He couldn't catch a wave - so he decided to build one in his backyard, one of the furthest places from the ocean in New Zealand.

When it comes to catching a wave, there are few places tougher for surfers to find one than Hāwea Flat.

The small settlement just outside Wānaka in inland Otago is two hours' drive from the nearest beach and more renowned for its nearby snow.

But entrepreneur and surfing enthusiast Ross McCarthy planned to change that with the launch of YourWave - essentially what happens when a bouncy castle and a wave pool collide.

The former Scarfie, with a Masters of Industrial Product Design, decided to build the stationary wave machine in his backyard - one of the furthest places from the ocean in New Zealand.

But why?

"I started in Dunedin, so we were pretty close (to the ocean) back then. But I've just always had a passion for watersports. 

"I've always loved surfing, I've always tried surfing, I've never been that great at it but I'm pretty good at building things."

The result was impressive.

YourWave is a stationary wave machine. Photo: RNZ / Nathan McKinnon

Think of a river washing over a huge bouncy castle that you can manipulate and inflate or deflate to your desire.

"A lot of people describe it as the ultimate Malibu wakeboarding boat. We produce a pretty gnarly wave that's getting up to head-height at the moment.

"There is a still a wee bit of R&D involved in this unit because we want to make one of possibly the tallest stationary waves in the world so it's going to come out around two metres high eventually, which is going to be really, really gnarly."

The idea came to him like many of the best of ideas do.

"Funnily enough, it came up over a few beers with just me and a mate. We saw original stationary wave machines and said 'Why don't they put it on a bouncy castle or inflatables to make it a lot safer', so the idea sprung from there."

That was 12 years ago.

What followed was the better part of three-quarters of a million dollars in Callaghan Innovation funding, a similar sum of private investment and a lot of trial and error.

Ross McCarthy has launched YourWave in Wānaka. Photo: RNZ / Nathan McKinnon

What set McCarthy's machine apart from other stationary wave machines was its versatility.

It can change from a left-hand to a right-hand break on the fly, as well as produce waves for everyone from the smallest surfer to those more used to making a splash in the open ocean.

He is ready to go public with the product, but was just waiting on the green light from WorkSafe.

For now that means a handful of locals, like Katie Tsuyuki, get exclusive access.

"I live about five kilometres from here and it's just so awesome to have YourWave right by us," she said. 

"It's a really great opportunity for anyone who's learning how to surf or already an avid surfer. They can change the different shapes of the waves to accommodate your level and that's a really cool asset to have here in Wānaka."

Sacha Wetzel agreed.

"This is proof that when you take the toys out of the sandpit, the child innovates. This is the best of the best because there's nothing here - you make everything you need right here. 

"It's proof that you don't need a city to make something amazing. Little town, big inventions."