Innovative Upright Windturbine Tower Cradle:

Greater Gabbard Offshore wind transport design.

The project originally began on a 12000dwt vessel with a stern superstructure. The cradle design was developed to meet the structure of the vessel based on her strength and motion analysis. As in all large projects, the client & charter party imposed project deadlines & conditions. These included a vessel motion boundary condition that all motions and structures were to meet a 2.5m significant wave height. This boundary would enable the vessel to sail more frequently, thus have an increased turn round time. This boundary condition was met by the design. However, an unforeseen issue occurred late in the project due to the flag of the vessel and its classification. This boundary would enable the vessel to sail more frequently, thus have an increased turn round time. This boundary condition was met by the design.
An unforeseen issue occurred late in the project due to the flag of the vessel and its classification. A substitute vessel was proposed with a forward superstructure which removed the visibility issues and would meet port authority regulations.
This late substitution to the vessel in the project occurred during the manufacturing stage of the cradles. After the unforeseen issue occurred with the flag of the vessel and its classification, MBM was on-hand to undertake this change to the project and find a solution for the client. As a result, a re-evaluation of all motions and structures were undertaken for this vessel, and MBM provided a cost-effective solution to overcome this introduced issue. Despite the main issues of structural strength and project management issues from this scenario, the new proposed vessel (BBC Konan) underwent a thorough motion analysis and structural survey to confirm the solution. Finally, the final solution (shown below) was achieved with only minor alterations/additions to the existing cradle. Additionally, the cradle design was a significant achievement, considering the short period available to complete all the required analyses and provide a solution that would maintain the project schedule for the end client. The design process utilized FE analysis, structural hand calculations, and vessel motion analysis, which were all based on DNV rules and regulations.

Offshore Wind Manufacture.

After the engineering drawings were produced by MBM, they were used in the manufacturing process. To ensure that the manufacturing progress remained within the project schedule, an initial inspection survey was undertaken to assess the tolerances of the design.

Loading of the Offshore Wind towers.

Once the manufacturing was complete, the process to position the cradles onboard was undertaken. MBM Consultancy was on-hand to make sure the positioning of the cradle on the hatch covers was accurate, and that all securing methods were adhered to, i.e. steel to steel contact was created between cradle and deck to create a strong weld.
During the loading sequence only minor adjustments and position issues were required to gain sea fastening. Initially, the team encountered several challenges during the loading of the ground-breaking project due to several factors, including a minor manufacturing issue, an unknown structure in the tower, the novelty of the operation, and a new loading technique. However, the team persisted and was able to overcome these challenges, ensuring the successful loading of the project. In the end, the team’s dedication and hard work proved to be invaluable to the industry, providing them with an exciting and innovative solution to a long-standing problem.
During the loading of the cargo MBM was onsite to co-ordinate the placement of the grillage, and maintain the correct procedure for securing the grillage/cradle to the hatch cover was adhered to and undertaken as specified in the detailed design and analysis.

The Voyage to the Greater Gabbard Offshore Wind park.

Although the sailing condition for the Greater Gabbard Offshore Wind park had a boundary condition of a 2.5m significant wave height, it did not hinder the vessel sailing. In fact, this boundary condition is an improvement compared to the boundary conditions imposed on barge transportations. As a result, the vessel can sail more frequently than other vessels, which is a significant advantage.

Furthermore, during the vessel’s first voyage with its full set of 4 upright towers, all parties involved, including MBM, the ship-owner, and the crew, acknowledged a sense of achievement. The successful voyage was a testament to the hard work put into the vessel’s design and construction, as well as the dedication of the crew. It was a moment of pride for everyone involved in the project.

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