A French yachtsman has been found alive and well but trapped inside his overturned racing boat after two rivals in a round-the-world race dashed to the vessel 200 miles off Cape Horn.

There had been fears for Jean Le Cam because he had given no definite sign of life since reporting his capsize by satellite telephone just after midnight.

An oil tanker and a Chilean coastguard plane spotted his pink 60-foot yacht wallowing in the ocean without part of its keel but were unable to make contact. The heavy seas prevented the tanker from approaching the yacht.

Vicent Riou, a fellow Frenchman in the Vendée Globe race, arrived at the boat and called Le Cam. He heard an answer. Le Cam is stuck inside because the escape hatch on the stern has been blocked. A Chilean tugboat with rescue divers is now steaming towards his position and should arrive early Wednesday.

"I think this rescue episode will take longer than we thought because of difficult conditions at sea," said Denis Horeau, director of the single-handed, non-stop around-the-world race. "We must be patient."

Le Cam, who was in third place in the French-run race, had been believed to be alive because an emergency beacon was triggered when the tanker drew close to his boat in the mid-morning.

The captain decided that it was too dangerous to send a launch to the rescue, so the operation was left to two nearby skippers Riou and Armel Le Cleac'h, the other skipper who sailed towards Le Cam.

The Open class single-handed yachts are supposed to be self-righting but they can remain overturned if they lose their keels. Photographs showed that the heavyweight bulb is missing from Le Cam's boat. The craft is equipped with an escape hatch to allow the yachtsman to escape if they remain upside down. Two have been rescued in past races after days inside overturned hulls.