The state-of-the-art 3,200 m3 Trailing Suction Hopper Dredger (TSHD) Charlock has been equipped with two Damen dredge pumps. One highly innovative semi-axial dredge pump is fitted on the trailing pipe, the other dredge pump is mounted inboard. Both dredge pumps work in series, enabling a highly efficient dredging process.
The semi-axial dredge pump is a new addition to the wide Damen dredge pump range. As for all Damen dredge pumps, it has been designed for the harsh dredging environment with special focus on minimising wear and maximising efficiency. The semi-axial dredge pump installed on the Charlock, type OBP9080HA, has various advantages for the owner. Its weight is relatively limited, reducing the required hoisting capacities of the gantries and winches on board. Moreover, the limited cross section minimises the drag forces in the drag arm. Also, the required power is limited; the semi-axial pump is equipped with a 1,200 kW electric motor. Nonetheless, the semi-axial dredge pump delivers some 16,000 m3/h of mixture at 50% concentration and at an excellent efficiency of 85%.
The cast dredge pump wear parts have been designed in close cooperation with the foundry. All cast elements, including the 2-parted pump casing, have been dimensioned optimising the foundry process boosting the casting accuracy and reducing the risk on mis-casts. Hence, the quality of the cast parts is improved. The various wear parts can be cast in different materials depending on the material to be dredged.
The semi-axial dredge pump will work in series with the Damen inboard dredge pump, type BP8065MD. The low pressure semi-axial dredge pump delivers the dredged mixture with minimal head at the inboard dredge pump. This single-walled centrifugal dredge pump either delivers the mixture to the hopper during loading, but it can also pump ashore using the bow coupling unit or rainbow. The inboard BP8065MD dredge pump is driven by a 3,200 kW electric motor.
Damen is pleased to have taken part in the design and delivery of a TSHD as innovative as the Charlock.