Abstract: A dredge hull carries a first spud vertically slidable through a spud frame on a longitudinally slidable carriage, and a second spud vertically slidable through a spud frame on a fixed carrier. Each spud has lifting means for raising it vertically, locking means for locking it in raised position, and release means for releasing the locking means so the spud can drop and drive into the sea bed. With the second spud raised and the first spud dropped, advancing means move the hull forwards relative to the carriage. The lifting and locking means include a lifting plate above a locking plate, both apertured to receive the spud closely and permit its free passage when horizontal and lock it when tilted, the lifting plate being tilted when lifted hydraulically, the locking plate tilting gravitationally. When the lifting plate is lowered onto the locking plate, both are movable hydraulically to horizontal to let the spud drop.

Abstract: The dredge is of the type having a bucket wheel, driven by a hydraulic motor through a gearbox, on the front of a bucket wheel carrier hinged at its rear to the dredge hull, and lowered to or raised from working depth by a cable engaged with a lifting sheave block near the front of the carrier, the dredge being slewed by cables from anchors to both sides of the dredge and engaged with slewing sheave blocks near the front of the bucket wheel carrier. Hydraulic fluid is bled from the motor to the gearbox, and then by a bleed line connected to the bearings of the sheaves of the lifting sheave block and the slewing sheave blocks. A check valve maintains a predetermined pressure in the bleed line to apply internal pressure to the seals of the gearbox, the lifting sheave block and the slewing sheave blocks.