Abstract: A method and apparatus for generating a high plume or "rooster tail" of water behind a water jet propelled marine craft, such as a jet ski, is characterized by the insertion of a water diverting member into the upper regions of the jet of water discharging from the jet propulsion system and diverting a portion of the water from the jet upwardly and outwardly away from the jet to form a tall plume of water above and behind the jet. In its preferred embodiment, the apparatus comprises a lever pivotally mounted on the upper side of the discharge nozzle of the propulsion system and selectively movable at its upstream end through a slot in the nozzle into the interior of the nozzle to divert a portion of the water from the jet stream upwardly and rearwardly away from the nozzle.