Team New Zealand appear to be right on the pace in the development race for the next America's Cup, after a video released this week shows they have mastered the upwind foiling tack.
Long regarded as the "Holy Grail" of the America's Cup, the foiling tack has been the last significant barrier preventing America's Cup teams from hypothetically foiling around an entire racecourse - a feat that could potentially define the outcome of the 2017 America's Cup in Bermuda.
Dean Barker's Team Japan were the first to crack the code, pulling off a foiling tack last month during testing in Bermuda. Defenders Oracle Team USA, who have been keeping a close eye on Team Japan, made the breakthrough two days later.
After both the Japanese and American-flagged teams shared videos proudly trumpeting their foiling tack development, Emirates Team New Zealand opted for a more understated approach.
Providing a general update of their progress in their testing programme, the video finished with a quick glimpse of what may be the most stable upwind foiling tack yet.
Team New Zealand skipper Glenn Ashby concluded, "I think we're going okay."
The introduction of giant 72-ft wingsail powered catamarans for the last edition of the America's Cup resulted in the development of foiling become the key battleground. Team New Zealand were the first to get their boat foiling for sustained periods downwind, and were a step ahead of their rivals in choreographing foiling gybes.
By the end of the 2013 America's Cup Oracle and Team New Zealand were just beginning to get the boats foiling upwind when the conditions allowed.
What each team is chasing in the new 50ft America's Cup race boats for the next event in Bermuda is strong, stable, continuous flight. That means not only foiling upwind for sustained periods, but being able to keep the hulls out of the water whilst tacking.
Having only launched their first AC45 test boat in June - nearly a year after some of their key rivals - Team New Zealand had a lot of catching up to do in their on-water testing programme. The advance of summer in the southern hemisphere should help speed up their progress, while the other five America's Cup teams face the approach of winter at their nothern hemisphere bases.
"It has been cold and windy a lot of the time," said Ashby. "We have had our fair share of ups and downs over the last few weeks, but we are making some fantastic gains."
The Kiwi team has been lying low, quietly chipping away and making gains on the water with their first in-house designed and built AC45 test boat. Their Olympic gold medalists - Peter Burling and Blair Tuke - are back in camp, and skipper Glenn Ashby has been relishing the opportunity to be out sailing despite the bitter conditions of the fading winter season.
"Boat speed wise, the AC50's will be faster than what we were sailing in San Francisco on the AC72's."
"The ultimate goal is to keep the hull dry around the track, so the testing phase we are in the moment is trying to come up with systems and techniques of how we actually get the boats around the track."