Worst day in Rio for Aust sailors

Australia has had some forgettable days in the water at the Rio Games.

Now they've had one on it.

Fresh from a disappointing back end to the swimming, Australian sailors struggled on Sunday with hopes of gold at Guanabara Bay now dimming.

One crew dropped from first to fourth, another from first to second and third almost dipped out of the medal running completely.

The positive news is that at least two of the crews are still good chances to claim minor medals.

Jason Waterhouse and Lisa Darmanin were topping the ranking in the Nacra 17 and they won the first race of the day on Sunday but a "shocker" of a final race - they finished 17th - saw them drop to fourth overall, nine points behind the leaders going into Tuesday's double-points medal race

"We thought that the breeze was going to shift right later in the day and be better on the right," Waterhouse said.

"We wanted to get off the start, tack out there and win the side and unfortunately it just didn't work."

A disappointed Waterhouse said the pair would still aim to make up the ground and win the medal race.

"Our goal was to go into the medal race with a chance to win a gold medal. Well, we're in that position," he said.

Another gold medal chance had two of their worst results of the competition, with Mat Belcher and Will Ryan finishing eighth and 10th in their 470 races.

They are still second overall but have slipped 11 points behind the Croatian leaders with three races to go.

"We have to be a bit patient and keep fighting," Belcher said.

"(It was) just a difficult day for us."

Finn sailor Jake Lilley had been a surprise in third place overall going into Sunday's races, but a 23rd and 17th finish effectively ended his chances of a medal.

He originally finished 11th before a last minute protest on another boat pushed him to 10th and into the top-10 medal race.

"It's great to have another opportunity to race against the best guys in the world, especially at my first Olympics," Lilley said.

"Today was obviously disappointing to lose my grasp on the bronze, but it's still a mathematical possibility."

Tom Burton, who did not race on Sunday, is currently second in the Laser and is guaranteed a medal even before Monday's race.

He's most likely to finish second.

Carrie Smith and Jaime Ryan are in 11th overall in the women's 470 with three races to go, after finishing sixth and 14th on Sunday.

They've been sitting on the edge of the top 10 all week, but have been unable to capitalise whenever they've had a good result.