The brand new 60-foot carbon race yacht Fortuna III has won line honours in the Rolex Buenos Aires - Rio de Janeiro Race, taking the winner's gun in Rio at the crack of dawn on Sunday morning.

Skipper Cesar Recalde and his team shook off extreme fatigue after a gruelling week's racing to celebrate their arrival in Rio with the popping of champagne corks and the firing of red flares, just as the sun was rising over Sugar Loaf Mountain.

The almost windless conditions at the finish could not have been more different from the past seven days, which have seen Fortuna III and the rest of the fleet pounding into high winds and big seas. This was Recalde's fifth time competing in the event, and he described it as the toughest 1,200 miles of his career.

‘This was the hardest race I've done,’ said Recalde, who first competed as a bowman in this event 20 years ago. ‘I've seen stronger winds in past races, but never for as long as this time and never so much against the wind.’ The worst period was when the wind blew up to 40 knots for over 10 hours, and Recalde said the wind had scarcely dropped below 25 knots for the past week.

What made it all the tougher was the unyielding construction of Fortuna III, a state-of-the-art carbon racing machine designed by German Frers. ‘She is extremely fast,’ said Recalde, ‘but you pay the price in comfort.’

Whereas less hi-tech, less stiff hulls will go through the waves a little more softly, Recalde says the motion of Fortuna III was fast but unforgiving. ‘We went through each wave with a terrific bang. The mast was vibrating, the whole boat was vibrating. It was a 'crash and bang' race.’

For a yacht competing in its first long-distance ocean race, these were hardly ideal conditions to test the yacht's seaworthiness, but everything held together remarkably well.

Recalde said they were fortunate that the wind built gradually throughout the race, giving the team time to build confidence in each other and the yacht. They spent the vast majority of the race sailing with the mainsail reefed and with the smallest of their foresails, the No.4 genoa.

There was little rest for the 17 men on board. ‘None of us have slept longer than two hours since the race began,’ said Recalde. ‘We only had five bunks on the windward side of the boat, so everyone else had to sit up on deck on the rail, sometimes for six hours without rest. We drove the boat to the maximum.’

The final approach to Rio could not have provided a greater contrast. Just 20 miles from the finish, Fortuna III got her first opportunity in a week to use the spinnaker as the wind turned to a more favourable direction.

However, as so often happens close to Brazil's famous city, the wind disappeared altogether.

‘Just 10 miles south of Rio and we were in a flat calm,’ explained Recalde. ‘That was a worrying moment because I have been there before when we made just three miles in 36 hours.

It could have meant that all our hard work would have come to nothing.’ But after a wait of two or three hours, a gentle 5-knot breeze came in which allowed Fortuna III to spinnaker her way to the finish.

Rated under the IMS handicap system as the fastest yacht by some margin, Fortuna III was always firm favourite to take line honours. To win on corrected time though, she needed to reach Rio by a good distance in front of the next yachts.

With 250 miles back to the next boat, it appears Recalde's team may have done enough to win the double, but as always this depends on the wind that the fleet encounters over the next day.

The tough conditions have already taken their toll on the fleet, with four retirements including one of the favourites Gaucho, who pulled out after breaking the forestay. Recalde believes the biggest threat to be Camba II.

‘They are making good progress in an easterly wind,’ said Recalde, ‘but they will soon be heading into a north-westerly. It's not very charitable of me to say it, but I hope they find the same calms that we had to endure near Rio,’ he laughed.

In the meantime, he and the crew of Fortuna III will celebrate line honours, get some much-needed sleep, and then watch and wait as they pray that no other yacht reaches the finish in time to snatch away overall victory.

First held in 1947, this is the 21st edition of the Rolex Buenos Aires - Rio de Janeiro Race, a 1200-mile race up the South American coast, organised jointly by the Yacht Club Argentino and the Iate Clube do Rio de Janeiro. The official prizegiving will be held on February 17 at the Iate Clube do Rio de Janeiro.

For further information on the race, visit www.yca.org.ar , and you can track the progress of the fleet with the official race viewer at www.hmh.com.ar/vrm