US Coast Guard rescue teams were still searching on Wednesday for Chinese mariner Guo Chuan, 50, who was reported missing on Tuesday during his non-stop trans-Pacific solo sailing attempt.

Wednesday Beijing time, Guo's vessel was found about 620 miles northwest of Hawaii's main island of Oahu. The airborne search team did not see Guo on deck, but the main lateen sail of the 97-foot trimaran was broken off in the water.

"It's hard to say how many percentage but it could be true that the mariner is onboard alive on the vessel," said Tara Molle, a spokesperson for Coast Guard Honolulu.

The Coast Guard sent an HC-130 Hercules, a long-range surveillance and transport aircraft, to the area where Guo's vessel was sending a location signal. The crew tried to communicate with Guo via wireless walkie-talkie, but failed.

Two rescue vessels have been sent by the US Navy and crews will access and board Guo's vessel to investigate, according to the Consulate-General of China in Los Angeles.

"It takes a couple of hours for our aircraft to arrive at that area, and way longer for the vessels," said Molle, adding that the aircraft crew had been working continuously since Tuesday afternoon local time except for refuels.

Guo set sail of his trimaran Qingdao China from San Francisco's iconic Golden Gate Bridge on Oct 17 for Shanghai hoping to set a new sailing world record for solo crossing.

The voyage was planned to be about 7,000 nautical miles long and take about 20 days.

Tuesday afternoon Beijing time, one week after departure, Guo spoke on the phone with his support team telling them that all was good and he expected to arrive in Shanghai on Nov 5 or 6.

Shortly after the call, the GPS on Guo's boat reported a sudden loss of speed, Guo's support team reported.

"After that, we haven't gotten through to or heard from Guo via phone calls or internet messages," said a team member.

24 hours after the team lost contact with Guo, Maritime Rescue Coordination Center China, in cooperation with the Chinese consulate in Los Angeles, contacted the Coast Guard in Hawaii for help with search and rescue.

Guo is a professional sailor in China, and was reported to be in good health and confident about the voyage. He holds two world records for sailing - a solo non-stop circumnavigation world record set in 2013 and an Arctic Ocean Northeast Passage non-stop sailing world record set in 2015.

In an interview with nofrillssailing.com in August, Guo said he fell in love with sailing back in 1998, when he and his friend were sailing his 40 feet yacht for fun. "Now looking back, I wonder whether it be destiny that my first world record was set on a 40 feet yacht as well," said Guo.

Guo, who had learned sailing and trained in France, attended the famous "Clipper Round the World Race" in 2006. He began working in the circuit as media crew on VO 70 class GREEN DRAGON in Volvo Ocean Race in 2008 and 2009, and finally race the MiniTransat in 2011.

His racing yacht, QINGDAO, is a Marc Lombard designed Akilaria RC2. Guo said he is more familiar with Akilaria and his technical manager used to work for Akilaria and they got much technical support and quality after-sales service from that brand. "For me, Akilaria is like an old friend," he said.

Discussing the non-stop trans-Pacific crossing with reporters, he said, "Most of the pressure will come from the weather."

"When the wind is strong, you may make some small mistakes and then they may become larger and larger. So that's one of the things I need to be really careful about," Guo said prior to departure.

Were he to arrive in Shanghai, Guo would be the first ever to finish a solo non-stop trans-Pacific sail from San Francisco to Shanghai.

yandongjie@chinadaily.com.cn