Scheldt Tunnel - Oosterweel Link

A critical milestone for Antwerp’s infrastructure

The Oosterweel Link is one of Belgium’s most significant infrastructure programmes, completing the Antwerp ring road and easing mobility around the city. At its heart lies the Scheldt Tunnel, an immersed tunnel connecting the Left and Right Banks beneath the River Scheldt. Multraship was engaged to manage the towage of eight immersed concrete tunnel elements, each 160 metres long and weighing approximately 60,000 tonnes, from the casting yard in Zeebrugge to the installation site beneath the Scheldt.

The programme reached a defining milestone in 2025 with the successful delivery and immersion of all eight elements. Each one had to be towed almost 60 nautical miles along a live, heavily trafficked waterway, then held precisely within the operating range of shore-based winch systems and kept on standby through the immersion phase.

What made this project exceptional was not only the scale of the elements, but the density of marine traffic on the Scheldt, one of Europe’s busiest commercial shipping routes, and the millimetre precision required to align each element in tidal, current-affected conditions.

Precision in confined waters

• Tidal & current forces. The Scheldt’s strong tidal currents and shifting flow patterns called for real-time adaptation of every tow configuration. The behaviour of each element under water movement was modelled against predicted tidal windows to keep it safely and controllably manoeuvrable throughout.
• High-traffic waterway. Operating on one of Europe’s busiest commercial routes demanded close coordination with many involved stakeholders to keep the waterway as available as possible through every phase.
• Immersion precision. Each 60,000-tonne element had to be held precisely within the operating range of the shore-based winch systems. Any deviation during immersion risked misalignment with the elements already in place, making positional control critical.
• Weather sensitivity. Strict weather limits were set for every phase. Despite intensive monitoring and forward planning, conditions changed without warning on several occasions, forcing entire operational sequences to be rescheduled at short notice.
• Regulatory approval. Belgian waterway authorities required comprehensive proof that every method was safe and every risk fully mitigated before granting operational approval, a process that demanded iterative refinement and early engagement.
• Multi-stakeholder coordination. Continuous alignment across construction clients, shore teams, crews, towmasters, harbour pilots, port authorities and Vessel Traffic Services, all working in step through highly time-sensitive immersion windows.

“Towmasters need to know when and how to deviate from the original scenario if weather conditions change at short notice. We deliberately test and simulate these scenarios ahead of any major project, so we are aware of every potential risk and able to handle it. Had those simulations not taken place, the consequences could have been catastrophic.”

Jan-Andries Arts · Commercial Manager, Multraship Towage & Salvage

Our approach: involvement and discipline from day one

Early technical engagement
Multraship’s towmasters joined the project team well ahead of any operational phase, so towage methods and constraints could shape construction planning and sequencing from the outset.

Simulation & scenario testing
Towmasters and crews simulated every operational phase in detail, testing proposed methods, identifying risks and stress-testing the response to sudden weather deterioration before committing any element to open water.

Environmental planning
Phase-specific plans were built around weather patterns, tidal cycles and current behaviour. Go/no-go procedures were formalised and strictly applied, with contingency schedules agreed in advance to allow rapid rescheduling.

Authority & pilot coordination
Multraship worked closely with Belgian waterway authorities, port pilots and Vessel Traffic Services throughout preparation, ensuring every method was compliant and accepted by all regulatory bodies before operations began.

Live execution & adaptation
During operations, towmasters kept live communication running across the full stakeholder network. When conditions changed, rescheduling was executed at speed, minimising downtime while holding agreed safety standards throughout.

“We support our clients as fully as possible to achieve a technically and operationally workable solution. These were also very dense transport routes, so our methods had to guarantee maximum availability of the waterways for other traffic. The authorities needed to be convinced that the methods were safe and that all risks were mitigated.”

Jan-Andries Arts · Commercial Manager, Multraship Towage & Salvage

Fleet deploymentMultraship deployed a dedicated fleet across two distinct operational roles: sea transport from Zeebrugge and precision positioning on the Scheldt. The operation drew on the full depth of our in-house assets and expertise.

5 tugs · sea transportation
Handling the 60-nautical-mile sea tow, managing towline loads, hydrodynamic behaviour and weather response across open water and through lock passages.

7 tugs · precision positioning
Coordinated in concert with the shore-based winch systems to achieve the millimetre-level accuracy required for immersion alignment on the Scheldt.

Specialist support vessels

CORMORANT – self-propelled floating sheerleg
Multraship’s flagship sheerleg, providing heavy-lift capability and on-site support throughout the immersion phases of the Scheldt Tunnel operation.

MULTRASALVOR 4 – salvage & diving support vessel
One of Multraship’s specialist salvage units, providing underwater support, standby response and operational flexibility throughout the immersion programme.

PATROL – waterway monitoring & safety
Provided waterway monitoring, stakeholder coordination support and safety coverage throughout the tow corridor and the immersion site on the Scheldt.

Dive into the full story behind the construction of the Scheldt Tunnel. From impressive transports to the complex sinking of the eight tunnel sections: let yourself be swept away by one of the most challenging infrastructure projects in Europe in Kanjers op Komst: The Aftermovie.