Weekend Whipper: Carabiner Breaking Fall
Triple Gear Failure—Hamish Ousby whips off Future Tense (26 5.12b/c) at Frog Buttress, Queensland,
Australia, and goes slamming into a shrub after a ‘biner breaks and two more pieces of gear fail.
Although Ousby was barely above his last piece—a “well entrenched finger sized nut, something like a BD 6,” says Matt Hunter, friend of Ousby who
captured the whipper on film—when he fell, the ‘biner clipped to the nut shattered.
With that short of a fall and with the amount of dynamic rope in the system, Ousby could have never generated the force to break a carabiner, under normal
Carabiners, when properly loaded on their major axis with the gate closed, meet a minimum test of 20 kN (4496 lbf or 2039 kg). Even in an open gate scenario,
carabiners test to a minimum of 7 kN (1574 lbf or 714 kg), much higher than the force Ousby could have generation.
So how did his ‘biner break?
Ousby couldn’t see where he was clipping and nose-hooked a wire-gate carabiner on the nut (the ‘biner was also over an edge). In controlled pull-tests,
nose-hooked carabiners have failed at less than 10% of their rated closed gate strength—”that’s less than 2 kN (500 lbf or 227 kg), a load that
can be easily generated in even the smallest of climbing falls or even just a light bounce test,” Kolin Powick, a mechanical engineer and Black
Diamond’s Director of Quality, wrote in Climb Safe: Weakness of Nose-Hooked Carabiners.
He explains: “It’s a combination of an open gate scenario coupled with the fact that the carabiner basket is being cantilevered off of the bolt hanger/sling/Stopper
wire, meaning the load is not in line with major axis (i.e., the carabiner’s spine). This off-axis loading causes the carabiner to be excessively torqued
and break at an extremely low load.”
With his ‘biner in pieces, Ousby came hurtling down onto his next piece of gear, but it was the piece below that which would fail first. For his third
highest piece, Ousby had slung a stuck Trango cam (which remained in place) with a 60cm sling. As he fell, the sling was pulled up the rope, “perhaps
wrapped around it,” says Hunter, and the ‘biner on the sling was unclipped by the BD 00 cam above.
Then the “badly” placed 00 cam blew.
His fourth piece, a “bomber” 0.5 cam, finally caught his fall.
Ousby was fortunate to be high enough on route to be spared a ground fall, but had the top carabiner been properly clipped (an easy mistake when cruxing
out and making a blind clip), his fall would have been a matter of feet.
Bottom line: Always ensure that a carabiner’s gate is closed and the carabiner is correctly seated.
Watch last week’s Weekend Whipper: Huge Fall on Ouray Ice Route
Video Submitted by Matt Hunter