Heerema´s Thialf to Install WTGs for Parkwind’s Arcadis Ost I

Heerema Marine Contractors state they are committed to delivering solutions for their clients worldwide, which means sometimes they must think creatively to get there! With Heerema Fabrication Group fabricating the required structures, they are now modifying Thialf’s cranes capable of lifting 14,200 metric tons.

The gate to the Baltic Sea
In 2022, Heerema will be installing 27 wind turbines for Parkwind’s Arcadis Ost I wind farm in the Baltic Sea using their novel Rotor Nacelle Assembly (RNA) installation method. HeeremaMC will execute this project with Thialf, the world’s second-largest semi-submersible crane vessel (only Sleipnir is bigger).

Sounds straightforward, except between HeeremaMC´s home base in the Port of Rotterdam and the Arcadis Ost project location sits Denmark’s Storebaelt Bridge, also known as the Swan. It connects the Danish islands of Zealand and Funen and has a clearance of 65 meters, while from Thialf’s floaters to the top of the vessel’s A-frames is a huge 105 meters!

Making the impossible possible
HeeremaMC have a bold vision that they want to make the impossible possible offshore. But, this commitment also translates into all of Heerema’s activities and this mindset drove the decision to modify Thialf’s A-frames to access the Baltic Sea. This action ensures they can unlock the region without compromising the integrity of HeeremaMC´s 14,200 metric ton cranes.

A-frame modification for Thialf
At the moment, Thialf is moored in the Port of Rotterdam undergoing an A-frame modification. This action is possible as Thialf’s A-frames already have hingable corners that can accommodate the NOV custom-designed semi-permanent adjustment system.

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.

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.

What does this mean for their clients?
The Baltic Sea is a unique region for offshore operations with a heterogeneous seabed profile that includes sand, mud, hard clay, and bedrock. This variety of potential seabed materials can make installations challenging, but Thialf’s floating vessel capabilities mean that no matter what’s below they can execute projects. With lots of offshore wind energy projects planned for the region, HeeremaMC is prepared to offer their unique solutions.

Now that Thialf will be working in the region the lifting capacity has increased by around 10,000 metric tons, so dare to think bigger! HeeremaMC can deliver a range of solutions for offshore wind installation, including wind turbine generators, gravity-based structures, monopiles, pre-piled jackets, and offshore substations.