Heerema Marine Contractors’ semi-submersible crane vessel Thialf has crossed the Storebaelt Bridge, known as the “gate to the Baltic Sea”. This crossing is the first time a Heerema crane vessel has accessed the region and is the result of innovative crane alterations that enable passage below the bridge.
When Thialf was moored in the Port of Rotterdam over the winter of 2021-2022, the team onboard successfully executed modifications to the vessel’s A-frames. This action is possible as Thialf’s A-frames already have hingable corners that can accommodate the NOV custom-designed semi-permanent adjustment system. The lifting capacity of Thialf is unchanged, with the vessel capable of lifting 14,200 metric tonnes.
Using this system, Heerema can lower Thialf’s cranes and fold the A-frames to create a sufficient air gap when combined with ballasting between the vessel and the Storebaelt Bridge. While ballasted down to Thialf’s maximum draught, the total air draught was just under 65 metres with the A-frames down.
The project has been greatly collaborative and was a Heerema Group effort as Heerema Fabrication Group’s Opole Yard completed most of the fabrication work. The team fabricated around 150 metric tonnes of structures required for the modification.
Upcoming projects in the region
Heerema will be installing the 7150-metric-tonne Baltic Eagle Offshore Substation (OSS) on behalf of Baltic Eagle GmbH. Before moving onwards to install 27 wind turbines for Parkwind’s Arcadis Ost I wind farm in the Baltic Sea using the company’s novel Rotor Nacelle Assembly (RNA) installation method.