Innovative Upright Windturbine Tower Cradle

Greater Gabbard Offshore wind transport design:

Project Overview: Adaptive Cradle Design for Offshore Transport

The project initially commenced with a 12,000 DWT vessel featuring a stern superstructure. MBM was tasked with developing a cradle design tailored to the vessel’s specific structural characteristics, informed by detailed strength assessments and motion analysis.

As with many large-scale marine projects, the client and charter party imposed strict operational requirements and deadlines. One of the key conditions was a motion boundary limit—requiring all structural and dynamic performance to accommodate a significant wave height of 2.5 meters. This specification was crucial for maximizing vessel operability and improving turnaround efficiency. MBM’s design successfully met these parameters.

However, during the later stages of the project, an unforeseen complication arose involving the vessel’s flag and classification status. This regulatory issue necessitated a change of vessel, prompting the selection of a substitute ship with a forward superstructure. The new configuration not only resolved visibility constraints but also ensured compliance with port authority regulations.

At the time of this change, cradle fabrication was already underway. Despite the timing, MBM responded swiftly to reassess the entire cradle system. The engineering team re-evaluated the motion dynamics and structural integrity for the replacement vessel—BBC Konan—and developed a revised solution that remained cost-effective while adhering to the original project timeline.

The adapted cradle design required only minor modifications, a testament to MBM’s agile engineering process and forward-thinking strategy. The revised solution underwent comprehensive motion analysis and structural review, ensuring all performance criteria were satisfied.

This achievement was particularly notable given the accelerated timeline. The final design integrated finite element (FE) analysis, structural hand calculations, and vessel motion studies, all conducted in accordance with DNV classification rules and standards.

Offshore Wind Manufacture.

Following the completion of the engineering drawings by MBM, the documentation was passed to the manufacturing team to initiate production. To ensure alignment with the project schedule, an initial inspection survey was conducted early in the fabrication process. This survey verified that manufacturing tolerances were within design specifications, helping to maintain quality control and prevent delays.

Loading of Offshore Wind Towers

Upon completion of manufacturing, the cradle units were positioned onboard the vessel. MBM Consultancy was actively involved during this phase to ensure precise placement on the hatch covers and to verify that all securing methods met design specifications. This included ensuring proper steel-to-steel contact between the cradles and deck to allow for robust and reliable welds.

During the loading sequence, only minor adjustments were needed to achieve full sea fastening. However, the team initially faced several challenges due to factors such as a minor fabrication discrepancy, the discovery of an undocumented internal structure within the tower, the complexity of a new loading method, and the innovative nature of the operation itself.

Despite these obstacles, MBM and the project team adapted swiftly, implementing solutions in real time to ensure successful loading. Their proactive coordination and commitment were instrumental in overcoming these issues and delivering a pioneering solution for the offshore wind industry.

Throughout the operation, MBM remained on site to supervise the placement of the grillage and to ensure all securing procedures were executed in accordance with the detailed design and structural analysis. The result was a safe, effective, and industry-leading cargo loading operation.

Voyage to the Greater Gabbard Offshore Wind Farm

The vessel’s operational boundary of a 2.5-meter significant wave height—established during the design phase—proved to be highly effective and did not impede sailing conditions en route to the Greater Gabbard Offshore Wind Farm. This threshold represented a notable improvement over the more restrictive limits typically associated with barge transport, offering the vessel greater flexibility and increased frequency of deployment—an important operational advantage.

During its inaugural voyage carrying a full load of four upright wind tower sections, the project marked a significant milestone. All parties involved—including MBM Consultancy, the vessel owner, and the onboard crew—shared a strong sense of accomplishment. The successful transit highlighted the effectiveness of the cradle system, the precision of the engineering design, and the professionalism of the crew.

This first journey stood as a proud demonstration of the collaborative effort and innovation that underpinned the project, setting a new benchmark in offshore wind logistics.

The video of the loading can be found on MBM Consultancy You Tube channel.

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