An improvement for inboard motor boats has a rigid exhaust conduit, a miniature rudder, and a rudder control system. The rigid conduit is provided for conduction of combustion gases exhaust outside the hull and has an aft facing outlet. The miniature rudder is pivotably mounted on the rigid conduit relative the aft facing outlet whereby combustion gases exhaust past the rudder. The rudder control system has a user interface inside the boat and has a control mechanism pivoting the rudder in response to inputs to the user interface.