USA 17

BMW Oracle racing USA-17 training off of Valencia, Spain in late January, 2010

USA-17 (formerly known as BMW Oracle Racing 90 or BOR90) is a 90 ft (27 m). LWL, 90 ft (27 m). beam, sloop rigged one-off racing sail trimaran built by the USA sailing team BMW Oracle Racing for use in a Deed of Gift challenge for the 33rd America's Cup. Designed by VPLP Yacht Design with consultation from Franck Cammas 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 (though some rumors have claimed 4× TWS). She can apparently sail at 20 degrees off the apparent wind. The boat sails so fast downwind that the apparent wind she generates is only 5-6 degrees different to 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.

In March 2009, USA (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.

BMW Oracle racing BOR 90 in original configuration sailing in the Pacific Ocean near San Diego

On November 8, 2009, the team announced that a rigid sail wing had been built for the yacht. 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 reported wind speed. During the first race of the 2010 America's Cup, USA was able to sail upwind faster than Alinghi 5 even without a jib. Since the sail area of USA's wing is much smaller than the sail area of Alinghi's mainsail and jib combined, it is clear that the rigid wing is much more efficient than even high-performance traditional sails.

Racing results

The first race of the 2010 America's Cup took place on February 12, 2010. USA beat the defender, Alinghi 5. USA was behind 1:27 at the start, 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 had to perform a penalty turn, having failed to stay clear at the start.

Winds were 5-10 knots. USA reached the windward mark in 1h29, so her velocity made good was about 13.5 knots, about 1.8 times wind speed. USA took 63 minutes to reach the downwind mark, so her velocity made good downwind was about 19 knots, 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 with reported true wind speed of 15 knots at mast head height at over 60 metres [2]. 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 velocity made good and wind speed is an approximation only.

On February 14, 2010, USA also won the second race, and thus the America's Cup, again by a considerable margin. USA 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 had to perform a penalty turn, having entered the pre-start area too soon.

Winds were 7 to 8 knots. USA reached the windward mark in 59 minutes, so her velocity made good was about 13.2 knots, about 1.65 times wind speed. The course was a triangle, so the velocity made good downwind was only 11.5 knots, about 1.4 times wind speed. USA averaged 26.8 knots, about 3.35 times the wind speed, on the faster first triangular leg.

Observers stated that the rigid wing had given USA a decisive advantage.

Specifications

Boat Type: Trimaran of carbon composite construction
Where Built: Core Builders, Anacortes, WA, USA
Architects: Van Peteghem and Lauriot Prévost (VPLP) and design team of Mike Drummond
Consultants: Franck Cammas
Hours to build: Over 130,000 hours as of August 2009
Overall Length: 113.3 feet (34.5 m)
Load Waterline Length: 90.0 feet (27.4 m) (measured at rest)
Waterline Length when Sailing: 113.3 feet (34.5 m)
Beam: 89.9 feet (27.4 m)
Displacement (weight): ~15 tonnes (17 short tons) (racing weight)
Length of main hull: 90 feet (27 m)
Length of outlying hulls: 113.3 feet (34.5 m)
Beam of main hull: 6.92 feet (2.11 m)
Beam of outlying hulls: 4.33 feet (1.32 m)
Overall height of main hull: 7.5 feet (2.3 m)
Overall height of outlying hulls: 5.81 feet (1.77 m)

Mast height: 185 feet (56 m) (as of August 2009)
Where Built: Hall Spars, Bristol, RI, USA
Sails: (as of August 2009)

Mainsail:  6,800 square feet (630 m²)

Headsail:  6,700 square feet (620 m²)

Gennaker: 8,400 square feet (780 m²)

Wing height: 223 feet (68 m)(compared to 102 ft / 31 m length of a Boeing 747 wing and 143 ft / 43.5 m length of an Airbus A380 wing)
Wing chord: 10 feet (3.0 m) to 30 feet (9.1 m)
Wing width: 2 feet (0.61 m) to 6 feet (1.8 m)
Wing surface area: 7,000 square feet (650 m²)
Weight of wing: 7,700 pounds (3,500 kg)
Where Built: Core Builders, Anacortes, WA, USA

Comparison of 87–90 ft America's Cup contenders:

	Year	LOA	LWL	Sail Area	Mast height	Displacement
Reliance	1903	43.89 m (144.0 ft)	27.43 m (90.0 ft)	1,501 m2 (16,160 sq ft)	67.05 m (220.0 ft)	189 tons
Ranger	1937	41.15 m (135.0 ft)	26.51 m (87.0 ft)	701 m2 (7,550 sq ft)	46.98 m (154.1 ft)	166 tons
KZ1	1988	36.57 m (120.0 ft)	27.43 m (90.0 ft)	627 m2 (6,750 sq ft)	46.78 m (153.5 ft)	39 tons
USA-17	2010	34.5 m (113 ft)	27.43 m (90.0 ft)	1,270 m2 (13,700 sq ft)	68 m (223 ft)	17 tons

External links

• BOR 90 Trials Bayshots Images
• BMW Oracle Racing official site
• VPLP Yacht Design
• Hundreds of images of the BOR 90
• ABC News Story on BOR and the BOR90 (video)
• CBS News Story on BOR and the BOR90 (video)
• http://www.americascup.com
• [3] Podcast of technical interview with the designer