America's Cup- Emirates Team NZ - getting from side to side
by ETNZBlog on 9 Nov 2012
Here’s the second part of the interview Sailing World editor Dave Reed had with Emirates Team New Zealand technical director Nick Holroyd. The interview was first published in the October issue of sailing World magazine.
There’s a lot of boat to cross for the manoeuvres; how does everyone get up on that hull quickly?
Raising the Genoa. Emirates Team New Zealand. Day 13 of testing for the team’s first AC72. Hauraki Gulf, Auckland. Chris Cameron/ETNZ© http://www.chriscameron.co.nz
One guy leaves the weather side early to load up a sheet winch and set up the boards. Then the majority of the crew crosses the boat as it’s going head to wind. You leave a couple guys behind to get the board down and then bring them across. We’re looking more to have weight on the high side out of the tack—you need that full power to sheet on the wing and get the acceleration going because your boat speed deltas between the bottom of the tack and getting going again are vast. Getting the guys up to the high side early to have stability is very important.
How about the helmsman getting from wheel to wheel?
There’s a triple act between Ray [Davies], Dean [Barker], and Glen [Ashby]. Someone’s taking the wheel off Dean, and he’s set up to take the wheel out of the tack. The boats are actually pretty efficient through the tack, unlike most multihulls, because the wing drag is low compared to soft-sail cats.
It appears your rig is farther aft than that of Oracle’s. What’s the tradeoff?
Again, it comes down to structure, and in this case, how much forestay tension you can achieve within the structure. A lot of forestay tension means a lot of stretch in the forestays, backstays, and under-rigging, which means a lot of work in terms of grinder input. The boards are highly loaded, and going through those manoeuvres is about keeping wing controls relatively simple. If you have too many controls to get the wing shape to where you want it to be, you’re likely never going to get there.
For the rest of this interview http://www.etnzblog.com/#!2012/11/ac72-design-getting-from-side-to-side!click_here