Britain's Giles Scott is guaranteed Olympic gold in the men's Finn class after opening an unassailable lead before Tuesday's medal race.
The result sees Scott continue Team GB's dominance of the event, winning a fifth successive Olympic title.
The 29-year-old finished eighth and second in his two races on Sunday to lead by 24 points.
Sir Ben Ainslie, who won gold in London and Beijing, praised his successor for winning "in serious style".
"To be able to put my name alongside Ian Percy and Sir Ben Ainslie is very special for me,"
Scott said not being selected for London 2012 put him in a "pretty dark place". 
"What we've managed to do now, to win in the way that I have, is just amazing," he added. "It's an amazingly, amazingly special moment."
Saskia Clark and Hannah Mills moved into the lead in the 470 dinghy class, winning the only race completed on Sunday after the eighth race in the series was postponed.
Similarly Luke Patience and Chris Grube, contesting the men's 470, saw their second race of the day postponed and lie in 10th place overall.
In the Nacra 17 mixed category, Ben Saxton and Nicola Groves head into the medal race in eighth position, 19 points off the top three.