Dredging & Marine Construction

Trailing Suction Dredge DC Orisant Built for Reimerswaal Dredging Launched at Royal IHC

For a joint venture between Reimerswaal Dredging and Group De Cloedt, Royal IHC successfully launched a multi-purpose trailing suction hopper dredge (TSHD) named DC Orisant. The launching and naming ceremony took place on January 11, 2018, at IHC’s shipyard in Krimpen aan den IJssel, The Netherlands. The contract was originally awarded in August 2016, and the keel-laying took place in July 2017.

Reimerswaal Dredging, located in Goes, the Netherlands, is a family-run business with more than 50 years of experience in the mining of sand and gravel from riverbeds and seabeds. The TSHD DC Orisant continues Reimerswaal’s goal to improve service by using high-tech ships with state-of-the-art technology. The company works along the Belgian coast as well as in the Netherlands and Germany and the U.K. continental shelf. 

The vessel is the first complete diesel electric aggregate dredge on the market, which enables it to sail at the highly economical speeds in all situations. The new trailer suction hopper dredge has a hopper capacity of 5,450 cubic meters (7,128 cubic yards) and has been designed especially for high speeds up to 16 knots to reach concession areas further offshore. It is fully diesel-electric powered, with an overall length of 142.3 meters (466 feet), a width of 23 meters (75 feet) and a dredging draft of 7.8 meters (25.5 feet). The vessel can accommodate 13 people.

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The DC Orisant boasts full system redundancy at every level, with a view to maximizing flexibility and minimizing downtime in the unusual event that a component fails. State-of-the-art technology includes an advanced Power Management System (PMS) that powers four generators with varying torques for optimum fuel economy and maximum reduction of CO2 emissions. On the ship’s bridge, the duty officer controls navigation and the dredging process on 10 large optimized screens, including several 46-inch screens. Dynamic Positioning (DP) is also a standard feature, which enables precision positioning of the ship. The stud poles mounted on the ship’s stern and bow allow the duty officer to moor the ship from the control position, even when mooring facilities on-shore are lacking. Given that these spud poles can be extended 18 meters (59 feet) below the ship’s keel, no crew is needed to moor the ship or set off, as the duty officer can do it all without assistance.

With its 12 buckets on a vertical bucket wheel, the ship’s dry discharge system can scoop a layer of material from the hold in both directions at a rate of 2,500 cubic meters (3,270 cubic yards) per hour. The bucket wheel system subsequently places the material onto the shore conveyor using a specialized system of conveyors. The shore conveyor, which can swivel 300 degees from port to starboard, has a long offloading belt that allows it to discharge at a distance of 60 meters (65 yards). The elevation of the conveyor can be adjusted and the conveyor is equipped with a control slide at the discharge end. The DC Orisant has a dredge pipe 1,100 mm in diameter and can also discharge material through the discharge pipe, rainbow nozzle, or the doors in its hull. 

The DC Orisant is a versatile gravel hopper that is suitable for many types of operations.  The dredge installation has been configured to dredge marine aggregates for the construction industry. The TSHD is also highly suitable for performing other operations such as maintenance dredging and beach nourishment. In addition, the DP installation will allow the DC Orisant to perform support activities during the construction of offshore wind farms. Delivery of the DC Orisant to her owners is scheduled for mid-2018.