Pull boat (3)
I believe the answer is:
tug
This clue is a double definition.
'pull' is the first definition.
(to tug something is to pull it)
'boat' is the second definition.
(I know that tug is a type of boat)
(Other definitions for tug that I've seen before include "Towboat" , "Working boat" , "water tower" , "Pull hard or suddenly" , "Boat to pull larger ones" .)