Duck famous navigator (5)
I believe the answer is:
drake
I believe this is a double definition.
'duck' is the first definition.
(drake is a kind of duck)
'famous navigator' is the second definition.
(Sir Francis Drake)
(Other definitions for drake that I've seen before include "English circumnavigator, d. 1596" , "Elizabethan circumnavigator" , "Elizabethan favourite" , "flyer" , "Sir Francis - -" .)