Ferries, freighters, and pleasure boats are getting an eco-facelift thanks to solar sails.

There are solar boats and there are sailboats, and now thanks to the patent of a Sydney (Australia) technology company there are solar sail boats and their popularity is growing.

Patent-holder Sydney-based Solar Sailor Holdings uses masts of photovoltaic cells to help watercraft take advantage of both the wind and the sun. They have recently signed a deal with the largest Chinese shipping line Cosco to retrofit their tankers with their solar sails. They will provide just 5% of the ships’ electricity, but enough to cut fuel costs by 20-40%.

Solar Sailor has also sold their technology- pivoting wing sails that rotate to take advantage of the best wind and sun conditions- to ferries in Hong Kong and they’re designing a boat for the 2010 World Expo in Shanghai.

At home in Sydney, Australia, the company operates a 100-passenger luxury ferry in the harbor. We stepped onboard the Solar Sailor for a tour with one of the boat’s engineers, Craig Thomsen.

Thomsen: Can you hear the motor running? (he laughs)

faircompanies: No noise. The engine is on right?

Thomsen: Yeah.

faircompanies: Why would you want a boat that doesn’t make noise? What are the benefits of that?

“Every time people talk about boats they talk about it being a pleasure craft, the last thing you want is all the noise of the engines. If you’ve got passengers sitting down to a dinner the last thing they want to do is talk over an engine or if you’ve got people watching whales they don’t want to be talking over an engine and smelling the smell of a diesel running out the back. We certainly do cruises where we’ve got dinners or speeches happening and basically the boat is running silent.”

Earlier, you were mentioning the case of coral reefs as well?

“Yeah, you’re out there in the middle of a pristine national park and belting diesel out the bottom of your boat is a very unpleasant looking thing to be doing.”

faircompanies: Can we see the motor?

(Thomsen opens a door in the boat’s floor) “Virtually no noise. The electric motor is a modified electric motor and it’s been used in industry for many years, almost 100 years. The only moving part is the motor. It’s just direct drive. The motor’s just spinning. No gear box, nothing.”

Is it ready to work off different systems, DC, AC?

“This motor can pick up directly off the DC system. If the DC system was to fail it can pull up 100% from the AC. But we can convert all combinations.

One of the key things with the boat is reliability. Over the last several years we haven’t missed a cruise due to the technical equipment. We have missed a cruise due to the main diesel generator being faulty. But the primary equipment we can run. If there’s good sunshine we can operate virtually all day at 5 or 6 knots without running the generator at all. If we need to run at high speeds we run the generator.

The thing with generators is a generation running at low load, which many generators all around the world are doing 20, 30% they’re well below their efficient band. So they’re consuming more energy than they’re creating. What we’re able to do with this generator is keep it at higher load and charge the batteries, run all the motors, run all the systems straight off the generator and then turn the generator off so we don’t run the generator at low load.

All the systems onboard take directly from the solar power. But the key thing with the boat is reliability so if one thing goes wrong there’s a backup and often to the backup there’s another backup.”

Are you considering other solar technologies other than photovoltaics like solar heat systems, solar concentrators (laughs)?

“In the boating environment it’s not practical to put some of these technologies on, but there are new technologies coming through and we’re actually trialing out a number of them. But what we do is we actually put it in as an adjunct beside it and check it out.

We’ve got 3 totally different photovoltaic systems on the boat. We’ve got the bow system which is glass. We’ve got the wing which is the flexible. And we’ve got the tiles on the roof which is another design which we’re testing.”

Is there one design that is working better with the climate of Sydney Harbor?

“Well one of the nice features of the wings is the ability to turn and focus the wings towards the sun. Also with the wing you can arrange it so none of it is in the shadow. Then the rest of the boat we just try to put lightweight good quality panels on.”

Right now we’re in summer, what happens in the winter when you don’t have the same amount of your engine energy which is solar? Can you run the boat on an everyday basis if you want with the sun that you get?

“With this boat we’ve got a backup generator so the boat is always able to run. It’s just the proportion might change as the energy you get from the sun drops off, but you’re always able to run. But the key is the captain can see what’s going on and he can slow down a little bit or he can turn the boat a little bit and take advantage of the wind. There’s often more wind in the winter.”

The boat can also use wind power, right?

“Definitely. These are aerofoils.” (points to solar panel wings above him) “And as an aerofoil you can still head at quite an angle into the wind and still get lift which is pulling the boat forward.

We’ve got quite complex control algorithms to make sure the wings are turned toward the wind and to take advantage of it. Then there’s the tossup between using wind or solar. We’ve got some fairly simple rules that we apply to take advantage of either. The control system has got rules built into it and it can switch between one and the other.”

In fact, these solar panels work as solar wings?

“Definitely, yeah solar wings. That’s one of the key things is to use the best energy that’s available at that moment. And because we’ve got 2 sides we sometimes put one side on solar and the other side on wind.”

So the boat would go the most efficient way possible?

“Yeah, as you move through different speeds the control systems would make most of those decisions for the captain.”

Do you think the solar technology is a selling point for the boat?

“We’re actually going through a number of very keen clients. We’ve got a whole raft of designs we’re completing for a number of different applications from whale watching to ferry work, pleasure cruises, the whole lot.

We don’t build boats, we don’t even design boats, what we do is build energy systems to fit onto boats and boating applications. And those energy systems involve wings and solar and batteries and generators and electric motors and all the associated control that goes along with it.”

Do you see this going more mainstream as far as the boating world?

“Oh look 15 years ago the hybrid car was virtually a novelty and today you’re getting to a point where it’s practically mainstream. People are definitely taking much more interest in this. It’s going to be an exponential thing.”