I carry every weekend I am at Cumberland Lake, Dale Hollow, or Laurel Lake. I have heard these arguments that try to establish some oversight by the Corps of Engineers. I have talked to lawyers and prosecutors, both state and federal, and can not find an instance that someone was arrested for carry at any of the above lakes, with the exception of another criminal complaint or activity (drug dealing, manufacturing etc). If you were to be stopped, searched and arrested for violation of a federal law, what law enforcement agency would be doing the stop, search and arrest? FBI, DEA, Federal Wildlife, TSA?
Put your weapon in any compartment made by the manufacturer and you will be legal. A boat is considered a vehicle, just like your car.