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Video - GB boats remain top
GB sailors Nick Rogers and Joe Glanfield surged into a medal spot in the men's 470 sailing event in Qingdao.
The pair, who won silver in Athens four years ago, are in third place overall after they finished ninth in race five and sixth in race six.
In the women's 470, Christina Bassadone and Saskia Clark dropped to 11th, while Laser star Paul Goodison was seventh.
Stevie Morrison and Ben Rhodes slipped to eighth in the 49er but Ben Ainslie and the Yngling team remained on top.
Rogers and Glanfield ended the day on 25 points, one behind second-placed France and eight adrift of leaders Australia.
But there was disappointment for Goodison, who dropped down the overall standings after finishing in 15th place in race three of 11 in the Laser class.
I think we probably can stop thinking about winning a medal
The 30-year-old was three minutes behind race winner Andrew Campbell of the USA.
Morrison and Rhodes, the 2007 world champions, endured a disastrous start on Wednesday after they were disqualified from race seven for crossing the start line too early.
They managed to consolidate their early damage by finishing third and second in the following two races but they ended the day in eighth place overall and are running out of time.
"It's not quite going to plan as of yet and unfortunately it's getting a bit late in the day," said Morrison.
"I think we probably can stop thinking about winning a medal - we're just thinking about doing as well as we can from here on in.
"You never know, people might go mad and you might win a medal, but I think Ben and I have sort of put that out of our minds now.
"We'll try and do ourselves proud and carry on - we're not going to give up - and just see where we get to and hopefully that'll get better each day."
Poor visibility and a lack of breeze ensured only one race could be completed in the Laser, Laser Radial, Finn and Yngling classes.
When conditions relented, Team GB's crew of Sarah Ayton, Sarah Webb and Pippa Wilson maintained top spot in the Yngling class, finishing second behind the US in race seven.
The trio have a seven-point lead at the top of the standings, five points ahead of the Netherlands, who came in fourth.
The wind was very, very light out there and it was a little bit scary at times
Two-time gold medallist Ainslie also kept his place at the head of Finn class standings, finishing second behind Croatia's Ivan Kjalkovic-Gaspic.
Ainslie has a six-point advantage over American Zach Railey, who came in seventh in race seven.
"It was a pretty difficult race - the wind was very, very light out there on the course and it was a little bit scary at times," asid Ainslie.
"It was probably the lightest day's sailing we've had so far and when it's that light, any change in wind in percentage terms makes that much more effect on the fleet.
"So, if you get slightly more breeze than most of the other boats you can make a huge gain. If you get it wrong, you're kind of stuck."
Bassadone and Clark finished in 15th in race five and 13th in race six, struggling to cope with the light coastal breezes.
There was better news for Penny Clark, who won race three of the Laser Radial by three seconds over New Zealand's Jo Aleh, moving up from ninth to fifth in the overall standings.
She trails leader Anna Tunnicliffe of the United States by 10 points.