The 3,200m3 capacity trailing suction hopper dredger ''Charlock'' has been equipped with two dredge pumps manufactured by Damen Dredging Equipment.

A Damen inboard single walled dredger pump of type BP8065MD

A Damen inboard single walled dredger pump of type BP8065MD

Charlock was delivered by the Barkmeijer Stroobos BV yard in the Netherlands for Dutch operator Van den Herik BV.

One innovative Damen semi-axial dredge pump is fitted on the trailing pipe while the other is mounted inboard, with both pumps working in series to enable a highly efficient dredging process.

The semi-axial dredge pump is a new addition to the wide Damen dredge pump range. The semi-axial dredge pump installed on the Charlock is of type OBP9080HA and provides a range of advantages for the owner. Its weight is relatively limited, reducing the required hoisting capacities of the gantries and winches on board and the limited cross section minimises the drag forces in the drag arm. Required power is limited and although the semi-axial pump is equipped with only a 1,200kW electric motor it 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 two-part pump casing, have been dimensioned optimising the foundry process to optimise the casting accuracy to reduce the risk on mis-casts. 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 of 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 delivers the mixture to the hopper during loading or it can also pump ashore using the bow coupling unit or via rainbowing. The inboard BP8065MD dredge pump is driven by a 3,200 kW electric motor.

Drawing upon a full range of dredgers in stock, Damen has supplied the Saudi Border Guard with two CSD 450 cutter suction dredgers within a very short time span.

The two CSDs 450 will work to a maximum dredging depth of -12m and deliver a mixture production of 3,000 m3/h. Both dredgers will be fitted out with an extensive list of options, including an accommodation unit and positioning, navigation and communication equipment. The addition of an anchor boom installation assures independence and the efficiency is boosted by adding a spud carriage pontoon.

The delivery also included two complete dredging packages which included floating and shore pipe lines, a full set of spares and training. The training will be given to the crew on the job, enable them to familiarise themselves quickly with the new dredgers.

The cutter suction dredgers will be based at different border guard stations in the Kingdom of Saudi Arabia, Jeddah on the Red Sea and Damman in the Gulf Ara. They will perform various maintenance dredging jobs such as clearing jetties areas and maintaining dredged depth in harbours.

The recent deliveries further strengthen the long standing business relationship between Damen Shipyards and the Saudi Border Guard.

By Larz Bourne