Science & Environment

Science goes in search of the perfect wave

Surfing Image copyright AFP

For centuries, people have been lured in by the thundering power of surf.

Surfing began somewhere in the distant past of Polynesian culture and by the mid eighteenth century, Captain James Cook sailed to Hawaii and saw locals climbing onto wooden boards and speeding along the waves.

Eventually, a craze for wave riding spread and now it's thought at least 36 million people worldwide identify themselves as surfers.

They all, however, face an inescapable truth: perfect, surfable waves don't always show up where and when they're wanted.

"Most of our good surfing waves around the world are adjacent to big expanses of ocean," says Dr Mark Davidson of Plymouth University, an oceanographer with a special interest in waves and surfing.

The best surfing waves start life in stormy seas far from shore. Winds whip the surface into peaks which race away from the storm centre and over time transform into swell that rolls along under its own steam.

Like fine wines, the best waves take time to mature.

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Media captionClaire Marshall tries out a prototype surfing lake in Wales

These water-borne pulses of energy continue their long journey towards land, sorting themselves out as they go, becoming less choppy and more refined - and bigger.

That's why world-class surf rolls to shore in spots like Hawaii, Bali and Portugal. Elsewhere, where there isn't a wide ocean delivering well-matured swell, people are attempting to improve the waves.

The aim of artificial surfing reefs is to enhance smaller waves into a surfable break.

"There's no magic here, you don't create waves," says Dr Davidson. "The idea is that you can focus waves, a bit like light travelling through a lens," he says.

A reef - natural or otherwise - acts as a magnet for swell, concentrating the waves' energy and making a bigger, more powerful break. That's the theory, anyway.

One of the newest artificial surfing reefs was installed on England's south coast, at Boscombe close to Bournemouth.

Boosting performance

Here in the English Channel, where long-distance swell is distinctly lacking, waves are driven by local winds which produce choppier, smaller surf.

In a bid to improve the quality and consistency of Boscombe's waves, Bournemouth Borough Council paid £3.2 million to install an artificial surf reef.

The football pitch-sized reef consists of sand-filled geotextile bags that were designed to raise the seabed and magnify existing waves.

But when the reef opened in 2009, it was a crashing disappointment for local surfers.

"It didn't produce the right shape of wave," says Mark Davidson.

He was brought in to assess the reef's performance, which he did by surfing it with a GPS unit fitted inside his wetsuit.

"That allowed me very accurately to evaluate my ride length, the peel angle of the waves and how fast the wave was breaking," he says.

Dr Davidson concluded that the reef was no good for surfing.

It kicked up steep, dumpy waves that collapsed over his head rather than breaking gradually, peeling from one side to the other.

Quality waves

Boscombe's surf reef is not the first to fall short. According to Davidson, of the 12 artificial surf reefs built worldwide, none have worked.

"As yet we still don't have a successful example in generating a quality wave for recreational surfing," he says.

The flaws could come down partly to the turbulent sea shifting the sandbags until they lose their original shape.

It's also clear that scientists still haven't yet got to grips with the complex mix of ingredients that go into sculpting natural waves.

"We're still learning," Mark adds.

Image copyright Surfsnowdonia
Image caption Some modern surf reefs are built around inland lagoons like this one in Wales

Another wave-making team has taken things a step further by removing their waves entirely from the unfathomable ocean.

I encountered some of these artificial waves in a most unlikely location - a peaceful lagoon many miles from the sea, at the foothills of the Cantabrian Mountains in northern Spain.

This is the prototype Wavegarden, the upshot of a decade's research and development and the brainchild of Josema Odriozola.

He was inspired to build the surfing equivalent of skate parks; a space for wave-riders to congregate and practise their sport.

Lying on my board in the purpose-built lagoon, it's a radically different experience to surfing at sea. There are no currents to battle or unwanted waves splashing in my face.

All I have to do is wait and a perfect wave will come my way.

Still, I'm nervous at first, unsure if I'll be able to catch the huge wave that rises up out of nowhere like a sea monster from the flat lagoon and races towards me, a wall of glassy, green water.

Blades of glory

The secret to the Wavegarden's success lies along the midline of the oval lake, hidden beneath the surface.

Key engineering details are carefully guarded but Josema tells me the device is essentially a blade, shaped like an aeroplane wing, known as the "wave foil".

A winch adapted from a ski lift drags the wave foil through the water, creating a wake behind it.

Josema explains how they've honed the wave foil's shape to minimise energy consumption while making the biggest possible wave - the Wavegarden can generate 1.2m-high waves and 2-metre giants.

As for the length of the ride, there's no limit: build a longer pool and you'll get a longer wave.

All that matters is that the pool is the right shape.

"There must be a certain angle between the swell and the shore, and these conditions don't happen so often in the sea," says Josema. "This is what we're recreating here, these special conditions."

On my first ride at the Wavegarden (admittedly with some assistance from Josema) I'm amazed when I catch the wave and get to my feet.

I find myself hurtling along, trees whizzing by, and suddenly I grasp the whole point of these artificial waves: they're truly exhilarating, but they are also the fast-track to getting better at surfing.

For years I've struggled to be in the right place at just the right time to catch an awesome wave like this. After a few more goes I begin to get the hang of these artificial waves which sweep up and down the lagoon, one every minute.

Now that Josema and his team have perfected the technology, surfers will soon be riding waves in various other unexpected places.

Wavegardens are due to open to the public in the inland reaches of Dubai, the US and even wave-pounded Australia. The first opened recently in the last place you'd expect to find a decent surf break, among the craggy peaks of Snowdonia.

So, will landlubbing, artificial waves take off?

I put that question to Boscombe-based surfer, Sean Taylor.

"Every surfer will be curious about a manmade wave and everyone will want to try it," he says. "But ultimately you're always going to want to come back into the ocean."

That's clearly the case for the hardcore surfers who still flock to Boscombe whenever breakers appear - next to the pier, but not over the reef - even if the waves are few and far between.

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