Dynamic rope
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A dynamic rope is a specially constructed, somewhat
elastic Elastic is a word often used to describe or identify certain types of elastomer, elastic used in garments or stretchable fabrics. Elastic may also refer to: Alternative name * Rubber band, ring-shaped band of rubber used to hold objects togeth ...
rope A rope is a group of yarns, plies, fibres, or strands that are twisted or braided together into a larger and stronger form. Ropes have tensile strength and so can be used for dragging and lifting. Rope is thicker and stronger than similarly ...
used primarily in
rock climbing Rock climbing is a sport in which participants climb up, across, or down natural rock formations. 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 ...
, ice climbing, and
mountaineering Mountaineering or alpinism, is a set of outdoor activities that involves ascending tall mountains. Mountaineering-related activities include traditional outdoor climbing, skiing, and traversing via ferratas. Indoor climbing, sport climbing, a ...
. This elasticity, or stretch, is the property that makes the rope
dynamic Dynamics (from Greek δυναμικός ''dynamikos'' "powerful", from δύναμις ''dynamis'' "power") or dynamic may refer to: Physics and engineering * Dynamics (mechanics) ** Aerodynamics, the study of the motion of air ** Analytical dynam ...
—in contrast to a
static rope A static rope is a low-elongation rope that is designed to stretch minimally when placed under load, typically less than 5%. In contrast, a dynamic rope is designed to stretch up to 40%. Static ropes have a wide variety of uses, for instance in f ...
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 Kernmantle rope () is rope constructed with its interior core protected by a woven exterior sheath designed to optimize strength, durability, and flexibility. The core fibers provide the tensile strength of the rope, while the sheath protects the ...
is the most common type of dynamic rope now used. Since 1945,
nylon Nylon is a generic designation for a family of synthetic polymers composed of polyamides ( repeating units linked by amide links).The polyamides may be aliphatic or semi-aromatic. Nylon is a silk-like thermoplastic, generally made from petro ...
has, because of its superior durability and strength, replaced all natural materials in climbing rope.


Rope types

Dynamic climbing ropes are classified into three categories: Single ropes, twin ropes, and half ropes (also referred to as 'double ropes'). *Single ropes are designed to be used alone, and are by far the most common, and used for top-roping,
sport climbing Sport climbing (or Bolted climbing) is a form of rock climbing that relies on permanent anchors (or bolts), permanently fixed into the rock for climber protection, in which a rope that is attached to the climber is clipped into the anchors to ...
, and
trad climbing Traditional climbing (or Trad climbing) is a style of rock climbing in which the climber places all the necessary protection gear required to arrest any falls as they are climbing, and then removes it when the pitch is complete (often done b ...
. *Twin and half ropes are used for lead climbing, and are designed to be used as a pair - they are not strong enough to be safely used on just a single strand, and they are tested to different standards as a single rope. **Twin ropes are used by treating the pair of ropes as a single rope, clipping both ropes through the same carabiner at each piece of
protection Protection is any measure taken to guard a thing against damage caused by outside forces. Protection can be provided to physical objects, including organisms, to systems, and to intangible things like civil and political rights. Although th ...
. **Half ropes are also used as a pair, but only one rope is clipped through each piece of protection- the climber alternates which rope is clipped through each piece. On wandering routes where protection is placed far apart on either side, half ropes can significantly reduce rope drag. Both twin and half ropes have the advantage of redundancy, as well as allowing a rappel along the full length of the climbing rope (by tying both ropes together), so that climbers can descend from a long multipitch route with fewer rappels than with a single rope. Some ropes are 'triple rated', meeting the standards for all three rope types, so they can be used in each configuration.


Length and diameters

Dynamic ropes used for rock climbing come in a variety of lengths and diameters, with the most common lengths being , , . Lengths will vary depending on rope maintenance and age, and there are even ropes as long as 80 meters for specialized ascents on routes that would normally require a
multi-pitch climbing Multi-pitch climbing is the ascent of climbing routes with one or more stops at a belay station. Each section of a climb between stops at belay stations is called a pitch. The leader ascends the pitch, placing gear and stopping to anchor themselves ...
attempt due to being only slightly longer than a standard rope length. Rope diameters are generally between 8.3mm and 11.5mm, with the different diameters used for slightly different purposes. Sport and multi-pitch trad climbers often value thinner ropes because they are lighter, and have less rope drag. Thinner ropes also run more smoothly through
belay 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 t ...
devices, especially assisted braking devices or 'tube-style' devices operated in 'guide mode', which can be tedious to pull thicker or stiffer rope through. Lighter, thinner ropes, however, have less strength than a thicker rope and will sustain fewer hard falls. Note that some belay devices are better suited for different rope diameters. This is particularly relevant with assisted braking devices, such as the Petzl
Grigri A Grigri (styled as GriGri or GRIGRI) is an assisted braking belay device manufactured by Petzl designed to help secure rock-climbing, rappelling, and rope-acrobatic activities. Its main characteristic is a clutch that assists in braking u ...
(which, for example, works best with a 9.4-10.3 mm thick line) or the Faders SUM. Users must make sure to read the instructions for the device carefully to ensure safety and recognize any limitations to rope diameter.


Standards and testing

All modern rock climbing dynamic ropes rated by the
UIAA The International Climbing and Mountaineering Federation, commonly known by its French name Union Internationale des Associations d'Alpinisme (UIAA, lit. ''International Union of Alpine Clubs''), was founded in August 1932 in Chamonix, France ...
must meet certain standards and pass testing for Construction, Sheath Slippage, Static Elongation, Impact Force on first fall, and Number of falls held.Sterling Rope Guide to Rope Engineering, Design, and Us

The force rating indicates the maximum amount of force the rope can deliver to a falling climber, measured in
kilonewtons The newton (symbol: N) is the unit of force in the International System of Units (SI). It is defined as 1 kg⋅m/s, the force which gives a mass of 1 kilogram an acceleration of 1 metre per second per second. It is named after Isaac Newton in ...
(kN), under test conditions designed to simulate a hard fall; typical climbing ropes range from 9kN up to an Arborist's 24kN. The force rating is often misunderstood by climbers, because all other climbing gear is rated by the breaking strength (in kN) of the material. Whereas a higher rating (indicating greater strength) is desired for other gear, for dynamic ropes a lower rating is generally desired, as this indicates it would give a 'soft catch' that is less likely to injure the climber or break or dislodge
protection Protection is any measure taken to guard a thing against damage caused by outside forces. Protection can be provided to physical objects, including organisms, to systems, and to intangible things like civil and political rights. Although th ...
or anchors.Alpine Exposures FAQ- Climbing Ropes explained
/ref> Unlike most climbing equipment, dynamic ropes do not have a rated tensile breaking strength. Instead, the strength of a rope is tested by the number of standard test falls a rope can sustain before breaking. The test falls use an 80 kg weight for single ropes (55 kg for half ropes), and a
fall factor In lead climbing using a dynamic rope, the fall factor (''f'') is the ratio of the height (''h'') a climber falls before the climber's rope begins to stretch and the rope length (''L'') available to absorb the energy of the fall, :f = \frac. It ...
of 1.7 (4 meter fall on 2.3 meters of rope). This tests simulates a very hard fall that would rarely occur. When climbing, it is possible to produce a fall factor as high as 2, however, real-world climbing situations include additional shock absorbing elements which are not included in the test standard, such as the body of both the climber and belayer, elasticity of their harnesses and anchor materials, and friction between the rope and the belay device, and any protection pieces.Mammut: Standards for dynamic ropes
/ref> Single ropes must sustain at least 5 such falls before breaking, and a rope that can sustain more than 9 falls is considered a 'multifall' rope. In practice, climbing ropes rarely if ever break due to a fall alone- all documented rope failures involve the rope being cut or damaged, for example by abrasion against a sharp rock edge. Ropes are especially vulnerable to being cut while they are weighted with the body of the climber, and moving over a sharp edge (for example if a following climber is resting his weight on the rope, or using the rope for assistance, while swinging or traversing under a roof, while being belayed from above). In general, thicker ropes will be stronger and more durable, and have a higher fall rating.


Rope care and maintenance

Modern ropes are made from
nylon Nylon is a generic designation for a family of synthetic polymers composed of polyamides ( repeating units linked by amide links).The polyamides may be aliphatic or semi-aromatic. Nylon is a silk-like thermoplastic, generally made from petro ...
and don't require a great deal of maintenance. Ropes that are frequently used are often inspected for cuts, abrasions, or frayed areas; any cut or fraying that passes into the core of the rope is cause for concern. Ropes can also be washed to clean them of any extensive dirt or grime. Ropes must also be kept away from chemicals or seawater which may damage them, or stored for long periods in direct sunlight which can cause UV damage over time. Every fall lessens the amount of impact a rope can later absorb, and hard falls can seriously compromise the strength of a rope, without showing obvious signs of wear. One definition of a 'hard fall' is a long fall (> 10–15 meters) with a
fall factor In lead climbing using a dynamic rope, the fall factor (''f'') is the ratio of the height (''h'') a climber falls before the climber's rope begins to stretch and the rope length (''L'') available to absorb the energy of the fall, :f = \frac. It ...
greater than one. Manufacturers often recommended that ropes be retired if they sustain an extremely hard fall, even if they do not show outward signs of wear.Mammut Rope Care Manual
/ref>


See also

*
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. Rope, cord and webbing Climbing ropes are typically of kernmantle c ...
*
Climbing rope 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 ...
*
Fall factor In lead climbing using a dynamic rope, the fall factor (''f'') is the ratio of the height (''h'') a climber falls before the climber's rope begins to stretch and the rope length (''L'') available to absorb the energy of the fall, :f = \frac. It ...
*
Static rope A static rope is a low-elongation rope that is designed to stretch minimally when placed under load, typically less than 5%. In contrast, a dynamic rope is designed to stretch up to 40%. Static ropes have a wide variety of uses, for instance in f ...


References

;Notes ;Sources
Spelean.com.au
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