NERVOUS? Of course I'm not. Why should anyone with no experience of anything beyond a rowing boat, no navigational experience at sea and not much on land, be nervous about taking charge of a 33ft twin-engined Corvette Cruiser, the pearl of the river Shannon? Nervous? Don't make me laugh - or I'll utter such a high-pitched bray that I'll frighten the trout right out of the river here at Carrick-on-Shannon.

I'm not going to worsen my own condition by asking the others if they have full confidence in me as their captain. After all, this kind of thing happens in wars: raw 20-year-olds with pacifist leanings become commanders.

And after all, I had consulted my crew. Well, sort of. Well, probably not at all.

From the way they're tapping their feet and scanning the horizon for nothing in particular, I'd say they're in shock, or at the very least surprised by the situation. Which is that, for a week, we're going to be responsible for The Donegal, a graceful Grand Banks trawler-style cruiser, capable of crossing the Bay of Biscay, with a distrait captain and a disparate crew.

Old friends at times like these are pearls beyond price. 'There's nothing to it,' says Deirdre, pale as a ghost.

'You'll learn in five minutes,' says Diarmuid, chewing on a cigarette. 'You've always been able to pick things up quickly,' says Lynda, throwing a longing look at the shore. 'Where's the TV?' says Sam. 'And anyway, we can all swim.'

But now, thank God, here's George. George is the mechanic assigned to guide us gently into the mysteries of the boat and the joys of the river this lovely June day.

George knows that we've sat in on a briefing from Carrick Craft's manager, Liam Lawlor, that we've laughed nervously at Liam's jokes, scanned the faces of the assembled Germans, French, Dutch and Americans for superior seafaring knowhow (and found it); that we've hardly taken in a word that Liam has been saying except red on the right, black on the left, and that we're now all chanting it like a mantra.

But George is a cool character. His eyes are calm and confident as he puts me through my paces; he is obviously a terrible liar. George acts as if I'm pushing a pram when I manage to hurl us out of our moorings for the first time. He looks as if he's wondering what he'll have for his tea as I charge full-throttle at the wrong arch of Carrick-on-Shannon's beautiful stone bridge. He looks as though he's never enjoyed himself so much, as, with a final desperate wrench and a lot of silent prayers from the crew, I haul us back into our mooring. With not a hint of a shudder, George pronounces us ready for the river.

If anyone had asked me at that point how I felt, I'd have said I was like a person who had been asked to deliver her own triplets, alone, without anaesthetic and with no previous experience of obstetrics, in the middle of a crocodile-infested swamp, at the height of a typhoon. But everyone had enough sense not to ask . . .

George waves us off, smiling like a father waving off his favourite daughter on an unsuitable honeymoon with an unsuitable bridegroom. He is still smiling when I advance on the river in a kind of foxtrot through the afternoon light.

We had taken the precaution of eating earlier. There was to be no casual anchoring midstream while we swapped river lore and ate our bully beef sandwiches; this was a run to Cootehall, mercifully unimpeded by locks, rocks or bridges.

Slowly, subtly, the rather febrile mood on board going north from Carrick-on-Shannon begins to change into something rivery and rhythmic as the water irises brush slowly past us and the cattle gaze at us kindly from the rushy banks. The magic of this beautiful benevolent brown river is beginning to take over, so that by the time we reach Lough Drumharlow we are meeting each other's eyes and breathing evenly, no longer behaving like people making a getaway from a bank robbery.

At Cootehall we manage to moor without exchanging a single harsh word as bodies hurl themselves from the boat and tie up, with instructions from Diarmuid who turns out to be the dark horse of the party. He knows all about knots and hoving-to and even double mooring. We all look at him out of the corners of our eyes, and wonder.

We repair to the Watersplash pub - just up the road from a greystone barracks which was the childhood home of the author John McGahern - and down Guinness that we all pronounce to be the best we have ever drunk. The sense of achievement at having navigated eight miles on one of Europe's safest and most uncrowded rivers, in broad daylight, at a snail's pace, is amazing.

Next morning, waking up early with the mist still on the river, we are all in buoyant mood. And by the time we reach Knockvicar Lock, it's as if the spirit of the Shannon has insinuated itself into our veins. We're not talking much, not reading, not listening to music: we're listening to the river. Even Sam, the youngest of us all who has a terrible thing for technology, is looking like a medieval novice in a silent supplicant order. Everything is still, except, of course, the lock.

This is another matter, and unless we're going to spend the whole week ambling up and down between the lock and Carrick-on-Shannon, we've got to address it.

Padraig Lynch, the lock-keeper (his tattoos, he says, are evidence of his misspent youth) is bracing. He kindly explains the logic of locks: basically, to get in and out without injury to craft or person, to keep calm, to refrain from verbal abuse, to face the future with confidence.

We get through our first lock, with Padraig remarking that he's got to know a bit of French and German by now. 'Enough to say: 'Don't kill your husband in my lock, if you don't mind.' ' This advice is in no way far-fetched.

Padraig recalls: 'There was this German couple here a few years ago. She was trying to tie up. He demoralised her completely.

'She said nothing till they were out of the lock and then - the whole lock was dead silent by the time they got out - we saw her running downstairs and coming back with a saucepan. She hit him with that saucepan everywhere she could hit him. We watched the boat veering all over the river, and we heard the thump of the saucepan, and we saw him trying to defend himself. And we all thought 'Good woman yourself]'.

'Yes,' Padraig concludes thoughtfully, 'you can see a lot of that kind of thing in locks.'

The sun beats down as we moor on Lough Key, with its wooded islands, its rhododendrons, its herons and its water hens. Boats drift past us on their way up from Killaloe and Banagher and Athlone, and distant places we have no intention of going to. 'A lot of lads do it to Banagher and back in a week, but them lads have the old foot down,' says Padraig. 'They want to see everything and they haven't the sense to realise they're going to see nothing.

'Anyway, what have you to see in Lough Ree but a whole lot of wather?'

So we avoided the whole lot of 'wather' and stuck to the upper reaches of the Shannon for the rest of that dreaming sun-struck week. We swam in Lough Key, we moored at Roosky under the bright blue eyes of lock-keeper Tony Hutton, and we spent a day drifting through the reeds and rushes to Grange, where boats loomed dreamlike at us out of the river and passed on soundlessly, hardly leaving a ripple on the river, as if they'd never been.

Towards the end of the week it was as if those other people we had been only five days before - those nervous landlubbers who'd muttered 'Forward right, backwards left' and fingered the red flag like rosary beads every time we approached a lock - had also never been. Those pale-faced urban-dwellers with concrete in their veins were now bronzed river creatures, more at home in the reeds and the rushes than on alien dry land.

'Ye look as if ye're going back to one of them oul' towns,' said the man leaning over the bridge at Carrick-on-Shannon as we threw one last, longing, backward glance at our little dancing cruiser.

The man leaning over the bridge was, as usual, right.

For reservations, ring Margaret at Carrick Craft, Reading (0734 422975); or B&I Line Holidays (051-236 8325).

(Photograph omitted)