In January 2003 VOSTA LMG received an order from Hudong Zhonghua Shipyard for the design and supply of all dredging components for a Trailing Suction Hopper Dredge (TSHD) for the Chinese Harbor Authority Huanghua Port.
The dredge was handed over in a festive ceremony by Hudong Zhonghua Shipyard to Huanghua Port Authority on 11 November 2004, after successful dredge trials in the Yangtze estuary.
"Shen Hua" has now started her duty; the required, continuos dredging work to maintain the required depth of the port waterway entrance of Huanghua Port. This was the initial reason for the Board of Management of Shenhua Group to invest into their own Trailing Suction Hopper Dredge. Huanghua Port, located at the North East Coast of China, belongs to the Shenhua Group and is the main hub for worldwide transport of coal being excavated in the mines located in the northern part of China.
The order for VOSTA LMG covered the complete engineering package and the delivery of the dredging components for a 5.000m³ Trailing Suction Hopper Dredge. As repeatedly happened in the past, VOSTA LMG also had the complete technical responsibility for this vessel. The dredge was built under consideration and use of latest developments in dredging technology.
The new TSHD is designed as twin screw vessel with CPP and two free hanging rudders. The deckhouse is arranged on fore ship and can accommodate up to 45 persons. The hopper is of semi-closed type with center box keelson and transverse saddles. The hopper load can be dumped through 10 conical bottom valves – arranged in two rows - or discharged via a bow coupling through a shore pipeline. This TSHD is equipped with two 900-mm dia. trailing suction pipes.
Basically the dredge has the following features:
The shape and the equipment of the hopper represent a new way of construction developed by VOSTA LMG. The hopper has smooth walls and the bottom valves are arranged in two rows. The unloading equipment, the bottom valves and the jet water system for diluting the load allow quick discharge of the hopper even without conventional bottom flaps with wide openings.
In order to benefit of building in series, a number of dredging components such as side suction pipes, hoisting frames, bottom valves, overflow weirs, just to mention a few are of proven serial design. The lines of the ship, however, have been optimized to suit the respective applications and the different propulsion and dredging concepts. The two tailor made dredge pumps are installed in a separate room and are driven direct from the two main propulsion plants.
Both trailing suction pipes are equipped with the latest development in draghead design. These active dragheads combine high excavation capabilities for loosening high compact soil at Huanghua Port with optimized hydraulic properties for mixture transportation. The dredge production can be optimized by controlling the draghead visor angle to the ground.
The VOSTA LMG Dredge
Control & Monitoring System (DCMS) for the vessel has a control concept using various local interfaces. The ergonomically arranged operating panel includes the conventional operating elements as well as modern process control via screen, keyboard and trackball.
The automation controls, visualizes and reports the entire dredging process. It controls the pumps and valves to ensure operation with the maximum and always optimized discharge rates. Amongst other parameters, the mixture concentration, mixture flow and pressure on the suction side are taken into account for optimization of the dredging process. Moreover, various automatic functions and sequences such as swinging out the side suction pipes, moving the valves into the required working mode etc. are of great help to the dredge-master to achieve quicker and safer operation. Besides the process visualizing system, a graphic side suction pipe position indicator shows the exact position of the side suction pipe. It is integrated into the entire system in the same way as the loading computer for exact monitoring of the loading condition of the TSHD.