Science

Next-gen cargo ships could use 164-foot sails to lower fuel use by 30%

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Depiction of a cargo ship equipped with the Wind Challenger Project system of sails
The five-segment sail will telescope down onto itself
Scale model of a Wind Challenger Project sail fully deployed
The sails can be lowered when in port or in rough weather
Artist's rendition of a cargo ship equipped with the Wind Challenger Project system of sails
Depiction of a cargo ship equipped with the Wind Challenger Project system of sails
View gallery - 5 images

Of the world's nearly 45,000 cargo ships, many burn a low-grade bunker fuel in their engines and produce pollution equivalent to millions of automobiles. To help reduce that toxic load and keep the price of shipping freight reasonable, engineers at the University of Tokyo (UT) and a group of collaborators have designed a system of large, retractable sails measuring 64 feet (20 m) wide by 164 feet (50 m) high, which studies indicate can reduce annual fuel use on ships equipped with them by up to 30%.

"Using today's technology, it's possible to make big sails, and to control them automatically," UT professor Kiyoshi Uzawa told DigInfo. "Also, navigation technology includes networked maritime information and weather forecasting, so ships like this can travel safely. Using wind energy, as in old-fashioned sailing ships, is actually feasible."

Each five-segment collapsible sail, estimated to cost about US$2.5 million, will be hollow and constructed of durable, lightweight aluminum and fiber-reinforced plastic. Similar in shape to an aircraft wing in cross section, the sails can be positioned independently of one another to maximize thrust and, while at anchor or in bad weather, can telescope down in what is known as "vertical reefing."

Uzawa anticipates that, with basic research completed, the Wind Challenger Project (WCP) group will be able to consider construction of a reduced-size prototype in the next few years to fully prove the concept. If all goes as planned, sea trials could begin as soon as 2016. If results from scale model wind tunnel tests and computer simulations bear out in the real world, he believes the sails could pay ultimately for themselves in five to ten years.

Due to the varying nature of cargo vessels, it seems likely that the WCP technology will be better suited for low-slung bulk material ships (ore, grain, oil) than for sea container ships, say, which stack freight high above deck. The group is not short on innovation, however, so it'll be interesting to see how that issue is approached.

It appears that a new era of tall, greener ships could be just over the horizon.

Source: DigInfo via Akihabara News

Check out the DigInfo video below to learn more about the new sails.

View gallery - 5 images
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20 comments
Gadgeteer
I'm not optimistic about the prospects. During the 1970s energy crisis, there was the similar Dynaship concept. That never went anywhere.
http://books.google.com/books?id=EgEAAAAAMBAJ&lpg=PP1&lr&rview=1&pg=PA58#v=onepage&q&f=false
sgdeluxedoc
Anyone actually done the math? The mass of these vessels may be a little bit more than sails can handle.. Perhaps "cargo" ships can do it, considering the average weight of a container, but what about the true guzzlers of the ocean, that is, TANKERS?
Andrew Kennedy
Looks like the ship looses 30% of its container carrying capacity to its sails. Perhaps it should have a tender behind. A butty as the non-powered canal barges used to be called.
sgdeluxedoc
Actually, although I *just* left a comment about doing the physics involved, I have to say,there could not *possibly* be anything BUT a NET GAIN.. which will mean reduced costs, translating (hopefully) into reduced cost to us (the consumer)... Wow... Chinese goods are already at a botom, price-wise, how could they *possibly* go any lower.. although IF THEY DO NOT CHANGE, count it as a GOOD thing.. there is a push in China, to increase the wages, and working conditions, of the average worker.. this may *just* make it possible!!!! So i say support it!!
Calson
It is a nice bit of public relations but the reality is that it would take more than 30 years to replace current cargo ships and that is supposing that 100% of the new ships adopt this technology. With the passenger ships using large sails of this type it has been a marketing gimmick with the sails in use only when entering or leaving a port and diesel power is used for the remainder of the cruise.
Cargo ships produce more particulate pollution with the bunker fuel sludge that they burn than all the cars, buses, trucks, and trains of the world combined. A side effect of global trade is an increase in cargo ship traffic and with it an increase in the type of pollution that has the greatest impact on global warming.
Adrian Akau
I think that this type of sail should be compared with kite sales: "SkySails has a cargo ship towing kite system of 8 and 16 tons, with future versions of 32 tons scheduled to be available in 2011 and 130 tons in the near future. A kite force of 8 tons is equivalent to a 600-1,000kW main shipboard engine. Running partly on wind power could save an average of 10-35% on the fuel used, and fuel consumption could be reduced by 50% in the best wind conditions."
MasterG
Did anyone ever watch beyond 2000 back in the 80s? This is not new, maybe now they may actually do it, back then they were talking about using the propellor only as a back up during storms but ships have grown alot since then. Only 30% saving?
jerryd
If ships all used this pollution would be far lower, Ship produce like they were the 6th largest country if they were a nation.
That said kites are better in most cases and high ships like container ones can't use any because of capsize risk.
Shipping cost are high and getting higher that along with recent Chinese labor, energy costs, Yuan increasing with American productivity and people switching to longer lasting quality products means the US is about to regain a nice amount of manufacturing.
I'm building 2kw windgens and match the Chinese on price but beat the pants off them in quality.
Walt Stawicki
can't even get double hulled tankers. gods law: profit to the stockholder, no other concerns. call me pessimistic, but admit my reality orientation
SEAMUS100
Good idea.
They might want to add other new ideas like maybe a "shark skin" type textured hull surface which would only add the extra weight and cost of a little extra paint.