A hopper valve module is adapted to be removably mounted in the well of a hopper of a hopper dredge vessel for opening and closing the hopper outlet, the module being attached to the vessel only adjacent to the hopper outlet so that the module may be removed as a unit. An annular ring is secured around the top of the hopper well with support arms extending upwardly therefrom to support a vertically extending cylindrical housing having a hydraulic drive cylinder mounted therein with a piston rod connected to a valve member which closes against a valve seat to provide a watertight seal.In a first embodiment of the invention a conicalvalve member is coupled by a universal joint to the piston rod and has a replaceable resilient covering for sealing against the valve seat at the bottom of the hopper well. A watertight enclosure is provided for the drive means.In a second embodiment, a cylindrical valve member is telescopically received in the housing and is coupled by a movable joint to the piston rod, the valve seat being at the top of the hopper well.