SRT Details

So the description that we go down and up a single rope on the other page wasn’t enough for you, huh? No worries, this page is here to provide a little more detail. However at the start, a disclaimer:

SRT is a potentially lethal activity, involving sophisticated equipment, complicated knots, hard rocks, and very big drops. No one in NUCC, and certainly not the author of this page, has any formal qualifications to teach it. You undertake any of the activities described on this page at your own risk, and please do not try to learn SRT from the Internet, be it from this page or any other website.

The purpose of this page is not to provide a comprehensive description of how ropework in caving works. The currently used standard for that in Australia is the book Vertical by Al Warild, the Captain of the New South Wales Cave Rescue Squad. It is an excellent book, and go read it rather than my blather below: it is available online here. Failing this, another excellent resource is Alpine Caving Techniques by George Marbach and Bernard Tourte. This is the French guide to alpine caving, and contains much excellent information. It is also available online here.

Still reading?

The caving around Canberra does require a moderate amount of vertical work, as many of the caves in the area have small to medium sized pitches. The largest underground pitch in Australia is at Bungonia, and it is only about a 60m drop. Many of the smaller pitches can be laddered, and it’s mostly personal preference as to where the ladders stop and the SRT begins. Frequently, you’ll find that point is at about 30ft, as that’s the length of the shorter form of caving ladder, so that anything more than about 9m deep will be SRTed.

But what actually is SRT? It’s the art of ropework with a single rope, and there’s a whole suite of techniques that NUCC teaches. I’ll list some of the more common techniques, and describe them in more detail below, in roughly the order NUCC introduces them.

Abseiling: Abseiling is going down a rope. It’s simple- you lower yourself off the edge and use friction to control your descent. In the good old days, people wrapped the rope around themselves to do this, but now cavers use devices to actually attach themselves to the rope. These devices are called descenders, and NUCC’s descender of choice is the Rack, although we do also use Bobbins and Stops, both of which are also very popular amongst cavers. What we don’t use are Figure Eight style descenders or ATCs, as both of these are required to be removed from your harness as you get on rope, raising the spectre of dropped descenders.

We have a standard abseiling drill that everyone in the club uses:

  1. Attach your long cowstail into the rigging krab or safety point
  2. Approach the pitch head and shout “ON ROPE” down to the person belaying you (they will shout back “ON BELAY”)
  3. Thread your descender onto the rope as high up as you can comfortably get it. With Racks, the rope goes from the top (up rope) to the bottom (down rope)
  4. Put your descender onto half-lock and then full lock; this will vary based on descender, but importantly with our Racks don’t let go of half-lock
  5. Climb out over the pitch and get comfortable (relax!)
  6. Test descender by going back to half-lock, and then easing off half lock to allow some rope to run through your descender. You only need to let 3-5cm through though
  7. Return to full lock
  8. Remove long cowstail
  9. Shout “ABSEILING” down to your belayer (they will shout back “ABSEIL WHEN READY”)
  10. Remove full-lock, and then move from half-lock into the abseiling position. With our Racks, you want to swiftly move your dominant hand holding the rope from manipulating the half-lock to controlling your abseil. The way to do this is move your thumb to your bum, and from there you can control the speed of your abseil. Loosen your grip and you go very fast, tighten it and you stop. DO NOT let go of the rope, or you can go into free-fall
  11. Enjoy the view as you abseil down the rope
  12. Once you’re at the bottom and have removed your descender from the rope, shout up “OFF ROPE”

And that’s abseiling with NUCC in a list. It seems a lot, but there will be an experienced caver there showing you what to do in the gym when you first abseil. After time it becomes muscle memory, and climbing over the edge second nature.

Prusiking: Prusiking is going back up the rope, and is necessary in most vertical caves in Australia. There is the odd gem of a cave where you can do what’s known as a ‘through-trip’, abseiling in a higher entrance and walking out a lower one after a series of abseils. These are to be savoured where you find them, as they are the exception rather than the norm. To go back up, we use mechanical ascenders rather than the prusik loops the technique is named after, as they’re far, far more efficient and easier to use. It still requires some stamina (as you’re fighting against gravity), but more important is technique, and we have weekly SRT sessions for members to refine that in.

Getting on rope for a prusik is more simple than for abseiling, as you’re usually standing up at the bottom of a pitch. The main safety concern is that once you start prusiking you maintain at least two points of contact with the rope at all times- your two ascenders. NEVER prusik with only one ascender, as not only is it inefficient, but you’re entirely reliant on that one device for your safety…

Anyway, the description below is for a frog system with two ascenders (hand and chest), which is the standard SRT setup for cavers in Australia. Europeans also use the frog system, but add an extra ascender on their foot; Americans use a completely different system called ropewalking.

  1. Approach the rope. You want to be as high up as you can get safely and easily to minimise the amount of prusiking you have to do, but don’t compromise safety to save a few metres. It’s NOT customary to shout “ON ROPE” when you start heading up, unless you think the people at the top of the pitch really need to know that you’re on your way up (for instance, if there was a lot of loose debris at the top of the pitch)
  2. Attach your chest ascender to the rope. You do this by pulling down then out on the tab of the cam on the chest ascender, slotting the rope into the channel, and pushing the cam closed.
  3. Pull the rope through the chest ascender from below several times or until the rope is taut. This ensures the ascender is attached, and removes any slack in the rope (which means less prusiking).
  4. Unclip your hand ascender from your harness , and unclip the D-ring securing the footloop so that it hangs free. Attach it to the rope in the same manner as the chest ascender slightly above head height
  5. Sit down in your harness, and your ascenders should take all your weight. Make sure that the rope falls straight down the pitch, not on an angle, as otherwise you’ll swing in towards the pitch (usually the wall) in a pendulum. Put both feet in the footloop, and the rope between your boots in in front of the foot loop. Also, read Notes 1, 2 and 3 at the end of this list!
  6. Grip onto the rope with your boots, and holding onto your hand ascender with both hands, stand up, putting all your weight into the footloop. Keep your posture straight, and your centre of gravity in close to the rope. Your chest ascender should move up the rope.
  7. Sit back down as much as you can, making sure that you take all pressure off the footloop, and let go of the rope with your feet. Slide the hand ascender up the rope as far as you can, but NEVER take it off the rope.
  8. Grip onto the rope with you boots, and holding onto your hand ascender with both hands, stand up, putting all your weight into the footloop like you did before. Continue with this sit-stand motion until you reach the top of the pitch.
  9. At the top of the pitch, DO NOT start climbing until you’ve put your long cowstail into a safety point at the top of the pitch. Because of the cam and the teeth on it, ascenders a comparatively weak devices and will either break or cut through the rope if subjected to a fall of any significance. That’s one of the reasons there’s two of them.
  10. Once you have a long cowstail attached to something above your ascenders, it’s safe to climb to a more comfortable spot where you can detach your ascenders from the rope. The chest ascender comes off first, followed by the hand ascender. If you’re having trouble getting off rope, check that the position of your body isn’t accidentally weighting one of your ascenders, as they can only be removed from the rope when unweighted. Alternatively, your hand ascender footloop might be snagged on something and being a menace.
  11. Shout “OFF ROPE” down to the people below you. They’ll probably shout something like “OK” back.
  12. Move away from the pitch and unclip your long cowstail when safe to do so, enjoying the sunshine (or savouring the fact that you’re one pitch closer to it!)

Note 1: to make going up easier, attach a weighted bag of stuff to the rope below you, and it will pull the rope tight. This will make each step more efficient, and also mean that you don’t need grip onto the rope with both feet in step 6. After about 10-15m there should be enough weight of rope beneath you that you won’t have to do this anyway. You can also have someone below you pull on the rope, as this provides much the same effect as a bag of caving tackle, but make sure that they’re not about take a rock to the face as you prusik up!

Note 2: there are several ways people attach their hand ascenders, but I am assuming yours is permanently tethered to your harness with a dynamic rope lanyard and a maillon connecting the lanyard to hand ascender. There is a second maillon attaching your footloop, and lightweight clip clipped into that which attaches the whole assembly to your harness storage loops when not in use

Note 3: when you put your harness on, you will have had to adjust the footloop so that it is the right length. Otherwise prusiking will be extremely difficult. You want the top of the hand ascender to be at about belly-button height when your feet are standing in the footloop

Belaying: So, time for the guilty admission: it is the exception, rather than the rule to belay someone performing SRT in a cave. There’s a few reasons for this, but first note that in the case of club-run SRT, a belay either means a bottom belay or a self-belay; top rope belays are almost entirely unsuitable for club-run SRT (see Note 1 though). - Many pitches are unstable or have loose debris on them, and the belayer risks being hit by debris knocked loose by the abseiler - Most caving descenders offer excellent control of your descent via friction, and an experienced caver will know several ways of adding more friction to their descender while abseiling - A lot of the time you will not have a clear line of sight to the abseiler, and thus a belay is difficult to run - Many pitches are either very long, or have rebelays in them. On long pitches the degree of rope stretch can make a belay impossible to establish. When there is a rebelay below an abseiler, it is impossible to belay them - Most self belay options have issues of their own and are difficult to operate safely in a cave environment

The first person down a pitch will will likely abseil without a belay, and is usually the most experienced SRT caver for that reason. If they feel that a belay is necessary, they will use an autolocking descender, of which the most common is the Petzl Stop. A Stop is not a beginner’s piece of equipment, as misuse of their braking capacity has been the cause of several nasty accidents overseas.

Instead, a beginner will be given a bottom belay (or fireman’s belay). It is standard in caving for beginners to be given a bottom belay, or for all to be given a bottom belay if the nature of the pitch dictates that (eg, loose rock). For a fireman’s belay, the belayer holds the rope with both hands, and attentively watches the abseiler. Once help is required, the belayer firmly holds the rope and rapidly moves away from the pitch, pulling the rope tight. This increases the friction in the descender and should halt their descent enough for the abseiler to regain control of their abseil. If they’re unconscious, the belayer should carefully lower them to the ground. Of course, there are some caveats:

Note 1: as always, there are exceptions to this, when there are potential dangers on pitch to the abseiler that may require rapid extraction (eg, foul air), although arguably, there are still better alternatives to a top belay

Changeovers: Sometimes you screw things up in SRT. It’s fine, it happens to all of us. You might get your clothes, you head hair, moustache, beard, or other miscellaneous hair (use your imagination…) caught in your descender. You might abseil into a pit full of foul air. You might abseil down to find that the pitch turns into a waterfall. You might leave your pack behind at the bottom of the pitch, and remember it part way up… The list is endless, and get even longer when you start rigging caves. The solution is broadly called ‘self-rescue’, and the first basic technique to learn to deal with entry level SRT problems is a changeover. That is, going from abseiling to prusiking, or prusiking to abseiling, whilst remaining on rope and suspended in mid air.

Firstly, DON’T PANIC! The most important thing to do is stay calm, and be rational, especially if you have encountered one of the more serious scenarios mentioned above (foul air, or hair/clothing (no, seriously, what hair did you think I was talking about?) in descender).

The second thing you’re likely to do is start doing a changeover. Changing from down to up is more likely, so I’ll describe it first.

  1. Lock your descender off. Seeing as you’re still here, I assume you know how to do that, and it must be a FULL LOCK.
  2. Unclip your hand ascender and footloop from your harness, and attach to the rope a little bit above head height
  3. Stand up in your footloop, and attach your chest ascender to the rope as high up as you can get it
  4. Prusik up the rope THREE times. I can’t stress this enough, each ascender must move cleanly and smoothly up the rope three time each! This is so that you know you’re attached to the rope properly
  5. Reach down and take your descender off lock, and then remove it from the rope. Continue up to freedom!

Going from up to down is more complex, but thankfully it is also far less frequently used. However, it is important to know how to do changeovers in both directions, and an independent vertical caver should be experienced enough that they can do a changeover with their eyes closed and no directions. Because what happens if your light fails?

  1. Move your chest as close to your hand ascender as you can get it with the footloop still being easy to stand up in
  2. Get your descender out, hold it as far to the left as you can get it (assuming it is positioned to the left of your chest ascender), and then kink it around to get where the rope enters the descender as close to where the rope exits your chest ascender as you can. The aim is to minimise the distance between the descender and your hand ascender ascender, but at the same time you can’t get it too close to your chest ascender that you can’t manipulate your descender. Practice is definitely required here!
  3. Tie your descender off to full lock
  4. Stand up in your footloop unweighting your chest ascender. Remove the chest ascender from the rope. This is what the finesse in Step 2 was needed for; your descender needs to be able to pivot so you can stand up and unweight your chest ascender, but if it’s too far down the rope, you won’t be able to reach your hand ascender when you sit back down.
  5. Sit back down. Fingers crossed you can reach your hand ascender. If not, you need to stand back up, put your chest ascender back on the rope, and adjust your descender (it should be possible without removing your hand ascender from the rope, but downprusiking the ascender is ok if you know how to do it). If you remove your hand ascender from the rope and don’t test it with three small prusiks before trying again, you effectively have no protection (a locked-off, but untested rack, an untested hand ascender, and you have too remove your chest ascender from the rope). Yes I know it’s unlikely, but don’t forget the Swiss Cheese Model- disaster can strike when all the holes line up, and you only need them to line up once to die.
  6. Test your descender to make sure that it’s working. Be VERY economical about the amount of rope you let run through your rack! Otherwise, you mightn’t be able to reach your hand ascender… Lock it back off again once tested.
  7. Remove your hand ascender from the rope and stow it. Continue off back down the pitch.

Rebelays: Rebelays are a basic fact of life in alpine style rigging. They’re absolutely vital with thin rope, as they save it from being destroyed, and handy with thick rope, as they can protect formation and allow multiple people to progress down a pitch at the same time. Essentially, each rebelay is the start of a new pitch backed up to the one above (and with multiple anchors if necessary), and you treat it like the top of a pitch (only you’re in mid air). There are obviously two variants, going down and going up.

GOING DOWN-

  1. Abseil down the rope until you are level with anchor karabiner of the rebelay. Lock your descender off and clip your SHORT cowstail into the anchor karabiner.
  2. Clip your LONG cowstail around the rope above your descender. Take the lock off, and continue abseiling down into the loop of the rebelay until your short cowstail takes all of your weight.
  3. Take your descender off the rope, and thread it back onto the rope as high as you can get it underneath the rebelay and lock it off. Make sure you put it on the side of the anchor continuing down the pitch!
  4. Unscrew your short cowstail if a locking karabiner. Get one foot into the loop of the rebelay and stand up in the loop and remove the short cowstail from the anchor karabiner. Sit back down, and the rack will take your weight. If you can’t get a leg into it (for instance, not flexible enough, very short loop), then attach your hand ascender above your descender, unclip the footloop and stand up in that, using it to unweight your short cows tail. Make sure you put the hand ascender between the anchor and your descender, not above the anchor, as then you swing off to the side and it’s pointlessly difficult.
  5. Test your rack to make sure that its working, and then go back to full lock
  6. Remove your long cowstail from the loop of the rebelay, remove the full lock, and continue abseiling.

GOING UP-

  1. Prusik up until you are just below the knot of the rebelay (make sure you don’t jam your hand ascender onto the knot- been there, done that, it’s as awkward as hell). Put your LONG cowstail into the anchor karabiner of the rebelay (different cowstail to going down!)
  2. In one movement, you then stand up in your hand ascender footloop, take hold of the rope going up towards the top of the pitch with your LEFT hand, open your chest ascender with your RIGHT hand, and put the rope into the chest ascender. You MUST move your chest ascender first; moving the hand ascender first can work in some circumstances, but it’s really horrible to do.
  3. Sit back down, moving your weight over to the up rope. You will swing over a little bit. Make sure that the chest ascender isn’t in the very bottom of the loop of the up rope, as if there’s a lot of pressure on the cam due to it being at the bottom of that loop, it can come off the rope.
  4. Unclip your hand ascender from the down rope, and move it over to the up rope. Prusik up both ascenders AT LEAST 3 times so that you know they’re functioning properly.
  5. Unclip your long cowstail from the anchor karabiner, and keep on going up

Redirects:

Rigging knots:

Knot crossing:

Basic rigging:

Rescue techniques: