In the ever-evolving world of offshore wind energy, keeping up with the rapid growth of turbine components is crucial. To meet this challenge, Van Oord’s heavy-lift installation vessel, Svanen, underwent a significant upgrade. The vessel was fitted with a massive new A-Frame, designed to handle next-generation monopile foundations for offshore wind turbines.
This impressive A-Frame, weighing in at 960 tonnes and measuring 26 meters in width and 30 meters in height, boosts Svanen’s total height to a staggering 125 meters. Installing such a colossal structure required the expertise of Mammoet and their powerful PTC210-DS ring crane, one of the few cranes worldwide capable of executing lifts at the necessary 65-meter height.
The installation was a masterclass in precision and efficiency. By prefabricating the A-Frame and lifting it as a complete unit, Mammoet and Van Oord ensured a safer assembly process and dramatically reduced the vessel’s downtime. A project that could have taken a year was completed in just a few months, with the heavy lift itself executed in just one week, thanks to their close collaboration.
Mammoet’s role in the project was twofold: transporting and lifting the A-Frame’s components. Fabricated by Holland Shipyards at two separate locations near Rotterdam, the components were shipped to Mammoet’s quayside headquarters in Schiedam. There, they were offloaded using a combination of gantry masts, crawler cranes, a 250-tonne harbor crane, and floating sheerlegs before being moved to a laydown area via Self-Propelled Modular Transporters (SPMTs).
The final stage of the operation involved the PTC hoist. The assembled A-Frame was transported 66 meters using 64 axle lines of SPMT trailers and parked on a temporary support, ready for the PTC ring crane to perform the lift. Configuring the PTC crane for the lift required a 107-meter main boom, a 67-meter luffing jib, and over 4,000 tonnes of counterweight.
One of the primary challenges was ensuring the different parts fabricated at separate locations would integrate seamlessly. The exact weight and center of gravity of the assembled A-Frame were unknown, necessitating a precise weighing operation once it was fully assembled. This weighing determined the final rigging configuration, ensuring a safe and accurate lift.
Julian Alkemade, Project Manager at Mammoet, highlighted the importance of this process: “We were able to estimate a certain weight before putting it on a vessel and shipping it to Schiedam for final assembly, but you always have the issue that if you combine those parts together, weld them together, bolt them together, you are unsure of what the exact weight will be.”
The installation’s success is a testament to the right equipment being in the right place at the right time. Mammoet’s early engagement in the project ensured the appropriate resources were available, allowing for a smooth and efficient installation. Remco Zandstra, Commercial Manager at Mammoet, expressed pride in supporting Van Oord’s ambitious goals within the energy transition, stating, “We are currently supporting Van Oord with a number of developments in the offshore wind power sector to support the efficient handling of monopiles.”
