Factual error: The men rowing the longboat into the wharf at Nassau are completely hopeless oarsmen. Needless to say, 18th century sailors would have been expert oarsmen. Untrained 21st century actors are not.
Continuity mistake: The scar on Singleton's face changes from the right side of his face to the left side several times.
Revealing mistake: The scene in the captain's quarters has water dripping from the ceiling. With the ship rocking from side to side, the water drops down perpendicular to the table the whole time, showing the scene is stationary and the camera is tilting. (00:14:00 - 00:14:35)