When leadership exceeds expectations of rank

Which naval leaders showed unexpectedly strong leadership?

Leadership is expected of captains, but Admiral Duncan's performance at Camperdown stands out as exceptional.

Leadership is expected once an officer reaches command, so the exceptional cases are those that exceed the role's normal demands. Admiral Duncan provides the clearest unexpected example in the answer. He was already regarded as a good admiral before Camperdown. His performance there exceeded those expectations and made the battle the useful test case.