International Dredging Review

International Dredging Review

Anglo Dutch Dredging Co. Ltd. (ADDC) launched the 21500 cubic meter hopper dredge Rotterdam on December 16 2000. ADDC is a wholly owned subsidiary of Ballast Nedam Baggeren b.v.

The dredge is 190 meters long making it one of the largest dredges in the world.

Mrs. H.M.A. Opstelten-Dutilh wife of the mayor of Rotterdam performed the naming ceremony which was performed in conjunction with the launch.

IHC Holland and Ballast Nedam reached agreement at the end of January 2000 on the design building and delivery of the Rotterdam and IHC subcontracted construction to its subsidiary van der Giessen-de Noord in Krimpen aan den IJssel the Netherlands. Both companies are part of the IHC Caland group.

The Rotterdam is a twin-screw trailing suction hopper dredge which can achieve a speed of 15.9 knots. The vessel id equipped with two suction tubes allowing dredging to a depth of 60 meters. It will be possible to extend the starboard tube. Fitted with an underwater pump and extended tube the dredge will dredge to 120 meters deep.

The hopper is equipped with eight single bottom doors at the center of the vessel and two cylindrical overflows. The load can also be discharged by means of the self-emptying suction system which forces the sand over the bow through a floating line or sprays it ashore through a “rainbow.” In both cases the discharge process is accelerated by a powerful water jet system fed by two jet pumps.

At the aft end the two main engines each provide a variable speed drive to a jet tube-mounted screw. Each engine is connected at the forward end to a main generator which provides power for the dredge pumps jet pumps dredging installation and other energy-consuming devices on board. Two electrically driven variable thrusters are installed at the bow.

The vessel is equipped with an extensive control and computer system for the benefit of the navigation and dredging processes. This allows all functions to be controlled from the fully integrated bridge. The IHC dynamic positioning and dynamic tracking system (DP/DT) is installed on board for the automatic tracking of the path to be dredged or for accurately holding position during dumping or discharging ashore. The desired routs and positions are set by means of the recently developed hydrographic dredging chart or the electronic marine chart or both. This system was developed for the dredging industry by IHC Systems.

There is accommodation at the aft for a crew of 39 and a deck crane with a lifting capacity of 45 tons capable of travelling the entire length of the vessel.

This dredge will enable Ballast Nedam Baggeren to reinforce its competitive position in the world market in large land reclamation projects where the sand must be extracted from great distances and at great depths.

Completion and trials will be in May and June and the dredge will be delivered at the end of the summer to be deployed on projects in Southeast Asia.