Warning after safety harness tether failure
The Marine Accident Investigation Branch advises clipping on away from deck fittings and other equipment
Sailors who use jackstays and clipping systems aboard are being urged to make sure their tether hook can’t become entangled in deck fittings and other equipment.
The advice comes following the death of Clipper Round the World participant Simon Speirs, who went overboard in the Southern Ocean during a headsail change on November 18, 2017.
The Marine Accident Investigation Branch (MAIB) has issued the safety bulletin as it continues to examine the circumstances surrounding the death of the 60-year-old CV30 Great Britain crewmember.
He was using a three-point webbing tether attached to the integral harness of his lifejacket that allowed him to clip on to the boat’s jackstays with a short or long tether.
The MAIB’S initial findings reveal the hook on the end of his tether that was clipped to a jackline became caught under a deck cleat, resulting in a lateral loading that was sufficient to cause the hook to distort and eventually release.
The harness tether was certified under ISO 12401 (small craft – deck safety harness and safety line – safety requirements and test methods). The MAIB said the tests to meet this international standard assumed the tether and its hooks would be loaded longitudinally rather than laterally.
It stated Speirs’ tether hook was of a conventional design and quality, and was commonly used by manufacturers of safety harnesses and tethers that were certified under ISO 12401.
‘When loaded longitudinally, the tether can withstand a load of over 1 tonne. However, when loaded laterally, a tether hook will deform at much less load. It is important that tether hooks remain clear of obstructions and are free to rotate to align the load longitudinally,’ advised the MAIB.
‘To prevent the strength of a safety harness tether becoming compromised in service due to lateral loading on the tether hook, the method used to anchor the end of the tether to the vessel should be arranged to ensure that the tether hook cannot become entangled with deck fittings or other equipment,’ it added. Adventure training skipper Rachael Sprot from Rubicon 3 believes it would be hard to negotiate all the obstacles on the foredeck whilst tethered.
‘There are often a limited number of places to clip on, especially in rough weather during a headsail change, but I have never heard of a harness line failing in this way before,’ she said.
‘Much as this is a terribly sad event, it does seem to be a freak accident and a stark reminder that the risks of ocean sailing can never be entirely eliminated,’ added Sprot.
Clipper Round the World Race organisers have already taken steps to minimise a repeat of a tether hook failure. All of its yachts now have 10mm of rope wrapped around the cleats to the point that the tether now slides over them.
Chairman of Clipper, Sir Robin Knox-johnston, said it was important to learn the lessons from the tragic loss of Simon Speirs.
‘The Safety Bulletin from the MAIB reinforces what we’ve said to crew at our Sydney stopover and we’ve taken steps to prevent a situation like this ever occurring again,’ he explained.
‘Sailing is a safe sport but when we see something like this, we need to put our heads together to see what we can do to remove the problem.’
A tether hook, and a tether hook after lateral loading
Simon Speirs’ tether hook became caught on a deck cleat
Simon Speirs went overboard during a headsail change