Yachting: Team NZ think odd wings will give them a real flier

By Suzanne McFadden

So it's true - Team New Zealand's black boat has funny wings.

The defenders of the America's Cup weren't trying to fool anyone when they revealed their keels last month with winglets poking out the sides.

The other boats had wings off the back of the bulbs, raising suspicions that the Kiwis were hiding their real keel for the Cup match in the big black shed.

But yesterday morning's unveiling showed what few expected - Team New Zealand have kept the same cigar-shaped keel on NZL60, the chosen boat.

Sir Peter Blake laughed at the suggestion of a ruse. "We were truthful - we said so at the time. This is us - naked."

To the untrained eye, all that was different under Team New Zealand's skirts yesterday were flames painted on the nose of the keel bulb - a tradition continued from the Black Magics of 1995.

Prada appeared to have changed little to the underside of their boat, ITA45, since they unveiled before the challenger finals.

But the Italians reckon they have made a "significant speed gain" in the last few days with a little tweak of the appendages.

The battle has been to get more speed upwind. Team New Zealand say they've done it with their wings and with a flatter-bottomed bulb. Prada claim their big gains are upwind, but would not say how they've got them.

In keeping with all feisty America's Cup word wars, there was much debate between the two rival camps yesterday on the merit of where you put your wings.

When asked why NZL60's wings were in the middle of the keel, principal designer Laurie Davidson quipped that aeroplanes don't have wings at the back.

Rival Prada designer Doug Peterson scoffed at this. "Obviously they don't have the computational methods to figure it out correctly."

He reckoned he tested wings like that in both 1992, with America3, and Team New Zealand in 1995 - and they never worked.

"They are alone in their thinking," he said.

The Kiwis were not perturbed by Peterson. Structural designer Mike Drummond said they were very happy with what they had done.

"We have tested our boats in the towing tank, the wind tunnel and on computers, and we've also tested various configurations in the water," he said.

"We tried what Prada have done - but the ultimate decision-maker is the speed of the boat. And this way, our boat was faster."

So what do these things do? Winglets simply make the boat faster upwind.

The wind tries to push the boat sideways, and the keel resists. Water spirals off the back of the keel, making extra drag - the wings stop the corkscrew effect.

The theory behind having the wings in the middle is that it stops the spiralling earlier.

While the winglets sparked conversation yesterday, Drummond said Team New Zealand's real innovations this time were in the strange-shaped bow and the three-spreader Millennium rig.

Peterson was not moved by the Kiwi mast, which supposedly has better-controlled bend.

"We have spent a lot of time on our rig," he said. "We don't want to trade masts with them."