Launch & Recovery Tool

To enable seabed trenching for subsea cable installation, Boskalis contracted TME for the design and fabrication of a launch and recovery tool. The tool launches and recovers a trenching vehicle from a cable laying vessel into the ocean and vice versa.

The tool forms a connection between an A-frame carriage and the trencher. It must latch with the trencher, pick it up from deck and hoist the trencher vehicle into the ocean. Conversely, the tool must recover the trencher from the ocean and place it back on deck in the correct position. To enable this in challenging weather conditions at sea, the main functionalities of the tool comprise:

• Latching with trencher
• Dampening of longitudinal and transverse motion of the trencher by hydraulic cylinders
• Telescopically extendable for vertical displacement
• Positioning of the trencher in the horizontal plane to position it straight on deck independent from how the trencher was submerged

As weight is an issue on the vessels stern for stability reasons, the tool is made from high-strength steel because of its favorable strength-weight ratio. The launch and recovery tool is Lloyds certified based on extensive load case and dynamics calculations.

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