Yesterday's leaders of the 49erFX, New Zealand's Alexandra Maloney and Molly Meech, needed a top six finish in today's medal race to win gold.

The duo got caught out on the wrong side of a big wind shift, however, and could only finish ninth. 

Grael and Kunze, Rio 2016 Olympic champions, finished second to overtake Maloney and Meech in the standings and claim victory.

"For us our goal was to have a clean start because in this light wind it’s very easy to get caught by the boat to leeward and I think we did that successfully," said Grael.  

"It was pretty shifty, I was very happy with how the racecourse was set up."

Britain's Charlotte Dobson and Saskia Tidey were fourth in the race to earn the bronze medal.

In the 49er event, pre-race leaders Erik Heil and Thomas Ploessel of Germany finished third to take the gold.

Dylan Fletcher-Scott and Stuart Bithell of Britain won the silver medal, while Šime Fantela and Mihovil Fantela of Croatia took home bronze.

Olympic silver medallists Jason Waterhouse and Lisa Darmanin of Australia secured gold in the Nacra 17 event, winning today's medal race to ensure the victory. 

Brazil's Samuel Albrecht and Gabriela Nicolino de Sá finished third in the race to hold on to the silver medal and Santiago Lange and Cecilia Carranza Saroli of Argentina came fourth to claim bronze.

The women's RS:X event saw China's Yunxiu Lu take gold with a second place finish in the medal race. 

Israel's Katy Spychakov and France's Charline Picon claimed the silver and bronze medals respectively.

Poland's Pawel Tarnowski had a six-point lead going into the men's RS:X, but an early start in the medal race cost him a place on the podium.

Instead, China's Bing Ye won the race to get the overall victory, with Poland's Radoslaw Furmanski securing the silver medal and France's Pierre Le Coq bronze.

The action in Miami is due continue tomorrow with the medal races in the laser, Finn and 470 events.