By Alex Dobuzinskis

LOS ANGELES (Reuters) - The U.S. Coast Guard called off its search for a Chinese sailor attempting to sail alone across the Pacific Ocean, after his empty trimaran vessel was discovered, officials said on Thursday.

A crew from the U.S. Navy assault ship USS Makin Island boarded Guo Chuan's boat on Wednesday, but found only his life jacket, the U.S. Coast Guard said in a statement. He had been trying to set a record for the fastest solo crossing of the Pacific.

Guo, who set sail from San Francisco on Oct. 19, was aiming to complete his solo, non-stop journey to Shanghai in 18 days.

He was last heard from on Tuesday afternoon Beijing time when his vessel was about 900 nautical miles (1,666 km) west of Hawaii, his support team had told the Xinhua news agency.

"Mr. Chuan was a professional mariner with a deep passion for sailing," Captain Robert Hendrickson, chief of response, Coast Guard 14th District, said in the statement.

"Our thanks to our Navy partners who helped us search for this vessel in a timely manner so far from shore in an attempt to locate Mr. Chuan," Hendrickson said. "Our deepest condolences go out not only to his family and friends but also to his racing team and the sailing community."

Guo had two records to his name, having set the pace to beat in the 40-ft solo nonstop circumnavigation in 2013 and the Arctic Ocean Northeast Passage non-stop mark in 2015.

His sailing team, in a statement on his website guochuanracing.com, said they believed Guo might have fallen into the water during a maneuver on his vessel that would have required him to unhook his safety lifeline.

A representative for his team could not immediately be reached for comment.

Guo had expressed optimism about his mission prior to setting sail last week.

"I am very confident to go now. See you in Shanghai within 20 days," he said at the time.

The Coast Guard said the crew that boarded Guo's 97-foot (30-meter) vessel, the Quindao China, left it adrift and Guo's racing team would recover it. Authorities broadcast a notice to alert other mariners to the vessel's presence.

(Reporting by Alex Dobuzinskis in Los Angeles and Shravanth Vijayakumar in Bengaluru; Editing by Alistair Bell)