Another option for setting up a rappelling station is to build a so-called Abalakov thread with a sling pulled through it. And yet an Abalakov thread need not be only used for a rappelling station. It can also serve as a belay station, or even as intermediate protection. For this reason it deserves to be addressed in its own chapter. It consists of an artificially created ice tunnel. This can be accomplished by drilling two holes, tunnels, using an ice screw (which is not left in the ice but is used only as a tool). Abalakov threads are most often used as rappelling stations in situations where you cannot build any other better anchor in the terrain (and at the same time you are not willing to leave a screw and carabiner in the terrain). In extreme situations you can have a belay station made of an Abalakov thread as well, but you will need to use a solid sling with sufficient loading strength. It could also be used as intermediate protection, but this is not particularly practical, as takes far too long to build an Abalakov thread. Abalakov threads must be built only in hard, homogenous ice in order for them to be strong enough. In other words, porous, excessively crystalline ice is not appropriate. The drilled openings must form an approx 60° with the surface of the ice. The openings should be at least 15 cm long. The subsequent drilling must not crack the ice at the spot where we create the Abalakov thread, and above all the column of the thread we create must be in good condition. Which is sometimes a problem, particularly during heavy frost, when the ice is very fragile and breaks off when drilling the opening. Meanwhile Abalakov threads in high quality ice can carry up to 11 kN.
Building an Abalakov thread is painstaking and time-consuming work. It can truly test your nerves. Already when drilling the second hole, properly aiming the screw so that it reaches the end of the first hole is truly an art. Not to mention the threading of the sling! It is definitely an advantage to use a thick sling with a round cross-section, as this is easier to poke through. If the sling is properly thick and malleable, it is a good idea to bend the end you’re sticking into the opening into a fold, making it into a small head. This will make it easier to guide the sling through the bend in the “tunnel”. It is almost essential to have special gear for creating Abalakov threads, various wires with hooks on the end, rods that can be fed into the hole with the sling, etc. Small chockstones on metal wires have also been proven to work as a tool for pulling the sling out the other end. For example, the nuts in number 2 to 3 sizes, which can pass through a hole in the ice ideally. The sling gets caught between the wire of the nut and can then be pulled out. When building Abalakov threads, you will get your fill of craftsmanship by hand. One undisputable advantage is that you can stand in the spot where you build the thread without holding on by your hand. It is impossible to build an Abalakov thread with only one hand, or at least to do so would be the work of a circus acrobat. If you can’t stand on your feet, there is always the option of hanging either into another ice screw embedded nearby or an ice tool embedded in the ice.
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Mountaineering Methodology – Part 5 – Snow and Ice
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