John Fisher fell overboard late last night Australian time, about 2,300 kilometres west of Cape Horn off the coast of Chile.
Organisers of a round-the-world yacht race say hopes of finding an Adelaide sailor missing in the Southern Ocean are fading because of deteriorating weather conditions.
The 47-year-old — who is a British citizen but lives in Adelaide and is a member of a local sailing club — was "wearing survival equipment when he went overboard", race organisers said in a statement.
A search and rescue operation was launched, but organisers of the Volvo Ocean Race have since said chances of finding the experienced sailor, who is a Sydney to Hobart veteran, were falling.
"The weather in the area is forecast to deteriorate significantly in the coming hours," the most recent statement said.
Mr Fisher's team, Sun Hung Kai/Scallywag, had remained in the area to search for the missing crew member but now appears to have given up the search.
"Scallywag has thus made the difficult decision to turn downwind and head towards the South American coast, the nearest safe landfall, approximately 1,200 nautical miles away," organizers said.
They said given the strong winds, there was "not an option to divert any of the other six Volvo Ocean Race competitors, who are at least 200 miles further east".
The race is described by organisers as a "45,000 nautical mile race around the world" and team Scallywag was contesting leg seven, from New Zealand to Brazil, at the time of the incident.
The Maritime Rescue Coordination Centre (MRCC) is continuing to assist with search efforts, race organisers said.
Crew members including John Fisher describe conditions
Mr Fisher is a member of the Christies Sailing Club based at Christies Beach in Adelaide's south, and the club has expressed its concerns on Facebook.
"Our thoughts and prayers go out to Kirsten, Ryan and Amy. No words can express our sympathy and pain," the club said.
The club has been opened up to other members "that want to be together to support each other at this tragic time".
The club's commodore, Marc Read, described Mr Fisher as having a passion for sailing "second-to-none".
"Full of fun, full of life … when he was on your boat, you had a good time," he said.
"[He] would never hesitate to jump on a boat to help out … teach them more the finer points of sailing."
Mr Read said Mr Fisher had wanted to take part in the race for a long time, viewing it as a "holy grail" of
It is not the first time an Australian member of the Scallywag crew has fallen overboard, with YouTube video showing a dramatic rescue from barely two months ago.
In January, during leg four of the same race in the Pacific Ocean, Australian Alex Gough ended up in the water.
The video shows crew members without life jackets, attracting criticism in the comments section of the video , including from one user who predicted a crew member would be killed.
"Not clear why professional racers don't wear life jackets," said another user, while another said the team was "lucky not to have the first casualty of the race".