Ropes

Rope Basics

In climbing and repelling, the rope is your lifeline. Understanding rope characteristics will help you choose the right one.

Rope Types:

Dynamic:
has the ability to stretch when a load is applied allowing the rope to absorb some of the force during a fall.
Static:
generally does not stretch when loaded; used for repelling, rescues and rope ascending.

How It's Made

Most modern climbing ropes have a kernmantle construction consisting of an interior core (kern) that is protected by a braided exterior sheath (mantle). This design optimizes strength, durability and flexibility.

Rope parts diagram showing where sheath and core are located — **Figure 46:** The Sheath serves as a skin for the rope and protects the rope from cuts and abrasions. The core supports the load, bearing the climber's weight.

Manufacturing Steps

Fibers are spun or bunched into yarns
Yarns are twisted into strands
Strands are twisted forming the core
Sheath is woven around the core

Fibers are spun into pieces of yarn, which are then are twisted to make strands that form a core and a sheath is woven around the core. — **Figure 47:** Diagram of rope components.

Percent Elongation

This is the amount a rope stretches under a specific load.

ΔL = change in rope length
L ₀ = initial rope length

Example:
ΔL = 0.2m
L ₀ = 1.0m

The object weighs one hundred kilograms and its initial length is one meter while the change in length is 0.2 meters. — **Figure 48:** Percent Elongation diagram.

Rope Setup:

Single Rope:

Half Rope:

Figure is always tied in and belayed on two ropes but only clips one strand of rope to each piece of protection.

Twin Rope:

Figure is tied into two ropes just like the half rope but figure must clip both ropes to all the pieces of gear.

Fall Factor

This is the ratio of fall length to the rope length. It is used to estimate the severity of a fall.

$FF = \frac{fall length}{rope length} FF = \frac{4 m}{10 m} = 0.4 m$

Fall factor diagram using 2 meter increments at the peak to estimate the severity of a fall. — **Figure 49:** Fall factor diagram showing the ratio of the height, in this case, 4 meters, a climber falls before the climber’s rope begins to stretch and the rope length available to absorb the energy of the fall which is 2 meters in this example.

Rope Friction

Rope friction is created any time the rope is in contact with itself, the rock, or a piece of gear and prevents the rope from elongating over its entire length. Thus, only the effective rope length (solid line) will absorb the energy of the fall.

Using a single rope set up, the rope is segmented into sections and is clipped in alternating positions as the climber climbs up, creating high rope friction. A figure at the bottom holds the rope. — **High Friction**

Using a half rope set up, one rope is in a more straight-lined pattern as the climber climbs up and another is in a looser pattern. A figure at the bottom holds both ropes. — Low Friction

* Climbers choose a half-rope system to reduce the amount of rope friction on a wandering route.

Common Knots:

Figure eight on a Bight: A large knot with relatively gradual bends as compared to an overhand and is easily recognized by the tell tale “8” shape.

Figure Eight on a Bight: produces a strong loop for securing carabiners or other items.

Water Knot: Knot using flat materials such as leather or tape tied by forming an overhand knot in one end and then following it with the other end, feeding in the opposite direction.

Water Knot: used to join two pieces of webbing.

Figure Eight Follow Through: A large knot with relatively gradual bends as compared to an overhand and is easily recognized by the tell tale “8” shape that is used to tie in the end of the rope.

Figure Eight Follow Through: a simple, reliable knot most commonly used to tie in to a climbing harness.

Double Fisherman’s Knot: Solid and strong rope knot variation of an overhand and two wraps on two ropes going around each other.

Double Fisherman’s Knot: used to join two ends of a line to form a loop or to join two climbing ropes.

Clove Hitch: Two successive half-hitches around an object, tied in a way that looks like an “X” or clove.

Clove Hitch: a good binding knot when constant pressure is maintained.

Safety Knot: A simple knot that prevents the end of a rope from sliding through a piece of gear or another knot.

Safety Knot: prevents the end of a rope from sliding through a piece of gear or another knot.