Thursday, January 21, 2010

Rigging gone wrong!

Just a quick post to share a rigging accident. With all the skills, training, risk assessment and experience that are generally soaked into good arborists, accidents do happen and equipment does let you down. I was given the photo to the right about two years ago by a customer that had purchased the black lowering device that you can see.
He was 'snatching' a relatively small section of stem and the groundsman was allowing the piece of timber to run as it fell, but as this was happening the 16mm Marlow stable braid rope melted to the capstan and fused with the black paint covering the device!

When visualising this event you might think at first that both the climber and groundsman would just be confused as the system locked up, but that no harm would come from it, apart from the damage to rope and capstan. However, the following occured; as the timber came to an abrupt halt the resulting shock force over-loaded the sling holding the lowering pulley, snapping it at the splice and yanking the pulley out of the tree. The tail end of the sling then whipped around the stem and slapped the climber on the back of the head.

No one was hurt, nothing was damaged from the fall but issues were certainly raised over the usefulness of the painted capstan. No explanation was ever given.
If you can shed any light on this issue please make a comment.

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1 comment:

  1. Well taking the second point where the 'Marlow Stable braid rope melted to the capston and fused with the black paint covering the devise' as you know I don't have arbiculture knowledge but I do have some knowledge of paint properties and fabrics. The speed of the fall did produce friction and heat - the rope must have had too much synthetic properties and would have benefited from the inclusion of a Teflon content but the paint also had a major cause to acerbate the fusing and seems to have had too much polyurethane in the mix again would have benefited from a Teflon property added.