How to not die while rappelling

[Alpinfox]

One VERY IMPORTANT issue that I did not discuss in my original post is the knot one uses to join two ropes when doing a double-rope rappel. Knot failure has caused many fatalities, so this is something that we should pay attention to.

 

Most of the testing that I have seen (EXAMPLE) indicates that the strongest knot for joining two ropes is the double (or triple) fisherman's knot.

 

Double Fisherman's:

 

Directions for how to tie this knot and some discussion of the pros vs. cons of a few knots are given HERE.

 

One potential problem with this knot is that it is possible to only tie half of the knot (a fisherman's on one side, but not the other). If one were to get distracted with something else and then forget to tie the other half of the knot and then weight the knot, it would fail. If one were still connected to the anchor via their daisy at that time, the knot failure would be inconsequential, but if not, disaster would likely result.

 

I choose to use the "Euro-death knot", aka "overhand" knot, to join two ropes.

 

Overhand:

 

I do this because it is much faster to tie and untie than a fisherman's knot, many folks believe that it is less likely to get stuck on edges or in cracks than the bulkier knots, it is relatively easy to untie, and when properly tied and dressed it has been found to hold > 1000lbs of force (more than enough for a body weight rappel.

 

Whatever knot you choose, make sure that you use long tails, the knot is properly "dressed", and that you pretension the knot by grabbing each strand and pulling all of the other strands against it. It also might be a good idea to get in the habit of having both climbers inspect the knot prior to the first rappel.

 

"Does this knot look good"?

"Yup"

"OK. See ya down there"

(smooch is optional at this point)

 

 

 

 

Link to another thread on CC.com discussing rappel knots

[catbirdseat]

Good advice from Monsieur Fox. It's easy to poo poo the importance of dressing a knot properly. What you are doing really is inspecting the knot to make sure it was done right. For example in the double fisherman, looking to see that the "two Xes" nest one one side and the two pairs of strands stack on the other. You get used to how a knot looks and insist that it looks right before you trust it.

[RuMR]

so what are the relative strengths of these two knots?!?!?

 

[billbob]

Was wondering, if you use a prusik while rapping with a double rope, or if you need to put on and use said prusik to stop/climb up, well, you put it on both ropes, right?

[slothrop]

Yup.

[RuMR]

I love it...instruction on cc.com

 

this is just like a mail order MBA...

[still_climbin]

Another mistake with painful consequences applies to persons with very long hair. When I taught climbing many years ago I witnessed, on two occations, hair being pulled through the rappel devise. In both cases another person had to rappel next to the painfully trapped woman and cut the hair (which was also painful but in another way). In one instance the rappeller continued to let rope and hair slip through the devise until she was virtually hanging by her hair.

 

I second the idea of holding the ends of the rope from below. In event of an injury, say from a falling rock, the lower person can stop a fall and usually lower the rappeller in a controlled fashion by varying force on the rope.

[rob]

Another step that may prevent this error from becoming fatal is to have a prusik back up knot located above your belay device.

 

This is what I was taught too, but recently someone turned me onto using autoblock backup instead (beneath the rope). It seems that the more I read, the more accepted this method seems to be, especially since it isn't as hard to unload and you don't have to worry about the natural tendancy to grab the rope (and thus the prusik, preventing it from loading) with your guide hand during a fall.

 

Are there any other pros & cons between these two backup methods (Prusik above the device vs. autoblock below)?

[Alpinfox]

A prusik below your device ain't gonna help much when the rope ends slip through your belay device (the ends will have already gone through your prusik).

 

[with the prusik-below-your-device method] you don't have to worry about the tendancy to grab the rope (and thus the prusik, preventing it from loading) with your guide hand during a fall.

 

I disagree with this. The tendency to grip while falling, thus preventing the prusik from catching, would still be a problem.

[rob]

I thought the scenario is this: If your backup prusik is on the guide hand (above the device), and you lose your brake hand (due to a fall/accident/picking your nose), your guide hand might instinctively grip the prusik and prevent it from loading, resulting in a fall/grounding. Letting go of the guide hand is non-instinctive.

 

However, if you set an autoblock below the device, controlled by your brake hand: If your brake hand grips tight, the autoblock may not engage, but what's the problem? Your brake hand is still in control of the rope and the device catches you. But if you lose the brake and grab with the guide hand (instinctively), the friction below the device will catch and prevent your untimely death.

 

This is how it was explained to me, anyway. I didn't think the purpose of a backup prusik was to prevent rapping off the ends of the rope, anyway -- I thought it was to serve as self-belay. If you rap off the ends of the rope, it seems unlikely you will have the instincts to let go of your guide hand to allow the prusik to engage quickly enough to prevent the rope from pulling through it.

 

Am I off base?

[Alpinfox]

I agree with everything in your second post.

 

In your first post I thought you were saying that a prusik below your device would prevent/save you if you rapped off the end of a rope. I disagree with that, but apparently I misinterpreted and that's not what you were saying.

 

I do agree that I wouldn't expect a prusik above the device to very often save folks who rap off the end of the rope, but some people espouse that system for that reason.

 

I think the best reason to use a prusik backup while belaying is to stop you should you for some reason let go of the rope (hit by rock knocking you unconcious etc). In that situation, the prusik above or below the device would do the job equally well in my opinion. Another good reason is if you are doing a long and/or free-hanging rappel on slick, skinny cords.

 

As I've said before, I almost never use a prusik backup.

 

As I've also said before, I'm not a certified guide, so if you want a more official answer, I'd encourage you to talk to a UIAGA or AMGA guide. There are a few that post on here.

 

 

 

 

[archenemy]

I love it...instruction on cc.com

 

this is just like a mail order MBA...

Yeah, I framed mine.

[northvanclimber]

Are there any other pros & cons between these two backup methods (Prusik above the device vs. autoblock below)?

 

the autoblock is really just there to take the place of your braking hand should you let go of the rope. the benefit is that when you want to continue rapping, you can easily release the knot and be on your way. in contrast, if you actually want to re-ascend the rope, you'll want a prussik ABOVE the belay device... but, if you then change your mind and want to go back down, prepare to battle with that locked up prussik!

 

and yes, you'd want the prussik to go around both ropes... unless ahead of time you figured you might run into a situation where you'd have to re-ascend the rope, in which case you could've put a big figure 8 knot at the top of rope at the station. in this case both lines of the rope act independently and has the added bonus that if there are any sharp edges and one strand of rope gets shredded, you won't die. obviously the last person to rap takes out the knot and comes down normally... um, assuming the whole rope shredding thing didn't occur!

[MountaingirlBC]

Totally agree.... and I'll even admit that I did rap off one of the 20ft marks on a Revelation thinking it was the middle. Used up one of my 9 lives that day.

 

Mammut sells ropes with THREE middle marks. One in the middle and the other two about 20 ft from each end. The marks are IDENTICAL - two bands of black dye.

 

Stupid, Stupid, Stupid!

 

It's impossible to tell the ends from the middle without flaking out the entire rope! A middle mark is at the anchor, but is it the middle or near the end? They could have easily made the middle two bands of dye and the ends one band. WHAT WERE THEY THINKING!?!

[MountaingirlBC]

At the risk of making myself look like an even bigger dumbass.... I've done this one too. Braids are bad for this so now I try to remember to tie them together behind my head before I rap. Was funny trying to explain to my hairdresser what I had done to so badly chew the shit out of the bottom few inches of my hair.

 

Another mistake with painful consequences applies to persons with very long hair. When I taught climbing many years ago I witnessed, on two occations, hair being pulled through the rappel devise. In both cases another person had to rappel next to the painfully trapped woman and cut the hair (which was also painful but in another way). In one instance the rappeller continued to let rope and hair slip through the devise until she was virtually hanging by her hair.

 

I second the idea of holding the ends of the rope from below. In event of an injury, say from a falling rock, the lower person can stop a fall and usually lower the rappeller in a controlled fashion by varying force on the rope.

[whidbey]

do not rap............ you will die.

[MountaingirlBC]

One more thing to add is to make sure you are using the right atc for the rope you're on. A regular atc does not provide enough friction for the smaller diameter ropes.

[whidbey]

good point mountain girl....

[mattp]

You don't necessarily need a new device for skinnier ropes.

 

If your rappel device doesn't create enough friction, you can run the rope around your leg, with or without a keeper biner on the front of your harness, and depending on how you rig it you can get as much friction as you want.

 

Alternatively and maybe in addition, I find that using a 24" sewn runner on my rappel loop of the harness, so the rappel rig is high enough that I use my guide hand below the friction device, also contributes to easier control.

[northvanclimber]

One more thing to add is to make sure you are using the right atc for the rope you're on. A regular atc does not provide enough friction for the smaller diameter ropes.

 

the petzl manuals always show that you can add friction to your rappel by using two carabiners to attach the belay device to your harness.. anyone tried this???? any good belay devices for ropes in the 8.2-9 mm range? the reversino is the only belay device i know of that's specifically for smaller ropes and the biggest it takes is 8.2 mm... the BD ATC-guide is supposed to be good down to 7.7 mm

[whidbey]

How come Matt has so much common sense to pass along,=.... Are some of us this stupid that we need an answer?

[whidbey]

Matt does know his shit... listen

[jmace]

A regular atc does not provide enough friction for the smaller diameter ropes.

 

Really...? I have been using a regualr ATC since I started climbing and I pretty much only climb on twins and halfs..

 

in fact Black diamond says the ATC is good to 7.7mm...

 

Black Diamond

 

just the regular 18 dollar ATC 7.7-11mm

 

[G-spotter]

I don't think she means a Black Diamond ATC when she says an ATC... like those ppl who say "Friends" when they mean cams.

[jmace]

least "friends" and cams look the same...