Abstract: A dredge with an elongated boom mounted to extend at an angle from the vertical has at a lower free end of the boom a pump inlet and disc-cutters mounted on the boom. The disc-cutters are rotated on axes of rotation lying at an acute angle to a continuation of the long axis of the boom beyond its free end whereby the disc cutters are tilted toward the inlet mouth at their near sides. The axes of rotation of the discs are also at an angle from the perpendicular with respect to the surface of liquid on which the dredge floats greater than that of the boom so that the axes of rotation of the discs are more nearly perpendicular to the vertical than is the axis of the boom.

Abstract: The spoil line of a dredger is kept afloat by a series of spaced floatation elements in the form of tire carcasses, the beaded mouths of which have been spread until the distance between the edges of the mouths is greater than the radial distance from the surface defined by the mouths to the outermost surface of the carcass, the carcasses being filled with foamed plastic material. The floatation elements are strung on the spoil line whereby the spoil line passes through their centers.

Abstract: In a vessel-mounted dredging device in which material freed by revolving cutters is pumped through a suction mouth and discharge pipe to a place remote from the cutters, a submersible dredge pump is mounted on a platform which supports cutter discs spaced from one another and positioned to deliver material to the suction side of the pump. The platform is mounted on a mast which is so constructed and arranged as to be movable vertically with respect to a carriage which is in turn vertically movable relative to the vessel. The platform is preferably hinged to the end of the mast, to permit the platform to swing to an angle to the horizontal, selectively.

Abstract: In a vessel-mounted dredging device in which material freed by revolving cutters is pumped through a suction mouth and discharge pipe to a place remote from the cutters, a submersible dredge pump is mounted on a platform which supports cutter discs spaced from one another and positioned to deliver material to the suction side of the pump. Trapezoidal teeth are pivotally mounted to swing to either side of a radius of each cutter disc, making the teeth effective for either direction of rotation of the cutter disc. The cutter discs are selectively rotatable in either direction, preferably counter-rotating with respect to one another. The platform is mounted on a mast which is so constructed and arranged as to be movable vertically. The vessel itself is so constructed as to permit a discharge pipe to extend fore and aft along the center line of the vessel.