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Video - Windsurfing gold for Ashley
Britain's Nick Dempsey failed to win a medal in the RS:X windsurfing event as New Zealand's Tom Ashley pipped Julien Bontemps of France to the gold medal.
Ashley and Dempsey had gone into the final race level on points, and only one behind leader Bontemps.
But while Ashley overhauled the Frenchman, Dempsey struggled to make an impact and finished seventh in the final medal race for fourth overall.
Israel's Shahar Zubari took bronze after finishing second in the race.
Zubari had been nine points behind the lead but he came back strongly to finish race winner Hong Kong's Chan King Yin and clinch the final place on the podium.
The 28-year-old Dempsey, who won a bronze in Athens, had gone into the final race lying in the silver medal position.
Another race, another lap, it could have been different
But any chance of a top-three finish this time slipped away from him in the 11th and final race, which was shortened from three laps to one because of a change in wind conditions.
"It was all pretty close going into the first beat and I knew exactly where I had to be but with the race being just one lap, it was all a bit short and a bit rushed," said Dempsey.
"Because it was so close, you had to go for it. I went for it and I got punished a little bit.
"You only had to be slightly out of contention round the first mark and that's the race over, really. It's just a shame it was one lap.
"This week's been excellent, really. I sailed brilliantly this week and it's just a shame that today went the way it did.
"Another day, it could have gone another way. Another race, another lap, it could have been different but that's the way it goes and that's the Olympic Games."