America's Cup organizers announced a full probe Friday into the capsizing of a catamaran that killed British Olympic champion Andrew Simpson, casting a pall over yachting's biggest race.

The high-speed AC72 "nose-dived" into the San Francisco Bay while performing a relatively common maneuver in normal conditions, they said after Thursday's tragedy during training for the 34th America's Cup in September.

The Artemis Racing crash was the second involving the spectacular new AC72 class boat, after one involving the Oracle team in October in which no one was hurt.

The latest incident has revived questions about the new boat.

Given the circumstances, the Oracle team would not train with its two AC72s before Monday, said America's Cup Regatta Director Iain Murray. Two other teams with AC72s are not yet ready to train.

The San Francisco Police Department will lead its own probe, along with coast guards, to "rule out any criminal negligence or intent", said captain Matt Bliven of the US Coast Guard.

Thursday's mishap happened during regular training and in normal conditions in San Francisco Bay, with flat water and winds of 18-20 knots, organizers told a media conference.

"The boat nose-dived ... the boat ended up upside-down capsized, broken into many pieces," said Murray, who struggled to compose himself at first. He said Simpson, known by his nickname "Bart" after the TV series, was "a mate".

"It appears Bart was trapped under the solid sections of the yacht out of view, out of sight to the myriad people on board trying to locate him, including divers with proper apparatus," Murray said.

"All the crews had been trained under water, they all carried oxygen and were prepared for the worst. Andrew was located eventually," he said, and doctors on support boats and later on the docks tried to revive him.

"Unfortunately they were unable to retrieve him and he passed," he said, adding another sailor, Olympic bronze medalist Craig Monk of New Zealand, suffered minor injuries.

The AC72 boats developed for the 2013 America's Cup are described by event organizers as "speedsters" powered by 39.6-meter tall wing sails and with the ability to hydrofoil, rising out of the water to reduce drag.

They can reach top speeds in excess of twice the wind speed, and place strenuous physical demands on crew members.

Organizers said on Friday they could not say how fast the Artemis boat was going, because it would be part of the investigation.

(China Daily 05/12/2013 page7)