- Ice screw
An ice screw is a
screw used to protect a climb over steep ice or for setting up acrevasse rescue system. The strongest and most reliable type of ice screws are the modern tubular ice screws which range in lengths from 10 to 23 cm. The approximate strength rating on a modern tubular ice screw is around 10 kN, although it has been found that short ice screws in "good" real-world ice hold about 7-8kN, no matter what thefall factor or configuration is1. The most vulnerable an ice screw is to failing is in the [http://www.theuiaa.org/upload_area/cert_files/UIAA101_DynamicRopes.pdf UIAA drop test] configuration. That is, when multi-pitch lead climbing and the leader has only placed one screw before falling. The dynamic ropes used in climbing can mitigate failure of an ice screw by keeping the impact forces low; however, this is using a new rope that has not had any previous falls.The older type of screw that is rarely used nowadays is a pound-in ice screw. Instead of screwing these into the ice you would pound them in with the hammer on your ice tool and then screw them out to remove them. The pound-ins have been largely replaced by modern tubular ice screws that are stronger and easier to use.
The subtle nuances of ice screw placement should be mastered before using them for climbing. Learn from a professional how to best protect yourself using ice screws.
Manufacturers
* [http://www.blackdiamondequipment.com/ Black Diamond]
* [http://www.omegapac.com/ Omega Pacific]
* [http://en.petzl.com/petzl/Accueil/ Petzl]
* [http://www.dmmclimbing.com/ DMM]
* [http://www.grivel.com/ Grivel]External links
* [http://www.terragalleria.com/mountain/info/ice/bd-test.html Ice screw placement]
* [http://strikerescue.com/images/47.jpgNegative (poor) angle placement]
* [http://strikerescue.com/images/46.jpgPositive (good) angle placement]
* [http://strikerescue.com/research Ice screw research by Beverly, M. M-PAS and Attaway, S. PhD1]
* [http://uk.youtube.com/watch?v=IC5ziGNUZsE Video of ice screw placement]
* [http://uk.youtube.com/watch?v=2guWbO0Z_Hc Video of ice screw testing]
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