America's Cup- Grant Dalton on the new AC72 - Aotearoa

by Richard Gladwell on 5 Feb 2013
Emirates Team New Zealand's Managing Director, Grant Dalton spoke with Sail-World's America's Cup Editor, Richard Gladwell, after the team named their second AC72 - New Zealand Aotearoa.

(Aotearoa is the Maori name for New Zealand, meaning the land of the long white cloud, said to the the first sighting of New Zealand by the first migration.)

Here he elaborates on the new features on the AC72 catamaran, and the thinking behind them, along with an assessment of the competition and where they are ranked.

There have been some hull changes notably in a fining up of the bow and stern, but overall the focus is on drag reduction, and a new phrase was used by the designers at her launch - parasitic drag.

That theme is continued in the new boat with constructed fairings on most items to reduce the boat's aero-footprint as she moves against the apparent wind.

Perhaps surprisingly, given what happened to Oracle Team USA, the designers have given up some 'pitch stability' to reduce drag.

However Dalton says the big changes aboard are in changes to the way on-board systems work, and a reduction of weight - over the now-commissioned first AC72.

The question to be resolved is the interplay between hydrodynamics (how the foils on the boat will work to lift the hulls) and aerodynamics (wingsail and drag reduction) to find the optimum situation, particularly sailing upwind and whether it is more efficient to sail in complete displacement mode, or fully foiling, or as most suspect whether the real answer lies somewhere in between - where leeway is minimised as is drag from the immersed leeward hull.

Dalton also looks at the opposition, particular Artemis Racing, who have been the first to sail with a second generation wingsail. Dalton says he is not surprised with the changes that Artemis has made, and believes that their original boat and wingsail were too heavy.

First of a series of four with Grant Dalton, Kevin Shoebridge (COO on the shorecrew), Dean Barker (Skipper on the sailing aspects) and Nick Holroyd (Design Director).