The vessel was traveling south bound from the lake isleworth canal at an approximate speed of 40 mph when the hull of the vessel began to fail (fiberglass delaminating) at the stern/keel.  At this point the hull separated and caught the water causing the boat to dramatically slow down and almost come to a complete stop, subsequently ejecting all occupants from the vessel.  The sudden change in speed also caused the motor to stall and shut down.  The occupants then swam back to the boat and boarded it via the starboard stern ladder platform.  At this point the vessel began to take on a significant amount of water.  The occupants donned life jackets and reentered the water as the vessel capsized.
WINDERMERE