America's Cup: Inside the Kiwi factory building Oracle's boat

A factory in Warkworth is behind every single team racing in the America's Cup.

Core Builders Composites has loaned tools to Team New Zealand but has done much more for the other teams, making complete boats, wings and dagger boards.

Tim Smyth is a Kiwi, but his main client is Oracle. He's been building their yachts for 17 years.

"It's pretty weird being in New Zealand where there's so much enthusiasm for the team," he told Newshub.

"We rationalised by the simple fact we are passionate for the sport."

Moulds from this year's boats are still on the factory floor.

The work requires expensive equipment, including a massive cutter accurate to 0.2mm.

It's the technology on which Oracle built its last victory.

"We feel incredibly proud that the product produced the goods," Mr Smyth said.

You would think being part of Oracle's last successful campaign, the future for Core Builders Composites would be assured.

That was far from the case. Once the Cup business dried up, it had to restructure and diversify to survive.

It's created the shell for a solar car challenge, made out of recycled materials from Coke and Boeing.

The company is also playing a part in the development of the Sky Path under the Harbour Bridge.

And there are projects he frustratingly can't talk about, like Rocket Lab and flying cars.

"If you can't say what you are doing, how does anyone know how good you are?" Mr Smyth said.

He denied Oracle's built a second boat for the competition and said there's no real secret weapon.

"Everyone was searching for that reason last time, especially after that comeback, but don't forget the development curve of these boats that any change you make, it's going a long way up a really steep curve."

It means a few tweaks might shoot the performance right up.

"If it helps someone to win then that's a good trick," Mr Smyth said.