It has been seven days since Chinese sailor Guo Chuan went missing near Hawaii. His wife believes he was wearing a life jacket at the time of his disappearance because he is a prudent and careful person, and is hopeful Guo will be found given the enhanced search and rescue operations involving multiple vessels.

“Guo is a very cautious person. He wouldn’t do anything without good reason or preparation. So I’m convinced that he had the life jacket on while sailing his trimaran. As a professional sailor he would have been used to wearing it, like a driver who always fastens their seat belt while driving,” said Xiao Li, Guo Chuan’s wife.

A Chinese merchant ship arrived at the area where Guo Chuan went missing to join the search and rescue effort Sunday morning. The vessel added five more lookout positions as it scoured several spots where the 51-year-old mariner could possibly drift to.

More than 1,000 ships affiliated with China’s COSCO Shipping Corporation have been told to keep an eye out along their travel routes in the hopes of finding Guo.

Guo, who is an outstanding sailor with a world record for a 138-day solo non-stop circumnavigation, disappeared near Hawaii in the Pacific Ocean last week while trying to set a new solo trans-Pacific world record by sailing non-stop from San Francisco to Shanghai. His support team said he was last heard from around 3:30 p.m. Tuesday, but they failed to contact Guo, who had just talked with his college classmate 20 minutes earlier.