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Prusik while abseiling - above or below device?


pmonks

1-Aug-2012
1:02:24 AM

Saw some folks on the weekend abseiling with a backup prusik below the device. When I've used one (which isn't often, I'll admit) I've always put it above, which has the advantage of not getting sucked into the device before taking your weight, but has the disadvantage of taking one of your brake hands out of the brake position (below the device).

Do you use a prusik (or other autolock system) when abseiling? If so, where do you put it?


wallwombat

1-Aug-2012
2:37:35 AM

On the odd occasions that I do , I have always done something like this.....

I normally use 60cm sling and a Klemheist knot but there are lots of variationss.


wallwombat

1-Aug-2012
2:41:08 AM

Thats not me, by the way.


pmonks

1-Aug-2012
5:51:51 AM

Yeah that looks a lot better - less chance of the device ingesting the prussic / klemheist.

These folks hadn't extended their device and the prussic was tied into their belay loop too, so the prussic was only about a hand span below the device (and only then because they kept it there). Looked like a clusterfsck just waiting to happen.


pezz

1-Aug-2012
6:48:57 AM

I run the same setup as the picture of wallwombat, minus the sling.. my prussic is short and i check it to make sure it cant enter the atc... i find that haveing it below the device it is way easier to unload than above

citationx

1-Aug-2012
6:52:33 AM

On 1/08/2012 pezz wrote:
>I run the same setup as the picture of wallwombat, minus the sling.. my
>prussic is short and i check it to make sure it cant enter the atc... i
>find that haveing it below the device it is way easier to unload than above
agreed


wombly

1-Aug-2012
6:57:41 AM

I'm an above nazi. I like having a backup system that is effectively independent. When the day comes that I don't thread my abseil device properly it's comforting to know that I won't be left hanging by my leg loop.


deadbudgy

1-Aug-2012
7:13:13 AM

When I use a back up I prefer it to be above the device. If you are knocked out with your backup attached to your leg loop, when the system tightens you end up sort of twisted around on your side with your harness cutting across your love handle. It may be easier to abseil with the backup on the leg loop but in the event of an incident I think the backup is going to work better if it is above the device attached to the belay loop or such.


Ben_E

1-Aug-2012
8:07:01 AM

^^^
If you are really knocked out I'd have thought you'd most likely end up hanging upside-down irrespective? Maybe someone can comment from experience.

In any case, I use a short loop of cord tied in a prusik attached to the leg loop, more or less as in the picture. I use it pretty much all the time and have never had it sucked into the ATC.

I don't find it slows me down much, if at all, and if I'm the second person abseiling I usually attach it to the rope while the first is heading down the rope.

I've found cord much better than sling, which did tend to get sucked into the ATC or even just jam around the rope when I didn't want it to.

kieranl

1-Aug-2012
8:39:58 AM

There are hazards with both methods.
For those favouring below the device, apart from theobvious "don't let the knot slide into the descender" there is this http://ascenttraining.blogspot.com.au/2011/03/safety-alert-on-abseiling-with-prussik.html

When clipping it above the descender you can get into diabolical trouble if the prusik is too long and the knot locks out of reach. Apparently people have died in this situation.

If you're going to use either method you should have another prusik or suitable sling to help you get out of any situation that happens.

And I should also stick in this link to Chocky's own Rap Backup tips which is pretty good.
http://www.chockstone.org/TechTips/RapBackup.htm

citationx

1-Aug-2012
9:01:15 AM

On 1/08/2012 wombly wrote:
>I'm an above nazi. I like having a backup system that is effectively independent.
>When the day comes that I don't thread my abseil device properly it's comforting
>to know that I won't be left hanging by my leg loop.

Is this why you use a prussik? because you're worried that at the top of a 60m you feel you're going to be incompetent enough to not thread your abseil device correctly? Good lord remind me NEVER to climb with you.
The point of a prussik is to arrest you in the case of runaway descent, or being clocked on the head by something falling (in my case, probably you, falling from the top when you incorrectly "clip" your saftety biner to the anchor and and then peer over the edge).
the point is it will catch you when something goes wrong and your partner(s) can immediately start moving to help you. unless your name is aaron whatshisface, in which case yes, it will just be a leg-noose.


davidn

1-Aug-2012
9:01:25 AM

On 1/08/2012 kieranl wrote:
>There are hazards with both methods.
>For those favouring below the device, apart from theobvious "don't let
>the knot slide into the descender" there is this http://ascenttraining.blogspot.com.au/201
>/03/safety-alert-on-abseiling-with-prussik.html

Is this actually possible with most harnesses? I thought most had the big flap of stitched back webbing at the end which would be almost impossible to suck through the clips.

kieranl

1-Aug-2012
9:24:09 AM

On 1/08/2012 davidn wrote:
>
>Is this actually possible with most harnesses? I thought most had the
>big flap of stitched back webbing at the end which would be almost impossible
>to suck through the clips.
I have no personal knowledge of this, just found the link and thought it worth posting. You will note that the harness shown in the blog has the ends of the webbing stitched back. However this is a convenience to keep the buckles threaded, not load-bearing. It wouldn't make it "impossible" for the end of webbing to be pulled back through the clips.

kieranl

1-Aug-2012
9:30:17 AM

On 1/08/2012 citationx wrote:

>Is this why you use a prussik? because you're worried that at the top
>of a 60m you feel you're going to be incompetent enough to not thread your
>abseil device correctly? Good lord remind me NEVER to climb with you.
>The point of a prussik is to arrest you in the case of runaway descent,
>or being clocked on the head by something falling (in my case, probably
>you, falling from the top when you incorrectly "clip" your saftety biner
>to the anchor and and then peer over the edge).
>the point is it will catch you when something goes wrong and your partner(s)
>can immediately start moving to help you. unless your name is aaron whatshisface,
>in which case yes, it will just be a leg-noose.
>
Do you never make a mistake?
I know some extremely competent climbers who have misclipped their abseil device and only their quick reaction time saved them when they weighted the rope (not me, luckily I have discovered my incompetence before weighting the rope).
The point of the backup is to save you if something goes wrong.


muki

1-Aug-2012
9:36:56 AM

On 1/08/2012 davidn wrote:

>Is this actually possible with most harnesses? I thought most had the
>big flap of stitched back webbing at the end which would be almost impossible
>to suck through the clips.

no dave the harness does'nt come apart completely and suck all the way through, it just opens up enough to allow the prusik below it to jamb in the descender, if it were a french prusik then you would have another problem, it wouldn't jamb at all, defeating the purpose.
I use a french prusik above and loaded into the belay loop (also backed up) and this covers me in many situations, unconciousness, lost control, no more rope, or damaged rope, and with knots in the ends, also uneven rapel on two different diameters or one of the two ropes bieng shorter, as when any of the above happen then the belay device is the first to fail and my back up riding above is then allowed to take over, also it's extremely easy to release once I decide to continue after I have stopped and let it lock.
Of course you have to understand all the cons of a french prusik, and have a second or somtimes (rarely) even a third for some tasks, I find a thin tape sling a good choice for prusiks, as it is universal on all diameter ropes.

PDRM

1-Aug-2012
9:41:13 AM

On 1/08/2012 muki wrote:
>On 1/08/2012 davidn wrote:
>
>>Is this actually possible with most harnesses? I thought most had the
>>big flap of stitched back webbing at the end which would be almost impossible
>>to suck through the clips.
>
>no dave the harness does'nt come apart completely and suck all the way
>through, it just opens up enough to allow the prusik below it to jamb in
>the descender, if it were a french prusik then you would have another problem,
>it wouldn't jamb at all, defeating the purpose.
>I use a french prusik above and loaded into the belay loop (also backed
>up) and this covers me in many situations, unconciousness, lost control,
>no more rope, or damaged rope, and with knots in the ends, also uneven
>rapel on two different diameters or one of the two ropes bieng shorter,
>as when any of the above happen then the belay device is the first to fail
>and my back up riding above is then allowed to take over, also it's extremely
>easy to release once I decide to continue after I have stopped and let
>it lock.
>Of course you have to understand all the cons of a french prusik, and
>have a second or somtimes (rarely) even a third for some tasks, I find
>a thin tape sling a good choice for prusiks, as it is universal on all
>diameter ropes.

The other benefit of rigging it above is that if rapping with a load and need to add more friction you can. Much harder to do if below the device. The advice to always carry a second loop is sound also in case get hung up in either configuration.

P


IdratherbeclimbingM9

1-Aug-2012
9:41:38 AM

On 1/08/2012 davidn wrote:
>On 1/08/2012 kieranl wrote:
>>There are hazards with both methods.
>>For those favouring below the device, apart from theobvious "don't let the knot slide into the descender" there is this http://ascenttraining.blogspot.com.au/21/03/safety-alert-on-abseiling-with-prussik.html
>
>Is this actually possible with most harnesses? I thought most had the
>big flap of stitched back webbing at the end which would be almost impossible
>to suck through the clips.

I checked that link article.
What a stupid place to clip off a potentially load bearing safety device! Anything connected to a non-rated part of a harness far from being safe, is a potential liability instead.
~> That link was a storm in a T-cup, and I noted it answered it's own identified issue at the end...

A friend suggests clipping the krab from the prussik to the "inside" of the leg-loop. Haven't tried it, but it sounds like a good solution.

After many years of abseiling within context of caves, canyons and climbing I have tried most methods as well as safety measures, and prefer (when I use one), the backup of clipping below the device (similar to ww's posted pic), but with a much shorter prussik like others have mentioned.

kieranl rightly points out the difficulties involved if the 'above device' system locks off out of reach, and after having been caught in that fashion many years ago, I vouch for knowing your srt techniques sufficiently well to extricate yourself from that situation!
At a minimum try footlocking a loop of rope and standing up, but then you have still to deal with the abseil device potentially holding you back from full height standing, and staying in balance one handed while loosening the locked off prussik with the other...
Then when you have achieved that task, re-weighting your abseil device given the extra length of tail you have in hand...
Carrying basic recovery gear (prussik and sling), as kieranl suggested is a blessing if you ever need it!

Regarding the points made by some about the hanging by your legloop scenario, ... I have found that it is actually quite comfortable due the prussik locks off like where your hand would normally be, and certainly no worse than hanging limp puppet fashion using the above device technique.

I am sure there is another older thread on Chocky dealing with this topic...

citationx

1-Aug-2012
10:01:35 AM

On 1/08/2012 kieranl wrote:
>On 1/08/2012 citationx wrote:
>Do you never make a mistake?

I can honestly say that I have never unclipped an anchor, or weighted something or done something that would have/could have resulted in injury or worse (edit: perhaps I should say "i never have had a fear that indicated that unclipping or weighting etc"). I may have forgotten to do something I needed to, but always while "still safe". I've never done random things that other people have mentioned like "wow, lucky i had that piece in cause i randomly slipped and fell only a short distance". Like, what? how do you randomly slip and fall?
I certainly don't use a prussik (if i use it) to protect myself against forgetting to thread my belay device properly and plunging to my death.


ajfclark

1-Aug-2012
10:04:47 AM

I remember watching someone struggle with an upper prussic as they popped around the lip of the roof abseiling down from Navare. They ended up with the prussic above the lip and were unable to free it as their weight was holding the rope tight against the upper face and around the lip.

Seemed like one situation that regardless of her usual practise, the lower prussic would've been the better option.


deadbudgy

1-Aug-2012
10:32:36 AM

On 1/08/2012 ajfclark wrote:
>I remember watching someone struggle with an upper prussic as they popped
>around the lip of the roof abseiling down from Navare. They ended up with
>the prussic above the lip and were unable to free it as their weight was
>holding the rope tight against the upper face and around the lip.
>
>Seemed like one situation that regardless of her usual practise, the lower
>prussic would've been the better option.

I think its more of a case of not rigging her backup properly. Just like using the lower backup, you need to take care to have your prussick the correct length.

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