International audienceA performance prediction program dedicated to merchant ships was developed to assess fuel saving abilities of a kite. The solving of the parameterization presented led to kite velocities and tethers tensions prediction continuously along a flight path within the wind window, including especially wind gradient and ship velocity. Both static and dynamic flight cases were considered regarding optimization strategy for kite tow efficiency. For dynamic flight case azimuth, elevation and orientation of the trajectory are continuously optimized in the present algorithm. Magnitude orders of towing forces induced by the kite were compared to those obtained in the literature. Especially in upwind conditions, which are the most frequent point of sail for fast vessels, results are dramatically improved. Finally, using a 320 m2 kite on a 50,000 dwt tanker, the fuel saving predicted is about 10% for a wind velocity of 9.77 m s−1 (Beaufort 5) and reaches more than 50% for a wind velocity of 15.68 m s−1 (Beaufort 7)

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International audienceTo meet the Microtransat challenge, ENSTA Bretagne chose to realize several sailing robots. The first, having served as a test platform, allowed us to develop two new boats, one for research and one for the Atlantic crossing. The different tests in the bay of Brest allowed us to improve the reliability of systems on our sailboat. Various studies have been conducted to improve reliability of sailboats both mechanically and electronically. This tests allowed us to test different concepts on the three Breizh Spirit boats. The results are very positive and we can now say that we have a boat able to resist to strong storms, to follow a predifined route, to supply its own energy and to navigate in sea waves. From the experience acquired from Breizh Spirit 1, we hope we will be able to cross the Atlantic Ocean

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