The first cargo ship in the world to be pulled by a giant parachute-shaped kite set out on a transatlantic voyage yesterday in an attempt to prove that wind can once again be used as a viable and "green" source of propulsion for commercial shipping of the future.
The German-owned Beluga SkySails is a 400ft diesel-powered freighter equipped with a 160 sq metre, remote-controlled kite that can be flown 600ft above its bows, thereby cutting the vessel's fuel consumption.
The ship left the German port of Bremerhaven yesterday for Guanta in Venezuela carrying a cargo of chipboard factory parts. "The voyage will take about 18 days and we expect to hoist the kite as soon as we hit easterly trade winds south of the Azores," said Verena Frank, the spokeswoman for the SkySails company.
Stephan Wrage, 34, an industrial engineer who developed his SkySail after dreaming up the idea as a kite-flying schoolboy, said his invention had the potential to be used by at least 60 per cent of the world's 100,000 commercial vessels and could cut their overall annual fuel consumption by up to 35 per cent.
"Only the tough conditions imposed on a ship during a long voyage of this kind can show whether the SkySail is effective and whether the materials can stand up to the stresses and strains it will undergo," Mr Wrage said.
His kite is radically different from the canvas of square-rigged sailing ships which were last used as commercial cargo carriers in the 1950s. Instead of being held in place by spars and ropes as the wind fills it, the "SkySail" performs acrobatics carving a steady figure-of-eight pattern through the air above the ship.
Its movements are controlled by a computer linked to the kite by a cable housed inside the thick synthetic hawser holding it to the ship. While performing its figure-of-eight movements, the kite reaches speeds more than four times that of the prevailing wind. "The effect is to dramatically increase the kite's pulling power," said Ms Frank of SkySails.
The company has already conducted more than 2,000 hours of tests on prototype kites. The voyage of the Beluga SkySails will focus on the ability of the kite and is cables to withstand fabric damage caused by strong sunlight and the chafe resulting from a constant 16-tonne pull on the weaving of the SkySail.
The Beluga Skysails crew also plan to fly the kite on the return trip. Ms Frank said: "The ship is due to pick up a cargo in Boston on its return voyage which will take it north of the Azores. At that point it should pick up westerly trade winds that should blow her back to her home port."