Cargo Ships With the Wind at their Backs


Who would have thought you could get patent protection for putting a sail on a ship?  It seems the novelty was lost in the days of Columbus.  But that’s what German company SkySails has done. 

SkySails’ computer-controlled kites can reduce fuel use in large freight tankers by 10-35% and are the subject of a recently-issued patent.  Both EcoGeek and Matter Network have reported on the kites, which span more than 1700 square feet and fly at a height of 600-1,000 feet to take advantage of stronger and more stable winds.

U.S. Patent No. 7,287,481 covers an aerodynamic kite for driving watercraft.  The device, which the patent calls an “aerodynamic profile element,” alleviates certain problems inherent in using large kites, such as control of the kite, unpacking and packing the kite (“unreefing” and “reefing”) and launch and retrieval procedures. 


The kite has an upper layer and a lower layer with four openings for air intake between the two layers arranged around the horizontal longitudinal axis of the kite.  Air enters the openings and fills the internal space between the upper and lower layers. 

A stiff kite stick fixed along the longitudinal centerline of the kite provides stabilization.  The stick may be shortened or locked in a particular position for ease of reefing and unreefing.  A gondola at the bottom of the kite connects to a pulling cable that can attach to a watercraft.  The kite has a network of reefing lines that extend to outer fixing points at the outer edges of the kite.

With the fuel savings the SkySails kite provides, it may become a very popular product for cargo ships.  But SkySails isn’t stopping there; it also filed a patent application for a device for converting wind into mechanical energy, which pairs its kites with energy converters.  Perhaps a subject for another post…

Eric Lane Avatar

Eric Lane

Eric Lane, the founder and principal of Green Patent Law, is an intellectual property lawyer and registered U.S. patent attorney in New York and is a member of the bar in New York and California. Eric has more than two decades of experience working with wind, solar PV, CSP, biofuels, and geothermal, energy storage technologies, carbon capture and sequestration, medical devices, data communications, mechanical, chemical, internet and software.