Sailing ships with a new twist

The Economist (Paid subscription required) ^ | Sep 15th 2005

[USFRIENDINVICTORIA]

Giant kites that act like sails could bring wind propulsion back to ocean-going ships, reducing emissions and saving on fuel costs

IN THE first half of the 19th century, ships began to adopt steam engines, first alongside and then instead of sails.

{snip} ... the high price of oil and stricter pollution regulations are strong forces working to turn back the clock. Wind propulsion is coming back in a new form: kites, not sails. Next year, SkySails, a German firm based in Hamburg, will begin outfitting cargo ships with massive kites designed to tug vessels and reduce their diesel consumption. The firm estimates that these kites will reduce fuel consumption by about one-third—a big saving, given that fuel accounts for about 60% of shipping costs. {Snip}

But the SkySails approach does away with masts and is much cheaper. The firm says it can outfit a ship with a kite system for between €400,000 and €2.5m, depending on the vessel's size. Stephan Wrage, the boss of SkySails, says fuel savings will recoup these costs in just four or five years, assuming oil prices of $50 a barrel.

SkySails' kites are made of a type of nylon similar to that used in the sails of modern windjammers, but they fly between 100 and 300 metres above sea level, where winds are less turbulent and, on average, more than 50% stronger than the winds that sails capture. An autopilot computer adjusts the height and angle of the kite, the surface area of which can range from 760 to 5,000 square metres. When the wind blows too strongly, one end of the rectangular kite is released so that the kite flaps like a flag. A powerful winch retrieves the kite when necessary.

[USFRIENDINVICTORIA]

This looks like a promising new technology. It's like kiteboarding, only a thousand times bigger.

Innovations, such as this, are what will enable us to continue to "have our cake and eat it too". We can reduce our dependancy on fossil fuels, while continuing to have economic prosperity. Unlike a lot of so-called "alternative energy" schemes, this one looks like it could actually work without government subsidy.

[USFRIENDINVICTORIA]

Sorry everyone -- I meant to include a photo. .

[dead]

Sounds logical, though that sail looks a bit too small to me.

[BenLurkin]

(Just another boat pic.)

[USFRIENDINVICTORIA]

Is this what the Swedish Bikini team travels on?

[BenLurkin]

Ooooo.

I hope so!

[Abathar]

Yeah, tell that freighter captain to start tacking to the wind and zigzagging instead of taking a strait route and see how far this idea floats.

[BadAndy]

"Sailing ships with a new twist "

Liberals will then start complaining the sails confuse sea birds or disrupt the trade winds or some other nonsense. They don't care about a cleaner environment, they want an end to capitalism.

[USFRIENDINVICTORIA]

"Sounds logical, though that sail looks a bit too small to me."


I suspect that it's partly the fault of perspective -- the kite would be quite a distance from the ship. Also, the article says that the winds higher up would be stronger than at the surface.


I don't know how large the kite in the picture is supposed to be. A 5,000 sq. meter kite would be about 50 feet by 100 feet.

[dead]

Yeah, tell that freighter captain to start tacking to the wind and zigzagging instead of taking a strait route and see how far this idea floats.

It's not supposed to replace the engine, just supplement it when the wind direction coincides with the ship's direction.

[USFRIENDINVICTORIA]

"Yeah, tell that freighter captain to start tacking to the wind and zigzagging instead of taking a strait route and see how far this idea floats."

The kites are airfoils -- you can go upwind almost as easily as downwind (downwind is somewhat faster though). If the shipping version works anything like the sport version, you can control the direction of the kite much like any aerobatic kite. The ship would just have to steam ahead as usual -- the autopilot would take care of the kite flying.

[USFRIENDINVICTORIA]

"Liberals will then start complaining the sails confuse sea birds or disrupt the trade winds or some other nonsense. They don't care about a cleaner environment, they want an end to capitalism."

You're probably right -- they might also say that evil capitalists caused global warming so that the winds would be stronger, to help boost profit margins of kite-flying shipping companies.

[Rebel_Ace]

"I don't know how large the kite in the picture is supposed to be. A 5,000 sq. meter kite would be about 50 feet by 100 feet."

I think you mean 50 METERS by 100 METERS.

[USFRIENDINVICTORIA]

"I don't know how large the kite in the picture is supposed to be. A 5,000 sq. meter kite would be about 50 feet by 100 feet."

Argh -- I meant 50 by 100 meters. About 150 feet by 300 feet.

[Little Ray]

Its just a spinnaker...

[Old Professer]

Times nine-something?

[TBall]

Looks cool, but I don't understand how could you go up wind?

[USFRIENDINVICTORIA]

You're right -- beat me to it by about 15 seconds.

One of the things that vexes me about the MSM is their reporters' total ignorance of anything smacking of math or science. If there's a number involved in the story, you can usually count on it being wrong. I hate that I made such an error.

[DeweyCA]

Think of the size and shape of a football field.

[USFRIENDINVICTORIA]

"Looks cool, but I don't understand how could you go up wind?"

Check out the site below for information about the sport of kitesurfing. I'm presuming the technology is essentially the same -- just at a larger scale.


http://kitesurfingschool.org/faqs.htm#Can%20a%20kitesurfer%20go%20upwind