Abstract: Split hopper vessel comprising two half hulls which are pivotably connected to each other by a pivot shaft which extends at a high level parallel to the longitudinal axis of the ship. Both half hulls are furthermore connected to each other by means of cylinder pairs installed at an interval at a distance below the pivot shaft in a directiontransverse to the pivot shaft. The housings and the piston rods of each pair of cylinders are by cylindrical bearings connected to a respective axle, in common for both housings and for both piston rods, which axles themselves are, centrally between the housing bearings and the piston rod bearings connected to the respective part of the ship by a self adjusting bearing. The fluid lines between the rod sides on the one hand and the piston sides on the other hand of each pair of cylinders are embodied as rigid conduits, which are connected to both sides of one single remotely controllable locking- and safety valve for each pair of cylinders.

Abstract: A floating device such as a hopper dredge having bottom valves (4-11) for discharging the holds (2), which holds according to the invention can be closed airtight and are provided with apparatus (18) to generate an overpressure within the holds (2), the bottom valves preferably being at a level above the keelline (3) of the device. Movable crane devices (24,26) are provided within the hold to handle components. The holds (2) have a hatch opening with cover (21) to allow entrance or removal of parts (8') which hatch opening can be covered by an inflatable tent (27) attached to the deck.

Abstract: A device for elevating water by means of a vertical chain (5,21) of buckets (10,20) supported and driven by an upper reversing wheel (7,25), the lower part of the bucket chain (5,21) running through a filling tank (1,15) having a height adjustable overflow edge (4,18) over which water from the lower level (2,19) may flow into the passing buckets (10,20). Structure (11,25') is provided for discharging the buckets (10,20) at the higher level (13,39). The bucket chain (21) in its entirety preferably is adjustable in the vertical direction.

Abstract: A method for sucking up soil or sludge by means of a suction dredge provided with a suction pipe having a drag head. Through the suction pipe (1) water and soil or sludge are sucked up. The soil or the sludge is loosened in front of the inlet opening of the drag head. Said loosening operation takes place at such a distance from the inlet opening (4) of the drag head (3) that by the loosening operation the gases being liberated remain substantially out of the suction action of the drag head (3). The loosening is performed by injection nozzles (28) and/or cutting blades mounted in a frame (10) swingably mounted about a horizontal axis (9) on the suction tube (1).

Abstract: A dredging apparatus comprising a floating device and a frame suspended adjustably therein. The frame supports reversing wheels 1,2 for an endless conveying member 3 provided with blades 4 for loosening and feeding upwards the soil material. The apparatus is further provided with a chute 29 for receiving the material discharged from the members. The endless conveying member 3 comprises a closed endless belt 3 flexible in at least one direction perpendicular to its surface and provided with digging blades or partitions 4 fixed thereon. The frame is provided with a tube 9 open at top and bottom. The upwards running section of the endless belt 3 runs through the tube 9 which encloses the belt 3 with blades 4 with a small clearance. Furthermore, the frame has a part 14 projecting downwards beyond the tube and supporting a reversing wheel 2 for the belt 3. The angle of that part with respect to the vertical is adjustable such that the belt section 22 can engage the bottom at the inlet of tube 9.

Abstract: The invention relates to a suction drag system for dredging vessels which can be placed or removed respectively on an existing vessel, such as a hopper barge (1,2), the system comprising a suction pipe (26,28) with suction head, a suction pump (29) with drive motor (30), an elbow section (25) on deck and derricks (41) to handle the suction pipe (26,28). These components are separate units to be installed on deck and are units each having a frame (8,9,10) which can be installed disconnectably transversely over the hold (4) onto the coamings (5,6) of the vessel, a further frame (7) being possible carrying the drive unit for the dredging system, these frames (7,8,9,10) in case of a split hopper barge (1,2) being pivotably connected (11) to one coaming (6) and pivotably as well as movably in transverse direction (12,13) to the other coaming (5).

Abstract: The invention relates to a split hopper vessel consisting of two halves, which can swing about a horizontal longitudinal axis between a closed position in which the hold formed by the two halves is closed and an open position in which the two halves are moved apart. The two halves are interconnected by hydraulic cylinders which can perform or assist the opening and/or closing of the vessel. The hydraulic cylinders under the control of non-return valves (10,11,53) which block the closed position and which by a control pressure system can open to allow the opening of the vessel. The flow of liquid from one side of each cylinder to the other side can be shortened, and safety structure ensures that all cylinders operate simultaneously, all non-return valves (10,11) having a pressure-activated switch, which when activated opens the non-return valve G.sub.1 in the line connecting both sides of each cylinder.

Abstract: The invention relates to a ship (1) with one or more derricks (4), in particular a dredge having at least one derrick (4) for handling the suction pipe (22) which derrick (4) can be moved between an inboard position (7) and a vertical position. The derrick has guiding tracks (8,9) for a crane jib (17) which tracks (8,9) in the vertical position of the derrick (4) are in line with guiding tracks (15,16) inside the profile of the side wall (3) of the ship. The cable for controlling the jib (17) is protected by a channel inside the profile of the ship side wall (3) between the latter guiding tracks (15,16). The guiding tracks (8,9,15,16) have upper and lower stops (29,28) for controlling the movements of the crane jib (17) which jib (17) is pivotable about a horizontal axis (18) between a position perpendicular to the derrick (4) and a downwardly directed position.

Abstract: Drag head for a hopper suction dredge, which drag head has a suction opening in the dragging direction, defined by side walls and a rear wall. The lower edges of these walls are positioned in one plane whereby the rear edge is positioned lower then the upper edge of the inlet opening with respect to a vertical cross sectional plane parallel to the dredging direction. The side edges and the rear edge are positioned in an essentially horizontal plane. The rear wall of the drag head extends upwards along a compound bent line such that the tangent of this line at the height of a horizontal plane through the upper edge of the inlet opening is inclined forwards at an acute angle.

Abstract: A hoisting yoke for a load. At its ends the beam or frame of the yoke has points of suspension for the load and a hoisting point. The hoisting point is displaceable for distributing the weight of the load uniformly over the points of suspension. The beam or frame of the yoke is provided with hoisting points at its opposite ends. The intermediate hoisting point is displaceable dependent on the load picked up by the hoisting points at the ends such that all of the hoisting points carry an equal part of the load.

Abstract: A suction dredger provided with sweeping arms at the side of the vessel which arms can be placed at an angle with respect to the body of the vessel and are provided with suction apparatus to suck away the upper layer of the water collected in front of the sweeping arms to pump it into the hold of the vessel so that said hold optionally can be used for storing dredging material or oil respectively. The invention further relates to the construction of the apparatus for connecting the sweeping arms to the vessel and to move said arms from an inward storage position into an outboard operative position and vice versa, the sweeping arms being in a tilted position when inboard and if necessary displaceable in the longitudinal direction of the vessel along its deck so that in the case of a suction dredger the normal dredging apparatus can perform its function without being hampered by the sweeping arms, the construction of said apparatus being such that the sweeping arm can be applied to any other type of vessel.

Abstract: A control system for controlling the variables of a process, comprising at least two proportional-integral-differential controllers each comprising a linear signal path, a differentiating signal path and an integrating signal path, all connected to an input junction. The outputs of the linear signal path and the differentiating signal path are added at an intermediate junction and the resulting sum signal is added to the output signal of the integrating signal path at an output junction. Each proportional-integral-differential controller supplies an output suitable for controlling one of the process variables such that this process variable is maintained as close as possible to a predetermined maximum value without any of the other process variables exceeding its respective predetermined maximum value.

Abstract: Method for controlling the position of the suction head of a dredge in relation to the sludge layer on the bottom of a water way. Acoustic pulses are transmitted in front of the suction head from the dredge to the bottom. The reflected pulses are received and the time difference between the transmitting and the receiving moment is determined as well as the energy difference between the transmitted and received pulses. Based on these differences the configuration and composition of the sludge layers as well as the preferred position of the suction head in relation to said sludge is determined. Thereafter the system for controlling the position of said suction head is operated to bring the suction head into the most favorable position.

Abstract: Large vessel having an opening in the bottom of the hull said hull portion being provided with an upwardly and downwardly movable grid structure shielding the opening against ice flakes which pass along the bottom of the hull.

Abstract: The invention relates to the combination of a radial bearing 4,5;38,39 and a seal 14,17,21; 42,45,46 which both make use of elastomeric bushings 6,7,17,42,45 having a smooth cylindrical surface supporting a shaft (1,36) provided with helical grooves 10,11,15,19,46 conveying the lubricating liquid said helical grooves conveying in the same or opposite directions, said combination of radial bearing and seal further can be combined with an axial bearing 40 having grooves in a disc 53 which rotates with the shaft (36) and which is in engagement with stationary discs 54,55 of elastomeric material.

Abstract: The invention relates to a suction dredge barge in which the air chambers (8,9) on either side of the hold (2) can be filled with mud via an overflow (14) at the top edge of the hold (2) said air chambers (8,9) having inclined bottoms (10,11) and discharge openings (12,13) towards the hold at the lower edge of said inclined bottoms (10,11).

Abstract: A method and apparatus for measuring the amount of mire and mud in a suction dredge hopper 2, which mire and mud is a constituent of a fluidized mixture. An acoustic level gauge 16 measured the position of the upper surface 3 of the mixture and a plumb weight 7 measures the position of the lower limit of the mixture defined by the top of a sand layer 4. A plurality of differential pressure responsive density measuring devices P measure the density of mire at different levels. From these measured valves the total amount of mud and mire is determined.

Abstract: The invention relates to an axial bearing comprising a shaft 1 with a disc 2, said disc having grooves 7 and cooperates with a stationary disc 5,6 made from elastomeric material the bearing being based upon the principle that the flank 8 or flanks 8,9 of the groove 7 under all circumstances from stand still to motion at full speed deform the smooth surface of elastomeric material and form a lubricating wedge.

Abstract: Dredge with drag pipe, consisting of a number of pipe sections interconnected by hinged joints, whereby drag lines are connected to said hinged joints and to the front and rear end of the drag pipe and furthermore the rotatably supported front end of the drag pipe is guided into vertical guiding elements at the side wall of the ship and the rear end carries the drag head. The dredge contains for each drag line a separate winch, controlled by an electronic control unit for automatically moving the drag pipe outboard, lowering the rising the drag pipe and moving the drag pipe inboard. During the whole dredge operation from the outboard movement of the drag pipe unitl the inboard movement thereof the unwound drag line length of each winch is measured, whereby the electronic control unit determines based on said measured drag line length at each moment the position of the drag pipe.

Abstract: A method for controlling the production of a dredging apparatus such that the highest possible concentration of the mixture is obtained, by using for controlling the dredger, the difference between the forces occurring at the dredging implement and the forces occurring upon maximum concentration. The value of that maximum force, which depends on the dredging conditions, is continuously adapted to the ratio between the existing concentration and the existing loosening force in order to obtain an immediate response to changing conditions during dredging.