Make sure that fast rescue craft docking head limit switch works and check it weekly says Marine Safety Forum. The MSF safety alert follows an incident in which a wire on a Scorpion davit broke during an FRC launch.
Says the safety alert: “A vessel was preparing to launch the FRC during re-validation trials. All checks were carried out. The crew boarded the FRC and the launching operation commenced. The boat with three crew members on board was lifted up. As soon as the davit swung out a loud “bang” was heard and the coxswain noticed that the davit wire began unstranding approx. 1metre above the hook. The FRC was pulled as soon as possible and stowed on the davit. The FRC crew disembarked safely. The vessel returned to port for an investigation.After inspection of Davit, the following was noted:
The Docking Head limit switch did not work (photo 1). It was wrongly positioned and it did not stop the docking head being lifted further (photo 2). The strain applied to the wire was too high. As a result, full hydraulic pressure was applied to the davit wire, well above the breaking strain, and the wire almost parted.
• Davit Operators to make sure that when operating davit the Docking Head limit switch activates before the ram lug makes contact with the sleeve (see photo 2).
• Weekly checks to incorporate checking safe operation of limit switch.
• Risk Assessment for “FRC/DC Launch & Recovery” to be reviewed.