The continued dangers of snap-back zones
Surveying vessels is a vital element of Skuld's Loss Prevention activities and a way that Skuld can identify trends across the membership and highlight any observations which could assist in mitigating against incidents. Information on Skuld surveys can be found on our Technical management page.
In October 2016, Skuld brought to its members' attention the dangers of mooring lines and the consequences in the event of one parting under tension. This complemented the UK Maritime and Coastguard Agency's Code of Safe Working Practices for Merchant Seaman (COSWP) best practice on mooring operations. It was highlighted that in contrast to previous guidance, it was no longer considered adequate to mark snap-back zones on the mooring deck around critical points such as the warping drum, roller fairleads and the pedestal rollers only. The code goes as far as to say specifically "The painting of snap-back zones on mooring decks should be avoided because they may give a false sense of security." This was following research which identified the complex nature in which a parted rope can react and the area it can affect.
Following on from this Skuld continues to experience incidents where crew members are exposed to the dangers of parting lines during operations and during surveys, vessels are seen to have snap-back zones marked within the mooring areas of the vessels in contradiction of accepted industry best practice.
Skuld would once again like to highlight to its members the potential complex nature of a parting line's snap-back zone and the need to treat the whole mooring deck as a hazardous area. To identify all hazards which the ship's crew can be potentially exposed to it is essential to conduct the appropriate risk assessment then implement sufficient control measures. In addition, ensuring crew follow the prescribed procedures and that all equipment is routinely inspected for signs of wear which could compromise its construction are the best ways to mitigate against incidents and crew injury. It is recommended that appropriate cautionary signage is displayed close to the mooring deck entrance highlighting the potential danger ahead.
The diagram shows the potential area of danger (snap-back zone) when the spring line parts at the spring line fairlead. The snap-back zone would be increased if both pedestal fairleads were used. (Swedish Accident Investigation Authority Report S-95/11 Morraborg)