Push boat (5)
I believe the answer is:
barge
I believe this clue is a double definition.
'push' is the first definition.
(I've seen this before)
'boat' is the second definition.
(I know that barge is a type of boat)
(Other definitions for barge that I've seen before include "Violently push" , "Move roughly; boat" , "Long, flat-bottomed boat" , "Flat-bottomed cargo boat" , "Move forcefully" .)