RoRo Deep Dredge challenges orthodoxy
The submersed excavation unit is equipped with a dredge pump and jetwater pump which are both electrically driven. The mixture piping is shown in blue and white. The unit is suspended by steel cables.
Netherlands based Damen Dredging Equipment has developed an innovative flexible dredging concept which challenges current technical limitations.
The new development, unveiled at the Western Dredging Association (WEDA) conference in Nashville USA this summer, is the answer to the increasing demand for raw materials as sand winning locations are increasingly located further from shore at greter dredging depths. The RoRo Deep Dredge, as this solution is called, can work down to 200m dredging depth.
Two vital aspects of the RoRo Deep Dredge installation are the key to its flexibility. First of all, the dredging equipment is placed on a Platform Supply Vessel, thus the storage and transport facility of the mined sand has been separated and is done by a number of barges. Secondly, the steel suction pipes of trailing suction hopper dredgers have been replaced by a flexible hose. Hence, the dredging depth can vary and becomes independent from the dredging vessel’s length.
The installation consists of a submersed excavation unit, which includes a drag head and a Damen dredge pump. A hose is connected to the unit and runs to a storage reel on deck. The flexibility of the system is evident, as the hose can be rolled on and off the reel to adapt the dredging depth, hence the name RoRo Deep Dredge. On deck, the dredge piping connects the reel to discharge spreaders. Barges sailing alongside are filled continuously.
As a result the dredging process is a continuous one, boosting the efficiency of the dredging gear. No sailing time is required for the dredging gear, thus idle time is sharply decreased. As the operating time of all equipment involved has been maximized, the profitability of investment is increased. Another important advantage is that the modular dredging system can be temporarily mounted on a commonly available vessel, resulting in a relatively minor investment and a shortened return on investment time.
The RoRo Deep Dredge is a flexible dredging concept which its developers believe will revolutionize dredging in the 21st century. An optimised use of invested capital and thus a lower cost per m3 could well challenge existing dredging orthodoxy. The modular approach will enable other types of vessels to enter the deep sea mining market.
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