QINGDAO, China (AP) -Lack of wind postponed the start of seven Olympic sailing races on Thursday, with organizers hoping breezes would freshen later in the day.

It was the second day in a row that lack of wind disrupted the racing schedule.

On Wednesday, many sailors waited on the water for four hours or more, and four classes - Finn, Yngling, Laser and Laser Radial - were not able to hold their planned second race of the day. Those races were rescheduled for Thursday, when men's and women's RX:S windsurfers and 49er dinghies are also on the program.

Winds were so light in the morning that the breezes barely moved flags and banners decorating the Qingdao venue, some 500 kilometers (300 miles) south of Beijing. A heavy mist also obscured visibility.

"The weather is not so good,'' said Qu Chun, event manager in Qingdao. "Any time the wind picks up, we will immediately try to start races.''

The sailing venue is known for light winds and heavy fog during the summer, but there had been enough wind to complete all planned races from Saturday's opening day through Tuesday.

Qu said organizers had not decided whether to use Friday, a reserve day for the men's single-handed Finn class and the three-woman Yngling boats ahead of their medal races scheduled for Saturday. He said they will probably not use the reserve day if two races can be completed on Thursday.

Those classes had both completed seven of 10 planned preliminary races, which Qu said was enough to go straight to the medal race, which counts double.

According to the Olympic weather service, winds were expected to increase on Friday and Saturday.