SOL: How to Beat the Core Shot
Rubbing, bouncing, and smashing … all of these things are a climbing rope’s nemesis. I’ve seen melon-sized rocks smash onto belay ledges and put several core shots in a climbing rope halfway up a route. While rope soloing the classic Zion route Spaceshot a few years ago, I tore through 3/4 of the rope core while swinging off Earth Orbit Ledge with one final pitch and five rappels left to get me back to the ground. What would you do hanging in mid-air, with nothing but 800 vertical feet below you, when colorful fuzzes of your climbing rope are falling from the sky like snow? Although a climbing rope is designed to be durable, dynamic, and strong, it isn’t impervious to natural wear and tear or unfortunate terrain contact. A core shot describes the degradation of strength in a section of climbing rope. A loaded rope rubbing over a single sharp crystal can quickly slice through the protective sheath and pluck away the critical core strands.
Identifying a Core Shot
Checking for core shots should be routine for every climber between trips, not just after a suspected injury to the rope. To check for them, slowly flake the rope into a pile on the ground. As you’re flaking the rope use your fingers to feel for inconsistencies in the thickness and texture of the climbing rope. If you come across a suspect section, try to fold that section of rope in half. A newer rope should arch smoothly, whereas a damaged rope will bend sharply. In addition, continue to assess the damage by feeling for sheath slippage and softer/thinner sections of core underneath the sheath. A good rope’s core should be tight against the sheath, to reduce the effect of the sheath slipping. A rope will get fuzzy with use; use these visual cues to search for soft spots and core shots. Unfortunately, there isn’t always a sure formula for when too much fuzzing or softness means it’s time to retire the rope, but if it looks and feels suspicious, it probably is.
The white core and damaged sheath clearly indicate a core shot, as pictured on the right.
Isolating a Core Shot
If the core shot is close to the end of the rope, it’s often a simple fix to cut and melt a new rope end, making your 60-meter rope a 55-meter that’s still very useful. However, if you’ve developed a core shot closer to the middle during a climb, when you still need the full length of the rope, you’ll need to isolate the core shot. The alpine butterfly knot is a simple knot that isolates the compromised section of rope and maintains its strength and shape when the strands are loaded laterally.
Wrap the rope around your hand twice, working from your thumb towards your fingers, so the core shot is in the middle of your palm.
Wrap the rope a third time, this time bringing the rope across your palm from your fingers back to your thumb.
Pinch the core shot and pull the strand towards you and over the other two strands, working towards your thumb.
Push the core shot underneath both strands, working from your thumb towards your fingers.
Pull the two lateral strands, keeping the bight of core shot extending.
Passing the Knot on Rappel
If you have core shot on your rope towards the middle and need the full length to rappel, you’ll first have to isolate it with an alpine butterfly knot. When rappelling down, you will have to stop the rap and pass the knot. Since a knot won’t fit through the belay device and a Munter hitch can severely twist a climbing rope, especially if being used on multiple rappels, you need to be able to remove your belay device mid-rappel and put it on below the knot to continue rappelling. Since you know that you’ll need to do this mid-rappel, it is advantageous to prep your setup before the rappel. As with many climbing techniques, there are various methods to accomplish the same goal. I prefer the following steps due to their safety, simplicity, and efficiency.
Attach your belay device to the rope to rappel; it’s best to keep the device on the belay loop rather than extended for this technique. Attach a friction hitch above the belay device; the Prusik hitch is recommended because it grabs the rope better. Clip this backup friction hitch to your belay device with a locking carabiner, make sure there is enough space for the device and the hitch.
Rappel to within one foot of the knot and let the friction hitch grab the rope and hold your weight. DO NOT let go with your brake hand, because it is backing up the friction hitch.
Pull up three feet of slack below the knot and tie an overhand-on-a-bight knot. Clip the bight to your harness with a locking carabiner. Now you can let go of your brake hand, since you have a new backup.
Remove the belay device from the rope and attach it to the slack rope, below the alpine butterfly knot and above the backup knot. Clip the device to your belay loop with a locking carabiner. Attach a friction hitch below the belay device; the autoblock is recommended here for its ease of tying and its ease of release. Clip the friction hitch to your leg loop with a locking carabiner. Because this friction hitch is backing up the rappel device, it’s OK to be hands-free. You can now remove the backup overhand-on-a-bight knot.
With a bent knee, wrap the rope around your dominant foot three times. You can now stand up on this foot, since the wrapped rope acts as a foothold. Remove the friction hitch above the knot completely.
You can now sit back, allowing your belay device and backup friction hitch to hold your weight. Remove the wraps around your foot and rappel to the next belay station.