Luciano Benetton: The green billionaire

This is the way Luciano Benetton sails off into the sunset. The man who gave us his United Colours, who revolutionised the Italian fashion business, who made our brains hurt by yoking cheap and cheerful knitwear with images of birth and death, Aids, prisoners on death row and babies trailing umbilical cords, has built the ship of his dreams.

She is called Tribù, and she is a 50m-long revolution: the first luxury yacht built to the same standards of environmental purity as the latest generation of cruise liners and cargo ships. She is the first ship of this type to be awarded a "Green Star" certificate of environmental efficiency.

A mega-rich man's politically correct whim? Far from it, Benetton insists. His firm was ahead of its time in stressing environmental concerns in its factories and offices, he says, and he has put those same values first – above price and speed, for example – in his new toy. "This was my choice," he says, "and a perfectly natural one, in line with the philosophy of the Benetton Group, which has always paid attention to environmental questions. I am very pleased that Tribù will be the first ship of this type to get a certificate.

"The requirements for the certificate are complex: you need special equipment for the treatment of waste water and rubbish, the separate collection of different types of waste aboard, the elimination of emissions which damage the ozone layer. I believe that respect for the sea and for nature in general is the duty of everyone, and for those who sail and who love the sea above all. And the dangers of global warming remind us of that fact every day, ever more urgently."

Benetton founded the family firm 40 years ago, using a bicycle to hawk around beautiful sweaters knitted by his sister. His two younger brothers also became involved, and today the firm has annual revenues of €2bn and shops in 120 countries, including a rapidly growing presence in China. Despite tough competition from "fast fashion" competitors such as H&M of Sweden and Zara of Spain, the company is still growing robustly.

And after much turmoil over the management of the company last year, Luciano now seems satisfied that his son, Alessandro, 43, educated at Harvard Business School and a former mergers and acquisitions analyst in London for Goldman Sachs, has what it takes to keep the firm growing strongly. The grand old man, the doyen of the Italian business world, 28th richest man in Europe with a family wealth estimated at £5.7bn, has been steadily preparing to make his exit over the past year or more. Now perhaps he is ready to cast off.

Throughout his long career, Benetton has possessed the gift of doing ordinary things with extraordinary style. He made and sold knitwear, of all uninteresting commodities – but in colours and colour combinations that dazzled and fascinated. For years and years he ran an advertising campaign that was no more than a series of portraits of people wearing Benetton jumpers – yet the scandals they caused multiplied their publicity value. He built a new corporate headquarters, and got the world's most poetic minimalist, Tadao Ando, to design it.

Now he has built himself a new boat, and it is a million miles from the floating bordellos favoured by his fellow tycoons. This week at the Monte Carlo Yacht Show, Mr Benetton was awarded a trophy in recognition of the new ship's "environmental compatibility". But while building a boat to the most rigorous environmental standards raises the cost, it is more than merely a gesture of public morality, a way to make the other moguls look cheap. Certificate in hand, Mr Benetton can sail his boat wherever he likes, including protected areas barred to conventional, polluting vessels. As ever, style and substance go hand-in-hand.

Tribù is actually two completely different boats. Outside she is all rugged functionality, with lines that would not look out of place on a navy frigate, only rounded somewhat, and white rather than battleship grey.

It is a ship, as Benetton told the Italian magazine Yacht & Sail, for going places. "It was the idea of the journey as a way of learning and exploration that pointed me in this direction," he said. "I wanted a functional boat fitted to my objective: to sail everywhere, even in difficult seas and in less than perfect conditions. A boat for taking to the open seas in security, comfortable but sober, with fundamental attention paid to functionality and to the needs of navigation: a Land Rover, in other words, of the deep."

Benetton does not intend to limit himself to short hops between Portofino and St Tropez. Other mega-rich boat owners have recently plumped for similarly spartan contours as a way of keeping a relatively low profile, deflecting the sort of attention that the stereotypical floating Las Vegas tends to draw. Benetton denies that he was motivated by such unworthy concerns.

"I have no interest in fashions in yachts," he insists. "I chose this design because it is suitable for trans-oceanic voyages, and allows me to live on the water day after day, following the sea's natural rhythms."

But step below deck and the effect is Tardis-like. This is not a ship, it is the drawing room of the gracious home of a man of wealth and taste. The ceiling is more than 2m high, floors are carpeted, furnishings offer no concessions to maritime etiquette. The huge double bed in the master bedroom has no grab rails, and the room is equipped with a grand piano. Bathrooms have severe modernist lines, jacuzzis, polished marble floors. The galley is a large and luxuriously appointed kitchen ("I intend to cook," says Luciano) featuring a machine for slicing prosciutto. And so on.

Piero Lissoni, the Milan-based architect responsible, says: "The project was a lot of fun... The client requested a dignified, silent and simple project. I think I satisfied him. He wanted a floating house, with the characteristics of a habitation, very much in line with his way of thinking and living. So it needed to be simple, rather elegant and above all not to resemble a boat."

Given flat calm seas, the joys of bumbling about in Tribu will be surrealistic – plinking away on the piano as the dolphins and albatrosses sail past the large picture windows. How well it will work when Luciano's more ambitious dreams come to pass – ploughing through the North Sea in the depths of winter, for example, or rounding Cape Horn – is another question. As the beds (and they are certainly not bunks) are not equipped with rails, for example, one can readily visualise Mr and Mrs Benetton being flung out of bed and landing in the workings of the grand piano. But Benetton is an experienced sailor, formerly owner of a more conventional yacht called Smooth Operators, so he has doubtless thought these questions through.

"Behind the construction of Tribù," Benetton says, "there is my desire to go round the world. Taking one's time, I'm not interested in going fast, I just want a boat that is trustworthy and solid. And clean, too."

As if to warn the rest of the family not to think of him as out for the count, he insists that Tribù will in no way impede him from remaining involved in the firm. "No, I just need to get myself properly organised. I will work aboard ship, I have all the necessary equipment."

Luciano remains chairman – yet at least semi-retirement beckons. "Yes, I have the intention of progressively reducing the intensity of my involvement," he concedes. "I am able to do this because I have passed some powers to my son, Alessandro, and there is a cohesive team of managers able to run the group according to our company policy. As a result I will have more time to devote to travelling, which has always been an integral part of my life.

"The living is much better at sea," he enthuses, gazing out at the sea and the sky. "This boat is designed to provide huge views from the windows." As a prospect it sounds rather lonely. But after 40 years in which, as he says, "I have not had time to draw breath", one understands the appeal.

Other feel-good billionaires

Richard Branson

Launched Virgin Fuels in 2006, in aid of research into renewable energy. His transport business will provide up to £1.5bn to renewable energy over the next decade. Spent £16m on bio-ethanol plants in American, and has committed more than £150m to similar projects over the next three years.

John Doerr

Californian venture capitalist who helped launch both Amazon and Google. Launched a venture called "Greentech" in 1999. His firm, Kleiner Perkins Caufield & Byers, has given more than £100m to a dozen "green" companies over the past two years.

Tulsi Tanti

Indian entrepreneur whose Suzlon Energy, worth £4bn, is the most valuable wind-energy company in the world. Supplier of 2,000 megawatts of wind turbine capacity globally. Started as a small-time textile manufacturer in his native Gujarat.

Ted Turner

America's largest individual landowner founded the Turner Endangered Species Fund in aid of biodiversity and conservation. Also created DT Solar, a renewable-energy company, with the intention of building industrial-scale solar panel plants.

Rubens Ometto Silveira Mello

Described by Forbes as the first ethanol tycoon. Boss of Cosan, the world's largest grower and producer of sugarcane, and second largest producer of renewable fuel.