TSHD DC Orisant launched by Royal IHC


On 11 January 2018, the name giving and launching ceremony took place of the new trailing suction hopper dredger (TSHD) DC Orisant at the shipyard of Royal IHC in Krimpen aan den IJssel (The Netherlands) where it is built.
The ceremony has been performed by Mrs. Ria den Herder, wife of Mr. Bert den Herder, owner of Reimerswaal Dredging.
The DC Orisant is being built by IHC for the account of a joint venture of Reimerswaal Dredging from Goes (The Netherlands) and Group De Cloedt, which has its main office in Brussels.

Although its primary role will be the dredging of marine aggregates for the construction industry, the DC Orisant has been designed in such a way that is also suitable for other dredging operations, such as maintenance dredging and reclamation works.
Also, thanks to its DP2 installation, it is highly suitable for deployment on offshore projects, like offshore wind farms.

The dredger has been designed to combine a high payload, up to 12,000 tonnes, with a high sailing speed, both while empty and while full, and with an exceptional low fuel consumption.

In order to make the new dredger highly economic with respect to fuel consumption as well as a high flexibility in use, the power train is fully diesel electric, which is said to be a first in the aggregates market.
The vessel also has a high degree of redundancy in its equipment, which makes it very suitable for offshore operations.
For the power generation, the DC Orisant has four Mitsubishi diesel engines onboard, i.e. two of 3,600 kW, one of 1,800 kW and one of 1,200 kW.
The two main engines of 3,600 kW are used during sailing.
They deliver power to the electric engines that drive the two fixed propellers.
In view of redundancy, each propeller is driven by two 1,800 kW electric engines, so in total there are four electric engines of this type.
The other two diesel engines are used during other operations than sailing, such as dredging and unloading or when moored in port.
These engines can be used in any combination with the 3,600 kW main engines or in single use, which gives a high degree in flexibility and a subsequent economic fuel consumption.
Another exceptional feature that adds to the flexibility is the possibility to work with two different frequencies of the generators: 45 and 60 Hz.


The vessel has been designed to carry material with a specific density of up to 2.2 tonnes/m3.
With a hopper capacity of 5,450 m3, this represents almost 12,000 tonnes.
The ship has a length of 142.3 and a breadth of 23 metres.
It can reach a speed of 16.2 knots.
For dredging it has a suction pipe with a diameter of 1,100 mm that can reach a depth of 35 metres.

For unloading, the dredger has multiple features.
Essential for the unloading of sand and gravel for the construction industry is the possibility of dry discharge.
For this, the DC Orisant has state-of-the-art installation consisting of a vertical bucket wheel with 12 buckets and a shore conveyor with a length of 63 meters.
The installation allows for discharging with a rate of 2,500 m3 per hour.
The shore conveyor can swivel 300° from portside to starboard, which in combination with its exceptional length gives the dredger a high degree in flexibility in piling the material on any certain spot on a land based facility.
This flexibility is further enhanced by two telescopic spud poles that make the vessel independent from mooring facilities.
Besides dry discharge, the DC Orisant can also unload by pumping ashore, for which it has a bow coupling, by rainbowing with a nozzle or by dumping for which it has seven bottom doors.

The DC Orisant is scheduled to be delivered to the joint venture in mid-2018.

Source: Royal IHC, 11 January 2018