Hugh O'Neill gave a us a very informative delivery regarding a marine pilots job. He had followed the career of his father who was a pilot in England, and went to sea in 1972, it taking 12 years to become a master mariner.
Hugh pointed out the many dangerous situations a Pilot has to go through when directing large ships through shallow waters. They have to take over totally from the Captain of the ship. Also how a pilot needs excellent local knowledge especially as ships can be worth billions of dollars. We learnt about the history of pilots in different countries. Captains from different countries often had to be handled in different ways to make sure the pilot had total control of the ship. Talked about the danger of different ships like oil and petrol tankers.  
We also learned a lot about the history of shipping. Hugh also did a master degree in History. In later years he was the editor of "Pilot" magazine.