Backing Up An Abseil
Talk to a dozen climbers and you'll likely get a dozen different answer's
on how "best" to backup an abseil. Numerous methods abound. Each
has advantages and disadvantages. I'll put a few far from original ideas
forward here. This article represents merely my own opinion. It's hardly authoritative
or complete and could well be inaccurate. I suggest you use your own judgement, consult
an appropriate book and seek the advice of qualified instructors. Please
read the full disclaimer.
Reasons To Backup An Abseil
There are a plethora of reasons to backup an abseil (and several not
to do so). I'll just pluck a few out of the air to set the scene, so to
- You might foresee a tricky descent, possibly
involving untangling the ropes.
- You might be a beginner and can not trust your
- It might be cold, windy, raining, icy or for
whatever reason you don't trust your break hand.
- You might need to be able to stop and let go to
clean the pitch on abseil.
- You might want to stop to take photos, check out
the route next door, scope for babes ;-), etc.
- An unexpected event may occur causing you to
release the brake line, such as: being struck by falling rock,
slipping on loose or wet rock, getting bitten by a wasp, accidentally
knocking your brake hand against the rock, bumping your funny bone, loosing a contact lens,
getting a cramped muscle, etc.
- You might be on a remote descent far from help.
- You might be carrying a heavy pack.
- The rappel is very long, and the device might
heat up sufficiently for it to fail.
- You're in the process of bringing down an injured
- You might choose to purely as a safety
- The list goes on....
Reasons Not To
Backup An Abseil
In other words you're 100% reliant on your brake hand. This is the
method employed by many climbers, given a certain type of descent, and has
the advantage of speed and simplicity. A climber might not use a backup
for numerous reasons, such as:
- The descent is straightforward and/or short and
the climber is experienced enough to judge the risks.
- Speed is critical to safety. Eg, an alpine
descent off a storm threatened peak. Again the participants are
experienced enough to judge the risks.
- You judge the potential difficulties that can be
involved in continuing a descent once a backup friction knot has been
weighted tight to be greater than any safety advantage gained. (More
on this later).
- You judge that reliance on a rap backup might
cause a relaxation of vigilance that is more detrimental.
Method's Of Backing Up An Abseil
The method you use will be dependant on the conditions of each descent. Let's
assume you've decided to backup the abseil. What are the options?
Abseil Backups Involving Another Participant
In this instance you want some from of
backup and you have another participant ready to help. Here I can think of
Very simple and fast given that someone is already on the ground (or
bottom of the pitch), and available to hold the rope. The descender heads
off as normal, except that their buddy down below holds the slack end of
the rope (pictured right) and is ready to pull down, and thus lock off the descender's
device (dependant on device used), at the first sign of trouble. I find this method very handy when
sending beginners down or if one of the team feels a little spooked by the
abseil. It's also just a great, painless and simple safety precaution. We
use this often.
Belay From Above
Pretty obvious. Anchored climber at the top belays the descender on a
second rope, as if they were lowering them, but giving the abseiler just
enough slack so that they can control the rate of their own descent on
their own rope. I
find this is sometimes necessary when sending beginners down.
Abseil Backups By The Descender Alone
Here you're on your own, or have decided to backup the descent without
involving your climbing partner. There are dozens of ways of doing this,
but I'll mention only the ones I've used:
A Knot In The Ends Of The Rope
Not a backup as such, but at least it might stop you abseiling off the
ends of the rope(s) if you're bailing off a multi-pitch in the dark. It's
happened. Even well experienced climbers have died this way. Again, opinions vary as to
when one should not include this simple safety measure. Many say it should
always be done. Others argue that the knot can lead to stuck ropes (knot
catches behind a flake in the wind for example), which
can be of danger, especially if speed is critical to safety. I
personally, almost always tie a knot in the ends of the rope(s), unless it's obvious
that the ends reach the ground. When abseiling, most climbers like to tie a knot in each end (eg, a stopper
knot), other's prefer a single knot
joining the ends, but in my experience this can lead to twisting. Just be
sure to remove the knots before pulling the ropes down. If you find the
ends are uneven while descending, it's possible to lock off the short tail
and let the longer line slide up, however beware of what this might do to
your anchor above; you could easily burn through a sling if you were
careless enough to be rapping off one.
Heaps Of Friction
You load the rope with enough friction to slow your descent to a crawl
even if you totally let go of the brake end. This can be very handy when
sending beginners down, or if, for example, you're carrying a heavy pack.
If you're not lugging around a rappel rack and set of brake bars (pictured
right), there are other ways to add friction. With a figure eight you can
feed the rope through a second time. With an ATC/Plate you can add a
second carabiner. Or you could add a second descending
device attached to the line above the normal one and tied off to your
harness with a sling - sounds dumb but it works a treat. You could do
something similar to the carabiner brake rappel,
to add additional friction. You could be a HardMan TM,
and wrap the rope around your leg - ouch. I won't go into detail on all
the options, but I'm sure you get the idea. You could still fall to your
death of course. It depends on how much additional friction you'd added,
the weight, device(s) used, terrain, etc.
Technology provides the backup. For example, descending with a Petzl
GriGri (pictured right) which will lock automatically when the handle is
released. It's not a real smooth ride though. I only descend on my
GriGri when the situation really lends itself to it's use, otherwise I use
the a normal ATC style belay/abseil device. There are other devices on the market which achieve a
similar result in mechanically backing up an abseil. The Petzl Stop Descender, and Petzl Shunt
(both pictured right) spring to mind. There are others out there too.
Check out the Petzl web site for
details on the models mentioned.
Friction Knot Above The Descending Device
This is perhaps the "traditional" method of backing up
an abseil. Here we simply add a friction knot of your choice, such as a prusik,
above the descending device and clipped to the harness. Your guide hand
goes above the knot, and pushes it down as you descend. You have to
keep the knot pushed down or it will lock. Make sure the knot is not placed so
high it's out of reach. In the
event that your brake hand is released the knot locks off your descent -
at least in theory. Many people dislike this method because the knot can
be difficult to loosen once it's been weighted. Put a beginner in this
situation and they might get themselves into more trouble than it's worth.
If the prusik is locked off, and you can't simply put your feet on the
rock and lift enough weight off to loosen the knot, you can employ other
techniques, such as wrapping the rope around your foot a few times and
Also studies have shown that in a panic situation
the instinct is to grip the rope, not release it. If your guide hand is
over the knot, as opposed to above it, gripping the knot may cause it to
fail (depending on the friction knot you chose), thus resulting in the climber "riding the knot" all the
way to the ground. Further-more, depending on the friction knot you've chosen,
it may also fail if the ropes are icy, or if you've somehow built up
enough slack to take a small fall, or if the knot was never seated
correctly, etc, etc - you can see why many people dislike this method.
It's far from fool proof. There is no guarantee that it will save you
even with the above issues aside. Never-the-less this is the method I personally
use if I deem a friction knot backup to be required. If I'm cleaning gear
on abseil I'll also get a fireman's belay. To quote John Long in "How
To Rock Climb": "If you don't know how to rappel, get a belay.
If you are doubtful that you can make a certain rappel, don't make that
rappel. Only if you are doubtful and must rappel, and no belay is
possible, should you consider the prusik backup as an option".
Friction Knot Below The Descending Device
As an alternative to the aforementioned method you can place a
friction knot (probably a Klemheist or
autoblock), below the descending device on the slack, brake end of the
rope and attached to a leg loop of your harness. Your brake hand goes just
above the knot sliding it down as you descend. In the event that you release
your brake hand, the knot slides up, cinches tight, and does the job of
your brake hand for you.
This is a more recent
means which is growing in popularity and appears in several books as the
"recommended" way. It has advantages over the "above the
device" method. The knot only has to have enough holding power to
lock off the brake end of the rope, the descending device takes the brunt
of the load. Also, once the knot has locked off the
climber can simply regain control of the brake end of the rope and loosen
the knot once more - the hassle with a jammed friction knot is removed.
this method the brake hand is doing everything, leaving the guide hand
free to deal with obstacles if need be, where-as the "above the
device" method requires a function from both hands.
There are, however, disadvantages with this method. The friction knot must never be
allowed to enter the descending device. If it does, it could cause both
the device and the knot to fail. To avoid this potential hazard the
friction knot must be formed with a loop of cord sufficiently small
enough, or (and this appears to be the more common means), the descending
device needs to be extended away from the harness via a sling. Another
disadvantage is that should you abseil off the end of the rope this method
won't save you, where-as the "above the device" method might (if
you've very lucky). Tie a knot in the end of the rap ropes to avoid this
problem. Also beware of rapping over a roof or undercut section. With the
device extended away from your harness it might be possible to pin it too
the rock with your weight.
Alternatively both ends
of the autoblock (friction knot), can be clipped to the carabiner attached to
the leg loop, rather than having one end girth hitched to the leg loop as
shown above. The former method is perhaps the more common.
Rappel Safety - A discussion paper on using a prusik knot to backup an
abseil from the rock climbing archive site.
I backup my rappel - Comments from climbers reproduced in Dawn's FAQ
regarding backing up an abseil with a prusik (or similar) knot, above or
below the belay device.
Rap Backup - From Karl
Lews web site.
- Backing up an abseil. From rockclimbing.com web site.
Rap Accident - Knot in ends of rope failed?
Home | Guide | Gallery | Tech Tips | Articles | Reviews | Dictionary | Forum | Links | About | Search
Chockstone Photography | Landscape Photography Australia | Australian Landscape Photography
Please read the full disclaimer before using any information contained on these pages.
All text, images and video on this site are copyright. Unauthorised use is strictly prohibited.
No claim is made about the suitability of the information on this site, for any purpose, either stated or implied. By reading the information on this site, you accept full responsibility for it's use, and any consequences of that use.