Inch, Strandhill, Bundoran . . . Ireland's popular surf spots are well known. But where do serious adrenalin junkies go? In an extract from his new book, KEITH DUGGANjoins a crew in Co Clare whose lives revolve around pursuing wild waves

YOU COULD hear the Lambeg crash of the wave before you saw them, lost in it. This was on a dazzling September afternoon at a patch of lunar coast in Co Clare, bashed by big emerald barrels of water.

You would never find the place without precise directions. It isn't a million miles from Doonbeg village but you have to make a sharp turn at such-and-such's unpainted bungalow and skip the first side road and look out for the school, and the narrow lane you eventually end up on promises to lead to nothing but a dead end. And in a way, it does: it brings you to land's end but the upward slope of the road obscures the sea until the very last second. When they are surfing there, you will find vans and cars not so much parked as ditched in the unkempt hedgerows, and not until you climb over the barbed-wire fencing and stand on the grassy bank will the wave show itself. It is so loud and spectacular and breaks so shockingly close to the vast rocky platform that it seems like a bit of a joke that nobody knew about it for so long.

The wave and the place have become known as Riley's. It was discovered in the last five years and only then because of the persistence of a roving Cornishman named Mickey Smith. He was out there among them on this day, although from the cliff's edge it was difficult to make out who was who. From the headland, you could see them in the water - black shadows on surfboards circling the wave.

"It won't be 'big' big, just good fun," Fergal Smith had promised on the phone the day before. The Mayo man is only 24 and has, over the last few years, opened a portal to big-wave surfing in Ireland and been the chief subject of the ethereally beautiful photographs which Mickey Smith takes of people surfing waves. The best of these images have never been seen; others appear in surf publications, and every so often one might show up in an Irish newspaper or magazine, but always, always they catch the eye because of their jaw-dropping clarity and beauty. And perhaps also because the child in everyone instinctively wants to know what that must be like: to glide through the canopy of an ocean wave. It looks like what it is: a form of magic. Smith's photographs are so detailed that you can see the expression on the faces of Fergal Smith or Tom Lowe or Tom Gillespie during those few seconds when they are in the heart of the wave. Sometimes they appear to be in a trance.

They are all hooked on this. A bunch of them, Cornish and Irish lads, fell into a kind of loose confederacy based on their mutual love of surfing waves and, in particular, the pure-ice big waves sculpted by Irish winters. They all live sufficiently close to the key waves in Clare - Aileen's, Riley's, Bumbaloids - to enable them to move from their kitchen sinks to the Atlantic in less than half an hour. They study online weather charts the way novices read scriptures and, given half a chance, they can switch into meteorological geek mode. Any idea that you might have about surfing, formed maybe from the dreamy classics of the Beach Boys or the zanier moments in Point Break or floral-scented travel articles about Hawaii, can be torn up when it comes to this group.

To begin with, it is not as if they go to the cinema or the pub together or hang out in any conventional sense. They are only a group because they congregate around the same patch of ocean whenever the swell dictates and because they were all present around the time when Aileen's, the wave beneath the Cliffs of Moher, was first surfed, in the autumn of 2006.

BEYOND THE water, they have different lives. Tom Doidge-Harrison is both an engineer and a board-shaper. Dave Blount works in IT. Tom Lowe lives in Spain and his appearances in Clare coincide with anticipated ocean swells. John McCarthy runs a surf school in Lahinch. Tom Gillespie studies economics, Hugo Galloway science. Seamus McGoldrick swapped astrophysics for traditional music. The Skajarowski brothers, Dan and Steph, work in the tourist industry in the summer and surf all winter. Bill Keane is what he always has been: a sometime carpenter and sometime mystic. Mickey has his music and film making and photography.

But Fergal Smith is a surfer, pure and simple. He was in school in Mayo during the fast years in Ireland, when all voices were full of money and when the ambition common to all smart kids was to make a pile. Smith was profoundly uninterested in all of that.

By the time he was 15 he wanted to "be" a surfer. As a career, it promised nothing more than penury and obscurity. To his peers, he might as well have said he wanted to be a priest. And maybe that would not have been so far off the mark because from the beginning, surfing was more of a vocation than a pastime for him. A handful of talented Irish surfers have come and gone down the years but the idea of trying to make a living from surfing in Ireland was preposterous. It was what Australians or Hawaiians did, not Irishmen.

Still, Smith went for it. He didn't permit himself the safety-net of a college course or a trade, he just dedicated himself to surfing. He has the ascetic self-discipline of any Olympic athlete. He trains on land and in the water and isn't bothered with night life. They all have tolerance for cold water but Smith sometimes lasts for eight hours on briny winter days, fighting ceaseless Atlantic currents and cutting northeasterlies just to ride three or four waves that he is completely happy with. He eats frugally during these marathon sessions and seems to have a squirrel's constitution for storing energy. The glamour is an illusion: they all like to say that surfing must be the only sport in the world where you have no choice but to piss yourself several times a day.

Fergal Smith lost whatever interest he had in competitive surfing years ago. He likes it best when there is absolutely nobody around. Those are the moments when he surfs at his freest and when Mickey Smith ends up with photographs that keep. Fergal is the youngest of this group but he has flung himself into this idea of exploring how Irish waves can be surfed with such terrific energy and faith that he sometimes seems like an older brother to all of them.

If they share a common trait, it is politeness. They are quietly spoken and friendly lads and they are stealthy in their ways. No showboating or talking it up. They go about their days almost invisibly. Because of the weather patterns, they are often up at dawn and already in the water while the rest of the country begins to stir to the news headlines.

And that is probably the most important thing about these men and what they do. On those mornings, when most of the country is crawling along twilit motorways or coming off shift work and when the bulletins are echoing with grim and grimmer news and when you can't wrap your scarf tightly enough around your neck, there is a handful of people who are slipping into the Atlantic water to pursue something that falls somewhere between sport and art. And when they are doing that, nothing else in the world matters.

WHEN YOU stand in front of the wave at Riley's or when you walk down the sheer trail at the Cliffs of Moher that brings you down to sea level, a strange thing happens. It is as if everything that happens above - everything in Clare and across the country - doesn't matter so much. The white noise and the worries of everyday life suddenly seem very distant.

It is not as if these men are escapists. They have bills to pay and inevitable family dramas. Half of them have become parents over the last few years. It's just that they have learned to prioritise what is important. Most of them have been lucky enough to surf in the world's dreamier locations - Bali, Hawaii, Australia, Tahiti - but they have known plenty of weeks and months of living hand to mouth as well. They lived in Ireland through the years when mad excess turned molten, but they were too busy with the waves to notice or care all that much. And now that the riches have all turned to dust, nothing much has changed for them. They never lost sight of what mattered to them.

Occasionally, Bill Keane will drive over to Riley's and peer over the edge of the cliff at the mayhem. There were years when Keane had the waves around Clare for himself and he is thrilled by the revolution that has occurred over the past decade. "That place is for the adrenalin junkies," he smiles.

"Those bodyboarders are like a different breed. They are out for a different thrill. Bodyboarding was kind of frowned on when I started surfing. There was this attitude that anyone could do it. So wrong. The things that Mickey and Dan do out there are bonkers. Not many can do it. And Fergal . . . he is the only guy in the country who can paddle into a wave in Riley's. They can all get towed in but paddling is different.

"I am mad to go there and look at what is going on but I am usually off somewhere else when there are good waves. It is way beyond my capabilities, so good luck to them."

If you want to see them up close at Riley's and have been told how to find the place, you have to be prepared to trek across a few fields that turn boggy in winter and walk through a herd of cattle that always look stunned with boredom. You have to jump a few watery ditches and climb a gate and then begin to walk across the long rocky ledge which is lethally slippery all year round but farcical in winter, when the surface freezes over. It is not the most inviting place to visit. Rock falls, from pebbles to boulders, happen regularly; the platform is strewn with smashed-up stone. About halfway across lie the dried-out hides of a horse and foal which fell from the headland a couple of years ago. The rock shelf has collapsed in the middle so you have to skip across a narrow ledge to get across to where the wave breaks. Most of them make that trek every time they come here, carrying their boards with them.

The wave at Riley's is glitteringly beautiful, and because it breaks so close to the reef it is exceptionally dangerous. Most of them have been scarred by it and still they trust that they will be all right there.

Cliffs of Insanity: A Winter on Ireland's Big Waves by Keith Duggan is published by Transworld