two power sources – wind and steam – but both were seldom operated at the same time.”People do motor sail,” Dane notes, “but sailboat owners generally don’t like the smell, noise or pollution caused by a fossil fuel engine. They call them ‘stinkboats.’” A sailboat with an electric engine, he reasoned, would provide the best of both worlds.
His interest spurred along by watching the first International Solar and Advanced Technology Boat Race in 1996, Dane sketched out a design for a wing that would serve both as solar collector and sail. He built a model of the key joint mechanism from pipe cleaners and his child’s Lego blocks, then showed it to some boat builders at Iain Murray & Associates, a leading Sydney-based competitive yacht design firm. As he recalls with studied casualness, “I went down there with beer in hand and said, ‘What do you think?’”
The designers’ response was cautiously positive. They made some calculations and said the idea was feasible, so Dane wrote up a 35-page prospectus and started to raise money for the project. Ulladulla local Marjorie Kendall, a farmer and fellow solar enthusiast, was so impressed that she invested half of the $130,000 cost of a prototype boat. With the money from Kendall in hand, Dane quit his medical practice and enlisted a diverse crew of friends and neighbors that included a surfboard maker, a model-train hobbyist and a champion sailboat captain. Together, they built the Marjorie K in only 82 days.
The EV of the Sea
The Marjorie K’s dramatic appearance last April at the Second International Solar and Advanced Technology Boat Race fit well with the race organizers’ intention to raise the profile of solar power. Solar-powered boats in particular tend to be ignored, says race adviser Hans Tholstrup. When people think of vehicles powered by solar, or photovoltaic (PV) cells, they focus on cars, Tholstrup says. “The reason is that we see cars as a necessity in life,” he explains. “We use them to get to work or to the shop. We’re a car culture.” Tholstrup, a self-described “futurist and adventurer” cheerfully admits to this bias himself; a former race-car driver, he drove the first solar-powered car across Australia in 1982. But propelling a boat with solar energy is in many ways easier than using solar energy to power a car, he says. Boats don’t have to deal with hills, the energy-draining stops and starts of traffic, or the shade cast by trees and buildings. “In addition,” he notes, “a pleasure boat lies idle all week long, when it could be absorbing power. You would have well and truly fully charged batteries.”
Others also believe PV cells to be well-suited to use on boats. David Roche, special projects manager at the University of New South Wales’ Photovoltaics Special Research Centre (PSRC), points out that boats operate at lower speeds than cars and, when outfitted with properly designed hulls, consume little energy. “You can do a lot with just eight square meters of solar panel, which you can easily get with most small craft,” Roche remarks. But that doesn’t mean there aren’t significant engineering challenges left. “The biggest obstacles are developing an efficient, cost-competitive cell and storing what you’ve generated” in batteries, he says. Roche notes that though the price of PV cells has dropped from thousands of dollars per watt a few decades ago to $4 per watt today, they still cannot compete with conventional electrical power, which costs one-quarter to one-half that much. He expects the PV industry needs at least another decade to compete with traditional power sources (see “Superior Solar Cells” sidebar).
On this subject, Dane is optimistic. “The silicon wafers used now in photovoltaics are in the same position that silicon chips were for computers 20 years ago,” he says. “The price is coming down, and the power is going up.” What’s more, Dane says, the enormous load of batteries required by an electric vehicle – the greatest drawback to a solar-powered car – can be a bonus for an electric boat. “You need tons of lead in the keel anyhow, so just put batteries in there instead,” he suggests. “What’s a burden for a car is ballast for a boat.”