''USA-17'' (formerly known as ''BMW Oracle Racing 90'' or ''BOR90'') is a sloop rigged racing trimaran built by the American sailing team

BMW Oracle Racing Oracle Team USA is an American yacht racing syndicate initially formed to compete for the 2003 America's Cup. They competed again in the 2007 event before winning the 33rd America's Cup regatta in 2010 – representing the Golden Gate Yacht Club ...

to challenge for the

2010 America's Cup The 33rd America's Cup between Société Nautique de Genève defending with team Alinghi against Golden Gate Yacht Club, and their racing team BMW Oracle Racing was the subject of extensive court action and litigation, surpassing in acrimony even ...

. Designed by VPLP Yacht Design with consultation from

Franck Cammas Franck Cammas (born 22 December 1972 in Aix-en-Provence) is a French yachtsman. He has lived in Brittany since his victory in the Challenge Espoir Crédit Agricole in 1994. After completing a two-year maths course for the ‘Grandes écoles’, ...

and his Groupama multi-hull sailing team, ''BOR90'' is very light for her size being constructed almost entirely out of carbon fiber and epoxy resin, and exhibits very high performance being able to sail at 2.0 to 2.5 times the true wind speed. From the actual performance of the boat during the

races, it can be seen that she could achieve a

velocity made good Velocity made good, or VMG, is a term used in sailing, especially in yacht racing, indicating the speed of a sailboat towards (or from) the direction of the wind. The concept is useful because a sailboat cannot sail directly upwind, and thus often ...

upwind of over twice the wind speed and downwind of over 2.5 times the wind speed. She can apparently sail at 20 degrees off the apparent wind. The boat sails so fast downwind that the

apparent wind Apparent wind is the wind experienced by a moving object. Definition of apparent wind The ''apparent wind'' is the wind experienced by an observer in motion and is the relative velocity of the wind in relation to the observer. The ''velocity ...

she generates is only 5-6 degrees different from that when she is racing upwind; that is, the boat is always sailing upwind with respect to the apparent wind. An explanation of this phenomenon can be found in the article on

sailing faster than the wind High-performance sailing is achieved with low forward surface resistance—encountered by catamarans, sailing hydrofoils, iceboats or land sailing craft—as the sailing craft obtains motive power with its sails or aerofoils at speeds that are ofte ...

Design

''USA 17'' was designed by VPLP.

Career

Launching and initial testing

''BOR 90'' was launched in

Anacortes, Washington Anacortes ( ) is a city in Skagit County, Washington, United States. The name "Anacortes" is an adaptation of the name of Anne Curtis Bowman, who was the wife of early Fidalgo Island settler Amos Bowman.wave-piercing A wave-piercing boat hull has a very fine bow, with reduced buoyancy in the forward portions. When a wave is encountered, the lack of buoyancy means the hull pierces through the water rather than riding over the top, resulting in a smoother rid ...

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. The

wingsail A wingsail, twin-skin sail or double skin sail is a variable-camber aerodynamic structure that is fitted to a marine vessel in place of conventional sails. Wingsails are analogous to airplane wings, except that they are designed to provide lif ...

was initially tall and some 80 percent larger than the wing of a Boeing 747 airplane; it was later extended to . The wing has a very high aspect ratio, meaning that it is very tall and narrow. It can change

camber Camber may refer to a variety of curvatures and angles: * Camber angle, the angle made by the wheels of a vehicle * Camber beam, an upward curvature of a joist to compensate for load deflection due in buildings * Camber thrust in bike technology * ...

to adjust

lift Lift or LIFT may refer to: Physical devices * Elevator, or lift, a device used for raising and lowering people or goods ** Paternoster lift, a type of lift using a continuous chain of cars which do not stop ** Patient lift, or Hoyer lift, mobil ...

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 A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is e ...

. 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 boat speed in a reported wind speed. During the first race of the 2010 America's Cup, ''USA 17'' was able to sail upwind faster than ''

Alinghi 5 ''Alinghi 5'' is a ( LWL), beam sloop-rigged catamaran built by Alinghi for the 33rd America's Cup. The boat was launched on 8 July 2009 when the hull was lifted from the construction shed in Villeneuve, Vaud by a Mil Mi-26 helicopter and ca ...

'' even without a

jib A jib is a triangular sail that sets ahead of the foremast of a sailing vessel. Its tack is fixed to the bowsprit, to the bows, or to the deck between the bowsprit and the foremost mast. Jibs and spinnakers are the two main types of headsail ...

. Since the sail area of ''USA 17''s wing is much larger 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.

America's Cup

Race 1

The first race of the 2010 America's Cup took place on February 12, 2010. ''USA 17'' beat the defender, ''Alinghi 5''. ''USA 17'' started behind by 1:27 after start box maneuvering with ''Alinghi'', but was ahead by 3:21 at the windward mark and by about 9 minutes at the finish. Her official finish time was 15:28 ahead of the loser because ''Alinghi 5'' had to perform a penalty turn, having failed to stay clear at the start. Wind speeds were during the first race. ''USA 17'' reached the windward mark in 1h29, so her

was about , or about 1.8 times wind speed. ''USA 17'' took 63 minutes to reach the downwind mark, so her velocity made good downwind was about , or about 2.5 times wind speed. The measured wind velocity is taken at near sea level, and does not account for effects of

wind gradient In common usage, wind gradient, more specifically wind speed gradient or wind velocity gradient, or alternatively shear wind, is the vertical component of the gradient of the mean horizontal wind speed in the lower atmosphere. It is the rate of ...

with reported true wind speed of at mast head height of over . The measured sea-level wind direction shifted away from 180 degrees between the time of setting of the course and commencement of sailing of the downwind leg, by which time wind direction was reported to be at around 160 degrees. As such the ratio between downwind

and wind speed is an approximation only.

Race 2

On February 14, 2010, ''USA 17'' also won the second race, and thus the America's Cup, again by a considerable margin. ''USA 17'' was ahead by 0:24 at the start, by 0:28 at the windward mark, by 2:44 at the gybe mark, and by over 4 minutes at the finish. Her official finish time was 5:26 ahead of the defender because ''Alinghi 5'' had to perform a penalty turn, having entered the pre-start area too soon. Wind speeds were during the second race. ''USA 17'' reached the windward mark in 59 minutes, so her velocity made good was about , or about 1.65 times wind speed. The course was a triangle, so the velocity made good downwind was only , or about 1.4 times wind speed. ''USA 17'' averaged , or about 3.6 times the wind speed, on the faster first triangular leg. Observers stated that the rigid wing had given USA a decisive advantage.

Notes

References

External links

BOR 90 Trials
Bayshots Images

official site
Hundreds of images of the BOR 90ABC News Story on BOR and the BOR90 (video)CBS News Story on BOR and the BOR90 (video)35th America's Cup
official site

Podcast of technical interview with the designer {{Sailing vessels and rigs Trimarans America's Cup challengers 2000s sailing yachts Sailing yachts built in the United States Sailing yachts designed by VPLP Sailing yachts of the United States 2010 America's Cup Oracle Team USA