Figure eight

Figure eight

Sometimes just called "eight", this device is most commonly used as a descender, but may also be used as a belay device in the absence of more appropriate equipment.

It is an aluminium (or occasionally steel) "8" shaped device, but comes in several varieties. Its main advantage is efficient heat dissipation. A square eight, used in rescue applications, is better for rappelling than the traditional 8. Because of the "ears" or "wings" on the rescue 8, there is less chance of forming a girth hitch whilst rappelling very quickly.
A figure eight descender

Figure eights allow fast but controlled descent on a rope. They are easy to set up and are effective in dissipating the heat caused by friction but have a tendency to put a twist in the rope. Holding the brake hand off to the side twists the rope, whereas holding the brake hand straight down, parallel to the body, allows a controlled descent without twisting the rope. Because of the many bends it puts into the rope, an 8 descender can wear a rope quicker than a tube style belay/rappel device. Many sport climbers also avoid them because of the extra bulk an 8 puts on the rack. However, many ice climbers prefer to use the 8, because it is much easier to thread with stiff or frozen rope.

Rescue eight

A rescue eight is a variation of a figure eight, with "ears" or "wings" which prevent the rope from "locking up" or creating a girth hitch, thus stranding the rappeller on the rope. Rescue eights are frequently made of steel, rather than aluminum.

Climbing Definition

Climbing

For other uses, see Climbing (disambiguation).
Rock climbers on Valkyrie at The Roaches in Staffordshire, England.
A competitor in a rope climbing event, at Lyon's Part-Dieu shopping centre.

Climbing is the activity of using one's hands or feet to ascend a steep object. It is done both for recreation (to reach an inaccessible place, or for its own enjoyment) and professionally, as part of activities such as maintenance of a structure, or military operations.

Climbing activities include:
Mountain climbing (Mountaineering): Ascending mountains for sport or recreation. It often involves rock and/or ice climbing.
Rock climbing: Ascending rock formations, often using climbing shoes and a chalk bag. Equipment such as ropes, bolts, nuts, hexes and camming devices are normally employed, either as a safeguard or for artificial aid.