IMCA: Hydraulic oil leak detected below moonpool

During operations on a pipelay/construction vessel, a hydraulic oil leak was identified below the moonpool after the worktable doors were opened.

 What happened?

Operations were immediately stopped, and the main hydraulic power unit (HPU) was shut down and isolated. Investigation identified the source of the leak as a failed “minimess” monitoring hose at the termination/crimp fitting within the aft worktable door hydraulic control cabinet. Review of Supervisory Control and Data Acquisition (SCADA) data indicated a minor low-pressure alarm had activated earlier. However, visual inspection of the area below the moonpool doors had not been possible at that stage. It is estimated that approximately 185 litres of hydraulic oil were released during the event, of which approximately 35 litres were recovered, resulting in a confirmed loss of approximately 150 litres to sea.

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