BMW Oracle Racing have just advised that their 90ft trimaran has dropped her rig while trialling off San Diego.
The statement from the team says that no-one as hurt in the incident and all crew are safe.
The incident happened four hours ago
Support craft were with the race boat at the time and are currently working to salvage the rig and get the boat back to shore.
The team is investigating the cause of the failure.
They were believed to be testing their third mast which is just a few days old. A fourth rig, believed to be a hard wing sail, is still being prepared and the team have two other masts.