Join the Club

Join the CEC

Renew your Membership

Online Store

Subscribe to our eBulletin

Safety Committee Article

A(nother) Rappel Anchor Problem

(A Cautionary Tale)

-Frank Pianka, Thunder Bay Section

Bolted rappel stations atop ice climbs, if possible at all in our heavily forested area, often end up buried under layers of ice. This means most climbers in the Thunder Bay region will use the most appropriate tree to rig their rappel with the result that the tree gets damaged from frequent use. A number of years ago the Thunder Bay section tried to address this problem by installing cable rappel anchors on the ice routes that see the most traffic. After consulting with a local wire rope fabricator, we settled on using about one and half metres of quarter inch aircraft cable with thimble in the eye spliced ends. The cable was run through a short piece of fire hose, which made the system easy to secure to a large diameter tree above the expected snow level as a single basket hitch, and the ends were connected using a half-inch diameter plated quick link. A piece of 25mm webbing was also added as a drop loop back up, but we found some climbers had to be reminded to use the drop loop. This system allowed users to simply inspect the back up, make any adjustments or additions they felt were necessary, and rappel off the quick link knowing that the pull down was going to go without a hitch.

When we picked up the cable assemblies from the fabricator, they did not have enough of the half-inch quick links and substituted a few half-inch stainless steel bow shackles, which they said had the same rating. We were getting positive feedback on these rap stations until one day a user reported what he thought was a crack in one of the bow shackles. One of our members set out to check it out and sure enough, there was a small hair-line feature on the outer curved surface of the bow shackle. He removed it from the cable, tapped it against a rock and the bow shackle broke in two! The exposed cross section showed two approximately equal areas of differing texture and colour that a metallurgist might be able to interpret, but we wondered if it was a matter of having subjected that outer surface to excessive tensile forces by tightening the shackle bolt too tight. We went back to the fabricator for an opinion and he said that he remembered us….that he doesn’t think they’d want to make anything like that for us again because of liability concerns….that the cable was in great shape and could easily last twenty years….and that those bow shackles aren’t rated. (!)

We did not ask for proof of the stated specs on the components used nor did we question the technician’s casual substitution of an unfamiliar piece of hardware (the bow shackle) for a familiar one (the quick link). The V-thread (abalakov) option is for the specialist, not the recreational climber, so perhaps this suggests moving back to the old system of threading yet another piece of webbing to back up rings, links or biners left by others. At least that way, the user of the rap station may take a closer look at what they are about to trust their life to instead of assuming it’s all been done for them.