Kite rig

They differ from conventional sails in that they are flown from kite control lines, not supported by masts.

They may be as simple as a person flying a kite while standing on a specialized skateboard, or be large, complex systems fixed to the vehicle, with powered and automated controls.

Windspeed increases with height, allowing kites to develop substantially more thrust per unit area than a conventional sail.

[2] Ship-pulling kites run to hundreds of square meters of area and require a special attachment points, a launch and recovery system, and fly-by-wire controls.

[3] A commercial cargo ship, the MS Beluga Skysails, was built, and launched in 2007, with a kite rig supplementing conventional propulsion.

[4] A European Union-funded four-year study of wind propulsion, using the MS Beluga Skysails, reported that the ship attained 5% fuel savings overall, which translated into 530 tonnes (530 t; 580 short tons) of CO2 for a typical year and itinerary.

[5] On her maiden voyage, MS Beluga Skysails saved an estimated 10–15% fuel, $1,000 to $1,500 per day, while the kite was in use.