To Extend or Not to Extend?

 TO EXTEND OR NOT EXTEND

Or, how to make a mountain out of a molehill

The following is written up while I'm bored and (mostly) not climbing as per my (a non-climbing) docs advice while waiting for double hernia surgery. It's meant partly in jest, but has some practical advice also.

When TRSing, many people feel they need to extend the top device to make sure that, in the event the top device fails to lock up, the secondary device will not slam into it preventing it from locking up. I personally seldom extend the top device and have never experienced them colliding and rendering the back device ineffective. I know, it only takes once… However, in reality it may be more of a common TRS myth than reality (and lord knows there's plenty of those), though I'm open to being proven wrong. 

If you are of the persuasion that you need to extend the top device, there is a simple way to do this using a 25cm 12mm Sterling dyneema sling (or equivalent - the more common 30 cm slings are a bit too long for my tastes) looped around the belay loop and connected to the 'biner of the primary device. It extends the primary device up ~4" which is more than adequate to keep most devices separated in the event the primary fails.

                        normal climbing mode                                                 top device failure mode

A common practice to extend the primary device up, is to use a Quickdraw. To me using a QD has several potential drawbacks. while the sling extension has some advantages:

1)  The sling is lighter and simpler.

2)  A QD can extend it far enough up that it can become an issue in relation to the face. While at rest, it may seem that it is not anywhere near your face. However when you "fall"/weight the rope, the harness is pulled up on your waist, while the upper body compresses down due to gravity. This is body specific. This drastically reduces the clearance between face and device especially if your head pivots down. If you have a long torso, you may not ever experience this. Whereas those with a normal or short torsos could more likely experience the potential for adverse interaction.

3)  It's not just the face that can be an issue. Hair can also become an issue. This happened to my son years ago and it not only caused an issue for the device locking up but also was difficult trying to extract hair from the device. He ended up having to pull out clumps of hair from his scalp in order to free himself  (no knife - ouch!) Word of warning - if you have long hair make sure to keep it out of the way (and carry a small knife)! A practical (but not life threatening) concern for keeping the devices separated: if the back up toothed device does make contact with the primary device, it may be difficult to release the toothed device so that you can continue climbing or transition to descending.

4)  Finally, when using a quickdraw to extend the upper device, you also greatly increase the # of connections and complexity of the system. In designing systems, simpler is almost always better and safer. The number of connections using the different methods:

• Direct to belay loop - 2: 'biner to belay loop; 'biner on TRS device
• Looped sling - 3: belay loop to looped sling; looped sling to 'biner; 'biner on TRS device
• Quick draw - 4: belay loop to QD 'biner; QD 'biner to dog bone; dogbone to top 'biner;  top 'biner to TRS device.

Finally, the above info is in relation to using both devices on a single rope. If you are of the persuasion you need to use two devices with each device on a separate rope strand, then use a normal 30 cm/12" sling works well - double looped through the connecting leg loop strap and harness belay loop keeper - exactly like the belay loop This gives about the same ~4” of separation as the method above but also helps separate the two strands of rope. 

There you have it. How to 'make a mountain out of a molehill'.

PS Device separation can also be slightly modified by your ‘biner selection (smaller for backup, larger/longer for primary device).