'Fresh to frightening' conditions set for America's Cup and Team New Zealand

Emirates Team New Zealand hold a 2-0 lead over BAR. Photo / Ricardo Pinto

The America's Cup challenger semifinals could become a battle of survival, with "fresh to frightening" conditions forecast over the next few days.

After light winds on the Great Sound forced the postponement of the opening day of the semifinals yesterday, the forecast later in the week looks set to test the upper end of the wind limit of 24 knots.

It will also test the boat handling and mettle of the respective crews.

Emirates Team New Zealand skipper Glenn Ashby said once the wind gets above 20 knots, the high-tech, but highly skittish, 50-foot foiling catamarans become very difficult to handle.

"It's going to be fresh to frightening at times, and we're going to have to work really hard to get the boat around the track in one piece," said Ashby.

"It really comes down to how well you can handle these boats. They are very whipped up in the big breeze and very, very difficult to sail. The choreography needs to be perfect to get the boats around the startbox well. You're almost semi-surviving in some of these conditions to do your manoeuvres, so it is going to be very, very interesting to see who can survive these conditions."

Gear breakage has already had an impact on the semifinals, with Team NZ's opponent, Ben Ainslie Racing, forced to retire early on in today's opening race due to a malfunction in their wing control system. The British team were unable to resolve the issue for their second race of the day, handing Ashby's crew a 2-0 head start in the first-to-five series.

It was a bitter blow for the Brits, who felt Team NZ might be more vulnerable in the stronger conditions.

The performance of the New Zealand boat in light air has been a talking point through the qualifying rounds of the America's Cup, but Team NZ helmsman Peter Burling said the team are also comfortable in the upper ranges.

"Like all the teams here, everyone has done a fair bit of sailing in stronger breeze. For us it was back home before we got to Bermuda. So it has been a while since we've sailed in those conditions, but we are really confident in our boat and our equipment and we're really excited about the next few days," he said.

"Obviously it is going to be close to the upper limits, but these boats are built for that."

Should the conditions over the next few days stay within the sailable range, regatta director Iain Murray expects we may see some speed records broken.

The speed radar is most likely to peak as the teams bear away at the first mark, where the boats accelerate through the "power zone".

"To approach that, and to be safe, they need to have as much speed as they can to keep the wind coming in front of them, or their apparent wind forward," said Murray.

The top recorded speed during racing at the last event in San Francisco at 49.3 knots, achieved by Team NZ. Murray said he has heard talk the 50 knot barrier had been broken by some teams in training, but pointed out speed readings aren't the most important measure in this America's Cup.

"The big difference here is, in 2013 it was early days of foiling and I think the understanding of the art of racing foiling boats has changed considerably since then. I'm seeing people aren't chasing top speed in these boats, they're chasing best VMG [Velocity Made Good], so typically these boats downwind, they're not trying to go 50 knots, they're trying to get to the bottom mark as quick as they can, and by doing that we are seeing the boats sail at unprecedented deep angles downwind."