'The bear away'

Both teams are now having to make what is known as a 'bear away' in order to cross the start line within the designated boundaries. Because you can't sail a boat directly into the wind, you have to tack or gybe, essentially zig-zagging your way from A to B. As you execute each turn you must bear away from the direction that the wind is coming from, but this can be destabilising if you try to make too sharp or too hasty a turn.

As you can make out from the second freeze-frame, New Zealand have been forced a little wider and are closer to the start line when they begin to bear away. That means the angle on their turn is significantly more acute.

The rest is here:
The anatomy of a capsize: how did a multi-million dollar America's Cup boat end up in the drink? - Telegraph.co.uk