A decision in the Team New Zealand design room early on is paying huge dividends in San Francisco.
Team NZ's huge upwind speed advantage over Oracle Team USA was laid bare for all to see yesterday as the Kiwi boat, eight seconds down at the bottom mark, kicked on the afterburners and rolled over the top of USA-17 in the space of two manoeuvres upwind.
Sailing higher and faster into the wind, Team NZ are averaging nearly two knots faster than Oracle, but it is the tacks where Jimmy Spithill's crew are really losing ground. Every time the two teams tack, Team NZ appears to gain at least 50m. That is because of their ability to perform a hull-to-hull tack.
Whereas Oracle crash down on to both hulls during the tack, Team NZ are able to complete the manoeuvre on one hull through their self-tacking jib system, which means tacking is almost automatic, with no need to haul or release the sheet.
"Our jib system is a lot better than theirs, it just is," said Team NZ tactician Ray Davies.
"The self-tacking jib is a huge advantage and I'd say they'd be kicking themselves for not having one."
Dean Barker said the decision to go with a self-tacking jib was made in the early days, and it has proven to be a sound one on the tight San Francisco Bay racecourse.
"You've only got 11 guys on the boat, you've got a huge amount of resources you have to throw at the hydraulics and sheet to keep the wing under control and we just figured it was too hard to have conventional tacking jib like the way Oracle's gone," said Barker.
After dominating on the upwind legs on the opening day, it was a surprise to see Team NZ look so wobbly in race four on Monday. Despite talking up their confidence sailing in the heavier breeze, they did not look comfortable when the wind picked up and made several ugly errors around the course.
Adding to the confusion, the Kiwi team then came out and blitzed Oracle yesterday in winds gusting more than 25 knots. But Davies has explained a problem with their moding on day two was behind their poor showing in the fourth race.
"We weren't tacking well [in race four] and that was our biggest issue.
"Our technique was not right. There's a windspeed where we have to change our technique on our boat and we were staying in sort of a lighter air mode and the breeze picked up a bit and we didn't click into the heavier tacking style which we were able to do today."