I believe the statement is: When a ship captain dies, it is a tragedy, because he is the leader of the boat, just as Lincoln was the leader of the country.
And the captain would always be the last one who leave the boat in every crisis and have to make sure everyone else are safe first.
Lincoln possess this characteristic of the ship captain. He hold on to his principles to the last minutes regardless of many people who dislike it and willing to kill him for it.
