Abseiling: The Right Setup

proadventure abseiling rules

Many factors come into play during abseiling: above all, the body weight and hand strength of the person abseiling, the material properties of the rope and belay (diameter, stiffness, roughness), and the geometry and state of wear of the abseiling device. Other factors such as humidity or temperature, which can change rapidly, directly influence the rappelling process. This article is not a guide to proper rappelling. It is intended for anyone who already rappels independently and for people who offer courses on how to do so.

Abseiling The Right Setup

Accident reconstruction

In both accidents, the injured person had learned the correct abseiling technique shortly beforehand in a course. In each case, a tube was used as the abseiling device and a short prusik was attached to the leg loop as the belay. In both cases, the cause of the error was a “blackout”: In the first case, the rope was correctly pulled through to the middle of the rope – but then incorrectly hooked into the tube for rappelling, namely on only one of the two strands leading to the ground – as in the partner belay. The Prusik was knotted around the two rope strands coming out of the tube, not – as is actually correct – around the two strands leading to the ground. The descender and Prusik were therefore only attached to one of the two rope strands that reached to the ground. The self-belay device was unhooked, and the incorrectly set-up belay chain was immediately loaded. A fatal fall to the ground was the result. In the second case, the descender was incorrectly hooked into one of the gear loops on the harness. The short prusik was correctly placed around the two rope ends leading to the ground and also correctly attached to the harness. The incorrectly set up abseil device was also loaded for the first time in this case, after the self-securing device had already been unhooked. The material loop failed immediately under the body weight. Now the correctly attached short prusik should have prevented the person from falling to the ground; however, it did not “grip”, so the person fell about seven meters to the ground.

Load test

Both errors could have been detected and corrected by a simple measure: if the abseil system had been loaded and checked before unhooking the self-belay. This so-called “load test” (self-check, analogous to the partner check) should be carried out as standard before every abseil! To do this, before unhooking the self-belay sling, we pull both the descender and the belay towards the belay station and sit down in the descender system. The descender now carries our entire load. The back belay grips the rope and prevents us from slipping back into the self-belay. Now we check if our rappel system fits (see picture on the left):

  1. Is the rope correctly threaded through the fixed point?
  2. Is the rope correctly inserted in the descender and is the carabiner of the descender correctly hooked and locked to me?
  3. Does the back belay grab, is it short enough, and is it properly attached to the leg loop so that it cannot stick to the tube under any circumstances?

If you already have to help manually during the load test so that the back belay grips, then it should be improved – usually a wrap helps more. Since many variable factors interact when rappelling, it must be ensured that the selected material combination also fits the individual weight and hand strength under the current conditions. If the hand force is low or the rope is thin, for example, the double carabiner method can be used to increase the friction in the descender (the tube is attached to the belay ring of the harness not with one, but with two carabiners). Once the load test has been performed, we can unhook the self-belay and begin the rappel. It has proven useful to hook the free carabiner of the self-belay into the rope strand, which then “pulls” when the rope is pulled off. This helps to remember the correct rope and prevents the ropes from twisting.

Rappelling methods

The two methods of descending most widely used in the DAV are the “classic method” and the “Swiss method”. A third method combines the advantages of the two. Correctly executed, all three methods are suitable. For the Swiss and combined methods, the FB cross-clamp knot (with 30 cm dyneema strap, see below) is a practical alternative to the Prusik knot for belaying. Practical tip: To attach the free-hanging rope to the belay device, first attach the back belay, then pull about 50 cm of rope through to the top. The back belay then holds the rope at the leg loop and the pull of the rope hanging freely downward does not interfere with threading the descender. At the same time, you use it to check whether the back belay on the rope grips reliably or needs to be improved.

Classic method

Classic methodDescender in the belay ring of the harness, the (short!) back belay (below!) on the leg loop.

Advantages:

  • When the back belay has grabbed, you can easily release it by lifting the leg.
  • Compact and clear.
  • The risk of long hair getting caught in the device is low because of the deep suspension.
  • Facilitates rappelling with particularly thick ropes, as the brake rope can be more easily fed into the tube from higher up.

Disadvantages:

  • Increased risk that the rear belaying device will be in contact with the descender and will then not grip.
  • Therefore important: short belay!

Tip: If you like, you can tie the short Prusik directly into the leg loop – a bit more time-consuming, but it makes it easier to create distance between Prusik and tube – and saves the carabiner on top of that.

Swiss method

Swiss methodAbseiling device in the relatively short tied-off self-belay, back belay in the belay ring of the harness.

Advantages:

  • Descender device and belay device are far enough apart that the belay device is not in contact with the device, so it can always grip.

Disadvantages:

  • Due to the gripping reflex, there is a risk that the person rappelling will cling to the rear belay in an emergency, preventing it from responding.
  • If the back belay has gripped, it may be more difficult to open again, as it cannot be released so easily.
  • Attention with long hair – hanging can be really dangerous!

Combination method

Combination methodDescender in the relatively short tied self belay, back belay (below!) on the leg loop.

Advantages:

  • Descender and belay device are so far apart that the belay device is not in contact with the device and can thus always grip.
  • When the back belay has grabbed, you can easily release it by lifting the leg.

Disadvantages:

  • Attention with long hair – hanging can be really dangerous!

General precautions for abseiling

  • Stand? The stand location must be solid! For all actions at the stand, we are always secured to it without redundancy. If you can’t judge when a stand is sufficiently safe, you should learn that first!
  • Rear securing? … is in principle always a safety plus. Whether belayed by a running knot (see p. 62/ 63) or, in a special case, by a traction belay, will be discussed in the next article in Panorama 5/20, which will deal with the organization of the rappelling process.
  • Rope ends? Both rope ends must reach the ground or the next belay. A (bag stitch) knot at the end of each rope strand is useful if it is not 100% certain that both rope strands are long enough. However, since knots sometimes have safety-related disadvantages (for example, they can get caught on the side of the wall in a lot of wind), you have to weigh things up here depending on the situation.
  • Rope connection knot for rappelling with two ropes? Always with the bag stitch in place! If this is properly tightened (to do this, pull each strand individually properly against the knot), it can not “roll”. Leave at least 30 cm of rope protruding!
  • Rappelling or lowering? It is often better to lower the first person down from the belay. The rope can then not get caught anywhere; rockfall is minimized; a lateral belaystation can be more easily pendulumed or climbed from above. For dismantling a sport climbing route, “lowering” is the first means of choice – but not possible if the rope is threaded through a textile deflection (melting through due to frictional heat)!
  • Braking stage? The combination of rope, descender, weight and hand force must fit! With low-friction combinations (such as thin ropes), a second carabiner in the descender often helps to increase the braking effect (= “double carabiner method”). If there is a lot of rope friction, on the other hand, you can turn the tube around so that the additional effect of the braking grooves is absent.
  • Wetness/icing? At the latest here rappelling becomes really demanding! This is because the friction in the abseiling device, in the hand and in the rear belay becomes worse. Self-securing sling? A 120 mm webbing sling (not made of polyethylene, because it is susceptible to aging) is knotted once 10 to 30 cm from the harness, depending on the rappelling method, and the locking carabiner is fixed with a mast throw.
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