USA 17 (yacht) - Background

Background

BOR 90 was launched in Anacortes, Washington in August of 2008 after more than 9 months of construction. She underwent initial testing in Anacortes before being shipped to San Diego, California for additional sea trials and development.

In March 2009, USA 17 (then referred to as BOR90) was pulled from the water for extensive modification in BMW Oracle Racing's San Diego shop. She emerged in early July, 2009, featuring wave-piercing hulls and other modifications. She was further modified subsequently, in particular in October 2009 to add an engine to power hydraulic winches.

On November 8, 2009, the team announced that a rigid sail wing had been built for the yacht.b The wing was initially 190 feet (58 m) tall and some 80 percent larger than the wing of a Boeing 747 airplane; it was later extended to 223 feet (68 m). The wing has a very high aspect ratio, meaning that it is very tall and narrow. It can change camber to adjust lift in order to optimize performance. The wing consists of two main elements, separated by a vertical slot through which air can flow. The rear element is made up of several separate sections, whose angle can be adjusted separately, much like the flaps on an airplane's wing. Thus the lift of the sail can be controlled very finely, both overall, and for each section.

The wing is more efficient than a traditional soft-sail rig setup. On November 10, BMW reported that they hit 32 miles per hour (28 kn) boat speed in a 10-knot (19 km/h; 12 mph) reported wind speed. During the first race of the 2010 America's Cup, USA 17 was able to sail upwind faster than Alinghi 5 even without a jib. Since the sail area of USA 17's wing is much smaller than the sail area of Alinghi 5's mainsail and jib combined, it is clear that the rigid wing is much more efficient than even high-performance traditional sails.