Second place-getter in the Work Category of the 2011 Treephoto Competition and regular blog reader Laurent Pierron sent us a link to 10.5 mm Beal Dynastat, suggesting this new rope as a possible solution to the access line innovation we blogged about earlier in the month.
Beal Dynastat conforms to two standards: EN 1891A and EN892, simply put, a tree climbing line and rock climbing line combined into one rope.
According to the Beal Dynastat brochure "In the event of a very violent fall an internal Vectran "fuse" will rupture, and the rope then becomes dynamic, with all the security characteristic of dynamic ropes. The fuse will rupture under a force of around 3 kN."
There are two problems with this. The rupture point is 'internal' and we believe the failure point should be very visible, preferably external.
Secondly, ropes conforming to EN 1891A are far too stretchy for single line access - EN 1891A ropes typically range between ± 2-5% elongation with a 250 kg load on-board.
The ideal access rope should be below 1% under these loads; eg Yale BlueTongue Access has an extremely low value of 0.18% or Sterling HTP
Unfortunately, these ultra-static (sub 1% elongation) access ropes cannot be used in a 'dynamic' climbing situation and this is why innovation is needed.
So thanks Laurent, Dynatstat is definitely a step in the right direction but its not quite there yet (in Treetools opinion).