A riverboat cruising between Memphis and Nashville has become stuck on a sandbar in Lake Barkley, the boat company said Thursday. The modern riverboat American Jazz was being assisted off the sandbar, American Cruise Lines said in an email. The small boat has not been damaged, the company said. The boat was carrying 120 passengers and 54 crew members, the U.S. Coast Guard said in a statement Thursday night. The agency said it sent a boat crew and marine investigator to the scene. The Coast Guard was working with the company to figure out how to dislodge the boat.