from infoniac.com: MS Beluga SkySails - World's Largest Cargo Vessel Equipped Pulled by a Kite

                 For over 10 years SkySails, a company based in Hamburg, has been making giant kites that are attached to ships in order to cut the level of fuel they use. The kites catch the wind and pull ships across the ocean.
The invention was put into regular use only in 2008, when the company attached one of its kites to 132-meter long multi-purpose heavy lift shipcalled MS Beluga SkySails.
Recently the company announced that it looks forward to use its new technology on a vessel that weights between 25,000 and 30,000 tons(27,558 to 33,069 US tons). This will be the world's largest ship pulled by a kite. It would be interesting to note that the kite measures 320 square meters (382.7 sq. yards). It will fly ahead on the ship at an altitude of 100 to 420 meters (328 to 1,378 feet).
An automated system will be used to control the kite's path. The kite will be launched and retrieved using a telescoping tower located on the bow and equipped with a winch.
Data on the system's operation will be shown on a display on the ship's bridge. It was reported that the SkySails system will cut the ship's fuel consumption by 10 to 35 percent each year and by up to 50 percent temporarily.
According to a research carried out by the United Nations' International Maritime Organization, in case the system is applied around the world up to 100 million tons of CO2 could be saved each year.