Anchors aweigh

Monia Chokri wears Breton stripes at a photocall in front of the marina during the Cannes Film Festival. She is flanked by fellow actors Xavier Dolan, left, and Niels Schneider.

Once in a while a trend will establish itself by stealth, with barely a radar blip to announce its presence on the international fashion scene. Skinny jeans was one, leggings another: by the time they had hit the runway, the cognoscenti had been wearing them for months. Nautical style is having just such a moment, and the tipping point was a shot of the suddenly-chic-again Naomi Campbell sporting a classic Breton top last month, as she lounged on a yacht floating off the French Riviera.

It all coincided so beautifully: the crisp, relaxed glamour of photo calls at the Cannes Film Festival; Karl Lagerfeld's Cruise collection showing at Saint Tropez, the capital of Côte d'Azur chic; and a flurry of celebrities donning stripey tops, platform espadrilles and chic, fresh colour palettes. Before we knew it, the fast-fashion stores, such as Forever 21 and Zara, had the trend sewn up and this classic look had sailed back into fashion's welcoming harbour.

Those who are deeply involved in sailing would assert that nautical style never went away, and certainly the uniform of the yachting set is a far and unvarying cry from the fashionistas' dressing-up-box caricature of gold-buttoned blazers and anchor-emblazoned T-shirts. Even less concerned with fashion are the professional sportsmen involved in the sailing competitions that enthusiasts follow around the world. At the third leg of the Louis Vuitton Trophy last week, in La Maddalena, a tiny island just off the slightly less tiny island of Sardinia, the serious sailors were out in force, and for them it's all about fabric technology. The 17 men on each team sailing the streamlined racing yachts include the mast man, who hangs out (literally) at the top of a mast more than 30 metres high, or the grinders - muscle mountains that manipulate the ropes to change sails with extreme precision. Waste a moment or make a mistake letting the wind out of the sails, and the race is lost. These guys ask a lot of their kit.

The spectators, though, watching from their yachts, have different, though almost as demanding, criteria. Their wardrobes must deal with both the hot sun and the sea breeze; they must be chic and crisp yet comfortable enough for jumping on and off the yacht; they must be glamorous, but sporty enough to seem completely at home on the water. They must achieve all this day after day, so one good nautical outfit is not enough.

There is no better place than one of the VIP yachts at the Louis Vuitton Trophy for studying the sartorial mores of this crowd - crucial preparation ahead of the race's arrival in Dubai in November. One yacht, The Snapper, is where Yves Carcelle, the CEO of Louis Vuitton, watched the race finals before joining the winning team (which, to the delight of the Dubai-dwellers who joined him on board, was Emirates Team New Zealand). With him were a number of fashion journalists from around the world, assorted dignitaries and sailors such as Paul Cayard and Bruno Troublé, who created the Louis Vuitton Cup in 1983 and is the man behind the Louis Vuitton Trophy now.

Apart from the said journalists (we were a motley crew, urban to the core), these are people who live and breathe sailing, and whose wardrobes, from caps to deck shoes, are functional enough to allow them to leap from boat to boat and multi-task enough to cope with a between-races swim, a three-course lunch and a formal docking ceremony. And they remain concerned, of course, with style. Take Troublé: he is not only a, experienced sailor and former skipper of the France-III team; he is also the brother of Agnès b - for whom nautical stripes are a trademark. He tells a tale of applying a touch of style to his 40-strong team, 25 years ago.

"I remember I did a race in SaintTropez with 40 people on board, and they were all dressed differently, so I bought 40 plasterers' overalls, all white with a zip, very cheap. And now we still use that sometimes because it's a very light material, like cotton, that protects from the sun, and is easy to remove. I did that 25 years ago and now other people are doing it. It's very lovely to see the white on the boat. Even if it's a bit loose it still looks good and it's very cheap."

This is not, of course, an excuse to wear an on-trend jumpsuit on board, however glamorous it may look (though Troublé's vote for worst on-deck item of clothing goes to high heels, which are an absolute no-no on a rocking yacht with perfect teak decks), but it certainly highlights one of the key tenets of seafaring style: palette. There's a reason that white and blue are so popular and that's because, on a sun-drenched boat in the Mediterranean, two colours are predominant: the blue of the sky and the sea, and the white of the yacht and the clouds. Take a look at those lovely old travel posters from the 1920s and 1930s advertising the Côte d'Azur, and the retro art deco-style ones for the Louis Vuitton Trophy this year, that were designed by the Italian artist Franco Costa. You will see graphic, clean, sporting lines and a palette of two or three cool-toned colours. This is the mood you are going for.

As far as Yves Carcelle is concerned, nautical style these days is more about mood than about must-have items. "There are colours that people associate naturally with sailing but I would say it's more mood. And the codes are a bit more broken today than they were several years ago. Thank goodness, these days, you don't need to have the five gold buttons on your blazer and so on. "It's sporty on the boat, but it's really sport-chic or casual-chic when people arrive on the ground and that hasn't changed. The traditional yachting outfit was a bit like real life: you all went to work with a grey suit with a boring tie and a white shirt. Today you can go to business meetings a bit more trendy. So I think this trendiness influences everything, including sailing."

He does, though, acknowledge that, in the 27 years that Louis Vuitton has been actively involved in sailing (first with the Louis Vuitton Cup and now with the trophy), the sport has influenced the brand as much as the brand has influenced the sport. "Of course, luxury and elegance go together, but since the beginning, Vuitton has been fascinated by innovation and technology. The first pair of sunglasses we did, in 1992, were with one of the first Louis Vuitton Cups. The first shoes we did were boat shoes. And from there we have entered into new categories. And, for instance, when we did the waterproof Keepall - that was a crazy idea: the most high quality bag, that you can throw in the water and swim with it? You will see more of that technology in the months to come."

In other words, the Dubai version of the Louis Vuitton Trophy will, it seems, see the launch of a number of new categories and products developed especially for the event. Carcelle will not be drawn yet on specifics but, he says, "The whole team is now going to put the energy into Dubai." In the meantime, what are the crucial pieces to be seen in at the trophy next November? Troublé has the fashion chops to explain.

First the watch: "Everybody, they all make sailing watches. But some brands have the credibility; some other brands, they don't have the credibility." Troublé and Carcelle both wear a Tambour watch in black which has a special countdown dial designed for match racing. "A lot of people buy this watch without racing, but I use it to start the race," he says. Next, the shoes. "They are leather, but a special leather which is waterproof. It's a very soft leather, by Sperry Top-Sider, that doesn't become rigid when wet and covered with salt, created in 1930."

Go for trousers or shorts rather than dresses. "There is a lot of work on the trousers with many pockets and doubled fabric, because you sit on the deck which is sometimes not only wet but antislip." On the luxury VIP yacht, though, a simple pair of super-white lightweight linen trousers, capri pants or shorts are perfect - although on no account wear blue jeans. A hat, to keep the sun off all day, is crucial. "There is a little cord to attach to the collar, so you don't lose it in the wind. That's a very new trend. We've lost so many caps you cannot imagine." A multi-tasking scarf or pareo works well for women, too. It can be used as a belt for a chic arrival, a hairband in the heat and as a wrap as the sun sets.

As for the famous Breton stripes? "We still wear this kind of shirt. This is typical of Brittany. My sister, Agnès b, she does a lot of things like that. It's trendy." The one must-have accessory for the trophy, though, is a pile of the coloured wristbands that let you on to the official yachts. As they change by day and according to your role, they accumulate up your arm like chunky bangles. Best of all is to ditch them all in favour of the grey one with black writing: the VVIP. If you're wearing that, you can get away with anything. But if that's the case, you probably already own the yacht.