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Have you read Rope Thickness and Belay Devices, Part One?
When ropes first began to really thin out, I purchased one that clocked in at a previously unheard of 9.4 millimeters. On its maiden voyage, I led out on the second pitch of something or other and placed a bomber mid-sized cam right off the belay. A few feet later I got something similarly solid, and shortly after that — just below the crux — I clipped a bolt. I was around 30 feet out from the belay with excellent protection, but that’s still not a lot of rope. Juggy holds were in short supply, slopers seemed more the norm, and soon, I was airborne. The fall was short by climbing standards, maybe six feet, but my wife, who was belaying with a (since discontinued) first-generation Petzl Reverso held the fall only with a maximum amount of effort.
To this day, she reports being barely able to hold that small fall. She had both hands on the brake, and that alone probably saved my life. Do the math: six feet of fall divided by 30 feet of rope equals a fall factor of only 0.2. Had I fallen but a few feet higher, I might not be here to tell the tale. Had that fall been of a much higher factor, say with only the first piece off the belay — or none — I certainly would be talus food right now. It’s important to note that, with the knowledge of the time, we did everything right.
 Fall factor is the length of the fall before rope stretch (20 feet in the above diagram) divided by the amount of rope in the system (10 feet). This is the hardest fall possible on the least amount of energy-absorbing rope… and you and your belay device (not to mention the climber) might be left holding the bag. |
The problem will be compounded by a heavy climber. Says Jim Ewing, Product Engineer for Sterling Ropes: “It’s much harder to hold a 100-kg (220 lbs.) guy with an ATC on a 9.2-mm rope than a 70-kg (154 lbs.) guy with an ATC-XP on a 10.5-mm rope.”
Okay… but how much harder?
To understand what catching a high-factor fall might be like, we can rely on anecdotal evidence from people who have been there and done that. Rich Goldstone, a climber of 52 years and a student of the sport is such a person. “I’ve caught one factor-2 fall in the field and twenty or so practice UIAA-level falls with weights,” reports Goldstone. “The impact is brutal — you are going to be thrown violently up or down. Some rope will run, and burns are almost certain without gloves. As far as I can tell,” he continues, “climbers evaluate their devices on the basis of how well you can pump slack to the leader. Of course, a low-friction device is likely to be best in this regard, while being inadequate for big leader falls.”
To boot, if the fall you’re catching is a true factor-two fall, i.e., the rope runs directly from your belay device, though zero protection and up to the climber, your device is going to invert. “We had an accident maybe two years ago in which a guy fell from a few feet up onto the belay ledge, then fell off the ledge and dropped 100 feet to the ground, because the belayer couldn’t control the rope,” reports Goldstone. “The belay failure here might have been exacerbated by the belayer reflexively braking downwards rather than upwards. Far too few people seem to know about this.”
If you’re cranking out single-pitch rock climbs, where theoretical fall factors cannot, by definition, exceed 1, rope thin-ness may be a valid consideration. But if you’re into multiple pitches, you’d better make sure your belay tech is on a par with your rope tech. And if the worst-case scenario — a fall directly onto the belay — occurs be ready for a catch that is challenging at best, no matter what size the rope.
Most of us will never have to catch a hard fall, and yet the spectre of such a situation hangs over all of us. If the time ever comes for you, will you be up to the task? If you glean only one salient point from this article, make it this one: You may not be as prepared as you think to catch a high-factor fall, especially if you use a thin rope — double especially if you use a thin rope and an older belay device.
Of course, you can’t know for certain unless a hard fall happens, but there are a few things you can do in terms of practices and equipment to hedge your bets. Look for more on that later this week in Part Three of Rope Thickness and Belay Devices: a Complex Relationship.
;)
Good articles, Jay. Back in the day, all climbing classes had the belay students (yes students) catch a simulated F2 fall. It’s a very very sobering experience that leads to 2 inescapable conclusions: First, It’s almost impossible to catch a F2 Fall with a tube/atc style belay device. And second, that it’s absolutely critical to set up your belays and lead protection so an F2 fall is not possible.
Climb safe,
maldaly
Great article on an important topic that gets overlooked. I know of five factor two fall scenarios that occurred in the field and all resulted in serious injuries to the belay, climber or both. Please take this seriously when climbing above the anchors.
We need belay devices made for smaller diameter ropes; is this not obvious? Why aren’t the hardware manufacturers filling this need?
Hi, Rick. Part of the issue probably relates back to the UIAA belay-device standard, or lack thereof. Many gear makers advertise that their devices are “effective” down to a certain rope diameter, but effective has yet to be defined universally. Until it is defined — and beyond! — it’s our responsibility to make sure we’re prepared for every eventuality. I’ve scheduled Part 3 to go live Monday morning. In it, there are several tips for mitigating this risk. Unfortunately, however, there’s no one-size-fits-all answer.
I’d like to clarify that I don’t think thin ropes should be avoided in all situations. I use a 9.5 regularly, and I love it, but for me that means single-pitch craggin’. These days, I’m almost never in a position to have to worry about high-factor falls.
I use a Sterling 9.2 and 9.5mm for sport climbing, and the SUM Fader device is absolutely awesome. For trad climbs I prefer a 10.2 rope with a grooved belay device or Gri gri.