ROCK THE BOAT

{v. phr.}, {informal} To make trouble and risk losing or upsetting something; cause a disturbance that may spoil a plan. * /The other boys said that Henry was rocking the boat by wanting to let girls into their club./ * /Politicians don't like to rock the boat around election time./ Compare: UPSET THE APPLE CART. Contrast: LET WELL ENOUGH ALONE.