There is already something like this in use: harbor pilots, who have specialized knowledge of specific ports and board vessels to navigate them through critical transit zones. It is reported that there were pilots on board navigating at the time of the collision.

Tugs are used in tight locations, but they can only change a ship's speed at a very slow rate compared to that ship's engines. By analogy, you can pull a train car and get it moving by yourself, but if that thing is moving at 5mph you aren't stopping it by yourself in any reasonable distance.