Paddles (4)
I believe the answer is:
oars
'paddles' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for oars that I've seen before include "Implements to propel a boat" , "Indirectly, they make waves" , "Means of propulsion" , "Rowing blades" , "Propellers for small boat" .)