Oracle Team USA aren't the only ones continually tinkering with their boat hoping to make it go faster.
The America's Cup defenders have certainly found a way to improve their boat, and what looked like a sure thing for Team New Zealand a week ago, has turned into a real battle.
Oracle have certainly improved their upwind speed and Team New Zealand skipper Dean Barker says they're continually trying to improve as well.
Barker says every day they learn a bit more about how to make the boat sail consistently better and they have to keep pushing, to improve loading and acceleration after tacking.
Team New Zealand's also been in a race environment for a lot longer than Oracle and they've learned a bit earlier than the holders, who have clearly looked at what works for the challengers and they've simulated it - and it's working for them.
Races 11 and 12 are scheduled for Wednesday, with Team New Zealand holding a 7-1 lead in the race to nine wins.
