The type of super-fast boat involved in the accident which killed sailor Andrew Simpson was known to be a "potential death trap", a sailing expert has said.

The Olympic gold-medal winner died when his AC72 catamaran flipped during a training session for the America's Cup off the coast of California.

The accident has raised questions about the safety of the boats, which reach speeds of 46mph, after they were introduced to this year's competition.

In October, Australian Olympic gold medallist Tom Slingsby and yachtsman James Spithill were involved in a dramatic capsize in their Team Oracle catamaran in San Francisco Bay. The incident virtually destroyed the multimillion-pound boat but the men escaped serious injury.

Gael Pawson, editor of Yachts and Yachting magazine, said safety concerns were raised after last year's accident.

She said: "A number of people said when the October crash happened that these are potential death traps and this was an accident waiting to happen.

"They are 72 feet long and sail at really high speeds which creates safety issues. These boats lift up as they sail and fly above the water. As soon as something hits, even clipping a wave, it will flip right over.

"They are sailing boats right on the edge of control and are pushed to the limit."

The lack of oxygen underneath the catamaran after it capsized would also have created huge dangers, Ms Pawson added.

The death of Simpson, 36, - the sailing partner of Hampshire ace Iain Percy - has rocked the sailing community.

Sir Keith Mills, the deputy chairman of Locog (London Organising Committee of the Olympic and Paralympic Games) was due to be made a Knight Grand Cross - the highest grade of knighthood - today but pulled out following the sailor's death.

Simpson, affectionately known as "Bart", is not the first sailor to have died during training for the race.

In 1999, Martin Wizner of the Spanish Challenge was fatally injured after being struck on the head by a broken piece of equipment, and a British crewman was also reported to have died in 1935 while training off Southend.