How in the living duck can a fricking boat on clear waters possibly sneak up on a harbor in broad daylight? Don't anyone dare give me some nonsense about casting invisibility on a whole boat, if there is such a magic in this world, they would be prepared, and at least look for the water's movement if not the depression the ship leaves in the water since it is still there.
And if the ship already left, why was a pirate still there? how did he get back to the ship? How did the boat get so far out when they were pursued right away?!