Rock climbing rope
Rope, cord and webbing
Climbing ropes are typically of kernmantle construction, consisting of a core (kern) of long twisted fibres and an outer sheath (mantle) of woven coloured fibres. The core provides about 80% of the tensile strength, while the sheath is a durable layer that protects the core and gives the rope desirable handling characteristics.
Ropes used for climbing can be divided into two classes: dynamic ropes and low elongation ropes (sometimes called "static" ropes). Dynamic ropes are designed to absorb the energy of a falling climber, and are usually used as Belaying ropes. When a climber falls, the rope stretches, reducing the maximum force experienced by the climber, their belayer, and equipment. Low elongation ropes stretch much less, and are usually used in anchoring systems. They are also used for abseiling (rappeling) and as fixed ropes climbed with ascenders.
Modern webbing or "tape" is made of nylon or Spectra/Dyneema, or a combination of the two. Climbing-specific nylon webbing is generally tubular webbing, that is, it is a tube of nylon pressed flat. It is very strong, generally rated in excess of 9 kN, or about 2,020 pounds of force. Dyneema is even stronger, often rated above 20 kN (about 4,500 lbf or 2000 kg) and as high as 27 kN (about 6,070 lbf or 2700 kg) In 2010, UK-based DMM performed fall factor 1 and 2 tests on various Dyneema and Nylon webbings, showing Dyneema slings can fail even under 60 cm falls. Tying knots in Dyneema webbing was proven to have reduced the total amount of supported force by as much as half.
When webbing is sewn or tied together at the ends, it becomes a sling or runner, and if you clip a carabiner to each end of the sling, you have a quickdraw. These loops are made one of two ways—sewn (using reinforced stitching) or tied. Both ways of forming runners have advantages and drawbacks, and it is for the individual climber to choose which to use. Generally speaking, most climbers carry a few of both types. It is also important to note that only nylon can be safely knotted into a runner (usually using a water knot or beer knot), Dyneema is always sewn because the fibers are too slippery to hold a knot under weight.
Webbing has many uses such as:
Extending the distance between protection and a tie-in point.
An anchor around a tree or rock.
An anchor extension or equalization.
Carrying equipment (clipped to a sling worn over the shoulder).
Protecting a rope that hangs over a sharp edge (tubular webbing).