Tuesday, April 21, 2009

Extending the Cordellete

The cordelette (a continuous loop of 7mm nylon cord) continues to be one of the very best tools for building full-strength, redundant anchors. The vast majority of the anchors that I build use the so-called cordelette method, whether they are 2-point anchors or 5-point anchors.

One of the challenges with a cordellete is that its length (usually about 8-10 feet once tied into a loop) can prove to be limiting. A cool trick that I learned not long ago is to use knots to effectively lengthen the cordelette. Study this diagram to see what I mean:

Thursday, April 16, 2009

Misuse of the Daisy Chain

Thought-provoking video from Black Diamond:

Monday, April 13, 2009

Bolt Failure

When I give anchor clinics at Gear Shops and Climbing Gyms, I always get the very logical question:
  • If bolts are so unreliable, why aren't bolts failing left and right?
A single crag in Santa Barbara has actually had two different bolts pull out during lead falls (most recently in Summer 2007). Both cases involved 5-piece Rawls, which are considered better than most other bolts in softer rocks.

And then this in Australia: bolt failure in the Blue Mountains

Sunday, April 12, 2009

Heavier Climbers = Bigger Forces

Excellent work by Chuck Weber, Quality Manager of PMI Ropes. I found this particularly relevant given my 195 pounds.

What Heavier Climbers Need to Know

Friday, April 10, 2009

The Verdict on Bolts

Way back in 1992, Duane Raleigh did an excellent study of different types of climbing bolts for Climbing Magazine. What I particularly like about Duane Raleigh's methodology is that he tried to simulate different hardnesses of rock in order to see how different bolts would perform in different rock types. The verdict that Duane Raleigh rendered is simply stunning. It turns out that even the biggest, strongest bolts are only as good as the rock that you put them in.

"Anchors Away - the Nuts of Bolts." by Duane Raleigh. Climbing Magazine. October, 1992.

After reading Duane Raleigh's study several years ago, the thought occurred to me - if the numbers that were recorded in the study are to be believed, then I should be able to walk over to almost any crag in the Santa Barbara and Ojai areas and simply and easily pull bolts out of the wall. The first bolt that I looked at was a bolt at "the Foot," in Ojai. On a cool winter day in 2004, I placed the nail-remover of a small household hammer beneath the hanger of a bolt atop that cliff. I never put more than moderate pressure on the hammer...the results sickened me. Five years and dozens of bolts later, I continue to be amazed at how poorly most bolts hold in the walls of our local crags.

More about bolts from Duane Raleigh: "Mechanical Bolts"

Fixed on Bolts

Crags on the Central Coast of California are littered with several generations of various types of bolts. One or two walls in particular could be described as a veritable museum of climbing bolts. Knowing what is good and what is sketchy can be more challenging than the crux mantle on T-Crack.

Bolts can generally be separated into three different categories based upon how they work. These three categories are: compression bolts, expansion bolts, and glue-ins.

Compression Bolts
These bolts are larger than the drilled diameter of the hole into which they are placed. They are forcibly hammered into the hole causing the shaft of the bolt to deform and compress. The bolt then springs back elastically and thereby grips the rock. Many compression bolts have an obvious striking service which is visible after placement. Those with a rounded striking service are referred to as “button heads.” Compression bolts are extremely sensitive to the shape of the bolt hole. Functionally, pitons are actually a close relative of compression bolts.

Expansion Bolts
These bolts are tapped into a hole and tightened down with a wrench. As the bolt is tightened, a tapered cone (or “gumdrop”) is drawn up into an expansion sleeve causing the bolt to expand. Be careful as there are three types of sleeve bolts. The type with solid hex-shaped heads, often referred to as "Rawls," are among the strongest and most reliable bolts in medium to hard rock. There are two different types of sleeve bolts that have an exposed, threaded end that sticks out of the hole. One of these is the externally-threaded sleeve bolt, a hardware store variety that is weak and unreliable. The other is the Fixe Triplex bolt, which is one of the best choices for softer rocks.

These bolts have a flared bottom-end of the bolt with an expansion clip. They are among the most common bolts in rock climbing. Placement of wedge bolts is hard to botch and they are even self-tightening when placed in solid rock—they expand further and further as they are drawn out of the hole. Be careful as wedge bolts are unreliable in medium and soft rock. There are also hardware-store wedge bolts that are considerably weaker than climbing-specific ones.

Glue-In Bolts

Glue-in bolts are molecularly bonded to the rock. This gives them the highest strength of all three types. They are also reliable in medium and soft rock; however, they require delicate skill to place properly.

Next time you're at the crag, look closely at the various bolts that you are clipping. Study them. Begin to make educated guesses about how each one works. Try to get proficient at identifying each type...as you'll learn, your livelihood may depend upon that proficiency.


The setting of safe and reliable anchors is one of the most fundamental skills in climbing. Yet few concrete rules-of-thumb exist for determining what is enough protection. Abstract ideas, intuition, and even superstition often stand in lieu of hard numbers.

So, what makes an anchor?
How many points of protection are required?
How strong does an anchor need to be?

First, let’s consider some numbers. According to Taupin & Verdier in the French treatise Amenagement et Equipment d-un Site Naturel d’Escalade, the routine forces in climbing are: 2,600 pounds for lead climbing falls and 1,000 pounds for top roping falls. Hopefully, these numbers reinforce in your mind the importance of building strong anchors...you are going to put many hundreds of pounds of force on your anchors.

Fortunately, the greatest possible force that you can put on an anchor is limited.

To back up a step, it is important to realize that climbing ropes stretch. When they stretch, climbing ropes absorb energy. When a climber falls, some of the energy created in the fall gets translated to the anchor (and to the climber) while some of the energy gets absorbed by the rope as it stretches.

The International Mountaineering & Climbing Federation (also known as the UIAA) provides standards for how much energy a climbing rope should absorb. The UIAA-assumed maximum force for UIAA-certified ropes is 12kN (about 2,700 pounds) at the tie-in point and 24kN (about 5,400 pounds) at the top anchor.

In other words, the maximum force that you can apply to an anchor using a climbing rope is 24kN. Admittedly, heavier climbers apply more force than light climbers and the UIAA test weight is only 176 pounds. Additionally, falling repeatedly over a short period of time reduces the elasticity of the rope thereby increasing the force on an anchor with each subsequent fall. Even given these exceptions, 24kN is a very useful number.

My standard for anchor building is this: the best possible anchor is the one that will hold the worst possible fall. Build 24kN anchors and it is reasonable to believe that you are not going to break those anchors using a climbing rope.

How do you get to 24kN? How do you know how much force a camming device or a bolt or a natural anchor will hold? Ahh...that's a whole 'nother conversation.