DEME’s new generation TSHD is put to work

TSHD Bonny River. Credit: DEME

DEME’s multi-year fleet investment programme continues with the arrival of its new trailing suction hopper dredger (TSHD) Bonny River. The vessel is currently being mobilised on its first assignment in Flushing in the Netherlands.

The 15,000 m3 Bonny River is the first of a new generation of THSDs that DEME is introducing. The vessel is able to dredge very hard soils and can work in waters 100 m and deeper. The dredger combines a very long suction pipe and large carrying capacity, with a limited draught. Additionally, the TSHD has a heavy-duty trail pipe with a rock drag head.

The vessel has a large jet pipe on its suction tube that uses extracted overflow water from the hopper that is pumped back to the seabed and integrated into the dredging process. This enables the vessel to achieve closed loop dredging whereby the turbidity generated by the process water is eliminated.

Further, the shape of the hull and two-speed propulsion gearbox help reduce fuel consumption. The Bonny River is a full DP2 TSHD, which allows the vessel to manoeuvre with precision. The vessel has a ‘Green Passport’ and a ‘Clean Design’ notation.

For its first assignment in Flushing, the vessel will reclaim approximately 300,000 m3 of sand at the New lock Terneusen project. The reclamation is the first phase of the project where a new lock will be built, and is combined with deepening works in the outer harbour of Terneuzen.

Bonny River will then head to the Belgian North Sea, once the first project is complete, and will backfill an estimated 45 km of trenches for the Belgian transmission system operator Elia’s Modular Offshore Grid project. The vessel will cover and protect the high voltage export power cables from the Offshore Switch Yard to Zeebrugge.

Three other dredgers are under construction as port of DEME’s fleet investment programme, these include Spartacus, a cutter suction dredger, and other TSHD’s Meuse River and River Thames.

The official naming ceremony for the vessel will take place later in the year.