Under the Bridge: Heerema's Crane Vessel Thialf Enters Baltic Sea (PHOTOS)

Dutch offshore installation firm Heerema Marine Contractors said Monday its semi-submersible crane vessel had 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 to enable passage below the bridge. While ballasted down to Thialf's maximum draught the total air draught was just under 65 m with the A-frames down," the company said.

Credit: Heerema Marine Contractors

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 tons, the company said.

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. Credit: Heerema Marine Contractors

"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 tons of structures required for the modification," the company added.

Heerema will be installing the 7,150 metric ton Baltic Eagle Offshore Substation (OSS)  on behalf of its client Baltic Eagle GmbH, before moving onwards to install 27 wind turbines for Parkwind's Arcadis Ost I wind farm in the Baltic Sea using its novel Rotor Nacelle Assembly (RNA) installation method.