SEA stories always seem to be about something else. Moby-Dick is a metaphysical quest wrapped up in a lot of research about whales. Lord Jim is about country and exile, and Joseph Conrad’s masterpiece Nostromo is a passionate indictment of capitalism. A Wild Call comes out in a series devoted to sailing and aimed primarily at the yacht and dinghy crowd, but even if you don’t know your keel from your burgee, it has the universal appeal of a love story.

It’s not the love story flagged up at the beginning when, following his father’s death and aware of a growing dissatisfaction with his day job in animal conservation, Martyn Murray starts to revisit his childhood connection with the sea and rediscovers a long-buried passion. Nor is it, or not entirely, the story of his chivalric rescue and restoration of a beat-up Cornish ketch he re-names Molio, after Arran’s most famous saint. Nor is it even the dream of a voyage out to Britain’s most remote archipelago, though he does, eventually, sail to St Kilda.

The yacht and dinghy crowd might well wish that Murray had dumped a lot of the romantic stuff, but the real heart of the book, and by no means the smoothly beating heart, is the story of his relationship to the red-haired woman he calls (though it might even be her real name) Kyla. I’ve rarely encountered such a compelling but troubling character in a real-life book, so much so that I wondered more than once whether she might be some kind of literary device, invented to give Murray a sounding board and a means of self-analysis. Never quite girlfriend, never quite soulmate, Kyla is a doughty first mate one minute and a fierce critic the next. She berates Murray for confusing escape with freedom, and mere play for a settled way of life. And then she’s gone again for a chapter or two, present only in e-mails which make her sound less petulant and more thoughtful than she appears to be in person, albeit full of rather patronising advice about what Murray needs to do or not do.

There’s another woman on the scene, called Cori, who seems warmer and steadier, but in the end just as remote and just as likely to be called away to other commitments or desires, and it’s never entirely clear whether Murray’s stoic reaction is front or reality. The only steady relationship is with Molio, the only consistent urge the three-part sail from Crosshaven in Ireland to Ardrishaig, from Loch Fyne to Plockton, and finally from Crinan to Hirta, the veiled beauty of St Kilda.

The book’s steady theme is indeed about freedom, or escape. Murray profoundly admires the sailing community, hobby sailors and liveaboards alike, and reminds us in every chapter how much and how wastefully Scotland has turned her back on her seaways, where a boat’s wake is erased in seconds, in order to carve up and tarmac the country. Where I live, which is just down the road from where Murray berthed his boat, is no distance by water from anywhere, but a long and nerve-wracking slog on deathtrap roads. We’ve turned our backs on our natural conduits, and it has changed our nature.

The book’s more political message is that what was once a natural community whose values were expressed in the principle of free anchorage and responsible fishing has turned into a narrowly acquisitive culture of profit. The burghers of Tarbert have never quite forgiven J MacDougall Hay for the harsh portrayal of “Brieston” in Gillespie but anyone who has had to fork out harbour charges (for which you become liable if you so much as come about near Tarbert) will recognise that Hay’s libel wasn’t quite without foundation. Murray feels passionately about such things. A spirit of generosity has gone from the world, as well as a culture of pilgrimage. Murray debates with Lama Yeshe, near the little Buddhist monastery on Holy Island, but the conversation is mostly about animal ecology and sustainable herding, and one senses that he dislikes the gaudy rock paintings that have replaced the faint runic scratches of the early settlers and saints.

The matter of Kyla, and of Kyla’s verdicts on Murray, is never quite settled, and she remains a disturbing semi-presence throughout the book. Murray is a subtle enough writer to let us consider the possibility that, yes, he is a lonely obsessive, with a profound fear of commitment and land-life. Not everyone wants to live in permanent damp, or having to deal daily with a Baby Blake toilet (a device which makes constipation seem like A Good Thing), or with no fixed view from your cabin window, but there is no clear answer to the book’s nagging question about the difference between freedom and escape. For those who commit their lives to rotting planks, the answer is self-evident, and the sailing “crowd” is really no such thing but consists instead of the only real individualists left standing, or rather rocking on the swell. This is a wise book, not least in coming to no firm conclusion. It’s certainly not just a book for sailors, because it speaks to something in all of us.

A Wild Call by Martyn Murray is published by Fernhurst Books, priced £11.99