Most beachgoers were oblivious to the top-secret action taking place offshore on August 29 but a keen-eyed multihull sailor didn't miss it.
Graeme Swan snapped Team New Zealand's AC72 catamaran hydro-foiling in the Waitemata Harbour nearly a week before the America's Cup team officially revealed their boat's new capabilities.
The increased speed gained from the latest advances could give the New Zealand boat a significant advantage over competitors.
Swan was taking his daily walk from Mairangi Bay when he spotted “huge wakes out to sea”.
The wakes were created by chase boats trying to keep up with the New Zealand catamaran, the sail of which Swan could just make out on the horizon near Tiritiri Matangi.
“As a multihull sailor I knew as soon as I saw it what I was looking at. They would get closer and then disappear again.”
Cutting his walk short and making some quick calculations, Swan knew he could rush home, grab his camera and get to North Head to capture some more action before the boats headed back to base.
It was here that he prematurely unveiled to the world Team New Zealand's secret weapon in a series of 25 photos.
"When I got there they were a couple of miles out doing a few more runs," Swan says.
"Then they came into the harbour entrance, stopped head to wind, had a bit of a fiddle putting their furled gennaker up. Then they brought the bow down, unfurled the gennaker and took off.
"It wasn't until I looked at the photos I saw they were up and flying."
Catching a glimpse of the catamaran lifting clear of the water on both foils and speeding across the harbour was an "absolutely exhilarating experience" for Swan.
His photographs posted on his Facebook page and shared with friends quickly went viral and caused a stir in sailing circles.
Many claimed the photos were digitally altered.
Prior to the official September 6 unveiling Team New Zealand would not confirm that they had been foiled by the Shore sailor's snaps.
Team New Zealand managing director Grant Dalton says all the teams will be testing foil design.
“Foiling is only part of the equation. Right now we see as many negatives as positives.”
The 34th America's Cup will be raced in San Francisco in 2013.
- © Fairfax NZ News