Thursday, May 29, 2008

Climbing Device--Grigri from Wikipedia

Grigri (climbing)

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The Grigri
The Grigri
An open Grigri
An open Grigri

A Grigri (or Gri-gri, Gris-gris, or Gri for short) is a hand-sized belay device designed to help secure rock-climbing or rope-acrobatic activities. Its main characteristic is a clutch that self-locks under a shock load. Belayers using a Grigri need to pay full attention to their climber and exercise skillful operation to ensure safety. "Grigri" is a trademark of Petzl, but the success of this tool has been so great that it has to some degree become a common name. Competitors include the Trango Cinch.

[edit] Mechanism of Operation

The Grigri works by locking when sudden acceleration occurs to the rope (like in a fall), therefore making it an automatic belay device unlike traditional belay devices such as a Sticht plate or an ATC. The device acts like an automobile seat belt, if you move the rope slowly you can run the rope through the Grigri without it locking but a shock load locks the device so rope won't run. One of the criticisms of automatic belay devices is that they can lead to a false sense of security. The automatic functionality may result in the belayer being less attentive to the climber than with a more traditional belay device. However, like any tool, proper training is required for proper use.

[edit] Pros and cons of use

Some climbers feel that the Grigri is only suitable for top rope climbing and not lead climbing due to the auto-locking feature. The claim is that since the device auto-locks, the belayer is required to hold the device open while feeding rope to the leader. A common mistake while belaying a lead climber is to hold open the device the entire time, thus defeating the auto-locking mechanism. However users can and should learn how to feed rope without holding the device open. Petzl have released information on how rope should be fed through in a lead climb. Including how to let slack out quickly so that the climber can clip a draw on a sport route.

When used correctly, the Grigri's auto-locking mechanism can protect against problems, such as inattentive or incapacitated belayers. For lead climbing, a grigri is more difficult to use correctly than an ATC; for top-rope climbing, the opposite is true. When belaying the same technique for "taking in" that is used with an ATC or similar device is used, however in the event of a fall instead of having to "lock off the device" the belay does nothing and the device locks by itself. However while paying slack out into the system if the device is held open (with one technique being referred to as "the thumb") and the climber falls, unless the belayer lets go the device will not lock and the climber will deck.

While designed as a belay device, big wall climbers have invented novel ways to use the Grigri that are not recommended by the manufacturer. For example some big wall soloists use the Grigri (sometime slightly modified but not necessarily) as a self-feeding hands-free self-belay device. In big wall situations, the Grigri allows for hands-free belaying on long aid pitches while the rest of the party does other things. It can also be used by the second to self-belay while jumaring the rope as one half of the ascender pair; the leader can belay the second hands-free allowing the leader to haul, take pictures, or do other chores; the second can use it to lower out while following a traverse.

The Grigri is also both significantly heavier although is not very heavy. Many climbers aim to reduce weight on their harness (equipment attached to the harness is known as a "rack") as much as possible as it can drain energy. and more expensive than other belay devices. However, there are applications where only an automatic belay device will work. The Grigri has a lower limit for the rope size for which the clutch will engage. This makes it unusable with many of today's skinny ropes - like those used in many alpine applications.

Many Novice climbers make the mistake of thinking that an auto locking device such as the cinch, grigri or eddy can make up for a lack of belaying skill. This is not true, and does cause accidents. It is very important correct training is received before belaying with any device commences.

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