Third Tunnel Element Successfully Immersed in the Scheldt

The third tunnel element (TE3) of the Scheldt Tunnel project has been successfully immersed near Antwerp. This element marks a significant milestone in the project, as it is the first to be placed almost entirely within the main shipping lane of the Scheldt. As a result, the impact of tidal currents and river flow increased significantly, making this immersion phase technically more challenging than previous ones.

Transport and Positioning in Dynamic Conditions

Weighing approximately 60,000 tons, the tunnel element was transported from Doeldok to the immersion site by Multraship using tugboats. Once on location, the element was carefully positioned according to the phasing plan.

Unlike previous immersions, which used only 150-ton land-based winches, TE3 required a hybrid winch setup: one land winch and five pontoon-mounted winches, anchored to the riverbed of the Scheldt. This configuration allowed for controlled maneuvering of the element, even under the influence of strong river currents.

The winch cables used in this setup were made of steel wires up to 72 mm in diameter, specifically engineered to safely manage the enormous forces during positioning.

Simulation and Work Preparation

To ensure a safe and controlled execution, hydrodynamic simulations were carried out in advance by MARIN (Maritime Research Institute Netherlands) and IMDC. These simulations provided valuable insights into the expected flow dynamics and the tunnel element’s behaviour during the immersion process.

Based on this data, IMMONTEC’s work preparation team developed a detailed immersion plan, including:

• Phasing drawings and a detailed schedule for immersion and positioning
• Risk analysis and corresponding safety measures
• Technical specifications for bollards and wire connections
• Checklists for all critical systems, procedures, and control points

Collaboration as the Key to Success

The successful positioning of TE3 is the result of close collaboration between multiple expert partners. We would like to thank Multraship Towage & Salvage, NPSE (Nautical Project Support & Engineering), MARIN, and IMDC for their expertise and dedication during this crucial phase of the project.

Thanks to this joint effort, TE3 now lies stable and precisely aligned on the riverbed of the Scheldt — exactly as planned. Preparations for the next tunnel element are already underway.

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