The 72-foot catamaran was attempting to change direction and turn downwind when it capsized, officials have said. Though difficult, the maneuver was considered normal.
One hull snapped. Investigators will have to determine whether a structural problem caused the catamaran to flip, or if the capsize broke the boat. Last fall, Artemis said the front beam of the catamaran was damaged during structural tests, delaying the boat's christening.
Oracle Racing won the last America's Cup in 2010 in Spain, and its owner, billionaire Larry Ellison, picked the San Francisco Bay to defend the cup. Three teams have signed up to challenge and are scheduled to begin racing one another in July to determine who will take on Oracle. The finals against Oracle begin in August.
Earlier, Bay City News reported that a German team is pulling out of the regatta's competition for youth:
Sailing Team Germany's youth team, which was slated to compete in the Red Bull Youth America's Cup from Sept. 1-4, announced over the weekend that it was pulling out of the competition after Simpson's death.
Team managing director Oliver Schwall said in a statement that he hoped the death would prompt race officials to "thoroughly rethink" the format and equipment used in the races.
The youth teams, comprised of sailors ages 19 to 24, use 45-foot catamarans rather than the larger 72-foot ones that will be used by the older sailors in races that start in July with the Louis Vuitton Cup and end in the America's Cup Finals from Sept. 7-21.
One youth team, the San Francisco-based American Youth Sailing Force, already capsized their 45-foot boat during a practice run earlier this month, while Oracle Team USA had their 72-foot boat heavily damaged and swept out to sea in a capsizing last October.
No one was injured in either of those incidents.
America's Cup officials are meeting today in San Francisco to discuss how the races should move forward following Simpson's death.
Officials haven't yet released specifics about the time and location of the meeting, but said it would include members of Oracle Team USA, Artemis Racing, Emirates Team New Zealand and Luna Rossa Challenge -- all four teams competing in the races with the 72-foot boats.
San Francisco Mayor Ed Lee said Monday he was also waiting to hear from race organizers about what, if any, changes might be made to the regatta and said he shared their concerns about the safety of the sailors.
Lee said, "I'm going to be working very hard to continue making sure this event is both safe and successful."