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SAILING ON AIR WITH AMERICA´S CUP CATAMARANS

/ / Sailing

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SAN FRANCISCO — Max Sirena, the Italian skipper of Luna Rossa Challenge, was standing inside a converted airplane hanger watching his shore crew at work on wing sails and gleaming hulls and wondering if it was still right to define the focus of all this expert attention as a boat.

“It’s really more a machine,” he said.

For decades, Sunday sailors could identify with America’s Cup yachts, with their monohull designs, soft sails, narrow decks and relatively benign speeds. But the 162-year-old competition, whose preliminaries begin this weekend with the start of the Louis Vuitton Cup, has now officially cut the cord with the yacht-club experience.

The 72-foot, high-performance catamarans to be used this year are capable of sailing well over 40 knots, or 46 miles per hour. They require their sailors to wear protective armor and helmets, and, since the death of the Artemis Racing crew member Andrew Simpson in May, they are also now required by the rules to wear portable air canisters in case they are trapped under water.

But what is particularly eye-catching about this class of big boats — machines, if you agree with Sirena — is their spectacular capacity to “foil.” Foil is the nautical vernacular for hydrofoil, and it means, in this case, that these catamarans are able to sail — at least downwind — with both hulls out of the water.

Live or on a screen, it looks like a special effect: the raptor-like yachts levitating as all that carbon fiber and sail area and manpower are supported by only the slender rudders and dagger boards still in the ocean.

“It’s the most amazing sensation when you look down, and there’s no part of the boat in the water, just the two foils on the leeward hull and the rudder on the windward one,” said Dean Barker, the skipper of Emirates Team New Zealand. “Just the sheer acceleration of the boat when it breaks clear of the water is quite remarkable.”

Iain Murray, the veteran sailor who is regatta director for the America’s Cup, took a ride on Oracle Team USA’s AC72 earlier this year and was struck by the shift in mood once the yacht began to foil.

“Well, look, the ride is incredibly smooth,” Murray said. “Most of my time going fast has been in boats bouncing all over the ocean. Whether it be skiffs jumping out of the waves or whatever, it’s a pretty rough ride. These things are not like that. They are very smooth, very progressed, very efficient and very quiet. You know you’re going plenty fast, but there’s no huge sensation of danger.”

Danger, as Murray is all too aware, is a major component of this Cup, however. Oracle, the defender, capsized last year while executing a bear-away maneuver in a strong ebb tide in San Francisco Bay and its badly damaged yacht ended up floating underneath the Golden Gate Bridge.

On May 9, during a training exercise with Oracle, Artemis’s AC72 also capsized doing a bear-away — a downwind turn away from the breeze — and broke up. Simpson, a British Olympic gold medalist, was trapped under water underneath the wreckage though it remains unclear whether he died by drowning or from another cause, with the San Francisco coroner’s report yet to be released.

Artemis’s yacht was not foiling at the time of the accident, and several sailors and officials believe that, no matter how unstable foiling might appear, these huge catamarans are often less vulnerable when foiling than when one or both hulls are in touch with the water.

Foiling is not new to sailing. Recreational hydrofoiling multihulls have been produced commercially since the 1990s, and the increasingly popular International Moth Class features small, lightweight, highly maneuverable boats that can foil in relatively light winds.

There is also Hydroptère, the avant-garde hydrofoil designed by the Frenchman Alain Thébault that set a record for a sailboat in 2009 by sustaining a speed of 52.86 knots (just over 60 m.p.h.) over 500 meters, or 1,640 feet.

But Hydroptère, the equivalent of a sprinter, was hardly designed to race around the buoys — upwind, then downwind, then do it again — like an America’s Cup yacht.

There have been multihulls in the America’s Cup before: Dennis Conner deployed a catamaran in 1988 in San Diego to trump an unwelcome challenge from the New Zealander Michael Fay, whose weapon of choice was a 90-foot monohull.

Unsurprisingly, the catamaran won: by a lot.

In the 2010 America’s Cup, after another extended legal tussle and another challenge, the American billionaire Larry Ellison’s BMW Oracle Racing team prevailed in a 90-by-90-foot trimaran by winning two races against the defender, Alinghi, in a 90-foot catamaran.

But those huge multihulls did not foil, and the rub is that the AC72s in use in this 34th edition of the Cup were not supposed to foil either.

In fact, the intent of the rules governing this new class of yachts was to discourage it. But Team New Zealand, one of the three challengers, found a corner of the rule to exploit and, ultimately, a way to produce all that lift without too much drag from the elements that remained in the water.

The three other teams in the competition — Oracle, Luna Rossa and Artemis — are following Team New Zealand’s innovative lead, with Artemis making the move last.

After its first boat was destroyed, Artemis, a Swedish team run by the veteran American sailor Paul Cayard, has yet to launch its second boat, which is designed to foil fully. It will not take part in the initial phases of the Vuitton Cup: a round robin that is now not much of a round robin with just two teams involved as it begins Sunday. Those teams are Luna Rossa and Team New Zealand, who exchanged design information and often trained together after Luna Rossa decided to challenge in late 2011.

But the winner of the round robin, such as it is, will still have the option to advance directly to the Vuitton Cup final. The remaining two challengers, assuming Artemis is operational, would then take part in the semifinals that begin Aug. 6.

All this is contingent on a resolution of the latest legal conflict in the Cup: Team New Zealand’s and Luna Rossa’s appeal to the international race jury in an attempt to block the imposition of two of the 37 rule changes passed after the Artemis accident. The main sticking point is a new rule that allows changes to the surface area of rudder elevators, a piece of equipment that helps control the boats when they maneuver. Barker and the team leaders maintain the rule change is not essential to safety and could affect competitive balance.

None of the rules in question would affect the yachts’ ability to foil.

Cayard said Artemis always had planned on getting considerable lift, just not out-of-the-water lift. While teams are now using L-shaped dagger boards, Artemis’s decision for its ill-fated first boat was — according to Cayard — to take a less extreme approach.

“A perfectly straight dagger board that just goes straight down in the water produces virtually no lift at all and very little drag,” Cayard explained. “And then you go all the way to an L-shaped board that has a horizontal wing and produces over seven tons of lift, which is the weight of these boats. So there’s a scale there.

“All the variants in between straight and the L are called J’s. So we were in the J board family, which was producing enough lift to lift about 60 percent of the displacement of the boat. We thought that was the sweet spot in the compromise between board drag and hull drag, but it turns out you are better to have no hull drag and 100 percent of the board drag.

“So how did we get caught? Well this was all calculations and computational fluid dynamics. This class didn’t exist and there was no real full-scale examples out there where you could just say, ‘Oh well, look at that!”’

When Team New Zealand started foiling last September in training with its first AC72 in Auckland, New Zealand, Cayard said that initial reports were that the New Zealand boat was too slow upwind and not entirely stable. “The early days of Team New Zealand really didn’t throw that much concern at us because it looked to be what we expected,” he said.

But Team New Zealand was using bigger dagger boards at that early stage of its development. It later reduced their size significantly, thus reducing the drag significantly.

“Toothpicks don’t have very much drag,” Cayard said

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