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Can Alinghi, the Swiss defender, outmaneuver 11 of the world's fastest yachts in the 32nd race for the America's Cup?

Can Alinghi, the Swiss defender, outmaneuver 11 of the world's fastest yachts in the 32nd race for the America's Cup?


CAD image of mechanical rigging assembly

CAD image of mechanical rigging assembly


CAD image of BMW Oracle Racing yacht's hull and keel

CAD image of BMW Oracle Racing yacht's hull and keel


Three years ago, the Swiss Alinghi team sailed to a stunning victory that returned the America's Cup to Europe after an absence of 152 years. For most of those years, the Cup was in the hands of those pesky Americans. But in 2003, Alinghi humbled the defender, Team New Zealand, 5-0, to reclaim yachting's Holy Grail.

The Swiss team not only returned the Cup to Europe, but it was the first to win the Cup on a first attempt, and the first winner from a land-locked country. Despite its Swiss identity, Alinghi is a multinational effort. The team is made up of 21 nationalities. And next year, these world-class sailors will defend the Cup against 11 of the world's best racing teams in the 32nd America's Cup in Valencia, Spain.

Alinghi captured the 31st America's Cup in Su164, the handiwork of principal designer Rolf Vrolijk. Built at Decisions SA in Switzerland and launched in 2001, the yacht was flown on a Russian Antonov jet to New Zealand where it was raced, tested, and developed against an older racing yacht.

Su164 was original in that, un-like most America's Cup Class yachts, the boat was made from two longitudinal pieces glued together along the centerline of the hull, from bow to stern. The result was a strong, stiff hull, reinforced to sustain the immense loads of the mast and keel ballast.

During the 2002-2003 America's Cup, Alinghi proved itself in key design areas of hydrodynamics and aerodynamics. Su164 has since been modified to comply with the latest version of the America's Cup Rules and now trains against a new yacht.

To share the experience of the 26-m racing machine with the public, Alinghi and Decision SA have developed a simulator, a replica of Su164, which carries up to 11 people and simulates upwind maneuvers. The simulator sits on the ground floor of the team's base in Valencia.

BMW Oracle Racing, the American contender, is another melting pot. Of its 36-man, two-boat team, only four are bona fide Yanks. Members hail from 16 nations. Even the skipper, Chris Dickson, is from New Zealand.

An early commitment from BMW meant the Americans could hire top-notch people and start preparing early. Experts in hydrodynamics, aerodynamics, appendages, structural engineering, CFD and tank testing, as well as performance analysis came on-board. The team developed a purpose-built facility where it constructed the boat to aerospace standards.

BMW Oracle's first-generation yacht, USA 87, will undergo full-scale testing against a proven workhorse, USA 76, while sail and rigging are developed. The testing will let engineers design a second and final version of the yacht.

Competition for the 32nd America's Cup began with a series of Louis Vuitton Acts in 2004 and 2005. These regattas provide a sort of test track before next year's Louis Vuitton Cup and America's Cup.

Louis Vuitton Act 12 (Match Racing) runs from the 22nd of this month to July 3. Next year, a fleet race event, Louis Vuitton Act 13, will precede the Louis Vuitton Cup. The winner of that race will challenge the defender, Alinghi, in the America's Cup Match.

WHAT'S THE POINT?
The self-proclaimed purpose of the America's Cup is to "produce wholesome, fast and maneuverable, day-sailing monohulls of similar performance intended for spectacular match racing in a wide wind range while fostering design developments that will flow through to the mainstream of yachting." The race is intended "for yachts that are raced 'around the buoys' with tenders present, as opposed to off-shore in high wind and rough sea conditions."

Ian Burns, design coordinator for BMW Oracle Racing (the American team), points out that "developments in sail design, on-board deck hardware, and navigational and tactical software pass down through the sailmaking and software industries." Hull and appendage developments, however, take a bit longer.

An obvious example is the winged keel of Australia II, the 1983 challenger. The keel, along with vertically cut upwind sails made of light, durable Kevlar sail-cloth, may have been the determining factor in the contest. In the deciding race, on the final downwind leg, Australia II carried a smaller, more stable spinnaker gaining 1 min and 18 sec to pass the American defender Liberty and extracting the Cup from the New York Yacht Club for the first time in history.

AMERICA'S CUP CLASS RULES
America's Cup Class yachts must carry a crew of 17, with the option to carry another person as an observer. This person may not contribute to the racing other than by the positioning of their weight. The additional person must sit aft of the yacht's helm (behind the helmsman) with their torso inboard of a vertical line above the sheerline. The weight of the additional person, fully clothed, plus any corrector weight (if needed) must total at least 100 kg. A team may carry 100 kg of weight in the cockpit instead of an observer.

All yachts are inspected and measured during construction and prior to, during, and after the race. A technical director and team of officials inspect yachts and equipment, and also interpret the rules.

The Defender and the Challenger of Record can revise design parameters for the next America's Cup. This time, the Challenger of Record is BMW Oracle Racing. Alinghi, the Swiss Defender, and BMW Oracle have written the fifth version (Version 5.0) of the rules. The changes reflect expected conditions in Valencia and translate the arcane rules into plain English.

Major changes to the rules include reducing displacement by 1 ton, adding 10 cm of draft to maintain upwind performance, increasing sail area, and allowing greater use of exotic materials, particularly in the rigging. Alinghi also received permission to use a new innovation: inflatable sail battens.

THE BOATS
America's Cup Class yachts are designed with only one competition in mind. The present design was established for the 28th regatta (race), in 1992.

America's Cup yachts are extremely fast upwind in light air and maximum downwind speeds can exceed 20 knots. Even at highly acute angles to the wind, these boats retain excellent speed. A 35° true wind angle and 10 knots of wind, for example, can produce speeds over 9 knots. This takes a complex combination of large sail area, heavy keel, and stiff, narrow hull. The boat capturing more of the wind's power and having the least drag usually wins.

"Keel design is important in reducing drag," says Burns. "But a balanced package is more important." It is also critical to reduce weight where possible so more weight can go into the lead bulb at the bottom of the keel. Greater weight at the bottom of the keel keeps the yacht closer to vertical, and therefore faster.

The keel fin for BMW Oracle Racing, one of the most important components of the high-tech yacht, was built by BMW at its German plant. Keel developments, however, will remain under close wraps until next year — too late to benefit the competition.

High-tech materials such as high-modulus carbon fiber, Kevlar, PBO, Spectra, and Vectran are used in the sails and rigging. USA 87's Kevlar and Mylar mainsails are made on a 3D mold. A continuous reinforced ribbon of carbon-fiber thread — some 13-km long — winds throughout the mainsails. Spinnakers are made of a much lighter cloth (nylon) and are not laminated. The headsail is made much like the mainsail. Each team will carry up to 650 kg of sails for the competition. The Louis Vuitton Cup demands up to 20 sails, plus 15 more if the team advances to the America's Cup.

The best team and the best boat design usually prevail in the America's Cup. And since 1999, BMW Oracle Racing has relied on CAD software vendor PTC, Needham, Mass., to help design its yachts. For example, the team used PTC's Pro/Engineer Wildfire 2.0 to develop the shape of the hull and keel, as well as structural components for two 108-ft masts. Pro/Mechanica provided structural analysis of the hull and rigging, while the designers used Pro/Toolkit for design automation.

BMW Oracle's designers, scientists, and engineers, who are spread around the world, used Windchill ProjectLink to collaborate and share design information. Detailed CAD models created with Pro/Engineer under-went computational fluid dynamic analysis and formed a 3D blueprint for construction of the scale models used in tank testing.

The quest for the Cup boils down to "fast boats, well sailed, that don't break," says Burns. And his team (BMW Oracle Racing) appears ready to meet those criteria.