The AC72 catamarans are still being developed and improved, even as the competition proceeds. Emirates Team New Zealand skipper Dean Barker said after Race 10 that if they were still sailing their boat the way it was at the start of the Louis Vuitton Cup in early July, they would lose every race in the America’s Cup Match.
Oracle Team USA has made their boat dramatically faster upwind during the first week of the America’s Cup. They have removed the long bowsprit for the gennaker and the supporting kingpost and stay from the underside of the boat. They have also moved to different daggerboards, with the winglets set at an obtuse angle to the main board. These boards are faster but less stable. The boat is clearly faster upwind, but they did drop down off the foils in the first leg of Race 10, losing speed and allowing ETNZ to establish a critical overlap.