Think about the cave environment. It is full of razor-sharp rocks and calcite deposits that can saw through your rope in minutes. The action of ascending on a rope is literally like a serrated saw going back and forth, and I have seen rope getting cut all the way through in only a few minutes of sawing, when done deliberately on the surface. These sharp bits of cave eating your rope are called rub points.
So, the aim of SRT is to avoid rub points, protect your rope, and your life.
There are a number of ways of avoiding rub points:
1 – A good free hang from the very top that is placed precisely right, so it doesn’t rub anywhere the whole way down.
Most simply, rig your rope from the top of the pitch very carefully. Often if you take your time and try a few different spots, you can find a place to put your rope so that there are no rubs. A good way of trying this is to drop a rock down beside your rope, and listen as to whether the rock hits things and bounces around on the way down. In the UK they go to great lengths to get a good free hang from the top, and this usually involves traversing or acrobatic manoeuvres to get to the drop, which while great once you are on the rope, can be scary and sometimes difficult to get to.
2 – A deviation (also known as a re-direct)
This is where you use a bit of tape to alter the path of the rope. So, perhaps halfway down the pitch there is a sharp rub but above it there is a stalactite. You would tie some tape around the stalactite, put carabiner at the end, and the rope you are ascending/descending through the carabiner. This simply moves the rope away from the rub point. Deviations are usually pretty easy to pass. You don’t have to fiddle with you gear, you just have to be careful not to accidently drop the tape that is holding the rope, as it can be hard to reach again. And also remember that they are not load bearing, so never hang off it, which is a mistake a beginner can make if they think it is a rebelay (see next paragraph).
3 – A rebelay
The third, and most commonly used, and safest, is called a rebelay. This is where you actually re-anchor the rope at some point during the pitch, to avoid a rub above or below. The difference here is that you have to rig your rope to stop and start at a certain point, which could be a bolt in a frequently done pitch, or could be a natural feature such as a stalacmite. For all intents and purposes, rebelays are the start of another pitch.
NOTE: I have not been able to find the author of the above image. If you know him or her please let me know so I can ask permission to use the image. The image was found on google pictures. It shows perfectly what rub points are all about, and what I have described. You never rig a pitch in a waterfall as even the fittest of cavers will get very cold, and when you get very cold your strength goes and you can get stuck.
Explanation of the above diagram from left to right
1) So – starting at the left. The first caver is waiting at the pitch head, clipped into a safety line, observing. It’s important for every caver to observe the one in front for safety (reminding him/her of anything they’ve done wrong, or any signs that there is a rub or other hazard unseen by the other cavers).
2)The second caver is doing a ‘bolt traverse’ along the wall of the cave, using his ‘cow’s tails’ (safety lines) to go from bolt to bolt. Sometimes you can stand, others you are hanging in space leaning backwards. This gets him away from the water.
3) The third caver has done the traverse and attached onto the downwards rope (which is a Y-Hang, meaning the rope has 2 anchors, each taking 50% of the load, for extra safety) – as this is the start of the vertical part of the pitch it is common, and he is abseiling down.
4) The fourth caver has crossed the rebelay, which is there to protect the rope from rubbing on the big rocky bulge on the right wall, and then abseiled further and also crossed a deviation which was probably there to get more distance from the water (if it was a lake or whatever). You can see that once the caver has crossed that rebelay there is then no load on the rope that is resting on the bulge. If that bulge was VERY smooth and not as large some cavers would risk it and just let it rub gradually, but generally you will find even a smooth looking surface has rock details that will damage a rope.
But how do you get all your gear past a knot, or a rebelay, or a deviation, without taking it off and putting it back on?
The challenge here is that you have to get your descending or ascending gear past the rebelay, bolt traverse, deviation, knot crossing, etc safely. I won’t go into how this is done, but it is basically a set of fairly common-sense steps that aren’t usually too hard. This is something you learn on the surface and generally have plenty of training days on a cliff somewhere before doing any SRT underground.
So why use rebelays?
A huge advantage of re-belays is that on the way back up multiple people can be on the same pitch at once, as long as they are separated by re-belays and separate anchors. You can see this in the image above – there are 3 cavers all on the rope at different stages, all independent, not impacting in any way on the others. As long as you are able to tell the caver above or below you that you’re on the next section of rope, it speeds things up a lot. (IE you need to be within shouting distance, with no running water nearby which chews up sound) – it has been known for cavers to use whistles. Radios do not really work in caves (apart from highly elaborate ‘hay’ rescue phones, rare).
Also – every re-belay is another attachment to the cave which adds safety. If a re-belay fails due to choosing a bad anchor or a bolt popping out of the wall it doesn’t matter as the re-belay above you, or the anchors at the top of the pitch, will arrest your fall. You will fall a few metres, but it will catch you and you’ll be alive and well.
Other ‘technical’ SRT manoeuvres
Other technical manoeuvres include knot crossings, bolt traverses, pull throughs, changing direction, down prusiking, not to mention the person who rigs all this stuff. Rigging SRT is not always easy and should only be undertaken by someone with extensive experience and knowledge of SRT.
When I was learning, I actually had my SRT kit in the lounge room and I’d put it on and off and play with it while watching TV. I rigged a rope off a tree in the back yard and would get on rope regularly.
Technical SRT caving gets tough at times. The above is not even the start of it. Plus, usually you are alone with nobody to coach you when you are actually in a real cave in a real situation. It gets very complex very quickly, a lot can go wrong, and is not to be taken lightly. However, in almost all situations, if you get stuck, you should just calm down, think about it logically, and you can normally figure out how to rectify the situation with the tools you have.
Take it easy, learn from a pro, practice lots, get your own SRT rig perfectly measured for your body, and once you’ve got it, do it regularly so you don’t forget!
When you are training in the outdoors you will make plenty of mistakes, but on each mistake, you will figure out the solution on your own with guidance of the instructor. As long as the pitch is rigged correctly, and your SRT gear your wearing is all calibrated for your height and weight, there should not really be any situation that you cannot somehow get out of. Probably the worst, just FYI, is when you jam your hand ascender right up to the knot at the top of a pitch or rebelay. Getting an ascender of a rope requires just an inch or so of rope above it for it to come free, because the movement of the rope lets it come off. Every caver I know has done it at least once, and you won’t do it again.
Master SRT before thinking about rigging. Walk before you can fly!
In Europe, they use what’s known as ‘Alpine’ style rigging. This means ULTRA light weight caving, due to the extreme depths they go to, they shred every single gram of weight possible. So, they use very thin rope that would rub through quickly, but they use rebelays all over the place so that its safe and so that multiple cavers can work at once.
In Australia we worry less about rub points, but we rebelay when it is obviously needed. The trouble is that in Victoria there are only perhaps a dozen or so permanent bolts. So quite often, as long as it doesn’t damage the cave, we rig rebelays and deviations off natural features such as boulders or columns. Caves such as Elk River that get lots of traffic (especially Elk River as tanks are hauled up and down) they have bolted the pitch.
What was that about bolting?
Parks Victoria consider bolting as damaging to the cave and only permissible if the traffic warrants it, and that it adds safety to the cave that would otherwise put cavers at risk. Bolting must be applied to Parks Victoria formally through your caving club. Bolts can be installed fairly quickly, in maybe 10 minutes if you are fast and strong, using a handheld drill and hammer. The bolts in Tasmania and UK/EUROPE are brilliant because they are so well crafted and are always in the perfect spot to eradicate rubs further down. And you always know where to rig if you don’t know the cave very well. Tassie is bolted mainly to protect formation, not the amount of traffic.
The VSA run SRT training days several times a year, for members, usually at Werribee Gorge or Whipstick Gulley in Warrandyte. The club has several sets of SRT gear for loan which you can use if you just want a taste, but can only be used in training environments.
I struggled with SRT – And still don’t necessarily enjoy it.
SRT did not come naturally to me. It took me a year or so of practice, first outdoors, and then in caves, before I felt comfortable on rope. And even now after doing hundreds of pitches in caves all over the place, I still get nervous on the first pitch head. Once I’m on rope and my STOP takes my weight, I give it a gentle squeeze which drops me a few inches – then I’m ready to go. Note – until that point, I am still connected to the safety by my long cows tail.
To me personally, SRT is just a tool to get me into horizontal cave systems. Some people find the horizontal bits boring and just like to do deeper and deeper and more and more technical caves. Everyone is different.
SRT, Rigging, Ropework and Technical caving takes years to really become an ‘expert’ … and in the Australian mainland we don’t have many caves that require absolute expertise.
There are some caves in Tasmania that are nearly 400m deep, which is a significant depth, but still not a fraction of the deep caves in Europe that are over 1500m deep (or the deepest at 2.3kms). And in Buchan specifically, the deepest single pitch is about 40m in Baby Berger Cave. There are many other vertical caves in Buchan with various size pitches, some of which are technical, and others a straight up and down.