Letters from the Edge

"My last month was spent climbing in Thailand on some very questionable bolts... About a week ago while I was waiting for a guided party to finish a second pitch on Thaiwand wall, a leader broke a bolt by pulling on the quickdraw. This caused him to fall and break the next bolt. He was lowered off with a badly injured leg. Both bolts fractured in the shaft at the hanger."

"Just returned last night from Cayman Brac and I wanted to drop you a quick line. Really great trip but... when Gene weighted the second bolt on 'Throwin' The Hula Girl' it broke! He came down on his butt and foot and suffered contusions, luckily missing his spine. It could have been ugly. The bolt was stainless steel..."

"Andy... reached down, grabbed the draw and said "Take". As he lowered his weight (the hanger broke). He landed on his back on some big boulders (breaking ribs and puncturing a lung). I tried to help him as my girlfriend ran for help, but he kept insisting that I not touch him and he just wanted to try to keep breathing."

Sardina, Thailand, Cayman Brac, Calanques. Warm weather, beaches, exotic food and incredible sea-cliff sport climbing, but all is not well in paradise.

With the growth of sea-side climbing around the world there has been an ever increasing number of bolt failures. The marine environment is tough on metals. The constant exposure to salt water promotes a specific powerful corrosion mechanism that is not seen at inland climbing areas.

High quality stainless steel bolts and hangers have failed in as little as 18 months when placed near the sea. Most of the time there is no visible indication they are unsafe. They may look fine but not hold body weight, much less a fall.

Affected cliffs don't even need to be right over the water. Breaking waves create a fine mist which can be transported inland for miles by the wind.

Chloride Stress Corrosion Cracking

The stainless steels used today in almost all climbing bolts are susceptible to a failure mechanism called Chloride Stress Corrosion Cracking or SCC. Just like it sounds, the chlorine ion, which results from dissolving salt in water, and stress must both be present.

A typical multi-piece expansion bolt has the shaft in tension, and the hanger has complex stresses placed on it when it is clamped against the rock as you tighten the nut. This type of bolt placed in a sea cliff is a bomb with a short fuse.

Once started, SCC spreads like a disease following the stress lines in the steel, much like grass grows in small cracks in concrete and forces the pieces apart. The cracks get larger over time, and soon the microscopic grains of the metal are no longer in contact.

Although SCC can occur on any part of a bolt exposed to salt water, it usually occurs under the hanger where salt water wicks into the crevice between the hanger and the rock surface. Bolts corroded by SCC typically break flush with the surface of the rock. Hangers typically break at the ninety-degree bend, and nuts can crack just about anywhere.

At least one bolt vendor sells stainless steel "clad" bolts and nuts. These have a thin outer cladding of stainless steel surrounding a core of mild steel. This type of bolt seems to be worse then others, since once SCC cracks the cladding, oxidation (rust) finishes the job in short order. If you see a stainless bolt with a rust "beard" on the rock under it, beware!

Glue-in Bolts

A few years ago the Thailand locals started rebolting with one-piece glue-in bolts made of stainless steel for the simple reason that they knew regular expansion bolts weren't working. These should be an major improvement since they don't have the high levels of stress that expansion bolts have. However, they are not impervious to SCC.

Steel gains much of its strength from "work hardening" which is residual stress created by the manufacturing process, and glue-in bolts have these stresses designed into them. No one knows how long stainless steel glue-ins will last.

The Tortuga (Turtle)

We wanted a bolt that could be trusted for over 30 years in this environment. But what material to use? We still couldn't ignore the more common corrosion mechanisms such as oxidation, galvanic and chemical corrosion.

 

* Oxidation (rust) is accelerated by water, salt and warm temperatures.

* Galvanic corrosion occurs when two dissimilar metals are in contact in the presence of an electrolyte. Salt water is an excellent electrolyte. Multi-piece bolts always have some potential for galvanic corrosion since it's almost impossible for the shaft, sleeves, nut and hanger to be perfectly matched.

* Chemical corrosion could take place if there is some unusual compound present in the rock that could attack the bolt. It's common for limestone to have a wide variety of compounds embedded in it.

So when we considered these other corrosion mechanisms in addition to SCC we realized that we needed a one-piece glue-in design made of something besides steel. There were several possible materials we could use, but we needed a marriage of material, costs and supplier.

Titanium was our first choice and after being turned away by several climbing equipment manufacturers we hooked up with Ushba Mountaineering. After our first meeting at the local pub, and several beers, we were sure this marriage was going to last.

We went through a meticulous design process before boiling it all down to the simplest solution. The new Ushba "Tortuga" bolts (Spanish for turtle) are simple "P" shaped welded cold-shuts made out of titanium. They are large enough to be used for both intermediate bolts and lowering anchors. They meet all existing UIAA standards for strength and will set new standards for anti-corrosion properties. (The UIAA has formed a special sub-committee to investigate marine bolt standards.)

We also had to think about the glue since the glue provides an important part of the overall solution. The glue isolates the bolt from any possible metals or chemical corrosives embedded in the rock and prevents water from wicking into small crevices next to the metal. It also has to withstand the marine environment in its own right! Here we gleefully took Sam Lightner's advice gained from years of gluing bolts in Thailand. The Hilti HIT C-100 appears to be your best bet.

So if you're putting up a sport route near the ocean, use the right stuff and put up a safe route that people will enjoy for years to come. If we do it right, climbing in Paradise is within our reach.

SCC in Aluminum?

After we determined that Stress Corrosion Cracking was affecting the bolts, we started wondering about SCC in aluminum carabiners and other gear. Unfortunately, aluminum is susceptible to SCC.

I had four carabiners (leaver-biners) that had been hanging over the ocean on Cayman Brac for 6 to 18 months. These were all tested to failure at Black Diamond and then sent to the UIAA for analysis. Although all broke near or above their rated strength, the one exposed the longest (18 months) broke due to SCC.

If you visit a sea side climbing area, wash your gear in fresh water when you get home. This includes all your nylon including the rope. If you live there or stay for several months, wash it every month to get the salt off.

Where else to use Tortugas?

This summer in Rifle I noticed quite a few stainless bolts that were showing rust, and even some that appeared to have galvanic corrosion (Bolts in the Skull Cave had white galvanic "growths" on them.). In areas such as this, where there's a lot of moisture, seepage and "active" rock, you should consider using a Tortuga.

More Information

You can get more info on the Tortuga by contacting Ushba at (970) 472-9640.

You can contact Hilti at www.hilti.com

Profound thanks to Jim Bowes of Ushba, Chris Harmston, Eric Hirst, Sam Lightner, Helmut Microys, Vance White and all our friends that helped us and have put up with our spray for the last 2 years.