Sources and Context
These days, as canyoneers, we get "how to" information from all sort of sources:
Online information
Manufacturer instructions and marketing
Peers
Retail personnel
Instructors
Often, information from these sources are at conflict, or when mixed, create strange setups and riggings, and when used out of context, can introduce unnecessary risks.
Rappel Extensions
One example is rappel extensions. It seems that this is one of the aspects of canyoneering that is surrounded by miss conceptions and sometimes, misuse.
What is a rappel extension? Is that piece of textile material that some canyoneers install on their harness ventral point, and goes to a carabiner's rappelling device to separate the rappelling device away from the harness. What is that for? Well, it depends on who you ask. There is a long list of of misuses, but the #1 thing that this will not do of you is:
It will not prevent inversion during rappel. If you are "top-heavy", extending your rappelling device will not prevent you going upside down during rappel.
Good reasons to extend your rappel device:
Get more friction out of some rappel devices. By extending it, the rope leaves some rappel devices at a sharper angle (noticeably tube devices like ATCs), thus creating more friction.
Make room for a self-belay prusik below the rappel device
Make more room to turn your body sideways to look down at the rappel line. Very useful for going down waterfalls with heavy flow.
Tandem rappels
Pick Off rescues or any direct assist rescues.
When NOT to extend your rappel device:
Overhangs. Some people think that extending the rappel device will prevent the tendency to turn upside-down on long rappels with overhangs. It does not. Turning upside-down is caused by your center of gravity being above the attachment point of the rope to your harness. You can modify the center of gravity by hanging your pack. You can modify the attachment point by adding a chest harness.
Self Rescue maneuvers or mid rope changeovers. Extensions will move your rappel device away from you, making it harder to place a rope grab above it to start your self rescue maneuver.
Soft-starts: Marginal anchors or anchors low to the ground, require a "soft-start" i.e a sitting start, to a hip-slide to go over the edge. If you have a rappel extension, it will get slammed against the rock, and it may cause you to get stuck or hung.
In this photo, you can clearly see what can happen if you rappel this edge with an extension: You will get stuck
(photo credit: Jeff Watkins)
Soft-start on a marginal anchor: Avoid rappel extensions for clearing low rappel starts
Potential risks:
Squeezing your rope and rappel extension together for more "braking power". This is a bad idea. Long term, the extension will get damaged by the rope friction. If you do this on a regular basis, inspect your extension regularly to detect damage early and replace before failure.
Getting stuck on edges where the rope makes contact with the rock
Your extension makes contact with the rope while rappelling. If the rope rubs on your extension, it can quickly damage it and cut it. Nylon and especially Dyneema is susceptible to this. If you can, use Technora extensions that are heat resistant.
Try not to extend your rappel device beyond your reach. This will make self-rescue maneuvers unnecessarily difficult.
This rappel extension is TOO long. Person will not be able to lock off on the device or add more friction on the fly.
Not a good idea: Squeezing your extension along with the rappel rope. Long term, you will damage your extension.
If you like braking with two hands, use this technique: “Guitar Hero” (coined by ACA Master Guide Rick Green from Excursions of Escalante UT). Brake hand at your hip, and non-dominant hand at the spine of the rappel carabiner.
Types of extensions:
Factory installed fuses or replacement fuses. These are ideal length short draws that can be cut easily for expedited self or assisted rescues. Some harnesses come with a pre-installed 'fuse'. A fuse should be considered as an expert option, and cutting is always the last resort, usually to prevent drowning.
Nylon or dyneema slings: These will result in a constant rappel device misalignment and movement.
Safety tether: Repurposing your safety tether as an rappel extension: If you use the lone one, you may place the device beyond reach for lockoff, or setting friction. If you use the short one, you may run into a problem if you need to clip-short for a self-rescue.
Dog-bone quickdraws. These are stiff and better for alignment, but will not serve as 'fuses' as they are very hard to cut.
From left to right & From good idea to bad idea:
VT Prusik: A good way to implement a quick extension. 3 lengths by folding. Technora is an added bonus for heat damage protection.
Small prusik: Girth on ventral point, rappel carabiner on eye
Petzl Fuse: A factory spec extension that can be easily cut. But extra instruction is needed to prevent rope-on-fuse friction wear.
Nylon girth short sling: By Sterling
Nylon & Dyneema mid girth sling.
Dog bone: Two tight ends. Needs 2 carabiners, or a rapide and a carabiner.
Dog Bone: One tight end, one loose.
12” : Sling. Not the best permanent solution.
24”: Sling. Not the best permanent solution.
48” : Sling. Not the best permanent solution.
Final thoughts
Our gear selection and practices get started with advice, instruction, self-learning, manuals, etc. But as time passes by, gear and practices get shaped by the type of canyons we do frequently, and the people we go out with. If you frequent canyons with low to the ground marginal anchors, you have very little use for extensions, safety tethers, or any anchor management tools or techniques. If you frequent routes with high bolted stations, it is the opposite. Similar effect on gear and practices for Dry canyons VS Swiftwater canyons. Happy rigging!