Green Marine were contracted to complete the decommissioning of the Pelamis P-001 WEC. This required extensive planning and engineering by the team. Initially grillages were designed an FEA analysis was carried out to design and fabricate grillages for support sections of the device on the GM1100 flat top barge.
Once this was complete a lift plan was created detailing the specification of the lifting equipment required. Once purchased, divers carried out subsea cutting to separate the device’s pontoons. As each pontoon was connected with hydraulic rams Green Marine set-up an oil spill containment area to prevent any uncontrolled leaks to the environment. These pontoons were then lifted by Green Marine’s GM700 gantry barge onto the grillage on GM1100 barge. Orca3D was used to calculate hydrostatic properties for the GM700 and GM1100 during the lifting and transferring process.
Green Marine then used CAD models to select cut points on the device, avoiding structural stiffeners or sensitive areas. Cutting was carried out on the barge to divide the device into smaller sections. The mass of each sections was calculated based on steel weight and any attachments or equipment. These were then moved using Green Marine’s own work boats for further onshore transport.