Authors: Wubbo J. Ockels
Date Submitted: May 31, 2007
Article Type: Journal

Abstract:

The use of large kites in ship propulsion has been getting a growing attention because of the urgent need to reduce the CO2 production and thus stop the use of fossil fuels. A novel application of ship propulsion by kites is proposed based on a Laddermill apparatus mounted on a ship. Such an apparatus consist of a winch, an electric motor/generator, a kite system (including launch and retrieval) and controlling electronics.

Rather than the traditional sailing by wind force the Laddermill [2] propulsion is achieved by a combination of the production and use of electrical power and the direct pulling force from the kite system. The feasibility of this application is investigated. It is show that when the overall Laddermill to ship thrust efficiency can be made around 50% the resulting speed of the ship becomes practically independent from the wind direction! Such a capability could thus well change the world’s seafaring.

Introduction:

Kites have been known since thousands of years. Kites have been mainly used for pleasure and as toys. Over these many years kites have shown little development, the shapes and applications basically stayed similar. Recently kites, however, have enjoyed fast development in shape through the use in novel sports such as kite -buggying, -surfing and snow kiting. A logical extrapolation of these sports leads to kites employed as new ship propulsion. The main drive is the reduction of fuel consumption for large ocean going vessels (Skysails, http://www.skysails.com)although joyfull applications can be imagined for recreational use (http://www.kiteboat.com ).

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