British windsurfer Nick Dempsey gave himself a chance of a medal when he moved up to fourth place on Saturday.
Dempsey won race seven and finished 10th in race eight of the Mistral to be 12 points adrift of the medals.
Israel's Gal Fridman and Brazilian Ricardo Santos jointly lead with 27 points ahead of Greece's Nikolaos Kaklamanakis on 33, with Dempsey on 45.
There are two more races on Monday with the final one on Wednesday. Natasha Sturges is ninth in the women's event.
Sturges posted a 12th and 11th place on Saturday ahead of the final three races.
Elsewhere in the sailing, Christina Bassadone and Katherine Hopson finished seventh overall in the women's 470 class after a seventh place in the final race.
The pair posted five top-six places in the 11 races, but it was not enough to propel them into medal contention.
Iain Percy - a gold medallist in the Finn four years ago - and Steve Mitchell are in fourth place after the first day's racing the Star class.
The pair were eighth in the first race and finished third in race two.
American pair Paul Cayard and Phil Trinter lead after winning the opener and finishing sixth in the second, won by Swiss duo Flavio Marazzi and Enrico De Maria.
In the Tornado class, British pair Leigh McMillan and Mark Bulkeley are in 11th place after an eighth and 14th in the opening two races.