Gondolier's propeller (4)
I believe the answer is:
pole
'gondolier's propeller' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for pole that I've seen before include "Rod; shaft; European" , "Round rod of wood or metal" , "Limit" , "Chopin, for example" , "Long, round rod" .)