Artemis flipped during manoeuvre: America's Cup boat accident that killed British Olympic gold medallist Andrew Simpson was repeat of a similar training accident last year

Simpson was trapped under the water for up to 15 minutes before his body was found

The wrecked Artemis boat, under which Andrew Simpson OBE was trapped and died (Getty Images)

Andrew 'Bart' Simpson's boat Artemis was performing the same manoeuvre as another America's Cup boat that flipped during training last year, it has emerged, as tributes pour in for the British Olympian, who died on Thursday after being trapped underwater for over ten minutes.

Race officials said the catamaran was performing a "bear-away" manoeuvre , turning away from the wind, when one of its two bows dug into the water's surface, and the vessel broke apart in San Francisco Bay.

It occurred in calm seas and under typical wind conditions for the bay.

Ten crew members swam to safety and were rescued by support vessels but Simpson, who was riding on the windward side of the vessel as it flipped, was thrown under the boat and couldn't be found quickly enough, officials said.

Iain Murray, the regatta director, said: "It appears Bart was trapped under solid sections of the yacht out of sight to the myriad people on board. We need to find out how you lose a person in a small boat with a lot of people looking."

A city Fire Department spokeswoman said Simpson was believed to have been underwater for up to 15 minutes before divers reached him, and efforts to revive him were futile. A second crew member suffered minor injuries.

Simpson himself had acknowledged safety concerns about the new generation of 72-foot catamarans. In September before he joined the Artemis Racing team, Simpson had sent his 3,000-plus Twitter followers a link to an article about America's Cup hazards by Stuart Alexander, The Independent's sailing correspondent.

"The flying machines which are the weapon of choice for the next America's Cup, one of the sporting world's more quirky events, are throwing up a mass of problems for sailors learning to control the new beasts and ... raising fears for the safety of the people racing them," the article began.

Simpson's death was the first fatality in connection with the America's Cup since 1999, when a member of a Spanish team was killed in a training accident in the Mediterranean. No one has died sailing in the actual America's Cup race.

But Thursday's accident was the second wreck of an America's Cup vessel during training for the upcoming race. In October, the boat entered by the defending champions, Oracle Team USA, flipped and was badly damaged while performing the same "bear-away" manoeuvre as the Artemis, America's Cup spokesman Tim Jeffery said. That accident occurred in heavier winds and no one was hurt.

In the latest edition of Wired magazine, published before Thursday's accident, Artemis Racing's own CEO and tactician, Paul Cayard, predicted that at least one of the teams would capsize again.

"We're going to start pushing harder, we are going to race, and those kinds of boats - catamarans - tip over," he said.