Team New Zealand's secret weapon in winning the America's Cup has been revealed - and it's not what you would expect.

An American surfer has emerged as one of the unlikely heroes in the Kiwis' ruthless 7-1 pounding of Oracle Team USA in the Cup final off Bermuda.

Nick Bowers was signed up by Team NZ skipper Glenn Ashby more than two years ago. 
The Kiwi syndicate moved Bowers, a former surfboard maker and professional kite surfer, his wife and young family to Auckland two years ago and kept his presence in the New Zealand camp an even quieter secret than the ground-breaking shift from grinders to 'cyclors".

Bowers' job title was 'performance analyst' but it was his cutting edge work with drones that provided Team New Zealand with a significant design advantage over its Cup rivals.

He designed special drones capable of not only keeping up with Team NZ's super-fast boat but capable of flying right alongside it and gaining priceless footage on how the catamaran's revolutionary hydrofoils could be improved.

Bowers' recruitment came thanks to the eagle eye of Ashby.

Bowers had just got into the sailing drone business, fielding a 5am phone call from a boat maker in Holland asking if he could go to Italy that night to shoot video of the world catamaran championships.

He was living in a tiny town in Wisconsin at the time, running a small video production company specialising in drone footage.

Bowers's captivating footage from the Italian regatta immediately caught the attention of sailing enthusiasts.

"I had never seen anyone be able to shoot the angles he was shooting," Bailey White, president of the US Sailing Association told the New York Times.

"While the boat was up in the air foiling, he was getting so low flying this drone that he was actually below the boat, so you got a sense for exactly how the boat was performing and how the sailors were doing."

An impressed Ashby offered him a position running Team New Zealand's visual data program, including all the cameras on the boat, plus drones.

The use of drones around filming boats for analysis is hardly new but Bowers cracked a code that took the process to a new level and provided the Kiwis with a huge advantage in the sport's technological arms race.

The top seed for the most high-powered drones is around 86kmph or around 47 knots in sailing terms.

But the drones were difficult to pilot at that speed - and they were also too slow given how fast the Kiwi catamaran was.

"I wanted to film one of these America's Cup boats sailing upwind, but nothing commercially available could do that," Bowers explained in an interview with the New York Times.

"It wasn't like I woke up one day and said, 'I want to build drones.' It was done out of necessity."

From there, Bowers virtually stumbled onto his unusual filming style which provided Kiwi designers with fresh and important new information.

Nick Bowers. (Photo / Emirates Team New Zealand)

He initially started filming without a monitor because he couldn't afford one. That taught him to watch the drone feed instead of the video feed and he quickly discovered this gave him both better control and better footage.

He was able to film less than a metre off the water, and right next to the Kiwi boat.

The drone was agile enough to get out of the way if anything went awry while he used the screen on the flight controller only for "rig shots" directly overhead.

Bowers said he combined what he knew about composites from his days making surfboards and about wind from his sailing and professional kite boarding days. 

He built a new drone in his bedroom at the end of 2015 after choosing a design that let him fly it into a strong headwind but still be "ridiculously efficient."

He succeeded and his cutting edge drone was able to pace the Kiwi boat in high winds and heavy seas. By replacing the factory-issued wide-angle lens with a different lens, he was also able to get cleaner and more professional footage.

The drone's footage assisted hugely with Team NZ's innovation, particularly around hydrofoils.

Bowers and his young family of four (he had a son while in NZ) moved to Auckland in late 2015. Every training and development session, he sailed in the chase boat behind the team for hours as they tested new, aggressive moves.

Back on shore, he would spend hours syncing his videos with the boat's telemetric data. 
Shortly after arriving in New Zealand, Bowers decided he needed an even more powerful drone to keep up with the Kiwi cat.

He was delegated a space in the Team NZ workshed and set about building a drone twice the size of the previous model and capable of reaching zero to 85kmph in one second.

Because of Bermuda's drones laws, Bowers did not travel with the team to the Carribean.

Instead, he and his family headed back to Wisconsin where he is trying to start his own company using a 3-D carbon fibre printer to stamp out new drones.

But the New York Times reported he isn't finished with sailing. He will be in Greece next month to shoot the Corfu Challenge event and has been hired by US Sailing.

"He can fly in conditions other people cannot," the organisation's Olympic development director Leandro Spina said. "When it gets pretty windy, Nick will fly. Other people will be like, 'No, it's too windy.' But he has no limitation with drones."

Team New Zealand will say 'amen' to that.