Wednesday, July 07, 2004

The New Ancient Dream: Solar Sailing...

Konarka technologies ( http://www.konarkatech.com/ ) and others are developing an interesting product; solar cells that are in a dye that can be sprayed onto cloth and thin plastic films. The idea currently seems to be to create small foldable solar power panels that you can unfold anywhere to power things like PDA's and cell phones, or military uniforms that are solar power panels in themselves. Not a bad goal in all.

Me being me, I have a somewhat grander vision. In the 1800's, most international trade was still conducted on sailing ships. Yankee clippers, huge sailing vessels designed in the United States were the fastest of these, setting records for speed from New York to Hong Kong and other places. These ships often reached speeds approaching and exceeding twenty knots on wind power alone. They had to sail South around the Southern tip of South America rounding the Cape of Good Hope because the Panama canal did not yet exist.

Their biggest drawback was the middle lattitudes where winds were calm. They could spend days at times becalmed in the doldrums, as those lattitudes were known around the equator.

This is one of the main reasons they were supplanted by coal burning steam powered ships. The coal ships could continue whether there were winds or not. They also took less manpower to operate as they did not have so much rigging and such to deal with.

Later diesel became more popular as it carried more energy than coal and could be used in hybrid diesel-elecric drive systems or direct diesel propulsion. Technology has gotten better and better and modern freighters have more automated systems and require less manpower even than early steamers to operate.

Additionally, modern sailing vessels, usually relegated to small private craft, are also capable of being far more automated than their 1800's counterparts, the tall ships still revered for their great beauty. Computer controlled line winches and sail positioning motors can very efficiently operate a sailing vessel. Still, the problem of being becalmed plagues sailing ships, and even were a sailing cargo ship built with modern automation technology it would not be commercially viable most likely due to it's vulnerablity to a lack of wind. This is despite the fact that it requires no on-board fuel and therefore has no fuel costs to operate. Electricity for the automating equipment could be generated by a wind turbine and a few solar panels, but when the wind dies down it must drift.

But think of the hundreds of square feet of sail cloth, impregnated with solar cells, still flexible, still catching the wind, and producing many kilowatts of electricity every day. Think of that free electricity converting sea water free for the taking into hydrogen and oxygen. The hydrogen can be stored and burned in fuel cells to drive electric propulsion units when the winds are calm. The output of very pure fresh water could supply the cooking, drinking, and showering needs of the crew. Such a vessel wouldn't have to pay a dime for fuel ever, nor be becalmed and drifting at sea. Imagine a wind and solar powered new Yankee Clipper on the scale of today's giant freighters freed from the yoke of paying for fossil fuels or nuclear power, with their large costs and ugly environmental impacts.

It makes me wonder if commerce shouldn't go sailing again.

Me being me, I e-mailed everyone I could find involved in thin film flexible solar sail production with the idea. I won't get to develope it, so why not give it away for anyone to use? I haven't yet run it past any companies involved in commercial shipping or ship-building. Maybe there's another place to plant some seeds.

Maybe we'll see the great cloth wings again on the high seas - and clearer skies and lower shipping costs. All we need is a star to steer those tall ships into our reality.

Dan Stafford

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