Americans have all heard the heroic accounts of firefighters and first responders at ground zero on 9/11, but an overwhelming rescue mission was also taking place on the water. Captain Rick Thornton told The Post he was four hours into his shift on the Hudson ferry on Sept. 11 when he spotted a plume of white smoke trailing from the World Trade Center. The Navy veteran abandoned his route and jetted toward the madness without consulting his superiors for permission.