Push a boat (5)
I believe the answer is:
barge
I believe this is a double definition.
'push' is the first definition.
(I've seen this before)
'a boat' is the second definition.
(I know that barge is a type of boat)
(Other definitions for barge that I've seen before include "Bump" , "Freight-carrying boat" , "Possibly lighter" , "Canal boat, towed along (5)" , "Move forcefully" .)