The operation to rescue the French sailor Jean Le Cam competing in the Vendee Globe single-handed around-the-world yacht race is well underway. However, race organisers say that it might take longer than hoped because of the rough sea state. The tanker Sanangol Kassagie is alongside his IMOCA 60 yacht, VM Matériaux, but unable to launch a rescue boat.

Armel Le Cléac’h, aboard Brit Air, and Vincent Riou, on PRB, expect to be on the scene in about four hours, at about 1500 (GMT). Le Cléac’h reported that he was 55 miles from VM Matérieux in 25-30 knots of squally southwesterly winds and 3m-4m high waves. He said that his priority was to get there as quickly as possible.

Alain Gautier, a safety consultant for the race, said that Le Cléac’h’s presence is important as it is not certain that the oil tanker can lower a boat into the water, and it was unclear whether Riou’s engine was working. It may be possible for a race boat to recover Le Cam, 49, from his yacht ? as occurred when Pete Goss rescued Raphael Dinelli in the 1996 Vendée Globe and with Loick Peyron and Vincent Riou in The Transat.

The pilot of the Chilean rescue aircraft was not able to establish whether the keel or daggerboards were in place on VM Matériaux.

Philippe de Villiers, the President of the Vendée Council, said: ‘Because of rough seas, the captain of the oil tanker can only stay alongside, but not launch a boat. Chilean authorities are requesting that the tanker stays there. Armel and Vincent should arrive at 1600. The plane is to fly over again hoping to take picture to see whether keel in place or not.’

Denis Horeau, the Race Director, said: ‘Patience is required as the seas are likely to remain rough. Race direction is in constant contact with Armel and Vincent. The rescue is likely to take longer than hoped. There is no direct contact between Jean and the oil tanker.’

Mr Gautier said that the phones on IMOCA 60s are inside an emergency kit, but considering the boat is upside down it may not be easy to find. Because of sea conditions Le Cam, a married father of two, may have decided to stay inside.

The organisers of the world’s most gruelling yacht race, were confident that Le Cam has survived because the emergency beacon, the second on his boat, is activated by hand. ‘I don’t think it was pure chance that the signal was switched on,’ said Mr Horeau. ‘It was a move by Jean to signal his presence.’

Twelve years ago, on January 5, 1997, the British sailor Tony Bullimore, survived for five days in icy waters after his 60ft yacht Exide Challenger capsized when the keel fell off during the Vendee Globe Race. Bullimore survived in an air pocket in the upside-down boat in pitch darkness, having lost his food supplies – his only food was a bar of chocolate. The Australian Navy ship HMAS Adelaide finally reached him, 1,400 miles south-west of Australia, after several days. When crew members knocked on the hull, Bullimore heard the noise and swam out from his boat. He was 56 at the time and wrote book, Suvived, about his ordeal.

The Vendée Globe is staged every four years, and the winner has always been French. The British sailor Ellen Macarthur came second in 2001. Two sailors have died in past races.