Sailor in trouble changing course (6)
I believe the answer is:
crusoe
'sailor in trouble' is the definition.
(Robinson Crusoe)
'changing course' is the wordplay.
'changing' indicates an anagram.
'course' with letters rearranged gives 'CRUSOE'.
(Other definitions for crusoe that I've seen before include "shipwrecked fellow" , "Lonely islander" , "Daniel Defoe's hero" , "See 9" , "Robinson on the island" .)