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Aspiring sling in the 'home-made' rope saver breaks at 24kN

Aspiring sling in the 'home-made' rope saver breaks at 24kN

Richard Tregoweth - Tuesday, June 14, 2011

'Home-made' rope savers are commonplace in New Zealand. Most of these savers follow the same method of construction. Climbers take a suitable length of rope (usually Sirius 10mm ) with a short piece of plastic hose threaded onto it. The hose is secured at the central point where the rope is folded in half. Stopper knots are tied at each end of the rope.

Some climbers stitch the two legs together (ART-style), leaving a large eye with the short piece of plastic hose at the apex. This is for ease of use and to keep things tidy but it is not entirely necessary. 

One 300mm Aspiring sling with a pulley attached (typically the ART Link or Cocoon pulley with the DB Tree cone) is tied with a prussic around the two legs of Sirius below the 'eye'.

In practice the 'eye-end' of the saver is placed over the anchoring branch or around the stem and the pulley is then passed through the eye, cinching it into position.

Another 300mm Aspiring sling with a Wichard shackle is attached below the pulley connection (again via a prussic) to act as the retrieval device. There is no PPE value in this part of the system.

The 'soft' components in this configuration include the Sirius 10mm with a minimum break strength 2340 daN and the Dyneema Aspiring sling at 22kN (2200 daN).

As far as Treetools is aware, no one has tested the break strength in this configuration - until now.

We did not include the pulley for the test (because we had tested the Link previously), opting instead for a 12mm shackle at each end.

At 2.2 minutes the stitching on the Aspiring sling gave way, with a peak force of 24kN - 2kN above the slings rating.

Apart from the prussic cinching up tight on the two legs of Sirius and some stress marking on the plastic tube there was no other apparent damage - no doubt that's comforting news for all you climbers using this configuration!

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