Create trouble (4,3,4)
'create trouble' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for rock the boat that I've seen before include "as the sea may?" , "Yachtsman's motion might" , "make trouble" , "Disturb a harmonious situation" , "Disturb the status quo" .)
'create trouble' is the definition.
(I've seen this in another clue)
This is all the clue.