The carefree life of the surfer has been the subject of numerous novels, the best of which, such as Peter Benson’s Riptide and Tim Winton’s Breath, contrast fluid adventures on water with social and familial constraints on land. As he turns 80, Paul Theroux turns to this tidal subject with Under the Wave at Waimea, a pungent but frustrating novel about the easy pleasures of surf and sex and the undertow of mortality.

Theroux’s protagonist, Joe Sharkey, is an ageing bore of a beach bum living on the North Shore of present-day Hawaii. At 62, he is content with his daily waves, family inheritance and younger girlfriend, Olive, an English nurse with extraordinary reserves of patience. He bathes in the glow of being “the Shark”, a big wave surfer of legend. His outlook on life is simple: “You drop in, you ride for a while, then you die. The ultimate hold-down.”

But Sharkey’s joints are getting rusty and his tattoos look mottled. His sunset years dim further when he kills a vagrant, Max Mulgrave, while drunk driving. Sharkey slips into a debilitating ennui, aided by a growing marijuana habit, unable to sleep, surf or, crucially, take any responsibility for the accident. Olive is convinced that discovering more about Mulgrave will bring Sharkey back from the edge.

Theroux splits the story into thirds: the days before and after the crash, an extended flashback to Sharkey’s troubled youth and then a final segment on the trail of Mulgrave’s past. Along the way, there are cameos for real life figures, such as the Hawaiian Olympic swimmer Duke Kahanamoku and the gonzo journalist Hunter S Thompson (a friend of Theroux). Inclusion of the latter allows for comparisons to be drawn between surfers and authors: “Maybe Hunter saw Sharkey as the man he might have been had he not been a drunk, an addict, a show-off, a writer.”

As with his best-known novel, The Mosquito Coast, Theroux here uses nature as a platform for the male ego, presenting an exotic location laid low by toxic masculinity. Even the names of the monumental waves — Jaws, El Gringo, Banzai Pipeline — are combative. As a veteran travel writer, he is particularly good at evoking the world’s squalor: the “seedy street-hooker edge of Waikiki”, the ruins left by the hydrogen bomb tests at Christmas Island. And the dialogue rolls along with the staccato rhythms of the pidgin English spoken by the native islanders and the lingo of the “haoles”, the white surfers whose meagre vocabulary is littered with “gnarly”, “awesome” and “stoked”.

This well-conceived and at times striking novel is undermined by two major flaws. Firstly, there is the issue of editing, with missing words, extra words, repetitive phrases suggesting a confusion of drafts and a bulky central section that impedes the dramatic tension built by Sharkey’s existential crisis and subsequent search for redemption. And then there is Theroux’s fondness for erotic interludes, enthusiastically detailed passages involving “surf bunnies”, the groupies that hang around the beaches. The descriptions of Sharkey’s conquests on the surfing circuit around Tahiti, California and South Africa read like literary sex tourism.

Yet, while Theroux’s latest novel is hardly his finest work, the way in which he captures the heady, claustrophobic island atmosphere and the thrill of riding a booming “muscle of water” continues to keep it afloat.

Under the Wave at Waimea, by Paul Theroux, Hamish Hamilton, RRP£18.99/Houghton Mifflin Harcourt, RRP$28, 416 pages

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