All aboard for a trip up Australia's Murray river by paddle steamer. Tim Heald feasts himself on fabulous food, drink and scenery

Two tinny toots, a puff of steam from her wood-fired engine and the paddle steamer Marion cast off from the docks at Mannum, South Australia, and began to nudge her way up the mighty Murray river, leaving a chorus line of pelicans circling disdainfully in her wake. Twenty-nine passengers were aboard, as well as a volunteer captain and crew. Most important of all, the boat carried a sommelier, a maîtresse d' and three chefs. This was not just any old river excursion; this was a gastronomic weekend afloat under the auspices of Robert O'Callaghan's Rockford Wines.

The Barossa valley, an hour's drive north-east of Adelaide, is full of passionate and eccentric winemakers, but none more so than O'Callaghan. If you doubt this, you have only to read the wonderful "cut-the-crap" notes he composes for the labels of his wine bottles.

Apart from wine, his enthusiasms include proper coffee (he has just acquired an industrial-sized espresso machine for his office), cricket (an accomplished bush-cricketer, the main reason he wanted to visit England was so that he could play in a woolly sweater, an ambition achieved one chilly day in Somerset) and wooden boats. The weekend I sailed up-Murray on the Marion, Robert and his partner, Pam, followed behind with their two dachshunds in his meticulously restored, clinker-built, pre-war cabin cruiser, now running under solar power.

"This mighty stream," enthused an early settler called Arthur Kinloch who sailed it in the Lady Augusta in 1853, "exceeding in the extent of its course the Ganges, the Indus and the Plata... and with thrice the development of the Rhine, the Rhône or the Elbe." Alas, years of abuse and neglect have reduced the once-mighty Murray, and its rescue is now the subject of government concern. O'Callaghan was brought up on the Murray, and it was always likely that he would embrace the idea of bringing the Marion back to life. He had known the old girl in a childhood spent messing about in boats and was distressed, like other Riverland locals, by the wrecked state she was in by the 1980s.

She was launched at Milang on Lake Alexandrina in 1897 as a common-or-garden barge. It was not an auspicious beginning, one eyewitness saying that "despite all the preparations, it took a lot of persuading before it would budge an inch". It was a full hour before "her timbers began to tremble and off she went".

Not far, though. For three years she lay "unused, and unsold" at her birthplace. Then, on Christmas Eve 1900, the Mildura Cultivator reported that William Bowring, a shipowner, had lost his pride and joy, a steamer called the Emily Jane, scuttled after catching fire. To replace her, Bowring purchased the Marion and had her converted into "the most up-to-date vessel on the river". She had electric light throughout, an 80ft-long hurricane deck, 11ft paddle wheels powered by a custom-built boiler, and engines from Marshall and Sons of London and Gainsborough. For a while she prospered, but trade on the Murray dwindled; steamer after steamer disappeared and, in 1963, the vessel was sold to the Australian National Trust as a static museum in Mannum.

For more than a quarter of a century she sat in a state of progressive dilapidation until, after the trust threatened to take her away, a public meeting was called, a rescue attempt launched and, against all the odds, the PS Marion was restored to full working condition. In November 1994, she was formally recommissioned.

She is now more of an ugly duckling than an elegant swan, but she has undeniable character. You wouldn't want to be on board in a high sea or a fierce storm, for she is three stories high and, in effect, flat-bottomed.

On my voyage, the old Marshall engines, with a furnace fuelled by a young volunteer periodically chucking in great armfuls of logs, were like giant old Meccano models, all clanking pistons, olive-green paint, burnished brass fittings and "pocketa-pocketa-pocketa" rhythms. Up top, Captain Kevin steered at one of the largest ship's wheels I've ever seen, while "Super" Syd, the mate, called down to the engine room on the original ship's speaking tube.

As a viewing platform for a cruise on a calm river on an autumn day, she could hardly be bettered. From the top deck you could see over the banks and far away; the soft throb of her engines seemed not to disturb the majestic pelicans, who put on all manner of Red Arrow-style displays at every bend; the hot and cold water in the showers ran really hot and really cold; the cabins were small but the bunks comfortable; and the food and drink - oh my paws and whiskers - the food and drink!

The wines were all from Rockford, introduced and explained by Peter Healy, who has a wine bar and a wine consultancy in Melbourne and has acquired something of the O'Callaghan style. Thus the 2002 white frontignac which accompanied the warm smoked kangaroo with pickled cherries on potato rosti at the black-tie dinner on Saturday was announced as "a perfect I'm-not- getting-out-of-bed sort of wine".

Brian Smith, the chef of the British Hotel in North Adelaide, was making his fifth trip on the Marion, and how he and his two assistants conjured up such banquets from "Essie", the original wood-burning stove in the cramped galley, I'll never know. On Saturday night, Essie became temperamental, and the three chefs could be seen frantically scurrying to and from the bonfire on the bank. This was how they roasted the mussels with Spanish onion, cumin seed and fresh coriander. Brian said it was the first time he'd ever cooked a Marion dish on shore.

My favourite meals were the prolonged brunches with dish after dish of mushrooms and brioche; lemon pancetta stuffed rabbit on creamy polenta with roasted olives; roast pumpkin and halloumi on shaved fennel with walnut skordalia; parmesan oregano crumbed sardines with green olive tapenade and rocket... You eat as well in Australia as anywhere on earth these days, and best of all on the PS Marion. I could write a longish essay too on the Rockford 1992 Basket Press shiraz or the 1997 shiraz vintage port which we finished off by the bonfire.

We didn't travel far - just 40-odd miles upstream to a night mooring by the billabong at Cournamount, where there was a raft of pelicans (they are technically a raft at ground level and a squadron when airborne), white egrets, magpies who sounded as if they were gargling with jam-jars, and kookaburras laughing as only kookaburras can. Between Teal Flat and Chucka Bend, Syd, the mate, pointed to a predatory bird perched on a willow branch at the foot of an ancient ochre cliff. "See that fellow with the long neck? They call him a snake bird."

He paused and stared thoughtfully at the Murray as the deck of the old paddle steamer rumbled rhythmically at his feet. Then he asked a rhetorical question to which no answer was needed from this brunch-sated passenger on the PS Marion: "How can you not fall in love with the river?"