New trend in dredging industry – CONVERTING AND UPGRADING OF EXISTING DREDGER

Engineering is continuously providing new technologies and solutions with time creating new options for users to be well-efficient and highly proficient. In the recent times, modification, conversion and upgrading of existing dredgers are proving to be good solutions for users to increase their capacity and capabilities with a reasonable amount of investment. Companies which cannot invest in a new dredger can convert their existing dredger, barges to a more functional and efficient dredger.

Upgrading of existing dredger systems is quite practical as it offers reusability and functionality of the old dredger with low investment.

Conversion of existing vessel into dredger can help in increasing the capacity and capability of the dredging companies in much lesser time with a huge saving in investment.

Modification of dredger is also needed when the dredger supplied may not meet up the requirements and slight changes in the parts or system can make it appropriate for the project requirements.

All type of dredgers can be subject for modifications that can vary from replacing a single pump with more efficiency to the whole suction/discharge system of the dredger or literally converting existing barges and vessels into dredgers.

Upgrading Dredge Pumps

Dredge pump or sand-slurry pump is considered as the heart of the dredger and plays the most vital role on the efficiency of a dredger.

 Dredge Yard’s Senior Design Engineer , Manish Jangir, says: “Latest tools in the market like CFD and optimum design calculating software have widen the paths of having an efficient pump design for the same old pump without changing any fitting parameters or the connections like the flange.

After achieving the final design of the pump, the manufacturing is done by using the latest production techniques, molding software for casting, and strict metallurgical testings.

Dredge pump impeller sketch

Upgrading suction and delivery lines

Suction and delivery lines of a dredger are the means of transport of slurry and the line design and components vary between dredgers. The efficiency of the dredger depends on the pump and the pumps efficiency certainly depends on the pipe line. And the maintenance cost depends on the quality and capability of the components. The major components involved in the pipe lines are: Pipe Pieces, Gate Valves, Suction Mouth, Swivel Bend, Bow Coupling, Turning Glands, Ball Joint Couplings, etc.

Few new trending components are discussed below:

Dredge pump Impeller CAD mode

• Pipe pieces

Kabi Eisa, Production Manager at Dredge Yard describes the double wall dredge pipe as the newest trending product in the dredging market. He also adds that the Double wall pipes are highly wear resistant due to their special design where three layers of material have been used. It consists of wear liner, concrete and steel pipe where wear liner being the layer that will be in contact with the sand or slurry.

Double Wall Dredge Pipe

• Dredge Valves

Dredge Gate Valves are slightly sophisticated components and for proper functioning, maintenance, it is very important to select the right type with right material and pressure handling capability for long life.

Dredge Valve

 Upgrading split suction trailing hopper dredger

“For example, the dredger in the image didn’t have a discharge line and could only offload the material through its bottom doors.

Dredge Yard developed the complete suction and discharge line on the ship which includes several pipes, bends, dredge valves, and bow coupling. The nominal diameter of pipe is 750 mm.” says Michel Debo, Dredge Yard’s Operational Manager.

Converting hopper barge into trailing suction hopper dredger

Another example shows a barge in Brazil, capacity 800 m3, which is in process of conversion into trailing suction hopper dredger. A complete trailing suction system has been installed on the barge. The system consists of drag head, turning gland, gantries, sliding piece, pipes, bends, valves, pump and bow coupling.

TSHD system

Suction Discharge System on Dredger

Discharge line on TSHD

Many hopper dredgers are upgraded by adding complete discharge line on the ship as pipes, bends, valve and bow coupling structure.

Modifying or converting old vessels will always be considered the most convenient alternative due to the cost cuts, less time involved in the makeover of an old ship than building a new one and the possibility of customizing the vessel according to the customers’ needs.