A 72-foot catamaran being sailed by America's Cup champion Oracle Racing capsized on San Francisco Bay on Tuesday afternoon.
While some of the crew members were thrown into the water, all were accounted for and there are no serious injuries, according to a statement released by the syndicate.
The boat was being skippered by Jimmy Spithill, who led Oracle to a two-race sweep of Alinghi of Switzerland in 2010 to bring the America's Cup to San Francisco.
The boat was believed to be carrying 11 crewmen and possibly some extra sailors and designers.
Tactician Tom Slingsby said the wing sail was badly damaged. He said the wind was about 25 knots and there was a strong ebb current. The crew was turning away from the wind, and as the boat accelerated it pitch-poled, or went end-over-end.
"We didn't know what was going to happen with the new boat. When the nose went down, the wing hit and a few guys went in the water," Slingsby said. "We were unsure if the wing would snap, so we all climbed off the boat.
"Luckily, everyone is accounted for and no one was hurt. The wing is pretty badly damaged, and we are working to get the boat back in position to return to Pier 80."
Oracle is testing its 72-footer for the 34th America's Cup next year. It was the boat's eighth day on the water since the launch in August. Two hours into the boat's first test sail in August, one of the daggerboards broke.
The America's Cup World Series is being contested in 45-foot cats, and there have been a number of capsizes.
Two weekends ago, Spithill capsized a 45-foot cat during an America's Cup World Series regatta in San Francisco. After recovering, he led his crew to the regatta's match racing championship.
Russell Coutts, a four-time America's Cup winner who is Oracle Racing's CEO, capsized a 45-footer last year during training.