News

2019 April 25 14:30

Jan De Nul Group extends its fleet with three water injection dredgers

Jan De Nul Group extends its fleet with three water injection dredgers (WID), the company said in its release.

Giovanni Venturi is the first out of three to be delivered by PaxOcean Shipyard. Jan De Nul Group recently purchased three offshore supply vessels and ordered the Singaporean shipyard to convert them into seagoing Water Injection Dredgers. Giovanni Venturi will be mobilised to its first project in Argentina. The other two Water Injection Dredgers Henri Pitot and Henry Darcy are in the process of being converted and will be delivered later this year.

These WIDs are fitted with power jetting systems used for the low-pressure injection of water into sediments. By doing this, the sediments fluidize and naturally move, just above the seabed, through natural sediment streams. They also have Dynamic Positioning (DP), swell compensation for stable working conditions at sea, and diesel-electric drives reducing considerably the CO2 emissions.

These vessels are smaller than traditional dredgers, and have high manoeuvrability and a limited draught. This type of dredger is perfectly suited for maintenance dredging works in smaller ports, but also for other services such as levelling the seabed for other installation services or for post-lowering of pipelines and cables in the seabed.

Contrary to the traditional dredging methods where sediments are mechanically transported, water injection dredging does not remove the sediments. Water is injected, sediments fluidize and nature takes care of the sediment transport. The sediments stay in their natural environment by only moving horizontally, just above the seabed. The process does not impact overlying water layers.

The fact that the sediments do not need to be transported by means of a hopper, barge or pipeline, turns water injection dredging also into a cost-efficient dredging technique.