Engineering:Figure 8 (climbing)
The figure 8 belay device is a piece of metal (usually an aluminum alloy) in the shape of an 8 with one large end and one small end.
Usage
This device utilizes a large surface area in contact with a climbing rope to provide sufficient friction along with the proper technique to be used as a belay device or for rappelling. A figure 8 (sometimes just referred to as an 8) is used in conjunction with a climbing harness and locking carabiner to control a belayed climber's descent, or one's own descent when rappelling.
Pros
Figure-eights offer a smooth controlled descent when rappelling and lowering climbers.[1] They can be used with nearly any diameter climbing rope and don't get as hot as other friction devices because of their ability to dissipate heat efficiently.[2] The figure eight can also be used with a doubled rope, which is also possible with a rack but not a bobbin.
Cons
The figure-eight cannot be removed from the rope without detaching the device from the harness, and so could be accidentally dropped, particularly when tackling a rebelay. They also twist the rope which is a particular problem where a rebelay prevents the rope from untwisting. They do not provide a convenient means to temporarily lock the descent at a rebelay.
References
- ↑ Cox, Steven M. and Kris Fulsaas, ed., ed. (2003-09). Mountaineering: The Freedom of the Hills (7 ed.). Seattle: The Mountaineers. ISBN:0-89886-828-9.
- ↑ "Belay Devices: How to Choose". Rei.com. 2013-06-20. http://www.rei.com/learn/expert-advice/belay-device.html. Retrieved 2013-10-24.
Bibliography
- Cox, Steven M. and Kris Fulsaas, ed., ed. (2003–09). Mountaineering: The Freedom of the Hills (7 ed.). Seattle: The Mountaineers. ISBN:0-89886-828-9.
External links
- Video Clip on Using a Figure 8 Belay Device
- Rei.com How to Choose a Belay Device
- Mountainproject.com
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