To launch the iShares Cup Extreme 40 Sailing Series, Ellen MacArthur sailed an Extreme 40 catamaran across the River Thames last week. Seven world class teams will compete in this fleet racing series, which consists of four regattas sailed close to shore at venues across Europe.MacArthur last sailed on the River Thames two years ago at the conclusion of her world record circumnavigtion aboard her trimaran B&Q. "The trimaran and the Extreme 40 share some similarities," she said. "They are super light and built for speed. But the Extreme 40 is not built to go round the world, instead they race close to shore right in front of the spectators. The 'fifth man' spot on the boats means some people will actually get to experience what it is like to sail a multihull at speed."The first event takes place on Lake Starnberg outside Munich, Germany, starting on May 25. The series then heads to Marseille, France, Cowes, England, and Amserdam, The Netherlands.The iShares Cup also includes iShares Endurances Races, where the Extreme 40s will enter distance races like the the Bol d'Or Mirabaud in Switzerland, the JPMorgan Asset Management Round the Island Race at Cowes, and the Centomiglia race in Italy. For more about the series, click here.