President Trump does not know the 'location' of nuclear submarines. In fact, no one does, not even the crew. The captain, the navigation officer, and the quartermaster, are the only ones who know where they are. The quartermaster station and maps are closely guarded. Nobody knows where they are except a few people with the need to know. Trump may know something like, near Korea, or in the Indian Ocean, but as far as exactly where they are, nobody knows that.
The same thing happened in WWII with surface ships. When ships were on their way to battle at iron bottom bay, occasionally the captain would tell the crew something totally different. The crew would be told they were on their way to Pearl Harbor for shore leave, and a few hours later battle stations is called, guns are firing everywhere, and all hell is breaking loose.
When you are at sea, especially on a submarine, you frequently have no idea in the world where you are or what you are doing there.
