Mariner’s Web

Lead Free Sailing in The America’s Cup

The Trimaran “DogZilla”  (USA BMW-Oracle) defeated the Swiss Catamaran Alinghi to bring back to the USA the oldest trophy in international sports – the America’s Cup. This is the first time a Cup challenger has won a Deed Of Gift (DOG) head-to-head match race.   Unlike the past 25 years or so when the Cup defender had accepted challenges from the winner of the Louis Vuitton Cup, this race was decided on the water in a 2 out of 3, head-to-head match race.  But only after a year of delays and numerous lawsuits did the race default to Deed Of Gift.  Under these rules there are very few restrictions put on boat design and you might say the sky’s the limit and you’d better have deep pockets to compete!

This 33rd America’s Cup was won 2 races to 0 by the USA for the second time in a multihull with a wing sail, which represented unprecedented “lead free sailing“.  There is no lead ballast in these boats that is normally found in a self-righting keelboat, as the carbon fiber daggerboards provides for the stability and hydrodynamic lift to propel these wide-bodied and tippy boats.  Each of the boats in this match race easily sail faster than the wind on all points of sail, with boat speeds over 3 times faster than the windspeed.  Don’t bring you’re monohull strategy and tactics to these races though, these boats are all about speed, not about maneuverability and quick turns in close proximity.  Each day of racing found one of these behemoths in irons prior to the start, struggling to get over the line well after the gun. But once the boats are powered up they quickly surpass the windspeed and the skippers appear to be flying in a tiny cockpit like the helm of some kind of a starship in space.  Once around the windward mark there is none of the excitement of a spinnaker set or gybe as the boats accelerate and trim in their main and headsail as the apparent wind continues to move forward.  Then it appears to the casual observer to be yet another upwind leg with a close angle of attack.  The science behind the boat and rig technology is fascinating to say the least – but the competition faded once they rounded the windward mark and played follow the leader.  To give credit to Alinghi who held the Cup in a great run of the past 7 years or so, the race was seemingly won by technology, as the sail plan and rig, the engine of these carbon vessels, were incomparable with each other for match racing (a misnomer here at best).

The first race was a windward-leeward course followed by a triangular course for the second and last race with the same outcome each day. Some close racing upwind and the trimaran pulling away off the wind, exceeding 30 knots when reaching in less than 10 knots of wind. The windward legs proved exiting as lead changes occurred mostly due to good or bad strategy depending upon your point of view and a significant right shift on day two.  The highlight of the entire regatta was when USA nailed a layline to the windward mark and turned a deficit into a lead while the defender overstood the mark doing a painfully slow tack to become destined to watch DogZilla’s stern (and The Cup) pull away.

For the techies watching, once one has grasped the size and scope of these ultra-light boats that are 90′ long at the waterline and almost as wide, with their towering masts, one becomes infatuated with the wing sail on USA.  Albeit impractical for anyone other than the elite sailor, this wing is a rigid carbon fiber airfoil made of flat panels with a painted cloth skin for durability.  The airfoil is made up of two fore-n-aft sections split vertically with the aft section divided into 9 horizontal panels, similar to what we might think of as a cross-cut sail but each is individually adjustable to control sail “twist”.  Twist is the shape at the leech (trailing edge) of the sail that is trimmed to attain “attached airflow” and reduced drag, the negative energy that slows down a boat.  The other aspect of the sail shape is the depth of the sail along its camber (luff to leech or front to back curve) which provides aerodynamic lift and the driving energy of the sail plan.  The vertical gap in-between the fore and aft sections provides for a “refresh” of air from the windward to the leeward side. This is the point of depth adjustment for the wing and it appears as more of a “V” shape than a curved wing shape when observed on the vertical plane.  This foil provides for an incredible aerodynamic lift coefficient of 2.0 which is almost double that of the typical cloth or laminate sail.  It was also demonstrated in race one that the wing sail could be used as a Uni-rig when there is enough wind velocity to achieve plenty of boatspeed without benefit of a headsail.

In the end the Sailing tycoons who fought in the courts and on the water shook hands.  But the losing team did show their dogbody side when they made a comment on camera associating the America’s Cup with America’s Court System. Even after keeping the Cup for several years they did not seem to realize that in fact The Cup is named after a boat, not a country.  The winning team already has a challenger of record for the next Cup and expressed their intention to provide an impartial, international competition for the 34th America’s Cup.  Hooray!

As is usually the case, there is plenty of opportunity for advancement in boat and rig technology from this America’s Cup experience.  It’s been a paradigm shift for sure – maybe I’ll find myself an A-Cat – and learn to fly!