In caving you just can’t pick a rock, do a granny knot around it and hope for the best. Hopefully you have read the section on ‘Rub Points’ before this. Rigging Caves, both from the surface, and also once you are in the cave, really is an artform.
Rigging – The art of setting up ropes to get you in and out of a cave.
There are a set of knots that you need to know, which will be suitable for any situation you will ever encounter. These are: The Figure 8, The Alpine Butterfly, The Munter Hitch, The Bowline and the Double Fisherman’s. In particular, I would highlight the figure 8. In actual fact, you can use the figure 8 in 80% of situations, although the other knots have various characteristics that make them more suitable for different purposes or situations. Some people use figure 9’s instead of figure 8’s, but this is academic and is really only better if you take a fall on it. The figure 9 is also technically a stronger knot, but again the figure 8 is more than strong enough.
What do you tie the rope to?
The next part of rigging to mention is identifying what to rig off. If the pitch starts right at the surface, and is not bolted, then the first thing you would look for is a rock nearby that is large enough to safely hold a rope without it slipping off, or alternatively a nearby tree (although some conversationalists may disapprove of using a tree in case it is damaged – in which case you can use a cave pack or improvise a way of protecting the tree.
Bolts are a riggers best friend!
I mentioned bolts. In the United Kingdom the routes through their vertical caves are highly mapped out and bolted. It is great! You know exactly where to rig and it is simply doing a quick figure 8, into a crab, onto the bolt and there you go. However, in Victorian caves we have very few bolts, and probably 90% of the anchors we use are natural features. These would be rocks and trees on the surface, and things underground such as columns, jugs, rocks, threads, stalacmites, or anything strong that will take a rope. Obviously, we never use any feature that is decorated. And decoration is not safe to rig off anyway, as it is not bedrock and is far weaker than solid limestone.
So, you know your knots, and with experience you learn how to spot good things to rig off. But as I’ve mentioned, the big no-no is rub points. And the best way of avoiding rub points is by picking a good anchor at the top. In the UK they take this to an extreme level, and will often use what’s called a ‘Bolt-Traverse’ to get to a spot so that there are no rub points and the rope hangs free all the way down. A bolt traverse is where you use your safety cords (called Cow’s Tails in Australia) to shuffle across a wall that has bolts every 2 or 3 feet. It can be very unnerving if there is nothing under you, which is usually the case.
The best rigging means positioning the rope carefully at the top, and taking time to achieve a free hanging rope all the way down.
If you can’t rig a free hang rope then the rigger has to watch for rubs as they descend, and if a severe rub is found then the rigger must find somewhere to rig a re-belay or a deviation.
It’s important to note now that if you are only abseiling, and you don’t have to prusik back up, rubs are less serious. It is the up and down sawing motion of ascending a rope that is dangerous. Also, if the rub is against a smooth surface it is less serious. Sharp jutting spiky bits of limestone are what you are looking for.
In America they use what we jokingly refer to as IRT – Indestructible Rope Technique. Over there (generally) instead of using light weight 10ml or 9ml rope, they use big tough 11ml rope, so that even if there is a rub point the rope is so thick the chances of it totally breaking are slim. They argue that the technical manoeuvres of SRT are more dangerous than the chance of a rub slicing your rope. Maybe. Maybe not.
Rigging rebelays and deviations is part of this art form. I won’t go into the details, but rigging these features requires some skill in making sure the lengths of rope are correct. Make the lengths too long and you risk a long fall if you make a mistake. Rig the ropes too short and they are too hard to get past. And finding anchors halfway down a pitch often needs some really creative thinking.
The rule of thumb in SRT caving is that the rigger goes first, to try out their own rigging. And usually the most experienced other team member is the de-rigger. Some poor soul has to come up last and un-rig as they go, usually stuffing the rope into a bag as they ascend. This is of course only if the trip is not a pull through (this is when you pull the rope down after each pitch and exit at a different part of the cave – not often possible).
Buchan is slowly being bolted more, and there are a few caves there that have well placed useful bolts. The bolt just below the pitch head in Jam Pot is a good one. And the bolt in the deep pitch of Oolite is also a good one. Bolts installed at the pitch head of the route to Elk River made their trips much easier. Parks Victoria do like to be asked first though, as technically you are vandalising the cave if you bolt it without permission. And, generally it should only be the frequently done caves that deserve bolts. Remember when using bolts always have a good pull on them first to make sure they don’t wiggle or come out, and inspect them for rust or decay. See the section on rub points for more information.
That is an introduction to the basic principles of rigging. It’s really something that comes with time. In a perfect world, every caver in the party knows how to rig. This means you can split the jobs up between the group and get it done quickly, and further to this, that each member will identify a mistake such as a carabiner gate not screwed up, etc.
Get your basic SRT skills going first, and once you are happy going up and down on rope, and doing rebelays, knot crossings, direction changes and deviations, then start learning how to rig.
Its yet another interesting challenge that caving has.