Anchor (climbing)

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In rock climbing, an anchor can be any device or method for attaching a climber, a rope, or a load above or onto a climbing surfacetypically rock, ice, steep dirt, or a buildingeither permanently or temporarily. The intention of an anchor is case-specific but is usually for fall protection, primarily fall arrest and fall restraint. Climbing anchors are also used for hoisting, holding static loads, or redirecting (also called deviating) a rope. [1]

Contents

Types of anchors

Natural protection - a basket hitch made from a sling, attached to a handle. Sanduhr 7062 a.jpg
Natural protection - a basket hitch made from a sling, attached to a handle.
An artificial climbing anchor consisting of a hex and two cams, equalized with slings. Climing anchor.JPG
An artificial climbing anchor consisting of a hex and two cams, equalized with slings.
A snow picket. Pickett02.jpg
A snow picket.

Depending on the surface being climbed, there are many types of protection that can be used to construct an anchor, including natural protection such as boulders and trees, or artificial protection such as cams, nuts, bolts or pitons.

Natural anchor

A natural anchor is a secure natural feature which can serve as a climbing anchor by attaching a sling, lanyard, or cordelette and a carabiner. Examples of natural anchors include trees, boulders, lodged chockstones, horns, icicles, and protrusions.

Artificial anchor

An artificial anchor consists of man-made climbing gear placed in the rock. Such gear includes spring-loaded camming devices, aluminum nuts used like chockstones, steel expansion bolts, and pitons. Artificial anchors may be permanent or removable.

Belay anchor

A belay anchor is used as a sole attachment to the cliff face, to support a belay or top rope. Ideally, it should consist of multiple redundant components (natural and/or artificial), none of which are likely to fail, and none of which in the event of failure would cause the entire anchor to fail. Any one component of a good anchor should be able to support the entire system by itself.

Running belay anchor

A running belay anchor is used as a safeguard in the event of a fall while lead climbing. The leader and follower climb simultaneously with protection placed in between. When the two climbers advance using a running belay, the belay is almost as secure as using a belay device and anchors because if the leader falls, all the slack is already out of the rope and the follower acts as a counterweight to catch the fall. A running belay is used as a faster alternative to pitch climbing when the risk, consequences, and likelihood of a leader fall are deemed to be acceptable.

Ice anchors

The snow picket is used as an anchor in mountaineering. It is driven into the snow and used to arrest falls. Snow pickets can also be placed horizontally in snow as a deadman, which provides a secure anchor to abseil on. Ice screws can be hand-driven into solid ice and are the equivalent of cams or nuts when ice climbing. Ice can also be protected using an Abalakov thread or v-thread. Because of the uncertain holding power of ice protection, it is sometimes attached to the rope using a load-absorbing sling or quickdraw, designed to reduce the load on protection by extending in case of a fall.

Attachment to the anchor

Indirect

When the rope goes from the climber to the belayer. Most often used under controlled circumstances at climbing walls or when the climber doesn't have the weight advantage on the belayer during bottom roped climbs. It is impossible to escape from the system.

Semi-direct

When the rope comes from the climber to the belayer, but the belayer is attached separately to an anchor. Often used when multi pitching and the belayer is on a stance. Or when top roping and it is possible that if the climber falls the belayer will be pulled from the stance above the climber. The belayer can, with a little effort then remove themselves from the system if required. It is essential that the belayer is attached to the anchor via the belay loop at the front of the harness. Attaching the belayers harness to the anchor via the back of the harness can cause the harness, when placed under strain, to constrict inwards elongating front to back, rather than side to side. This can result in crushed pelvis and serious harm to the belayer.

Direct

When the rope comes from the climber to an anchor. A hanging belay device may be used, although it is common in this instance to just use an Italian hitch. The belayer is totally free of the system.

Considerations

Force multipliers

The force on an anchor may be much greater than the weight of the climber. There are various mechanisms which contribute to excess force, including

Load-sharing anchor

A load-sharing (or load-distributing) anchor is a system consisting of two or more individual anchors which join together at a main anchor point to form an anchoring system. This configuration is a way to introduce redundancy and increase strength, typically for a belay anchor. If assembled correctly, the load will be distributed to each individual anchor, rather than placing all the load on a single anchor point. This decreases the chance that any single anchor point will fail, and, if a point does fail, the other(s) should still be able to hold.

Best practices

To ensure proper redundancy and effectiveness of a load-sharing anchor, some best practices are commonly observed. [2]

Redundancy

Selecting independent locations for the individual anchors is considered a best practice in climbing. This may mean using distinct boulders, crack systems, or objects for the placement location of each individual anchor. Load-sharing anchors are constructed such that the overall system will still be sufficiently strong if an individual anchor were to fail.

Equalization

In a load-sharing anchor, each individual anchor is connected to a main anchor point. The load-sharing anchor is said to be equalized if the load force is distributed equally to each individual anchor. This is accomplished by adjusting the length of each connecting member (between the main anchor point and an individual anchor) while pulling the main anchor in the anticipated direction of the load. Anchors can be either pre-equalized, in which the anchor is statically equalized between anchor points during rigging, or self-equalizing, in which the anchor system dynamically adjusts tension between anchor points during use.

Non-extension

A load-sharing anchor which does not extend in the event of an individual anchor failure has the property of non-extension. This important feature reduces the potential for shock-loading the remaining individual anchors during a failure. Non-extension can be accomplished by tying an appropriate knot in the interconnecting cordelette, or by using individual slings for the equalization. The principle of non-extension refers to the mitigation of shock-loading, rather than the elongation of materials under an increased load.

The principle of minimum swing is related to non-extension. The main anchor point in a well constructed load-sharing anchor will neither extend nor swing in the event of an individual anchor failure. Reducing swing can be accomplished by minimizing the inner angle between individual anchors, and by increasing the number of individual anchors. An additional technique is to place a directional anchor a short distance below the main anchor point.

Inner angle

Equalization of a load-sharing anchor, showing force distribution with a V-angle of 90deg Load Sharing Anchors.svg
Equalization of a load-sharing anchor, showing force distribution with a V-angle of 90°

When constructing a load-sharing anchor, it is important to take into consideration the angle formed between each individual anchor – the V-angle. Climbers typically try to minimize this angle, because a greater V-angle will produce more force at each individual anchor.

If the V-angle is greater than 120 degrees, the load on each individual anchor will be greater than the load on the rope. Angles in excess of 120 degrees can create a hazardous situation which compromises the safety of the anchor, and should generally be avoided.

The sum of forces on all the individual anchors will commonly exceed 100%, and in some cases, the force on an individual anchor will be greater than the load. This may seem contradictory when only the magnitudes are summed. However, if the forces on the individual anchors are added as vectors, the resultant force on the anchor system is equal to the load. In simpler terms, the forces in the vertical direction are equal to the load force, but there are lateral forces as well – which increase as the V-angle increases.

The force on each individual anchor is given by:

.

where,

This equation is a special case representation of the more general anchor force equation, [3] in which the load-sharing anchor is constructed from two symmetrically placed anchors.

From this expression, the anchor forces can be calculated for selected angles in a two-element, symmetrical, load-sharing anchor.

In trad climbing belay stations, load-sharing anchor are often constructed from more than two individual anchors, which are rarely co-planar. In these cases, each individual anchor would feel a reduced force from the above values, but best practice is to reduce the angle between the two outermost elements, and avoid angles in excess of 120 degrees.

Related Research Articles

Climbing Activity to ascend a steep object

Climbing is the activity of using one's hands, feet, or any other part of the body to ascend a steep topographical object. It is done for locomotion, recreation and competition, and within trades that rely on ascension; such as emergency rescue and military operations. It is done indoors and out, on natural and man-made structures.

Climbing protection is any of a variety of devices employed to reduce risk and protect others while climbing rock and ice. It includes such items as nylon webbing and metal nuts, cams, bolts, and pitons.

Traditional climbing Style of rock climbing

Traditionalclimbing, is a style of rock climbing in which a climber or group of climbers place all gear required to protect against falls, and remove it when a pitch is complete. Traditional bolted face climbing means the bolts were placed on lead and/or with hand drills. The bolts tend to be much farther apart than sport climbs. For example, a trad bolted route may have bolts from 15–75 feet apart. A sport route may have bolts from 3–10 feet apart, similar to a rock climbing gym. The term seems to have been coined by Tom Higgins in the piece "Tricksters and Traditionalists" in 1984. A trad climber is called a traditionalist.

Tree climbing

Tree climbing is a recreational or functional activity consisting of ascending and moving around in the crown of trees.

Glossary of climbing terms List of definitions of terms and concepts related to rock climbing and mountaineering

This glossary of climbing terms is a list of definitions of terms and jargon related to rock climbing and mountaineering. The specific terms used can vary considerably between different English-speaking countries; many of the phrases described here are particular to the United States and the United Kingdom.

Ice climbing Activity of ascending ice formations

Ice climbing is the activity of ascending inclined ice formations. Usually, ice climbing refers to roped and protected climbing of features such as icefalls, frozen waterfalls, and cliffs and rock slabs covered with ice refrozen from flows of water.

Rock-climbing equipment

A wide range of equipment is used during rock or any other type of climbing that includes equipment commonly used to protect a climber against the consequences of a fall.

Abseiling Rope-controlled descent of a vertical surface

Abseiling, also known as rappelling, is a controlled descent off a vertical drop, such as a rock face, by descending a fixed rope.

Free climbing Form of climbing not using aid climbing

Free climbing is a form of rock climbing in which the climber may use climbing equipment such as ropes and other means of climbing protection, but only to protect against injury during falls and not to assist progress. The climber makes progress by using physical ability to move over the rock via handholds and footholds. Free climbing more specifically may include traditional climbing, sport climbing, bouldering and most forms of solo climbing. Free climbing a multi-pitch route means free-climbing each of its pitches in a single session. At the end of each pitch, climbers anchor themselves to belay stations where they can rest.

Aid climbing Style of climbing

Aid climbing is a style of climbing in which standing on or pulling oneself up via devices attached to fixed or placed protection is used to make upward progress.

Sport climbing Form of rock climbing

Sport climbing is a form of rock climbing that may rely on permanent anchors fixed to the rock for protection, in which a rope that is attached to the climber is clipped into the anchors to arrest a fall, or that involves climbing short distances with a crash pad underneath as protection. This is in contrast to traditional climbing where climbers must place removable protection as they climb. Sport climbing usually involves lead climbing and toproping techniques, but free solo and deep-water solo climbing on sport routes is also sometimes possible.

Self-locking devices are devices intended to arrest the fall of solo climbers who climb without partners. This device is used for back rope solo climbing for "ground-up climbing" or "top rope self belaying". To date, several types of such self-locking devices have evolved.

Belaying Rock climbing safety technique using ropes

Belaying is a variety of techniques climbers use to create friction within a climbing system, particularly on a climbing rope, so that a falling climber does not fall very far. A climbing partner typically applies tension at the other end of the rope whenever the climber is not moving, and removes the tension from the rope whenever the climber needs more rope to continue climbing.

Lead climbing Competitive discipline of sport climbing

Lead climbing is a climbing style, predominantly used in rock climbing. In a roped party one climber has to take the lead while the other climbers follow. The lead climber wears a harness attached to a climbing rope, which in turn is connected to the other climbers below the lead climber. While ascending the route, the lead climber periodically connects the rope to protection equipment for safety in the event of a fall. This protection can consist of permanent bolts, to which the climber clips quickdraws, or removable protection such as nuts and cams. One of the climbers below the lead climber acts as a belayer. The belayer gives out rope while the lead climber ascends and also stops the rope when the lead climber falls or wants to rest.

Rock climbing Sport in which participants climb natural rock formations

Rock climbing is a sport in which participants climb up, down or across natural rock formations or artificial rock walls. The goal is to reach the summit of a formation or the endpoint of a usually pre-defined route without falling. Rock climbing is a physically and mentally demanding sport, one that often tests a climber's strength, endurance, agility and balance along with mental control. Knowledge of proper climbing techniques and the use of specialized climbing equipment is crucial for the safe completion of routes.

Ascender (climbing) Devices used for ascending, braking, or protection in climbing

An ascender is a device used for directly ascending a rope, or for facilitating protection with a fixed rope when climbing on very steep mountain terrain.

Dynamic rope Rope designed to stretch under load

A dynamic rope is a specially constructed, somewhat elastic rope used primarily in rock climbing, ice climbing, and mountaineering. This elasticity, or stretch, is the property that makes the rope dynamic—in contrast to a static rope that has only slight elongation under load. Greater elasticity allows a dynamic rope to more slowly absorb the energy of a sudden load, such from arresting a climber's fall, by reducing the peak force on the rope and thus the probability of the rope's catastrophic failure. A kernmantle rope is the most common type of dynamic rope now used. Since 1945, nylon has, because of its superior durability and strength, replaced all natural materials in climbing rope.

Belay device Mechanical piece of climbing equipment

A belay device is a mechanical piece of climbing equipment used to control a rope during belaying. It is designed to improve belay safety for the climber by allowing the belayer to manage their duties with minimal physical effort. With the right belay device, a small, weak climber can easily arrest the fall of a much heavier partner. Belay devices act as a friction brake, so that when a climber falls with any slack in the rope, the fall is brought to a stop.

The American Death Triangle, also known as the "American Triangle", "Triangle Anchor" or simply the "Death Triangle", is a dangerous type of rock and ice climbing anchor infamous for both magnifying load forces on fixed anchors and lack of redundancy in attachment to the anchor. This anchor is based on the "Stone Dog Hitch".

References

  1. Cox, Steven M.; Kris Fulsaas, eds. (2009). Mountaineering: The Freedom of the Hills (7 ed.). Seattle: The Mountaineers. ISBN   0-89886-828-9.
  2. "Basic Principles of Climbing Anchors". Climbing Techniques.org. Retrieved 25 March 2016.