It's not a question of intelligence, it's skill and experience. Most people have never spent time in a container yard, but the operation of cranes, top picks, operating a forklift in a tight dynamic area, strapping and unloading coils and the coordinating of logistics is very difficult to do with out years of experience.
But he would explain this loading to me. At one point, he taught this along with fire drills aboard ship. Pretty smart kid....12 years younger than myself.