Knots

Right from the start it is necessary to mention one important point in order that the use of knots in mountaineering may be correctly understood. The fixing of a knot to a rope reduces the strength of the rope almost in half. Tying knots therefore leads to the degradation of the features of the rope or webbing. For this reason it is necessary to tie knots to a rope judiciously, only in situations when it is critical and brings us some indisputable advantage. The reduction in the strength of the rope is caused by several factors. Above all, in a knot mechanical and thermal (friction) stress occurs as a result of forceful bending around small diameters, which leads to compressing the fibres of the strands of rope on the inside of the bend and stretching the fibres outside the bend. The application of both pulling and pushing tension occurs, caused by the lateral compression of adjacent strands of the rope in the knot. And last but not least, the mutual shifting of the individual structural elements of the rope also contributes to the reduction of strength, from the level of the fibres all the way to the molecular level.

There have been a series of experiments on the load-bearing properties of knots and their comparison, but unfortunately their authors always used different methodologies and therefore their results in certain findings differ, and there is not much point in examining them in great detail. On one point, however, they agree – the stronger variant of knot is the one where the load-bearing strand of the rope runs out the top of the knot, that is, as close as possible to the eye formed (in other words, for the strand of rope which we will load immediately after entering the knot to form a curve with the largest possible bend radius inside of it). Also, the more a rope is wound in turns inside a knot, the stronger the knot. For example, a simple angler’s knot with one loop can bear less than, for example, a triple angler’s knot, where there are three loops. Or a figure eight knot, where the rope is crossed over more times in the eye and bent in curves with larger radius, carries more than, for example, an overhand knot.

The load-bearing strength of a knot is further influenced by how the knot is loaded, whether normally or anomalously (for an explanation of these terms, see the Terminology section below). The list in the table indicates the different strengths of knots under various loads.

loop normal anomalous
Figure eight 1020 daN 675 daN
Overhand 930 daN 825 daN
Double f. eight 990 daN 750 daN
Butterfly 950 daN 1100 daN
Figure nine 1300 daN 975 daN

Knotting terminology

The various phases of a knot have their own respective names:

Phases of knotting – from left: bight – loop – eye.

Phases of knotting – from left: bight – loop – eye.

Other frequent concepts associated with the nomenclature surrounding knots are as follows:

Knot tied on the end – tying a knot at the end of a rope in such a manner that we lead one end of the rope forward, like a head, whose trajectory (path) is then followed by the other parts of the rope. After tying this knot only one usable strand of the rope is left, the second is only a short tail piece of rope.

Knot tied in the bight – tying the knot somewhere arbitrarily in the middle part of the rope. The apex of the bend in the rope now becomes the imaginary head, and two strands follow its trajectory. After tying this knot, two relatively long strands lead from the knot.

Hitches, loops – knots formed by an eye which can firmly enwrap an object when pulling on the rope leading out of the knot. These knots exist in cinching forms as hitch knots (e.g. the clove hitch) or in non-cinching forms as loop knots (figure eight on a bight, bowline,…).

Double-triple – … knot – multiple winding of loops around the strands of rope, or a knot forming multiple eyes (two-three-or more).

Standing part – the part of the rope that passes through the knot or emerges from the knot and continues on as the rope. Also called the “fixed end of the rope” or “usable end of the rope”.

Working part – the part of the rope emerging from the knot, and returning back into it. It actually forms the knot.

Tail of the rope – one of the strands of the rope emerging from the knot. It is also possible to encounter the term “loose end of the rope”. In a practical sense it only comes about through the process of knotting, and is actually that head that defined the trajectory of the rope during knotting. Here in the text this end of the rope will be somewhat informally, but aptly and sweetly, referred to as the tail end.

Anomalous loading – possible only with a knot tied in the bight of the rope, with two long strands of the rope leading out. Pulling force is applied along these two strands, i.e. the knot is “pulled apart”.

Peripheral loading – possible only with a knot tied on the end of the rope. Does not result in pulling on the strand or strands of the rope emerging from the knot. Pulling is applied only to two or more opposite points on the working end. At the same time knot itself is loaded more or less “anomalously” from inside the knot.

Knots can be divided into various groups according to various criteria. A somewhat simple and for mountaineering perhaps optimal classification is into anchoring knots, bends, prusik hitches and handling knots.

Anchoring knots are used for fastening rope. In mountaineering most often to points of protection (e.g. piton, nut, and others equipped with carabiner), or to a harness on the body of the climber when tying in to the rope.

Bends are most often used in mountaineering for joining two ropes together, and for joining the ends of a short piece of rope or webbing, called a sling.

Prusik hitches are used in mountaineering mostly for shinnying along a rope, for fixing (securing) a rope, either when self-belaying or rappelling, or during various rescue processes, such as pulling an incapacitated climber to a belay station, pulling one out of a glacial crack, lowering to an injured party, etc.

Handling knots are somewhat of a special group, serving mostly for handling the rope or influencing rope movement during various operations with it. We can include various stopper knots, shortening knots, so-called slip knots, etc. in this group.

Anchoring knots

Figure eight (a.k.a. Figure of Eight on the Bight, Middleman’s Knot, F. Noeud en huit) – use – for rope: YES; for webbing: YES

Figure eight

Figure eight

The basis for creating this knot is a figure eight formation. The options for use of this knot are varied:

1. Most often used for tying in to rope, it is considered the primary tying knot.

The knot does not show a tendency to slip, and upon strong tension it can be untied relatively easily (it is necessary to take this information with a grain of salt; if the knot is pulled after a heavy fall, for example, untying it will be understandably more difficult).

2. Of course it is possible to use a knot tied with a figure eight for anchoring any rope to a point of protection. For example, using a figure eight bend to anchor to the end of a fixed rope.

3. This knot can also be made on a short piece of rope for the purpose of creating a knot as a piece of protection. The knot can then be inserted to a rock crack which narrows such that the knot placed in it holds when pulled. An overhand knot is often used for this purpose (see text below), but it can happen that the volume of the eye is sometimes small in relation to the size of the rock crack, and therefore the figure eight knot can be used, which is somewhat larger than the overhand knot in terms of volume.

4. The knot can be relatively easily tied with one hand at the end of a rope hanging down to a person from above. This works well for tying two end pieces of rope or webbing which have been threaded through a rock tunnel. This way a climber can tie in to a rock tunnel with only one hand:

Video: Tying the ends of a runner pulled through a rock tunnel with the help of a figure eight knot. Accomplished with one hand.

  • Don’t grip the knot with your hand right at the ends. The tail ends of the knot under the hand must be at least 30 cm long;
  • When first gripping the ends of the knot, always have the thumb of the hand on top (!) along with the other fingers;
  • Don’t let the knot tighten around the wrist too much, or you won’t be able to withdraw the palm of your hand.

The figure eight loop is ranked among the very safe knots, usually sport climbers use it to tie in to a seat harness. It is necessary to run the strands of rope neatly next to one another, and after completing the knot, to cinch it tight. This knot can be easily visually checked thanks to its regular shape, which means that it is appropriate for beginners. Of course, even despite its safety, it is recommended when tying rope to the harness to make a backup knot on the tail end.

In-line figure eight

In-line figure eight

If you want to tie a figure eight in the bight, and we presume it will be anomalously loaded (i.e. both strands of the rope exiting the knot), it is better to tie a somewhat modified version of the figure eight knot, the so-called “in-line figure eight”. A figure eight knot tied in this manner has better load-bearing parameters under anomalous loading. Of course, the knot (eye) formed should be loaded only in one optimal direction – on the image indicated that would be downward. In the opposite, suboptimal direction of loading the knot slips and capsizes in various ways. So for situations when we can’t guarantee which end of the rope will be up and which will be down during anomalous loading, it is better not to use this knot and to rely instead on the butterfly knot (discussed further on in the text).

Double Figure eight (a.k.a. Rabbit Knot, F. Noeud huite double, Noeud en orelles de lapin) – use – for rope: YES; for webbing: POOR

Double figure eight

Double figure eight

With a double figure eight knot we create two knots on the rope, where one can be enlarged after pulling the strand of rope through to the detriment of the other. It’s practical use is in the option of creating a so-called “floating anchor”. This anchor ensures equal distribution of loading forces on all points of protection (in the picture these are three bolts, and thereby five carabiners are needed for this, most appropriate for this purpose would be oval or “O” carabiners with locking sleeves). Such a “floating anchor” is good for anchoring a fixed rope in rugged terrain, for example, where it is necessary to reduce the loading of each individual point of protection. It is necessary, however, to mention that the creation of a “floating anchor” takes up a significant part of the rope, so the length of the fixed rope would be shortened by a matching amount.

Double rewoven figure eight – use – for rope: YES for webbing: NOT APPLICABLE

A very good formation for creating double knots, appropriate for tying rope in a combination harness (sit and chest harness at the same time). This knot does not have a tendency to slip, and after heavy loading it can be relatively easily untied. The knot seems somewhat large, as the rope is actually threaded through the knot three times, but its shape is rather flat, and therefore it does not get in the way too much when climbing (it is necessary to take this statement with a grain of salt, anyone who is used to a smaller knot will be “blown away” by their first encounter with this knot, but it is a question of getting used to it). As with the majority of figure eight variations this one can also be easily visually checked, and is therefore appropriate for beginners. There’s no harm in leaving the tail a bit longer in order to tie a stopper knot, but it is not expressly necessary. It is almost unthinkable that the figure eight bend would untie itself. The tying of his knot will take up a relatively large amount of rope. For an adult approx. 2 m of rope is needed for tying in; the amount of rope necessary for use in the terrain will therefore be shortened by this length. (For example, from 50 m of rope, if both the leader and the second tie in with this knot, approx. 46 m will remain for the climb.) More about this knot in the section of the book Tying In.

Overhand knot (a.k.a., Middleman’s Knot, Thumb Knot, F. noeud de vache) – use – for rope: YES; for webbing: YES

Overhand loop

Overhand loop

The overhand knot is the simplest formation for creating a knot. As with the figure eight knot (of which it is sort of a “little brother”) the overhand knot has a wide range of uses:

1. For anchoring rope to a point of protection. For example, for anchoring the end of a fixed rope.

2. Tied on the end of the rope. It does not display a tendency to untie itself, which however need not be the case for thick rope with poor knottability. If you suspect that knots are difficult to pull tight on your rope, tie the tail end with a backup knot which ties off the working end of the rope. However, a known problem of the overhand loop is its tendency to jam under heavy strain when catching a fall. It can be problematic to untie; especially in outdoor terrain, for example in winter when your hands are numb, untying can be practically impossible.

3. Tied on the bight. It is often used for this purpose, even if it is not always optimal for tying on the bight (see for example the butterfly knot referenced in the text). Situations in which an overhand loop is tied on the bight include: a) a braking knot on the rope during progress along a glacier; b) tying on the bight for multiple seconds a single rope.

4. Creating a sling with a knot for placement into a rock crack (as a point of protection). The knot is placed into a rock crack which narrows, where the inserted knot holds fast while the loop of the sling sticks out, allowing a carabiner to be clipped as intermediate protection. It is often used on sandstone rocks. More on the creation of this point of protection in Part 2, Belaying and Rappelling in the Knotting section of the book.

Double rewoven overhand loop – rope: YES; webbing: NOT APPLICABLE

Used for tying a combined harness (seat harness + chest harness used in conjunction). However, the knot created is too “spherically” large, and can get in the way a bit when climbing, particularly in tight chimneys, or when crawling over an overhang on your belly. In other words, everywhere where we are pressing our chest against the rock. It is better therefore to use the double rewoven figure eight (see above in the text). If for a simple overhand knot a disadvantage is its significant jamming under load (it can’t be untied afterward), then this does not apply for the double overhand loop, the strands of rope are in the knot in a multiple composition in the knot, and this knot therefore is not as difficult to untie and can be untied easily and comfortably. More on this knot in the Tying In section of the book.

Figure nine knot (a.k.a. F. Noeud en neuf) – use – for rope: YES; for webbing: NOT APPLICABLE

Figure nine knot

Figure nine knot

The figure nine knot has a high breaking strength, or more accurately said, a figure nine knot does not reduce the breaking strength of the rope too much. This destines the figure nine loop for use wherever significant loading occurs, or where we are forced to use a somewhat weaker rope (whether because it is thin or disrupted in some way, e.g. wet polyamide rope, worn rope, etc.).

The figure nine knot is a bit complicated, be careful not to make a mistake when tying it. After tying it is necessary to align the strands of the properly knot. At the same time it is necessary to count on using a larger part of the rope to tie it than we need, for example, with figure eight or overhand knots. The size of the knot is also larger. These small complications have kept the figure nine knot from achieving much popularity, and few therefore use it.

Most frequent uses of the figure nine knot:

1. For tying in to the rope – attaching a rope to a harness, where the knot is tied by threading the end of the rope through it. If you suspect that knots are difficult to pull tight on your rope, tie a backup knot into the tail end which closes off the fixed strand of the rope.

2. For any anchoring of the rope to a protection point, e.g. anchoring a fixed rope in the terrain.

Bowline (a.k.a. F. Noeud de chaise) – use – for rope: YES; for webbing: NOT APPLICABLE

Bowline

Bowline

A conflicted knot that has its pros and cons. Used for tying in to a rope, it can be used for anchoring the rope to a protection point. But it isn’t particularly the safest knot. Why? The bowline does not hold under peripheral loading (simply put – when pulling the eye of the knot apart). The bowline therefore is not at all suitable for joining two lines of rope into a loop. Many fatal injuries testify to this!

Aside from this, the bowline is inclined to untie itself, particularly on thick rope with poor knottability. All of these dangers with untying can be dealt with by tying a backup knot on the tail end of the rope.

The principle applies that if we use the bowline then we must always do so with a backup knot. This can be done either on the inside or the outside of the knot. Outer knots are done most often as a simple overhand; a better and safer variant, however, is to do it as a double fisherman’s knot. The inner backup knot is tied in such a manner that its tail end leads back into the knot.

Bowline knot tied with ono hand.

Bowline knot tied with ono hand.

The bowline is easily tied with one hand around the waist. This can be used for emergency tying of the rope to the body in any precarious situation where we have to hold the rock with one hand, and only one hand remains for tying in.

Video: You can tie in this way in an emergency, when you are holding the rock with one hand and only one hand remains for tying in.

When loading the strands of rope exiting the knot, the bowline holds. Even after heavy loading it can be untied easily. That is perhaps the only significant benefit of this knot.

Clove Hitch (a.k.a. F. Noeud de cabestan) – use – for rope: YES; for webbing: YES

Clove hitch

Clove hitch

A knot which constricts under load. It is used for anchoring rope. It can be tied on the end of the rope, but also on the bight. It is tying on the bight which is done more frequently. Its benefit is that the strands of rope can be shifted in the knot without us having to completely untie the knot; all we have to do is barely loosen it and we can operationally change the length of the strands emerging from it. At the same time this knot can be secured in the carabiner.

This knot is cinched and holds when loading only one strand of rope emerging from the knot. It does, however, have several problems: 1. If one of the strands is short; be careful, the short end can very easily slide out of the hitch, and thereby poses a risk of the complete unwinding of the hitch. For this reason the clove hitch is not recommended for tying on the end of the line in any way that leaves a short tail. 2. On the other hand, tying this knot on the bight, where both strands leading from it are longer, is acceptably functional. It is necessary, however, to tie it with care! Rope strands threaded chaotically across each other in the knot can cause sliding of the rope in the knot when pulling on only one strand. 3. On thin carabiners especially the clove hitch can sometimes unpredictably slip when pulling on one of the strands. For this reason, during activities using the clove hitch on a carabiner where we are expecting to pull on only one of the strands, and the second strand at the same time is completely relieved even of its own weight, we should avoid the use of the clove hitch and not use it. There is a risk that the unloaded strand will slip through the knot.

Of course, when pulling on both strands of rope the clove hitch on carabiners holds very well. At the same time the force of the pull on both strands need not in any way be equal. Thanks to friction within the knot it is enough for the second strand of rope to be only imperceptibly pulled and slipping will not result.

The most frequent use of the clove hitch is when self-belaying at a belay station. It is also used when removing the position of the top belayer who is belaying a second from above from the protection point of the belay station (for example in the following situation: the belay ring is on the very summit of a tower, but the belayer needs to be on the edge of the face to jerk the rope). In this case the belayer self-belays using the first strand leading from the clove hitch and connects the second strand to a belay device using an overhand knot. The pull will then act on both strands and the slipping of the clove hitch is thereby inhibited.

Butterfly Knot (a.k.a. F. Noeud papillon) – use – for rope: YES; for webbing: POOR

Butterfly knot

Butterfly knot

The butterfly knot is tied on the bight. It is used for anchoring rope when we expect loading both on the eye of the knot as well as anomalous loading (i.e. on both strands of rope emerging from the knot), and we cannot predict where the strain will come from. It is only tied on the bight. This prioritises this knot for multiple anchoring of a fixed rope to points of protection (creating a makeshift rope railing). For similar purposes the common overhand loop is used, but compared to this knot the butterfly has better parameters. On the one hand a smaller loss of load-bearing strength of the rope in the knot, and thereby less strain on the rope itself. The knot is a bit of a pain to tie, and therefore the knot is always a mess after tying and the strands are not neatly threaded. After tying it is always necessary to smooth out the knot. After loading the knot can be released quite well.

More in e-book.

Title Part 1Mountaineering Methodology – Part 1 – Basics

ISBN 978-80-87715-07-9

MMPublishing, 2013

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Title Part 1 GPMountaineering Methodology – Part 1 – Basics

ISBN 978-80-87715-12-3

MMPublishing, 2014

Available for download from Google Play.