Monday, November 28, 2011

Stuff You Should Read

As climbers we make decisions that affect our safety all the time. Some of these decisions involve choosing the proper "application". How we apply a tool we have in our toolbox is very important. Some examples of tools we have as climbers are belay methods (ATC, Reverso/ATC Guide, Grigri, Munter hitch), knots (figure eight, flat overhand, bowline, clove hitch) and friction hitches (prusik, autoblock, and klemheist). Generally, my choice to use a particular tool isn't a random or haphazard decision.

Here's a simple example. If I need to do improvised rope ascension I can use friction hitches to grab the rope. However, I don't randomly choose any of the friction hitches I'm familiar with. I apply the best one for the task at hand. If I'm using a piece of cord to tie a friction hitch so I can ascend I'll use a prusik, as it grabs well but still releases easily. If I am have webbing, I'll use a klemheist as it grabs a bit better while using the slippery, flat webbing. I won't even consider an autoblock, as even loaded autoblocks slip easily when you grab them.

There's a lot of information out there, and much of it should be taken with a grain of salt. The list below isn't meant to be your final word when making technical decisions. It's only a reference that can help when choosing which knot to tie, which belay device to use, and which friction hitch to wrap in different scenarios.

Hang 'Em High: Hang 'em High is a test of belay device behavior under extreme loads. There's interesting information about why the GriGri is better than the Cinch, and also good information about how much load belay devices can hold. The article is a bit older now but still good for understanding loads, belay devices, and what a belay device should be able to hold in extreme conditions.

X-Mission: Tom Moyer and the SLC Mountain Rescue crew have done testing on all different types of material. Some of the interesting results in this link: a clove seems to be stronger than a bowline in pull testing, double fisherman's knot holds better than a water knot in tape, Big Honkin' Knot (double eight on a bight) is actually weaker than a single eight on a bight. 7mm prusik is really strong.

Tom Moyer's Test Page: More testing on materials from Tom Moyer. The water knot and EDK testing are pretty cool, testing of high strength cord too.

Guide Tricks for Climbers - SP Parker tested the clove hitch to see what happens with static slow pull testing. He had different results depending on where the load strand was (spine or gate). Either way the results show no slippage.

Climbing Mythbusters - Geir Hundal did some testing to bust a few climbing myths that everyone asks about. There's some cool stuff here including info about dropping gear, clove hitches, and the EDK. Also some good info about leader loads on gear while belaying with a grigri and a plate

Clove Hitch Testing - Testing by Dave Lane and John Yates (Yates climbing equip.) showing that the clove hitch won't slip.

Technical Rescue Magazine - Tests of belay methods for rescue loads. Very interesting and compelling arguments for the use of the Grigri for high load belays, and for the Tandem Prusik Belay for securing fixed lines and for use on the belay line during rescue scenarios.

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