Lifting Sling Failure on Freefall Lifeboat
The Transport Accident Investigation Commission of New Zealand (TAIC) has published a report on an incident in which there was a lifting sling failure on a freefall lifeboat on board a general cargo vessel.
The vessel was alongside and the crew were conducting a launch-and-retrieval drill for the vessel’s freefall lifeboat. The lifeboat was lowered into the water with no crew on board. Four crew members then boarded the lifeboat and manoeuvred it around the harbour for 10 minutes before connecting it back to the retrieval davit. A purpose-built lifting sling made up of four wire rope pennants was used to connect the lifeboat to the retrieval davit. Once the crew were seated with their restraints fastened, hoisting the lifeboat from the water commenced. The lifeboat had been hoisted to about deck level when first one and then the remaining three wire pennants parted and the lifeboat fell several metres back into the sea.
One of the crew members had released his restraints in anticipation of disembarking the lifeboat. He was thrown clear of his seat and sustained a cut to the head, requiring overnight hospitalisation. None of the other three crew members was seriously injured. The lifeboat was undamaged.
Initial findings were that the wire pennants had parted under tensile overload because they had all been significantly weakened by severe corrosion. Corrosion had gone undetected inside a plastic sheathing that the manufacturer of the lifting sling had placed around the wire pennants. The presence of the plastic sheathing encasing the wire rope meant that neither the crew nor the various surveyors tasked with inspecting the launching system could inspect and maintain the wire rope as required by IMO SOLAS regulations.
Members may wish to pay particular attention to the possibility of hidden corrosion, particularly that which may be hidden under sleeves or sheathes on lifting slings, wire ropes or other lifting equipment.
Further information can be found at taic.org.nz/ReportsandSafetyRecs/MarineReports/tabid/87/ctl/Detail/mid/484/InvNumber/2014-202/language/en-US/Default.aspx?SkinSrc=%5BG%5Dskins%2FtaicMarine%2Fskin_marine
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