BEIJING, Nov. 4 -- Chinese sailor Guo Chuan has been believed to be dead after having gone missing in the Pacific for nine days, senior French sailing weather analyst Christian Dumart told Xinhua on Thursday.

The 51-year-old Chinese mariner went missing on October 25 when he was attempting to sail from San Francisco to Shanghai in 20 days or less to set a new solo trans-Pacific world record.

"There is no chance that Guo Chuan is still alive. We had a lot of exchanges with Dr. Jean Yves Chauve, one of the world specialists in sea survival. He said there is no chance after 48 hours for a person who is not wearing a survival suit or a diving suit," Dumart said in an email to Xinhua on Thursday.

A skipper rarely wears a survival suit or diving suit, except when his boat is about to sink, he added.

It is hard for a single-handed sailor to survive when he falls overboard, according to Dumart.

"It takes a few hours for the persons onshore to realize that an accident has happened, and nobody knows the exact place where the accident happened," he said.

If the sailor was wounded when thrown into the water, the situation could be worse, he noted.

"A skipper who falls in the water is sometimes hurt. He will not survive several hours if he is wounded," he said.

"Even if (the rescuers) knew right away that an accident has occurred, it takes several hours for the planes, the helicopters or the closest boat to arrive at the zone of the accident. In Guo Chuan's case, the boat was about 1,100 kilometers from the closest airport. By the time you get there, the person has started drifting. It is also very difficult to spot a person in the sea," the French expert said.

He believes that it's also going to be very difficult to find the Chinese sailor's body.

"The probability of finding the body in deep seas where you have few boats is very slim. If the body sinks, it will disappear forever. If it floats, it will drift for months in the sea or end up on a beach or a reef, possibly in a deserted place. In the tropics, it will decompose rapidly," he said.

"I have never heard of a single-handed sailor falling off his boat at such a distance from the closest land and being rescued alive," he added.