UKC

Everything you wanted to know about abseiling but didn't dare ask

Bob Wightman

This has been read 109,949 times
Abseiling from the In Pinn, 67 kb
Abseiling from the In Pinn
© jez s, Jun 2005

Abseiling Tips

How do I pronounce “Abseil”?

Abseil is a word of German origin and rhymes with style not sail.

Why do American climbers call it “Rappelling”?

They chose the French term for sliding down a rope whereas we chose the German. Nothing more to it than that.

Why do climbers not like abseiling? It's great!

photo
Abseiling the Bergshrund, Mt Blanc du Tacul
Abseiling is one of those activities that appears to be enjoyed by those who do not know of its risks. Consequently, most non-climbers like it whereas most climbers do not. The reason for this is probably because most non-climbers have never done an abseil under anything but tightly controlled conditions. One abseil under normal conditions would convince them otherwise!

So why do most climbers have a dislike for abseiling? Basically it is down to two things:

  • single system with no backup.
  • Easy to get wrong.

However with a little thought many of the risks may be reduced, though not entirely removed.

What is the best rope to use for abseiling?

If you are just going to be abseiling less than half a rope length then any rope will do as you simply take the middle of the rope and attach to the belay point then lower or drop the two ends.

If the abseil is longer (up to a rope length) then you will need two ropes. The only restriction here is that both ropes should be the same diameter. Using an 11mm rope with an 8.5mm rope will lead to problems as the two ropes will interact with the abseil device differently with the thicker rope having more friction and passing through the device more slowly. A slight difference in diameter (9mm & 8.5mm) is nothing to worry about.

What Knot should I use to tie the ropes with?

There is much discussion as to which knot is best to use to join the two ropes together and over the years thoughts have changed.

The table below summarises the various knots that are in common use for tying two ropes together for abseiling. One point to note is that for all the knots, the “tails” should be at least 30cm in length to allow for slippage and tightening of the knot.

KnotDifficultyNotes
Double FishermansEasy to get wrong. This is the knot by which to judge all others. If tied correctly, it is the strongest knot available for this purpose. If your ropes are of different diameters then it is the only knot to consider. It does have some major drawbacks though: it is very difficult to undo after being loaded; it is also symmetrical meaning that it is likely to snag easily.
Figure of Eight Not as easy as is imagined. To tie the figure of eight correctly requires that both ropes travel a particular path through the knot. This is very difficult to ensure in a stressful situation. In addition to this, the knot has an alarming tendency to roll along the rope when stressed at right angles to its main axis.
Not recommended
Overhand Fairly easy. At first the overhand knot looks as if it would be weaker than the figure of eight but in fact it is both stronger and more resilient to pulls across its axis
Reef Simple and easy The reef knot (square knot) is very simple to tie but, like the double fishermans, is a symmetrical knot so suffers from the same problems of being prone to catch. It is a very poor knot to use for ropes of different diameters. Perhaps its best use is in the centre of a double fishermans knot, using the latter as a safety backup.

Come on! Which is best?

It depends on the situation. But current thinking/best practice indicates one of the following.

The double fishermans. Or, a reef knot backed up by double fishermans.
When: Your ropes are of different diameters; You absolutely have to be sure.
Overhand knot
When: the face down which you are abseiling is featured and you do not want to chance getting the rope stuck. Most abseils.

See this article at Needlesports for more info on knots for abseiling.

What makes a good anchor for abseils?

Basically any anchor that is good enough to belay from. Unless you are abseiling from a permament abseil station it is likely that you will have to sacrifice some of your own equipment to make the anchor. Usually this is no more than a couple of wires or a length of sling or cord to replace existing loops (where the condition of the existing loops may have been affected by the elements or excessive use).

What's the best style to abseil? Commando?

Certainly not! Commando style is all well and good when you have solid anchors and an easily impressed audience. Out in the hills it is a different matter and you should aim to stress the system - particularly the anchor as little as possible.

Most stress on the anchor occurs in the first few metres of the abseil so it is at this point that you should be as smooth as possible, creeping over the edge whilst making sure that the ropes do not run over any sharp edges and that they have not snagged beneath you. Keep your feet apart for stability and walk down the rock as smoothly as you can.

There's a sharp edge! How do I protect the ropes?

photo
Rope Protector
The best way is to use something like an empty rucksack to pad the edge. A piece of karrimat would work just as well or purchase one of the many commercially made rope protectors (see photo) Attach to the rope that you are going to pull when retrieving the ropes with a prussic. This avoids it working over the edge. The second person can adjust its position whilst the first is abseiling.


I'm nearly out of control! How do I slow things down?

photo
How to clip a krab to increase friction
In order to increase the friction all that is required is a second karabiner, preferably a screw-gate. With the rope(s) threaded through the device and the main karabiner take this second krab and clip it into both the bight of rope and the harness attachment point, thereby doubling up the main krab. This has the effect of forcing the rope through tighter curves as it passes through the system which increases the friction. Note that the gate of the second karabiner is facing the opposite way to the main krab even though they are both screwgates.


I can hardly move! How can I decrease the friction in the system?

photo
How to clip a krab to decrease friction
To decrease friction, again take a second karabiner but this time clip it into only the bight of rope passing through the device. It must be positioned so that it lies between the back of the device and the main krab. This has the effect of allowing the rope to pass through less severe curves as it passes through the system.


How can I prevent dropping the figure of eight when attaching the rope?

There is a simple way to do this. Keep the Figure of Eight device clipped via the large hole. When you come to use it, pull a bight of rope through the large hole as you normally would and pass it round the back of the smaller hole, again as normal. The device is now trapped by the weight of the rope so you can unclip from the larger hole and into the small hole ready for use.

To remove, simply reverse the above procedure.


photo
Have the figure of 8 clipped via the large hole.
photo
Take a bight of rope and without unclipping the Figure of Eight pull it through the large hole.

photo
Now pass it round the stem of the device.
photo
Take the device out of the krab and turn it round so that you can clip into the small hole.

How do I stop from sliding off the end of the rope?

Tie a knot in the end of each rope to prevent you from sliding off the end. You need one on each rope as just doing it on one rope could cause the system to pull through the belay. This also helps find the end of the rope in those instances when they get caught after being thrown down, either because of wind or because the rock is heavily featured. In order to help remember which rope needs to be pulled at the next stance (or ground) - clip a krab into the end knot of that rope.

How do I remember which rope to pull?

Clip a quickdraw between your harness and onto the rope in question. This also has the benefit of keeping the ropes separated when you come to pull them.

What about an emergency backup?

Given that in most situations you are totally reliant on the anchor and the ropes and that there is little you can do to back these up, the only other weakness in the system is yourself.

If there is a chance of debris falling on you then it is beneficial to use a French Prussik or Klemheist knot around both ropes. Whether this knot is above or below the abseil device is down to personal preference - I have seen valid arguments for both - my personal preference is to have the knot above the device.

How do I make a full length abseil on a single rope?

There are rare occasions when you need to abseil a full rope length but only have one good rope available. For example: The other rope has been damaged in some way and you do not want to trust it. Another scenario is if you are climbing lightweight on a single 9mm rope and have brought along something like a length of 6mm cord for emergencies. So how do you make a full 50m abseil?

  • Start by passing the good rope through the belay then joining the ropes with either a double fisherman's knot or a reef knot backed up by a double fisherman's.
  • Tie a figure of eight on the bight or an alpine butterfly knot into the good rope next to the double fishermans, and clip a screwgate krab into it.
  • Clip the krab back onto the good rope.
  • Now abseil on the good rope, the krab effectively ties the rope to the belay when tensioned from this side.
  • At the end of the abseil, pull on the unused rope. The ropes will pull as normal.
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