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Beware of Climbing Bolt Failure

Anchors Break at Salt Water Climbing Areas


A climber hangs from jugs on a big roof on Burnt Offerings (7a+) on the Fire Wall at Tonsai Bay.

Beware the bolts if you're cranking at beautiful Tonsai Bay in Thailand.

Photograph courtesy Matt Robertson
Martha Morris leading at Casteli on Kalymnos in Greece.

The bolts at Casteli on the island of Kalymnos in Greece will eventually rust and weaken.

Photograph copyright Stewart M. Green
Eric Morin belays Martha Morris at Otter Cliff in Acadia National Park, Maine.

You don't have to worry about salt water corrosion at Otter Cliff in Acadia National Park since it's a trad area.

Photograph © Stewart M. Green

Climbers love to head across the world and climb on warm, sunny, seaside cliffs in exotic locations like Long Dong in Taiwan, Railay Bay in Thailand, Vietnam, Cayman Brac, The Calanques, Costa Blanca, Sardinia, and Dominican Republic. Most of the cliffs at these locales are bolted sport climbs up steep limestone walls, some rising directly out of the ocean. But before you go next time, heed a warning from the UIAA (International Mountaineering and Climbing Federation) about all those bolts, bolt hangers, and climbing anchors that you'll trust your life to.

Stainless Steel Bolts Break

With the growth of these climbing areas by the sea comes a growing and alarming number of hardware failures. The bolts and bolt hangers simply break, usually without warning, and not just from falls but also from lowering from anchors or resting on a bolt with body weight. The bolts that fail are not cheap carbon steel bolts but durable stainless steel bolts that are the standard for climbing bolt anchors worldwide.

Short Falls Can Break Bolts

The preliminary results of an intensive study by the UIAA indicates that the failure of fixed anchors in marine locales, especially in warm tropical locations, is amazingly high. Every bolt placed at climbing areas like popular Railay Bay in Thailand should be considered suspect and subject to failure. The UIAA report notes that 10 to 20 percent of the bolts examined would fail with a meager force of 1 to 4 kilonewtons, while the UIAA standard for fixed bolt anchors is a minimum of 22 kilonewtons. In other words, the force of only a short climbing fall will break the bolt or hanger.

Corrosion by the Sea

The UIAA website reports: "Overall, some fixed anchors broke bearing only the weight of a climber. And all examined were stainless steel, which meets the UIAA safety standard and has a reputation of holding up well against corrosion. The corrosion in this particular locale appears to be accelerated by the proximity of the sea and year-round warm, wet weather."

Salt Water Causes Corrosion

Climbing bolts and bolt hangers fail because of corrosion caused by constant exposure to salt water. Failure of the stainless steel bolts used for climbing is by a mechanism called Chloride Stress Corrosion Cracking (SCC). A bolt is held in place in rock by friction, stress, and tension on the bolt shaft, the nut, and the bolt hanger. The corrosion cracking occurs on any part of the bolt or hanger that is exposed to salt water, including sea mist, which corrodes and cracks the metal and leads to breakage. Most bolts shear off flush with the rock surface, while bolt hangers usually break at the 90-degree bend or at the bolt hole.

Difficult to Assess Bolt Damage

It's difficult to assess the strength and viability of a climbing anchor by merely looking at it. Most of the damage is unseen by the naked eye or the bolt is high above the ground and out of sight. Every climbing area, route, and bolt is different so environmental factors like wind direction, exposure to the sun, distance from the sea, and moisture on the rock will affect the integrity and strength of the bolts. One indication of possible bolt damage is a rust beard or reddish streak below the bolt. If you see that, avoid that climb.

UIAA Recommendations

To avoid future accidents and possible fatalities from bolt failure, the UIAA makes these recommendations for anyone climbing at marine environments:

  • Before any climbing, we strongly recommend that you inquire with local climbers and/or with the local people who equipped the routes about the quality of the anchors in place.
  • Some areas are regularly re-equipped. If the bolts are less than 3 years old, experience to date suggests that the probability of finding a weakened anchor is low, even though bolt failure has been known to occur within 9 months of installation.
  • On the other hand, if you detect signs of rust on the anchors, this can indicate a badly weakened anchor. In that case, do not load the anchor, and retreat from the climb (experience from the field shows that some anchors would break when loaded with only the weight of the climber). Alert the local climbers/local people who maintain the climbing area, so that they can inspect and replace the weakened anchor. You could also replace the weakened anchor yourself-please replace the anchor with one of similar or superior corrosion resistance.
  • As a precautionary principle, we strongly advise you NOT to climb on routes in tropical, marine environments that show signs of rust on anchors and/or where you do not know either the person responsible for maintenance of the climbing area, or when the equipment was installed.
  • In the absence of reliable information about the integrity of anchors from the locals who maintain the bolts at a tropical, marine cliff, climbers must consider coastal, bolted routes as adventure terrain where all fixed anchors are questionable, as is the case in alpine climbing.
  • Ultimately, it is the climber him/herself who is responsible for his/her decisions and actions regarding the integrity of the anchors.

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