Knee Ascender/Stairwalking SRT

[Fulk]

I experimented with rope-walking many years ago – so long since that I can’t remember the exact set-up I was using. Anyway, I remember going up to Gaping Gill, tying a big thick length of Bluewater rope to a huge boulder near the lip of the shaft, feeding it down, installing a rope-protector over the edge and abbing straight down (such innocence in those days; re-belays? deviations? What are they?) I then rope-walked out in a reasonable time, though I can’t remember how long.

However, I did experiment at Alum Pot some time later, when the rebelays had been installed at the NW end. This time I timed myself. I abseiled down and rope-walked up to the rebelay in 7.5 minutes; I then went back down and ‘frogged’ it back up in 6.5 minutes. I’ve don’t doubt that this says more about my familiarity with the two techniques (i.e. familiarity with the Frog, unfamiliarity with rope-walking), rather than anything bout the inherent advantages of each system, nevertheless, I figured that even if I ‘improved’ my time with the latter system, it simply wasn’t worth it on account of the extra hassle – at least, for everyday caving in Britain. I daresay if you’re digging at the bottom of Titan or some such, it might be worthwhile sorting out a rope-walking system.

 

[MarkS]

Brilliant, that’s some great advice, thank you! I think we’re going to pop over to Hunter’s Hole for a trial at some point in the next few weeks so I’ll remember the disadvantages you mentioned and see if the modern gear designs might have rectified any of the issues you had. Whether or not Petzl’s own bungee harness strap design might offset the bungee enough to reduce the snag issue could be interesting. I shall report back with some snaps and let you guys know the outcome!

If you don't have somewhere with a large drop nearby, I'd definitely consider rigging a long rope over a pulley so you can be lowered down after each climb. That way you can focus on the prussiking technique rather than constantly doing changeovers.

 

[sam1991]

If you don't have somewhere with a large drop nearby, I'd definitely consider rigging a long rope over a pulley so you can be lowered down after each climb. That way you can focus on the prussiking technique rather than constantly doing changeovers.

Unfortunately I think the only proper long pitch we have nearby is probably Atlas Pot in Thrupe Lane Swallet, which we have yet to manage to explore (I’d love to, but can’t seem to find a leader), so a pulley is definitely a good idea!

 

[wellyjen]

Good luck with having a play with one of these systems. Have some one around who can do a mid rope rescue, if you get in to a spot of bother experimenting!

 

[PeteHall]

Yeah I did wonder how much energy it would actually save over a proper long pitch; in terms of speed it makes sense, but in comparison it’s basically squats versus walking up stairs isn’t it?

The energy saved by rope-walking is actually quite significant.

Every time you sit back into your harness when 'frogging' you lose a percentage of the height that you've just lifted yourself. The percentage will vary depending on your harness set-up and technique. Next time you frog up a rope, take note of where your nose gets to at the top of your step, then see how far it drops by the time your sitting back in the harness, then compare this to the total distance you move up during the step. If you wanted to be scientific about it, you could do this on a training tower and get a friend to mark the height of your nose on the rope, before step, top of step, and after step; I wouldn't be surprised if this was something like 50% for a lot of people.

When rope-walking (this can be done very efficiently with the addition of a Pantin and no funny knee jammer), every inch you go up, you stay up, as your weight remains on your legs the whole time like walking up the stairs, or climbing a ladder. You do not lose any height sitting back into your harness.
Since you don't get a sit down between steps and you are lifting your full weight on one leg at a time, it obviously takes greater strength and fitness to keep going, but the total energy used to get up the pitch will be greatly reduced.

Since I'm not as fit as I used to be, I tend to mix techniques, rope-walking until I'm tired, then doing a bit of frogging while I catch my breath and let my legs recover a bit before rope-walking some more.

The other major inefficiency, is pushing forward with the legs.

If you push your legs forward as you step up, you need to counter this by pulling with your arms, so your arms and legs are working against each other in a horizontal direction, when you are trying to move in a vertical direction. It is incredibly common to see people pushing their legs forward as they climb a rope, as it's the natural direction your leg will push from a sitting position. Here is a good example on the Eurospeleo website (no personal criticism intended, as we don't know the context of what is going on here, it's just an excellent picture to highlight the issue)

You can see straight away that the foot-loop is at 45 degrees and as this caver tries to stand up, their legs will be pushing out and arms pulling forward to return to a vertical position before any vertical progress is made. It is also clear that the rope is being pulled through the chest-jammer at a significant angle which will increase wear on the jammer and reduce efficiency of the climb. Compare this to the (idealised) position shown by Petzl:

A simple way to maintain this position is to catch your foot loop on the heel step of your boot (as you normally would) and point your toes vertically down (or as close to vertical as you can). This forces the legs to push straight down and to push you straight up. It greatly reduces overall energy consumption and also means that you won't get tired arms.
Also note that the foot-loop in the diagram above is secured to the leg with a couple of bands; pulling a knee-pad down to the ankle and threading the foot-loop through is a great way of holding it in place while rope walking.

I reckon that most cavers would gain more by improving the efficiency of their technique, than they will by adding an additional jammer on the knee.

Unfortunately I think the only proper long pitch we have nearby is probably Atlas Pot in Thrupe Lane Swallet, which we have yet to manage to explore (I’d love to, but can’t seem to find a leader), so a pulley is definitely a good idea!

A pulley at the Wessex training tower is probably your best bet.

 

[wellyjen]

When you also have a situation where the cave helps to keep you upright when prussiking, then pantin based rope walking is very fast indeed. Either with the rope close, or against one wall (without rub), or in a narrow rift, or shaft (typical Derbyshire lead mine shaft). If given a choice between setting up a rope to drop down the centre of a pitch, away from the walls, or safely closer to one of the walls, then the later will allow speedier rope walking.
I find trying to pantin rope walk a free hanging pitch needs a lot of extra effort, compared to frog, to keep upright all the time, which negates the height saved each step in not loading and unloading the harness. Americans use roller boxes to keep themselves upright when rope walking I believe, but they also have historically not done rebelays. Things may have changed and I'm not up to date with what they do now.

 

[caving_fox]

Every time you sit back into your harness when 'frogging' you lose a percentage of the height that you've just lifted yourself. The percentage will vary depending on your harness set-up and technique. Next time you frog up a rope, take note of where your nose gets to at the top of your step, then see how far it drops by the time your sitting back in the harness, then compare this to the total distance you move up during the step. If you wanted to be scientific about it, you could do this on a training tower and get a friend to mark the height of your nose on the rope, before step, top of step, and after step; I wouldn't be surprised if this was something like 50% for a lot of people.

Tucking your heels under your bum (contra to the image above) (with a tight chestharness) really improves the efficiency of frogging. You need to adjust hand jammer and foot loop lengths so that this is possible. You can then get a full leg extension without pulling (much) on the arms, and no relaxation 'sitting' in the harness. Very important to adjust chestharness tension at rebelays and pitch heads for freedom of movement. (I still don't use a pantin which might need a different leg position)

 

[PeteHall]

Tucking your heels under your bum (contra to the image above) (with a tight chestharness) really improves the efficiency of frogging. You need to adjust hand jammer and foot loop lengths so that this is possible. You can then get a full leg extension without pulling (much) on the arms, and no relaxation 'sitting' in the harness. Very important to adjust chestharness tension at rebelays and pitch heads for freedom of movement. (I still don't use a pantin which might need a different leg position)

Something like this?

Also from the Petzl Pantin guide (sorry link above was broken, but hopefully now sorted), but can be done without a Pantin and both feet in the foot loop.

The key thing (whatever method you use) is to push feet straight down, not out and the easiest way to do this (as far as I can tell), is pointing toes downwards to maintain a vertical body position.

 

[PeteHall]

When you also have a situation where the cave helps to keep you upright when prussiking, then pantin based rope walking is very fast indeed. Either with the rope close, or against one wall (without rub), or in a narrow rift, or shaft (typical Derbyshire lead mine shaft). If given a choice between setting up a rope to drop down the centre of a pitch, away from the walls, or safely closer to one of the walls, then the later will allow speedier rope walking.

Couldn't agree more. The quickest pitch I have ever climbed was a slightly off-vertical mine shaft (what a climber would call a slab) using a Pantin and rope walking. Keeping toes against the wall for balance and to reduce bounce, it really was like walking up the stairs!

 

[Flotsam]

When I was last caving many years ago I used precisely the method described for multi pitch mostly vertical trips in major European caves. Also larger pitches in the UK. It was very fast in part because I used to be extremely fit.
As I remember the setup consisted of an original roprwalker, an original Jumar on a chest harness and something like a Croll onva webbing sling to my left foot with a

 

[nearlywhite]

I've used it and as some have said it doesn't need a chest roller. It's normally called a modified Mitchell system in the States and there are a few variations - it really depends on your harness and the natural sit. Sort those out to be more vertical and the less bungee/roller stuff that's needed.

For many people it's not worth bothering with, however, I have seen it really help 'pancake prussikers' and drastically improve efficiency. As for rebelays; it's faffy if you haven't set it up right for you.

For reference I use a frog but am considering adding in a modified Mitchell back into my setup once I've fiddled about with my harness (strapping the waistband to a braness).

 

[Jon]

I'm interested in making a chest roller along with an srt setup similar to this: https://www.croydoncavingclub.org.uk/node/3344 mostly just because I want to try it. I already use a French style srt setup anyway.
There's lots of mentions of building simple chest rollers, has anyone got any examples apart from the one I posted and https://get.google.com/albumarchive.../AF1QipNocbXlK2qv14tyNmU_p_S0WqHTNsJkysexhpWM ?

 

[Pitlamp]

I think they featured in issues of BCRA Caves & Caving in the early 1980s.

Also (from memory only) there may have been a design featured in one of the ULSA reviews from the late 70s / early 80s.

If you have access to a caving library you can probably find some useful information.

Or, the Americans probably sell them.

 

[Flotsam]

I was "rope walking" 35-40 years ago. I used one of the original American ropewalkers on my right foot. An original Jumar on a webbing strop on bungee cord on my left foot. And I think a Croll on my chest. The Jumar was chosen because it didn't sieze onto the rope and released easily. Very fast it was too. The chest harness fit was critical and I was very slim which kept my C of G close to the rope. I used to do changeovers without an issue. The only issue I ever had was on a long French trip my foot harness wore through and broke on a pitch, the ropewalker rattled down the rope.

 

[cavemanmike]

I made this a few years ago and works really well . The top loop of the bunjee attaches to the harness, red strap goes around knee too keep jammer in place