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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.

Windship Technology Ltd, a sail power concept that is being developed by a consortium of five key players in the global shipping industry, could revolutionize the way tomorrow’s vessels carry goods across the world’s oceans.
The new concept, known as the Auxiliary Sail Propulsion System (ASPS), uses fixed wing sail technology whereby two 35 metre high masts installed on the deck of a vessel will each have three aerodynamic wings fitted. The masts or rigs rotate automatically to exploit the power of the prevailing wind and, as the speeds and angles of the wind change, the system develops more power allowing reductions in engine power to be made in order to achieve the same speed and so maximise on fuel saving.
The consortium approached Lloyd’s Register to give an independent assessment of the ASPS. LR’s Technical Investigation Department (TID) then carried out CFD work on a Supramax bulk carrier in varying wind directions and speeds. These showed that ASPS has the potential to provide more than 50% of the required propulsive thrust a vessel needs depending on conditions. In the right conditions this could save a typical bulk carrier 30% of its fuel costs on a voyage.
Hector Sewell, LR’s Head of Sales and Marketing, said: “Should these results be reflected in actual operation of a real ship, the operational fuel savings will be very significant and will be of great interest to the owners and operators of suitable ships. We look forward to helping clients understand how such a system can help them.”
The designer of the ASPS is the Hampshire UK based award-winning yacht designer, Simon Rogers. He said: “I am very excited by the new concept which is taking the very latest principles of sailing and applying them to modern ship design.”