The dredgers consist of two identical pontoons on which a frame with a control cabin and winches is placed. Behind the cabin, a hydraulic power pack with a 178kW Scania diesel engine is placed to feed the DOP submersible dredge pump, the cutter unit and the winches.

A total of six winches are placed on the frame for lowering the dredge pump and manoeuvring the vessel. De Groot Nijkerk's modular approach to building sees the ladder and dredge pump attached to the central winch/ cabin frame. A 200m long floating pipeline is also being supplied.

The vessels will be assembled on site under the supervision of a De Groot Nijkerk engineer and will start work extracting coal dust from the bottom of a pond and river.

The sand winning dredger will be delivered to its West African owner next month in three 40ft containers and will also be assembled on site under De Groot Nijkerk supervision.

Specially designed to win sand from depths of up to 30m, the catamaran style vessel will include a power pack on the stern and a control stand under a sun awning.

A hydraulically driven 95kW DOP1815 dredge pump again features. The discharge diameter of this pump is 200mm, with the delivery line running between the pontoons to the stern where it will be attached to an HDPE floating pipeline to be delivered by De Groot Nijkerk complete with rubber hoses and floaters.

Driven by a Caterpillar 3306 DITA engine of 216 kW, the hydraulic power pack feeds manoeuvring and hoisting winches, the dredge pump, and a 125m 3/hour Johnson jetwater pump.

Due to its modular construction this vessel can, in future, be easily provided with a ladder and cutter unit. The hydraulic drive of the cutter unit can be facilitated by switching over the hydraulics used for the jetwater pump.

MJ Information No: 16916