The special vessel Ivy, which for more than a year has been one of the biggest obstacles for the Fehmarn Belt construction, has now finally been approved by the Danish Maritime Authority after passing the crucial tests. Thus, the most important technical prerequisite for lowering the first tunnel elements into place has been fulfilled.
Ivy is a specially built pontoon with a central role in the project. The vessel consists in practice of two units that fasten the tunnel elements between them at each end and control the submersion. With 66 winches and a total of 23 kilometres of steel wire, the system can handle the 217-metre-long and more than 70,000-tonne heavy elements and lower them to depths of up to 40 metres with high precision.
It is precisely this operation that determines whether the construction can move from preparations to stable progress. Therefore, Ivy has been a direct prerequisite for the submersion to begin.
New problems in December
The vessel was delivered in the autumn of 2024, but has since struggled to obtain the necessary approvals. Certificates have been missing, temporary permits have been revoked, and at one point the authorities withdrew the vessel's temporary sailing certificate. This meant that a planned first submersion in February 2026 had to be abandoned.
The problems with Ivy have therefore had a direct impact on the entire schedule. The submersion of the tunnel elements is the most complex and crucial phase of the construction. Before this phase can begin, the project cannot enter a stable production flow where the elements are continuously submerged and connected.
At the same time, the conflict between the client Sund & Bælt and the main contractor Femern Link Contractors has run in parallel. The contractor has made a claim of 14.5 billion DKK, and there is an ongoing international arbitration case regarding delays. Along with the quality of the tunnel trench, Ivy has been a central element in the overall uncertainty about the project's progress.
With the final approval, one of the two major technical hurdles has now been removed. The other concerns the quality of the tunnel trench, which remains a subject of disagreement. Here, the Femern project reports that the first 650 metres are now ready, and that the first submersion can be carried out during the spring.
