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Juapa News
Posted on 01 February 2012
AC45’s TO GET WING EXTENSION
Last year at this time the AC45 was hitting the water for its first sea trials, no more than four months after the ORACLE Racing Design Team undertook the project. It is also in Auckland where in the coming days Emirates Team New Zealand and Luna Rossa Challenge are set to begin testing a wing extension for the speedy wingsail catamaran.
Judging by the picture at the top of this issue, where ORACLE Racing Spithill is as close to capsizing as you can get without actually going over, it’s hard to imagine the AC45’s needing more horsepower. But that was the concern with the America’s Cup World Series heading to light-air venues in Naples (April) and Venice (May), Italy.
“The extensions aren’t fixed permanently. We can put them on or take them off, so they’ll be used at our discretion for light-wind venues to add more power to the boats when we’re racing in lower wind ranges,” said Iain Murray, ACRM Regatta Director.
“We know that the lighter the wind gets there’s an exponential increase needed in area,” Scott Ferguson of the ORACLE Racing Design Team.
Ferguson drafted a couple of options to increase the area. Option #1 (as above) simply added the extension, an increase in area of 6.4 square meters. But the added area of 8.7 square meters is achieved with the new, four-meter extension and slightly extending the trailing edge of the third flap.
Once the shape was settled, the project was handed off to Paul Bieker of Bieker Boats (which designed the wing and platform handling systems for the AC45) and Thomas Hahn of Ixent GmbH. They did the structural design and detailing of the wing extension system on the behalf of ACRM. Glyn Davies of ACRM is overseeing the building of 12 extensions at a factory on Auckland’s North Shore.
The mods add about 25 kilograms of weight, and the extension had to be built out of glass as opposed to carbon fiber to not interfere with transmissions from the television antenna mounted atop the wing. The antenna also had to be cooled, so Bieker, Jolly and ORACLE Racing’s Tom Speers teamed up to design a venturi at the top of the wing to cool the antenna.
“The whole idea is to make sure you can fly a hull,” said Ferguson. “This should do it.”
COMPETITORS’ FORUM DISCUSSES CUP COURSE
ACRM Regatta Director Iain Murray hosted a Competitors’ Forum yesterday in Auckland, New Zealand. The forum was split into two groups, with the four main teams aimed at the 34th America’s Cup – ORACLE Racing, Artemis Racing, Emirates Team New Zealand and Luna Rossa Challenge – discussing matters involving the AC72.
A main topic of discussion was the racecourse, and a short one at that. Said Murray afterwards:
“The boats go faster than anyone anticipates, and there is now an appreciation of how hard they are to sail. It is going to be hard yards.
“The teams are very keen to know the course configuration, the leg length, course width, distances between the jibes and so on.
“Where we are coming form is that we have been able to hold good courses and have a variety of winners in races that range from 12 to 45 minutes in the 45’s. We will hold a two-lap course on a 3-mile course. To drag that out to 75 minutes would require five laps, and the feedback we are getting is that three half-hour races is a better solution.
“The attention span is better when you are watching 30 minutes rather than an hour long race. And our objective is to keep the viewers in their sets for the whole race.”
Murray, at the beginning of January, issued the possible course diagrams for the 34th Cup, one of which is illustrated above.
“If you take the Cityfront leg of about 3 miles, you are looking a set, three jibes and a drop – all in six minutes.
“You have to do six big winds (grinding maneuvers), just to jibe the boat.
“And you haven’t even pulled it up or down. So that is eight big winds, and then you factor in having to pull the sail up in 55 knots apparent windspeed. There is a lot of horsepower required there, and for 11 people to manage all of that is going to be very tough. It is going to take well-oiled, well-managed sailing machines to manage sailing these boats.
“If you look at the numbers up and downwind, that is 16 massive grinds for every two legs.”
Related article: Racecourses revealed for 2013
