Abstract: A flap is provided for the suction head of a hydraulic dredge to divert the dredge suction force generally in the direction that the head is swung along the bottom of a body of water and to guide material into the mouth of the suction head. The suction head includes top and bottom projections or lips projecting outward beyond the sides of the head, and the flap is pivotally mounted between such lips for swinging about an upright axis. Control mechanism swings the flap between alternative positions in which it extends outward from one of the sides of the suction head and from the other of such sides, respectively. An indicator is provided so that the position of the flap can be determined easily by the dredge operator.