Thoughts on single rope techniques and releasable anchors

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Thoughts on single rope techniques and releasable anchors

Post by Flynny » 03 Jun 2018, 10:46

Moved and edited by admin. For the original post, which includes a more detailed trip report, go to: viewtopic.php?f=29&t=69
Below is the key excerpt which discusses some important thoughts on more advanced abseiling rigging techniques and their usefulness in Blue Mountains canyons.


There has been much talk about using Single Rope Techniques (SRTs) on the ozcanyons group over the last few years and they seems to be gaining more momentum, especially in the newer generation of canyoners. It’s the norm in most other countries. Those other countries also tend to have either much higher water flows or much less prevalent anchor options.

Though I trained in their use and used SRT way back in my brief stint as a guide and it made sense to me in that situation for private groups I’ve always preferred the simplicity of throw and go, loop the rope through the anchor and every one abseil on double ropes.

When heading out with Tim’s group I’m happy to fit in with their SRT method of isolating the stands with a butterfly knot and people abseiling on alternate stands.

Last weekend I attended a training day with the Upper Blue Mountains Club where we practised setting SRT with a releasable anchor. I.e. isolating the abseil strand with the Munter/mule.

The advantage of this is if someone gets stuck on rope for whatever reason you can undo the mule under load and use the munter hitch as a belay to lower them to the ground.

Now in mumblecoughmumble years of canyoning I’ve never come across a situation where I needed to do that but it got me thinking (must be getting old or the weekday job of Safety Coordinator is rubbing off on my weekend self): what if that 1 in 100000 case came along. Sure there are other methods to preform a rescue but are they as safe and as quick and if they didn’t work would I be kicking myself for not using the “Rigging for Rescue” technique?

Anyhoo Anna is pretty keen to put this technique to use in every canyon trip she leads and I thought it might be a good idea to run this trip that way for practice (Ev had done the training day too, so it’s a shame she missed it.)

So I rig the first drop. I really had to think about it as it was a long abseil requiring 2 ropes working out where to put the munter so the knot would not impede it took more thought than it should have. It’s pretty bloody obvious but I guess that's why you practice these thing is relative benign situations so these it becomes second nature.

3/4 of the way down the last abseil I run into the spot of bother and think maybe I’ll need Anna to put the lowering me down method into practice. There is a knot in the rope below me. Usually no big deal. Just stop pull the rope up and undo it (tip for young players. Stop early and pull the knot up to you. The closer you get to the knot the harder it can be to get slack and if you abseil down onto the knot you’ve got buckleys of getting it undone).

Usually when the rope knots itself it's just a few loops caught on themselves and a bit of a shake gets it clear. This had somehow done a proper job on itself and I had trouble getting it undone while hanging in space. I was nearly ready to call out for Anna to pull the mule and lower me when I got it sorted and continued down.

Now what if I hadn’t been able to undo the knot or hadn’t been on a lowerable system?

I hadn’t yet locked off properly and was trying to undo the knot left handed so I could lock off to get both hands free as my first option. Second option would be to prusik back up to the ledge or top and sort it out there so I’m confident I could get myself out of that situation. But what if it happened to someone less experienced or without those skill sets? (Other than the obvious everyone on a private group should get themselves those skills sets. Good point but we were all beginners once.)

Those at the top could deploy the spare rope, someone could even abseil down to me to help out. That all takes time and hang syndrome becomes a factor. Abseiling down to help out puts the rescuer at risk too. So much to consider.

Anyhoo I clear the knot and continue down.

How much did the rigging for rescue slow us down? Last year with a slightly bigger group the trip took us 6hrs 23min car to car. Today, practicing what’s still fairly new to us took us 6hrs 49min. Though there is probably a bunch of other factors in there as well.

So what are my thoughts? I’m still undecided.

Anna was keen to only lock off one side of the rope and keep the other stand at the top to avoid confusion.

I prefer to do a munter/mule in both strands to allow people to rig up alternate strands and quicken things up. If you then need to lower then the person on the spare strand gets off and it’s quick to undo that one altogether and lower the other. Which is fine until you have 2 ropes joined with a knot at the top and then it’s not possible.

So here what I see as the pros and cons. Feel free to comment if you have other ideas.

Pros of releasable SRT using Munter/mule:
  • Simple to set up and fairly quick to tie once you practice a bit
  • Ability to quickly and safely lower a stuck abseiler down to the ground.
  • Ability set the end of the abseil strand just on ground/water level to make getting off the rope at the bottom quick and easy
Cons of releasable SRT using Munter/mule:
  • It does take longer to tie and untie (not to mention it’s a ugly looking knot)
  • Rope wear and tear. A single strand taking full weight obviously is under more strain than if you were abseiling on double strand.
  • Chardie pointed out abseiling on double rope with an isolating knot at the top gives you some back up if you cut one strand on a sharp edge. Not an advantage if you use throw and go with out isolating.
  • Only possible to use one strand if the abseil involves joining ropes.
  • Can be tricky if the anchor is close to/below the edge but not too much more than normal.
So I’m still tossing this one up. the ability to quickly and safely lower a stuck abseiler down to the ground is a big consideration though if you have a competent person at the top with a spare rope is it that much quicker and safer?

If the stuck person is unconcious I’d say yes.

What is the liklihood of that happening though? And does that likelihood justify the slightly longer more complicated set up of each and every abseil?

I don’t know.

Being able to set the end of the rope just to water hieght is a big advantage in highwater but we don’t tend to have that in Australia.
Last edited by tom_brennan on 03 Jun 2018, 20:52, edited 1 time in total.



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Re: Nightmare canyon. Can an old dog learn new tricks. Thoughts on SRTs and releasable anchors

Post by tom_brennan » 04 Jun 2018, 08:43

I'll keep referring to SRT here, even though SRT historically has been more about ascending single fixed lines for caving/tree climbing.

Rachel and I did a fair bit of SRT when we were in the US last year. We found it was generally slower, but being new at it, that's probably not surprising.

I've probably got two main concerns with using it.

My number one concern is rope damage. With the right edge, it doesn't take much to seriously damage or cut a rope, and with only one strand, the weight/force on it is effectively doubled. This is probably a greater risk with inexperienced abseilers (for whom you would most want the rescue capability), as they are less likely to be able to manage the sharp edge risks when they are abseiling.

My second concern is the extra complexity. There are a greater variety of forms of SRT than DRT, so more chance that individuals are not as familiar with the specific method being employed. There are also extra risks, like clipping into the wrong strand. There are also ways of mitigating against some of the extra complexity, for example, not deploying the second strand until the last person is ready to descend.

People have died as a result of both single ropes cutting and the complexity, so they aren't just theoretical concerns.

I'm not aware of anyone dying in Australia as a result of DRT (where using SRT would probably have saved them). Obviously in other parts of the world, SRT has developed as a result of deaths and unacceptable risks using DRT, but that is condition-specific.

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Re: Thoughts on single rope techniques and releasable anchors

Post by T2 » 04 Jun 2018, 13:29

Craig, thanks for starting this discussion. It's a really important topic.

I also agree that, like you point out, just because something works well for one type of canyon, doesn't mean it should be universally used. So these techniques, like all ropework, is about building up a large toolbox that allows us to pick the best option for each drop or group.

For canyons with higher water flows, the standard Aussie double rope "toss and go" technique can be very dangerous. But in our drier canyons, as Tom points out it is rarely an issue. Most groups also abide by the rule of keeping an emergency rope at the back, so assistance or rescue can be carried out using that rope if someone becomes stuck.

I think a releasable system is mostly of benefit with beginners / less experienced people. I think the most likely scenario where it would be of benefit is when someone gets hair or clothing caught in their descender.

Personally, I increasingly abseil on single ropes, but only occasionally rig them for rescue (I think there's actually two discussion that need to be had). There are a range of benefits that come with abseiling on single ropes. In particular, drops can be set to the precise length, saving time getting off rope and avoiding having a coil of rope at the bottom that gets trodden on and tangled in branches etc. I'm also increasingly using a fiddlestick, particularly for longer drops or those that have a difficult pull down. (I intend to write a detailed post of the pros and cons of this technique for the forum in the coming weeks.) Another point is that the main wear point on ropes is where it runs over the edge near an anchor. Using doubled ropes, that wear occurs very close to the middle of your rope each time. When using a fiddlestick, that wear goes to the end. And when using single ropes that are set to the abseil length, that wear patch is moved around much of the rope length.

Rope wear is an issue no matter what technique you use. I would point out that the kind of actions that slice ropes -- such as someone abseiling off to the side then being swung back across a sharp ironstone edge -- can cut on double ropes too. That's one of the reasons that, when using double ropes, I'll tie a stein / stone knot at the top of a drop where I am concerned about the issue. By isolating the strands, you prevent the abseiler from falling if one strand is cut.

Where you are concerned about rope damage, there are good techniques for rigging on single ropes that allow you to creep the rope, moving the wear point for each abseiler (or even during the abseil). This can be as simple as running the rope through a maillon / rap ring then through the descender of whoever will be last down. You can also use a figure 8 or similar on the anchor to add more friction into this system. By doing this you can lower instantly when needed, but also shift the rope wear point as you go without needing to undo the munter mule.

Personally, my experience has been the fiddlestick definitely speeds up trips with longer abseils. I also find single rope abseils, even just setting a 'biner block, speed up canyons with lots of shorter drops. I think setting releasable anchors would slow things down slightly, but when you have beginners it will only take one person getting their hair caught in a trip for you to more than make up that time.

P.S. These conversations are exactly what I think this forum should be about. Thoughtful, detailed discussions that examine how we all do things and what can be improved.

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Re: Thoughts on single rope techniques and releasable anchors

Post by Kosta » 04 Jun 2018, 15:24

The previous posts make it sound like there is toss-and-go (the classic double rope technique) and one version of SRT. However, there are many different versions of SRT and they all have different purposes and use cases. Thus, when we talk about using SRT, we should also specify what we are doing and what for. Off the top of my head, I can think of the following techniques that I have used in the past:

1) Stone knot and SRT/DRT combination:
The stone knot isolates the strands of that go through the anchor which means it is safe to abseil off only one strand. This can be used for true redundancy in a DRT setting (when there is a high and unavoidable danger of cutting the rope during the abseil), but it also allows for different SRT tricks:
  1. If people only abseil on one strand, the next person can already get ready on the second strand while the first person is still on rope. This can speed up the descend for larger groups.
  2. One strand can be kept unused. This acts as the safety rope in case the abseiler is stuck and requires assistance. Subsequently, no dedicated safety rope needs to be kept at the back. The last person abseils DRT.
  3. On longer abseils, where two ropes need to be joined, the first rope can be deployed and used before the second rope is attached. This is particularly useful when multiple abseils come in rapid succession (e.g. Malaita Wall). One can start the next abseil when only one rope is at the front and doesn't have to wait for the second rope to become available.
2) Contingency anchor:
The releasable munter/mule anchor mentioned above falls into this category. One end of the rope is deployed down the pitch while the other end (which is still long) is kept at the top. The rope is fixed in the anchor and people abseil on the single strand. The anchor is fixed in such a way, that it can be released while the rope is on tension (i.e. mid abseil). Once released, the abseiler can be lowered from the top. This can be used for different reasons:
  1. In case the abseiler gets stuck (e.g. hair caught), the person can be lowered from the top quickly without anyone needing to abseil to assist.
  2. If the rope goes over an edge, the abseiler can be continuously lowered at slow speed to avoid the rope wearing through.
  3. When abseiling into moving water, the rope length can be adjusted to end just at water level. This is useful if the bottom of the abseil can't be seen. Then, the rope gets deployed short and once the first abseiler can see the bottom it gets adjusted while the abseiler is on rope.
3) Pull cord techniques
This is where things get fundamentally different. The techniques described so far, apply to everyone but the last person. The last person still needs to abseil double strand for the pull down to work. When using a pull cord, the last person also abseils on a single strand and a thinner rope (the pull cord) is used to retrieve the rope from the bottom. Different techniques for this exist, some of them are:
  1. Biner block: a carabiner is tied into the rope with a clove hitch. The carabiner can't slide through the anchor (which usually has to have a mailon or ring). Thus one can safely abseil off one strand of the rope. The other end of the rope is extended using the pull cord. At the bottom, the pull down is performed as usual. The advantage is, that the pull cord is much smaller and lighter than the proper rope.
  2. Fiddle Stick/Smooth Operator: The rope is tied to the anchor using a stone knot with a stick inside. The stick has the pull cord attached to it. Once the last person is down, one can pull on the pull cord which pulls the stick out of the knot. The knot falls apart and the rope comes down. The big advantage of this technique is, that it is no longer required to pull the rope through the anchor. This makes for a less strenuous pull down. It also allows ghosting: you can tie the rope directly around a tree or log without needing a sling. Thus, you can perform your abseils without leaving anything behind.
  3. Macrame knot: somewhat similar principle to the Fiddle Stick, but without requiring a stick by using an elaborate knot instead. It's somewhat unreliable and I would consider it an emergency technique only.

My personal opinion/experience:
I don't really see the need for contingency anchors in Australian canyons given their complexity in setting them up and the skills required by the anchor operator.

The stone knot SRT/DRT combination has come handy in the past for consecutive long abseils such as Malaita Wall or Kanagra Main. It doesn't change anything fundamental, it just allows a group to move a little faster.

Lately, T2 made me use the Smooth Operator which really is a game changer. Not needing two times the rope length at each abseil means you don't need to carry as much and pull downs are much easier. But the really big difference is, that you don't require proper anchors set up. I would really like this technique to become commonplace in remote/exploratory/wilderness canyons. Then we can stop littering canyons with slings and start removing the ones that are already there. I think, this would be something worth working towards.

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Re: Thoughts on single rope techniques and releasable anchors

Post by T2 » 04 Jun 2018, 15:50

+1 to everything Kosta wrote. Brilliant summary.

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Re: Nightmare canyon. Can an old dog learn new tricks. Thoughts on SRTs and releasable anchors

Post by Flynny » 04 Jun 2018, 16:45

tom_brennan wrote:
04 Jun 2018, 08:43

I'm not aware of anyone dying in Australia as a result of DRT (where using SRT would probably have saved them).
The Carra Beanga incident springs to mind, though with everything else that went wrong on that trip coupled with the experieced guy being at the bottom it may not have helped on it's own

Like the grizzled old head I am I've struggled to see the point of SRT in the past (and given I'm on the weight limit that some skinner ropes recommnd for single strand I was very warey of them anyway.)

After heading out with a few different groups that use different methods I can see their point in certain applications.

And as others have started broadening your bag of tricks is always a good thing. However knowing how to do something is different from being preactice and efficient in something which is a big thing I took away from our training day. In my head I knew I'd been train in these techiques and thought I'd still be able to preform them easily but putting them into use was not as smooth as I thought.

Without meaning to drift off topic It just reinforced to me that even something as "simple" as prusiking should be practiced regularly to remain proficient.

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Re: Thoughts on single rope techniques and releasable anchors

Post by tom_brennan » 04 Jun 2018, 17:52

T2 wrote:
04 Jun 2018, 13:29
There are a range of benefits that come with abseiling on single ropes. In particular, drops can be set to the precise length, saving time getting off rope and avoiding having a coil of rope at the bottom that gets trodden on and tangled in branches etc. <snip> Another point is that the main wear point on ropes is where it runs over the edge near an anchor. Using doubled ropes, that wear occurs very close to the middle of your rope each time. When using a fiddlestick, that wear goes to the end. And when using single ropes that are set to the abseil length, that wear patch is moved around much of the rope length.
A fair proportion of those benefits can be obtained by using decent rope management with DRT.

When I'm carrying a 60m rope, it will be coiled in two halves of 30m. If I get to a 5m drop, only say 6-7m (4 coils based on my arm length) from one half will get unflaked and pulled through the anchor. Another 4 coils from that half will get unflaked, the remainder of that half secured, and both halves tossed. Most of the unused rope stays coiled, avoiding the issues with large amounts of loose rope, decreasing the time to deploy and pull, and moving the wear points around the whole length of the rope. On a long drop (say 25m), coiling the rope in halves allows 2 people to being coiling at the same time.

So yes, it doesn't have all of the benefits of some of the single rope methods, but certainly far more effective than setting every abseil off the middle of the rope.

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Re: Thoughts on single rope techniques and releasable anchors

Post by tom_brennan » 04 Jun 2018, 18:03

T2 wrote:
04 Jun 2018, 13:29
Rope wear is an issue no matter what technique you use. I would point out that the kind of actions that slice ropes -- such as someone abseiling off to the side then being swung back across a sharp ironstone edge -- can cut on double ropes too. That's one of the reasons that, when using double ropes, I'll tie a stein / stone knot at the top of a drop where I am concerned about the issue. By isolating the strands, you prevent the abseiler from falling if one strand is cut.
I agree it can happen on both double and single, and I've heard of plenty of stories of damage from both. The key variable with a sharp edge is the force on the rope as it contacts the edge.

If I'm an 80kg abseiler on double rope - using weight as a crude approximation of force - there's 40kg on each strand.

If I'm on single rope, there's 80kg on that strand - essentially double the force. So it's going to have a much greater chance of both damage and complete failure.

IIRC the Carrington Falls incident was the result of the failure of a single rope.

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Re: Thoughts on single rope techniques and releasable anchors

Post by Flynny » 04 Jun 2018, 19:56

I agree with Tom in that the likelihood of a rope being completely severed by dragging across an edge is proportional to the strain in the strand and I'll also add it's proportional to the pressure on the edge.

Pressure = Force over Area. Double ropes not only share the strain between two strands but are likely to have twice the area in contact with the edge by simple mean of there being 2 of them.

Not to mention there is also double the material to cut.

Soooo many considerations

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Re: Thoughts on single rope techniques and releasable anchors

Post by T2 » 04 Jun 2018, 20:43

When you look at the US, where the canyons geologically closer to the Blue Mountains than anywhere else (sandstone that is often very abrasive) the standard technique is to descend on single rope. Recreational canyoneers also overwhelmingly use thinner ropes than most Aussies, with 8mm ropes very common. Of the accidents and fatalities that have occurred there in recent years, I'm not aware of any of them being caused by a rope slicing.

In my opinion, the situations that will lead to a rope cutting are almost universally the result of poor abseiling technique and / or poor rigging. If you abseil smoothly, straight down a drop, the forces involved are nowhere near what would be required to slice through the rope. You should also examine potential risk factors such as sharp edges when rigging a drop and look to use an alternate anchor setup if there is an obvious danger.

People assume they are safer by blindly abseiling on double ropes, but that's often not the case. And regardless of which approach you take, if you have poor abseiling technique and a lack of awareness of potential hazards, you'll be at far greater risk on doubled 11mm ropes than a skilled abseiler would be on a single 8mm strand.

As more experienced canyoners, I think we have a duty to make sure people we canyon with are talked through these issues, understand the kind of things to think about when setting ropes, and also grasp that we're all on a life-long learning journey.

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Re: Thoughts on single rope techniques and releasable anchors

Post by Kosta » 04 Jun 2018, 21:51

Sharp edges are always something to look out for and if possible avoid by placing the rope strategicly when going over the edge. I agree, if it is unavoidable, then having double rope adds safety. I wouldn't necessarily put a stein knot in though. The reason is, that if the rope is loose, you can move it a little after each abseiler to have a different piece of rope on the edge each time. If the strands are isolated, this would require to undo the knot. Of course, SRT looses out big time here because you can't move the rope at all (unless you use a contingency anchor method).

When I was canyoning on Reunion Island a few years back, they had the rule, that the rope must not touch the rock. If it is unavoidable, they set a contingency anchor and the rope was continuously moving very slowly. It's a strange feling to abseil while the rope moves as well. Can't remember what the last person did. Probably LMAR.

On this topic, I recently heard, that polymer ropes (HTP, and the like) are less likely to get cut on sharp edges because they have less rope stretch. Can anyone confirm this?

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Re: Thoughts on single rope techniques and releasable anchors

Post by tom_brennan » 04 Jun 2018, 22:08

Good summary Kosta.
Kosta wrote:
04 Jun 2018, 15:24
The previous posts make it sound like there is toss-and-go (the classic double rope technique) and one version of SRT. However, there are many different versions of SRT and they all have different purposes and use cases. Thus, when we talk about using SRT, we should also specify what we are doing and what for.
Yes, I was being a bit lazy grouping the SRTs together, since the potential issues I was pointing out were common to all. They do have other pros and cons relative to each other (and DRT) that other posts have noted.

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Re: Thoughts on single rope techniques and releasable anchors

Post by Flynny » 06 Jun 2018, 05:29

To the point of sounding like there is only one SRT, my post was specifically about SRT using the munter/mule as a releasable anchor for lowering a stuck abseiler. I did mention other techniques such as isolating strands with a butterfly (or stone, if you prefer) knot and I'm happy it has broadened out as it's a good winter discussion .

I'd have to say I struggle with the concept of Smooth Operators and Fiddle sticks. Sure they provide less need for tape and less impact on trees but ignoring my possibly irrational fear of the possiblility of unintentional release under load and the thought that it's just something else to get tangled in shrubbery on the pull down...

Setting one strand the exact length of the abseil eliminates the advantage of faster, safer rescue of a stuck abseiler.

Sure you could argue that in the remote "wilderness" canyons you are suggesting their use should be encouraged should attrac a mre experienced (read people who have built a wider skill set. ie less absolute beginners)but still that faster rescue offered by releasable system was the only thing that was swaying me away from throw and go drt

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Re: Thoughts on single rope techniques and releasable anchors

Post by Flynny » 06 Jun 2018, 08:54

Some info on suspension sindrome from the ever reliable wiki pedia
Suspension trauma (Syn. "orthostatic shock while suspended"), also known as harness hang syndrome (HHS), suspension syndrome, or orthostatic intolerance, is an effect which occurs when the human body is held upright without any movement for a period of time. If the person is strapped into a harness or tied to an upright object they will eventually suffer the central ischaemic response (commonly known as fainting). Fainting while remaining vertical increases the risk of death from cerebral hypoxia. Since there is no evidence that these effects are specifically due to trauma, or caused by the harness itself, climbing medicine authorities have argued against the terminology of suspension trauma or harness hang syndrome and instead termed this simply "suspension syndrome".



Cause
The most common cause is accidents in which the person remains motionless suspended in a harness for longer periods of time. Motionlessness may have several causes including fatigue, hypoglycemia, hypothermia or traumatic brain injury.

Symptoms
Onset of symptoms may be after just a few minutes, but usually occurs after at least 20 minutes of free hanging. Typical symptoms are pallor, sweating, shortness of breath, blurred vision, dizziness, nausea, hypotension and numbness of the legs. Eventually it leads to fainting, which may result in death due to oxygen deprivation of the brain.

Treatment
If someone is stranded in a harness, but is not unconscious or injured, and has something to kick against or stand on (such as a rock ledge or caving leg-loops) it is helpful for them to use their leg muscles by pushing against it every so often, to keep the blood pumping back to the torso. If the person is stranded in mid-air or is exhausted, then keeping the legs moving can be both beneficial and rather dangerous. On the one hand, exercising the leg muscles will keep the blood returning to the torso, but on the other hand, as the movements become weaker the leg muscles will continue to demand blood yet they will become much less effective at returning it to the body, and the moment the victim ceases moving their legs, the blood will immediately start to pool. "Pedaling an imaginary bicycle" should only be used as a last-ditch effort to prolong consciousness, because as soon as the "pedaling" stops, fainting will shortly follow. If it is impossible to rescue someone immediately, then it is necessary to raise their legs to a sitting position, which can be done with a loop of rigging tape behind the knees or specialized equipment from a rescue kit.

When workers are suspended in their safety harnesses for long periods, they may suffer from blood pooling in the lower body. This can lead to suspension trauma. Once a worker is back on the ground after a fall has been arrested on a fall protection system, a worker should be placed in the “W” position. The “W” position is where a worker sits upright on the ground with their back/chest straight and their legs bent so that their knees are in line with the bottom of their chin. For added stability, make sure that the worker’s feet stay flat on the ground. In this position, a KED board can still be used if there are any potential spinal injuries and a worker needs stabilization before transport.

Once the worker is in this position, they will need to stay in that position for at least 30 minutes. Try to leave the worker in this position until their symptoms begin to subside. The time in the “W” position will allow the pooled blood from the legs to be slowly re-introduced back into the body. By slowing the rate at which the pooled blood reaches different organs, you are giving the body more of an opportunity to filter the pooled blood and maintain internal homeostasis. http://www.rigidlifelines.com/blog/entr ... -treatment

Prevention
Prevention of suspension trauma is preferable to dealing with its consequences. Specific recommendations for individuals doing technical ropework are to avoid exhausting themselves so much that they end up without the energy to keep moving, and making sure everyone in a group is trained in single rope rescue techniques, especially the "single rope pickoff", a rather difficult technical maneuver that must be practiced frequently for smooth performance.

On that last bit what we found with the pick off technique was even with practice it takes a while to set up, puts the picker offerer at risk and is difficult to do especially when picking off someone larger than your self.

Making sure you have all the gear readily available, Spare 'biners slings and prusiks ready to deploy, have your descender extended... all takes time as does performing the pick off, maybe not the 15-20min but add in cold conditions and number fingers and it all adds up.

If the stuck abseiler is conscious deploying a safety (either a spare rope of isolated strand) and having them clip on then performing either a U-haul or Z-line from the top so that they can be unweighted enough to clear there obstruction and continue down would be my preferred option.

The Releasable/contingency anchor main benefit comes when the abseiler is unconscious, very close to the ground or, in serious trouble. Sure there are ways to release a DRT and isolated SRT anchor but they again come with time constraints and risks. For me a Pick off would be absolute last resort

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Re: Thoughts on single rope techniques and releasable anchors

Post by Ganguddy Goodoo » 06 Jun 2018, 14:15

I'm a throw and go man. I would only use a munter/mule contingency SRT set up with kids/novices/injured group members or in high water. KISS

One thing to be aware of if you are new to SRT is to make sure you have enough friction in your device. Your old Pitt Stop probably will not cut it.

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Re: Thoughts on single rope techniques and releasable anchors

Post by BlueCanyons » 06 Jun 2018, 19:08

I'm a just leave this here:
http://ropewiki.com/Figure_8_block

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Re: Thoughts on single rope techniques and releasable anchors

Post by Bayjam » 06 Jun 2018, 21:58

Hey guys... Quick question, and maybe im just not picturing this properly, but how do you do a munter mule when your anchor is a maillon or rap ring? Do you pull the door through twice and create the knot then pull it all back out for the last person to abseil double rope? I must be missing something obvious

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Re: Thoughts on single rope techniques and releasable anchors

Post by Flynny » 07 Jun 2018, 05:29

but how do you do a munter mule when your anchor is a maillon or rap ring? Do you pull the door through twice and create the knot then pull it all back out for the last person to abseil double rope? I must be missing something obvious
Put the rope through the mallion as normal. Use a karabiner to tie the munter/mule. Lst one down undoes the knot and collects the biner

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Re: Thoughts on single rope techniques and releasable anchors

Post by BlueCanyons » 07 Jun 2018, 08:59

Bayjam wrote:
06 Jun 2018, 21:58
Hey guys... Quick question, and maybe im just not picturing this properly, but how do you do a munter mule when your anchor is a maillon or rap ring? Do you pull the door through twice and create the knot then pull it all back out for the last person to abseil double rope? I must be missing something obvious
Rich makes pretty good videos on the subject:

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Re: Thoughts on single rope techniques and releasable anchors

Post by poodlebean » 07 Jun 2018, 14:21

I know so little about knots and rescue techniques etc etc. We had a paramedic join he upper blue mountains bush club last year and every time we did an abseil, she's want to isolate the rope. I asked why and though I really like the idea of having a second rope for somebody to descend on if something goes wrong when I go down. I know if I got myself into difficulty I tend to hit the panic button pretty quickly... lack of experience, short fuse, crampy hip....

It also occurred to me that often the last person down has not been the most experienced person. Sometimes it's been me. And I'd be able to do jack shit to rescue somebody who went down on 2 ropes. But on one rope I could probably help to some extent at least even if that help might not be the most professional available at the time.

At this stage, regardless of what people prefer to use it has made sense to me that planning for an experienced person to go first and last is probably best planning. Put all the noobs in the middle. That way if an emergency arises in the top, bottom or anywhere between, there will always be help available...they can instruct the noobs how to help if necessary.
If I was a noob at the top on my own and somebody was on rope and in difficulty, I would feel very distressed at being unable to help.

training: I did attend a rescue day once. The agenda was quickly hijacked by experienced attendees who wanted to practise their own stuff. I felt sorry for the trainer on the day who had volunteered their time both in preparing the agenda which was ignored and running the day (or trying to).

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Re: Thoughts on single rope techniques and releasable anchors

Post by Bayjam » 07 Jun 2018, 18:41

Thanks guys. I use the munter when using a carabiner but I was wondering about the logistics of using one on a solid rap ring. I agree that it's a great backup and allows an abseiler to be lowered safely, but pulling through a rap ring (or rusted closed maillon, as we often come across) then muntering, then pulling it all undone for the last abseiler seems alot of work. I thought there might be an easy way that I'm missing.

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Re: Thoughts on single rope techniques and releasable anchors

Post by Flynny » 07 Jun 2018, 19:49

Bayjam wrote:
07 Jun 2018, 18:41
I thought there might be an easy way that I'm missing.
The missing bit is the spare karabiner

A quick dash to the shed for some photos

Rope goes through rap ring/ mallion as normal
amunter-1.jpg
amunter-1.jpg (364.87 KiB) Viewed 3084 times


Clip a biner to the anchor and tie the munter to that
amunter-2.jpg
amunter-2.jpg (375.16 KiB) Viewed 3084 times


tie the mule and stopper
amunter-3.jpg
amunter-3.jpg (372.57 KiB) Viewed 3084 times
This strand is now ready to abseil on

The second strand can be kept at the top or it can have a second munter/Mule tied (leave a fair loop between the two sides) so that both strands can be used for abseiling if your group like to set up on alternate strands for faster on and off rope,

amunter-4.jpg
amunter-4.jpg (406.7 KiB) Viewed 3084 times


Last one down undoes the rope and collects the biners than abseil double rope as normal

Granted its an ugle knot but that took me about 2min to set up with getting photos.

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Re: Thoughts on single rope techniques and releasable anchors

Post by Bayjam » 07 Jun 2018, 20:05

Bloody hell... That's what I'm talking about. "what am I missing?" that's exactly what I'm missing. Righto I definitely hadn't thought about doing the munter in the carabiner attached to the ring. That's great Flynn.
Hey Admin... I'm already happy with this forum... And now just learnt an important lesson. Thanks guys

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Re: Thoughts on single rope techniques and releasable anchors

Post by Flynny » 07 Jun 2018, 20:53

poodlebean wrote:
07 Jun 2018, 14:21


It also occurred to me that often the last person down has not been the most experienced person. Sometimes it's been me. And I'd be able to do jack shit to rescue somebody who went down on 2 ropes. .....

At this stage, regardless of what people prefer to use it has made sense to me that planning for an experienced person to go first and last is probably best planning. Put all the noobs in the middle. That way if an emergency arises in the top, bottom or anywhere between, there will always be help available...they can instruct the noobs how to help if necessary.
If I was a noob at the top on my own and somebody was on rope and in difficulty, I would feel very distressed at being unable to help.
Rescue (and belay for that matter) is most definately easier and more effective from the top. I'm guilty of often going first in my group rather than send others and waiting at the top. Trying to rescue a stuck beginner from below is difficult at best.

poodlebean wrote:
07 Jun 2018, 14:21

training: I did attend a rescue day once. The agenda was quickly hijacked by experienced attendees who wanted to practise their own stuff. I felt sorry for the trainer on the day who had volunteered their time both in preparing the agenda which was ignored and running the day (or trying to).
Geoff is keen to run more beginner day that teach a bit of self rescue. It's best if you can get yourself out of trouble, or better yet avoid it in the first place.

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Re: Thoughts on single rope techniques and releasable anchors

Post by tom_brennan » 08 Jun 2018, 16:15

[This is almost a separate thread, since it's only loosely related to DRT vs SRT]

As I see it there are two main methods of failure of an abseiling rope over an edge.
  1. Catastrophic - the rope is cut or badly damaged immediately. I would say this is only likely to occur where a loaded rope is pulled rapidly sideways across a sharp edge.
  2. Chronic - the rope wears through over the course of one or a number of abseils (or non-abseil uses). Obviously this happens to every rope eventually over time. However, it can happen in a single trip, or even abseil. There are many ways in which this can happen. Some examples include:
    • gentle sideways movement across a sharp or abrasive edge
    • prusiking, where the rope moves up and down small amounts each movement
    • long abseils with a jerky device - again the rope is moving up and down against the rock
The first method of failure can be mitigated by:
  • using thicker or tougher ropes, which are harder to harder to cut
  • using double ropes, as the weight on each strand is halved
    • if the strands are isolated, this provides an extra level of protection as both strands would need to cut
  • careful abseiling and placement of rope, and observation of sharp edges
The second method of failure can be mitigated by:
  • using more static rope, as bouncing on descent or ascent is reduced
  • shifting the position of the rope after each abseil (or in ome cases, even while the abseiler is moving)
  • careful abseiling and placement of rope, and observation of rubbing points and sharp edges
In both cases it may be possible to pad the edges, but this may or may not be possible in real world situations.

Having only really canyoned significantly in the Blue Mountains and Utah, I can't speak for other parts of the world. However, I would say the Blue Mountains has plenty of drops with the potential for the tope to run over sharp ironstone edges, and thus the first method of failure needs to be considered.

Utah has a variety of sandstone types, but generally they are fine grained but abrasive. They wear easily and the sand gets into everything. It is tough on gear, which definitely lasts less time than it does in Australia. Rope wear via the second method is common, but in general the rock is fairly smooth, without sharp edges.

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