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Hi there, how's things.
Anyone use 6mm aramid cord for their anchors, particularly anyone involved with their local rope rescue team? I'd love to hear your thoughts on it.
Do you use the tripled strand on each anchor point as recommended by (most?) manufacturers, or something a bit quicker?
BFK, bear paw, both?
Anyone ever tested it to destruction?
Sit back and rap with me, brother.
8mm CanyonLux, (aramid) wrap three, pull two on a sturdy tree. We’re messing around with running both strands of TTRS off of the outermost holes of a wide bear paw plate to quickly observe balance of the strands.Quote:
Originally Posted by peds
If I’m the attendant in the system, 6mm is going to make me nervous.
6mm sure does add to the pucker factor after coming from 12mm semi-static for your anchor. 8mm certainly sounds like a more reassuring upgrade!
Just checked out the Canyonlux, sounds like a useful rope to own.
https://sterlingrope.com/canyonlux/
How many anchor points would you want behind a 6mm before you'd relax a little? Four, five, six? A whole freaking spider web?
We've been using 6mm aramid cord for anchors locally. It's strong and lightweight, which is a huge plus in the field.
Good to hear. Do you go for the tripled strand on every anchor point as recommended by the manufacturers, or have you found a quicker and easier way of setting up?
We love the weight of our new 6mm, but we are trying to streamline the setup process. Not looking to cut any corners, just want to simplify things.
I'll chime in. I'm on my local SAR team, we're an MRA (Mountain Rescue Association) team. Hope it makes sense and I don't come across as completely incompetent.
I'm trying to picture exactly what you mean by tripled strand on each anchor point; I'm not quite seeing it. Not sure if or what your team's requirements are for anchor strength.
We use a dual capability two tensioned rope system (DCTTRS).
If we're wrapping a tree, we'll go for a basket hitch and tie a figure eight to fix/focus a master point as one anchor. So if we had a long enough cord, we'd tie that into a large loop/sling. Wrap the sling around the tree and tie a figure eight. This would create redundancy, with 2 independent loops around the tree, and two independent loops at the master point. You have 4 strands coming from the master point, 2 on each side of the tree.
Our criteria is that the total strength of the anchor needs to be a minimum of 20kN. This gives the old 10:1 safety factor assuming a rescue load of about 2kN (2 people, each 1kN). This is common, and a source we reference is the Technical Rescue Rigging Guide by Rick Lipke. We go with the general rule that a knot reduces the strength of the rope/cord/webbing by 33%, though this is for more traditional cord, not something like aramid.
If the aramid cord has a min breaking strength of 18kN, then the cord strength is reduced to 12kN. Now that's specific only to that cord. If everyone is dang certain that it's aramid and has this higher strength, then you'd need only 2 strands to meet the strength requirement. However, we also require each anchor to be redundant (as is common for any anchor). If doing a basket hitch, you'd still need two independent loops around the tree, so you'd have a total of 4 strands coming from the master point (2 on each side of the tree).
Say instead of a basket hitch around a tree, you've got a 2 point anchor, with webbing around each tree. Tie one strand of 6mm aramid to each anchor point, you'd have a 24kN anchor (approximately) and it would be redundant assuming you fix and focus a master point (though depending on what you tie, the master point could be only a single, non-redundant loop). Thin looking for sure, but we also have another rope in the system to a separate anchor (DCTTRS).
I think we'd still be hesitant with only two strands of a high strength 6mm cord. I know it's stronger and more abrasion resistant, but we, and probably most, are not used to something so thin. On our team, 6mm cord is used only for purcell prusiks and prusik hitches for personal attachment and rappelling (attaching to a rope of at least 8mm diameter, and rappelling on at least 9.5mm diameter).