A spokesman for the World Cruising Club, which organises boat races around the world, has said the changes of finding the crew of the Cheeki Rafiki yacht are now "non-existent".
Jeremy Wyatt told the BBC: : "I think we have to be realistic and face facts that they're not in a raft and therefore the chances of finding anyone are non-existent now."
"In some ways it's a hard fact, but I think, after a week of searching, it's really the only conclusion you can safely draw," he added.
With no sign of a life raft or of debris, and with nearly 20,000 square miles having been searched, the hunt continues for another day.
Veteran yachtsman Tony Bullimore tells ITV News that there is a "strong possibility" the yachtsmen are still alive in the life raft.