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The Hidden Danger of Daisy Chains |
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Daisy chain loops will rip under relatively low forces and if rigged incorrectly, detachment from the system could result.
daisy chain techniques
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Daisy
chains were invented as a
tool in big-wall climbing, used redundantly (a pair) in anchoring,
leading, and rope ascending in direct-aid style climbing.
Only more recently in the evolution of
climbing have these sewn strands of nylon become popular with climbers
who will rarely if ever venture more than 80' above the ground or do a
direct-aid ascent on traditional protection.
Like any climbing tool, the daisy
chain has inherent strengths and weaknesses and although it is
generally more foolproof than other devices, the daisy chain has a
hidden flaw which could be a deadly Achilles heal if set-up
incorrectly and a large enough force applied!
(Right)) An
example of a correctly set-up daisy chain with only one of the loops
clipped - the carabiner cannot easily disconnect from the system in
this configuration. If stitches between loops rip-out under a
large force fall, the carabiner will eventually reach the end of the
sling where the full rating of approx. 20kn is in effect.
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(click on smaller photos to enlarge)
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No
matter how large the ledge might be, Finley
Helmuth is not
happy about being clipped into this red-sling anchor, knowing that only
a 600lb force could quickly separate his locking carabiner
from
his daisy and put him flat on his back.
Off the ground, this
set-up could be deadly and this
incorrect way of clipping a daisy chain should be avoided, even if
there are multiple loops clipped- only the end loop is a safe secondary
clipping point as it is 'full strength'. The sub-loops on a
daisy chain are not full strength.
(below right) One way
of correctly clipping a carabiner
into the
daisy chain to avoid detachment.
(above left) A carabiner INCORRECTLY attached to a
daisy chain through multiple loops where when the two bar tacks rip out
at around 600lbs (approx. 3kn), the carabiner will
disconnect from the daisy completely. The carabiner
pictured is rated to 22kn . The overhand on a bight that the
daisy is connected to with 2 strands of 7mm nylon are rated to approx.
17kn with the knot in the cord being the weakest point.
One of the most likely situations where daisy chain connection failure
could occur would be when the daisy is used as the sole attachment
point for the belayer to an anchor, and when the leader takes a fall on
this multi-pitch climb above this anchor before placing protection, a
factor-2 fall (or something close) could easily create enough force to
rip-out all of the stitches in the one daisy loop (above left) and
would disconnect the belayer from the anchor with this incorrect rigging.
Everything in a climbing system will be tested in this potential
highest force situation and the link between loop stitching on the
daisy would easily be one of the weakest links. A
cross-loaded
carabiner might be the potentially second weakest link
although
the belayer's hand grip strength on the rope is far less than all of
these and without a self-locking device, the belayer would be the
weakest link in the above scenario- so bring two!
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So what are we worried about in the rappelling configuration at right?
It
would be very difficult in rappelling to
create forces above 600# on this daisy chain loop and if one set of
stitches blew out, the rappeller's weight would drop two
inches onto the next
loop. This breaking of stitches is probably the least of your
worries if you're trying to hold
a 600# load while rappelling
I would say that the strength of many rappel anchors is more critical
of an element than the strength of these daisy loops as I have seen too
many anchors over the years that don't possess this total strength.
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Using the daisy chain to extend the rappel device to facilitate a 'backed-up' descent.
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What
are the alternatives?
Although there is nothing inherently wrong with 'daisy chains' or
'personal anchor systems', there does exist the option of not using
these devices at all, except in specific big-wall environments where
climbers are continuously connected to ascenders or anchors with a pair
of daisy chains.
One of the first things that happens on Day 1 of first level AMGA
courses is that instructors usually ask that daisy chains be put away
for the
duration of the course.
Why? Because these loops of nylon
can be more of a hindrance than a help and the AMGA staff are often
emphasizing carrying the
minimal amount of tools for a guide/climber to safely get the
job done.
Using the climbing rope as the sole attachment directly from the
climber to the anchor, using either an overhand/figure 8 on a bight or
clove hitch as the attachment knot.
Due to it's ease of use and
functionality, the clove hitch shown at right and below is a
well-tested and favored link in this part of the anchoring system.
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Wrap-up
It's
always good to
consider the potential for each part of the climbing
protection system to fail and thus to be aware of what
is truly the weakest
links in
any system (as opposed to the perceived weakest
link).
What
are the potentials
for these scenarios to occur? We haven't seen a rash of daisy chain
failures due to the multiple loop clipping scenario, (although I've
heard of a few close calls), so it is likely not very
high.
But,
knowing that a small factor-2 type fall can easily rip
out the stitches between loops (I've done this a few times on aid
climbs), should create a high awareness of the hidden danger of
having just any two
loops on a daisy clipped into the attachment carabiner.
Using
only one loop at a time or having the end loop always clipped
are other techniques used to avoid this
hidden danger.
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ClimbingLife Guides, 2009 All Rights Reserved
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