A 63-year-old French national, Alain Deloard, an accomplished French sailor with 17 trans-Atlantic voyages under his belt, abandoned his fibreglass yacht after activating an emergency beacon on Friday.

“A plane has been able to pick up a signal from the sailor and he appears to be in a life raft, so there are grave concerns for his safety,” said Joel Katz, CEO of Sydney-based Orion Expeditions, whose flagship vessel MV Orion is scheduled to rendezvous with the life raft at 6:00pm tomorrow.

The Orion, the only vessel responding to the distress call it received on Friday, was 11 days into an 18-day Antarctic and Sub-Antarctic tour when it was asked to divert to the rescue. It is equipped with 10 Zodiacs and highly experienced crew perfectly suited to mount a recovery effort in heavy seas.

“It is going to be tough,” says Orion expedition leader Don McIntrye. “The forecast is for 30 knot winds gusting to 40 knots and the seas will probably be around 7 metres. He has to hang on until tomorrow night and that will be really challenging as his life raft could capsize at any time.

“His biggest threat won't be sharks but the physical damage from the waves and hypothermia from the cold. Hopefully he will be wearing a survival suit. The French have a very good understanding of the need for survival suits. It'll really improve his chances of survival.”

But Orion's Captain Mike Taylor said finding the yachtsman could also be a challenge: “Now that it's become apparent he is in a life raft and not in a boat, it has become more problematic because a life raft is harder to see. It's a very big ocean out there.”

“Providing we can locate him – and that's a very big 'if' – the plan is to put the ship as close to the raft as we can and launch a Zodiac,” Taylor said. “The Zodiac is about the same height as a raft, so it's a simple case of tethering the two together and pulling him into the Zodiac. That's it in a nutshell."

“It must have been a hell of a job to launch the raft in the kind of conditions he faced earlier on. So my assumption is he is going to be in a traumatised state.”

Taylor has experience in maritime searches - he was on the ship that recovered the kayak of Australian adventurer Andrew McAuley who disappeared, presumed drowned, 35 miles off the coast of the South Island of New Zealand during an attempt to kayak solo across the Tasman Sea in February 2007.

The moment the yachtsman is brought onboard, he will be attended by Orion's chief medical officer Dr Chris Bulstrode, an emeritus professor in trauma at Oxford University with extensive work experience in Haiti, Gaza and other disaster zones.

“The first thing I will want to know is if he is conscious,” Bulstrode said. “If he is, I will have very little to worry about other than warming him, giving him fluids and sorting out any injuries he's got. It'll be very straightforward."

Bulstrode said a regular passenger would almost certainly perish under such conditions, but in this case the chances of survival are high.

“He seems to be a very experienced sailor and they are tough buggers, so I would put his chances of survival way higher than most, perhaps as high as 75 percent,” he said. “With all his experience, he must have experienced some similar kind of disaster in the past.”