Rigging question

[Chads93GT]

Let me know if I did this right.

Last week I went rappelling after work at a short bluff, only about 50'. The anchor trees were about 6" in diameter, and I wanted to anchor off both. I did a tensionless hitch around one tree, then further down closer to the cliff edge I tied in an inline figure 8, and ran a piece of webbing back to the 2nd tree so equal tension was on both the webbing and the rope, running to both trees. I had to also do this because without the webbing and the inline 8, the rope would have wanted to slip off the lip that I wanted to drop, as this place was the only lip that allowed a 50' free fall.

Did I correctly use the inline figure 8 and webbing for a 2nd backup?


I was also wondering. Say I had enough rope to tie a double figure 8 in the rope and run a tail to each tree. Is it ok to simply wrap each end of the "bunny ear" around the tree in a tensionless hitch as well? What would you do?

Nothing about what I asked seems incorrect to me, but you guys have been doing this way longer than I have. Let me know your thoughts. Thanks.

Chad McCain

[chh]

Sounds like you solved the problem. Especially if you needed a redirect to keep you over your desired drop. There are other things you could have done, but options sort of depend on how much rope you have, how far away the trees are and in what configuration they are in relation to lip, how much webbing or other rigging gear you have, etc. Sometimes a prussik (or 2) on the main line is a nice way to fine tune the tension between two anchors where your inline 8 would have been. Also a double figure eight with tensionless hitches on the loops is one way to do it, but holy cow, that would be a lot of rope to use and time fiddling unless the trees were in very fortunate spots. The way you did it seems better.

[jharman2]

Thanks for posting something actually related to caving on cavechat! Interesting concept; maybe it will catch on.

I see nothing wrong with your method. Tubular webbing, despite being standard fare for redirects, can stretch significantly adding a great deal of bounce to the pitch. This problem becomes much worse when the angle between the webbing and the primary leg becomes greater than 90. On long pitches with a redirect at the top you can really have a bouncy ride.

I don't want to hijack your thread, but is it wrong to use Spectra for a redirect?

[jaa45993]

Chad,

Several times I have used the exact method you describe. Seems to work. It's real nice when you have already rigged to one anchor and then decide you need a redirect or backup. Real easy to throw in the inline 8 and go from there.

jharman,

I don't think there is anything wrong with using Spectra for a redirect. I hope not, because I've done it! Just don't mention that you use it for cowstails, or people on cavechat start preaching about physics laws and Hitler, Nazis, and Ron Miller! It may sound strange, but trust me, I speak from experience.

[Chads93GT]

Lol ive noticed spectra cowstails and being the devil!

I figured what I did was right, and it wasnt too bouncy but I was on a rope walker and I try my best to walk smoothly up the rope. that bouncing around is for froggers, not me, lol.

Glad to hear what I did wasn't taboo. I was looking at it and was like "Well, this will work" but I was also wondering what someonoe else would think about it who knows more than I do. It was the first time I have actually had to use the inline figure 8 for a backup and redirect, so I thought that was cool. If I had enough webbing I would have doubled it up to make it less bouncy, but alas, I didnt.

The prussic idea is brilliant! I actually used a bachman with the 4mm cord on my rope pads as there were no anchcors to tie them to, so we anchored them to therope and slide them up and down for the best placement.

Would the same webbing with a prussic cord on the end count as a backup if I would do that method without an inline 8 to tie into? Obviously you can climb and hang from prussic's, hell ive done it, but I don't know if that would actually work as a backup as well or not. It definately would have made it easier to adjust to get the rope in the right spot, as it was i had to tie and retie the webbing and clip it back into the inline 8 many times before I was satisfied.

[Amazingracer]

I have used the method for rigging several times. This is even how we rigged when we rappeled the Black Canyon in Colorado. There was no one tree that looked suitable so we tied an inline 8, tied webbing back to two trees, equalized the load there, then backed the rope up to a third tree with a tensionless hitch.

Wasn't worried about any stretch from the webbing either, we had 1600' of rope stretch so the webbing stretch was negligible.

[jaa45993]

that bouncing around is for froggers, not me, lol.

Not for competent froggers! That bouncing around is a sure sign of poor frogging technique.

Would the same webbing with a prussic cord on the end count as a backup if I would do that method without an inline 8 to tie into?

I think this would be fine. The inline 8 would give me more of a warm, fuzzy feeling, but from more of an over-engineering standpoint than a practical one. Kind of the same reason I go ahead with the knot and carabiner on a tensionless hitch even though it is mostly just there to make you feel better. Prusiks are routinely used to hold life-safety loads. Climbing on them would be one example. The other thing that comes to mind are rescue applications. NCRC teaches the tandem triple-wrap prusik for belaying a 600 lb. rescue load. A single triple-wrap prusik is used for the progress capture on many haul systems, including 3:1's and counter-balances.

In your scenario, I think the prusik would be fine for a deviation. I might use a triple-wrapped one. If it was used for a backup, like if you had some inkling that the primary anchor could blow, I would stick with the inline 8. My worry would be that the prusik could disengage when unloaded, and then slip if suddenly shock loaded. Although, if you used two triple-wrapped prusiks, it would provide more security, and might actually be safer than the knot, as it could allow some absorption of shock load before really tightening down.

Just speculating here. What do others think?

[Chads93GT]

I have used the method for rigging several times. This is even how we rigged when we rappeled the Black Canyon in Colorado. There was no one tree that looked suitable so we tied an inline 8, tied webbing back to two trees, equalized the load there, then backed the rope up to a third tree with a tensionless hitch.

Wasn't worried about any stretch from the webbing either, we had 1600' of rope stretch so the webbing stretch was negligible.

Was this by chance the trip that LJ and Andrea Tognetti were on? And bill Putnam? IE the pics that bill posted?

[chh]

Prusiks are routinely used to hold life-safety loads. Climbing on them would be one example. The other thing that comes to mind are rescue applications. NCRC teaches the tandem triple-wrap prusik for belaying a 600 lb. rescue load. A single triple-wrap prusik is used for the progress capture on many haul systems, including 3:1's and counter-balances.

In your scenario, I think the prusik would be fine for a deviation. I might use a triple-wrapped one. If it was used for a backup, like if you had some inkling that the primary anchor could blow, I would stick with the inline 8. My worry would be that the prusik could disengage when unloaded, and then slip if suddenly shock loaded. Although, if you used two triple-wrapped prusiks, it would provide more security, and might actually be safer than the knot, as it could allow some absorption of shock load before really tightening down.

Just speculating here. What do others think?

This is pretty much my line of thought as well. I wouldn't likely use two prussiks unless there was some reason why the other anchor is suspect. And in that case, I might rethink the whole approach anyway depending on circumstances. However I reason that if 2 prussiks of an appropriate diameter can be used as a standard belay for a 600 lb. load, It should be fine for me and/or tandem climbing, even as a primary anchor with a hard knot behind the prussiks to the anchor to back up possible slippage. In fact I've set tyroleans with and without a secondary line in this way and hung and bounced on them. Whether or not this is standard practice I don't know but it seems to work well.
Plus I think the ease of adjustment with a prussik is pretty nice. You can really dial the tension to the seperate anchors especially if there is some distance there to deal with. In addition, as per chad's setup, you can dial that tension on the tree nearer the lip with your weight ON the main line which gives you a much more hands on idea of how the anchors are sharing the load.

Chad, use a longer prussik cord with a munter mule on the biner close to the lip if you anticipate the need to lower. That gives you the ability to lower from either the tree with the tensionless hitch or the tree with the deviation.

Cheers

[Chads93GT]

Ok, I will now have to read up on how to tie the munter mule. never had to use it so i never practiced that one. Maybe then I will understand more, lol. This is the downfall of usually rigging on bomber trees. I never have to tie anything fancy so i am rather limited on situations i have had to tie off with. Thanks for the advice. Good stuff.

[chh]

Sorry chad. It's actually two different hitches. The munter, which I'm sure you've seen or used. And the mule knot which is basically a slip knot used to lock off a munter hitch or other belay device. The mule knot is usually compounded by an overhand lock off, much like how you lock off a rack. So it might help to look them both up seperately, I don't know.
DO learn them both though. I'm continually amazed at the number of accomplished climbers and cavers who don't know how to use these hitches. They are essential. Right up there with the figure 8 on a bight for me.
Ok. Enough soapboxin'

latah gatah

[Chads93GT]

Well I tend to read up on the knots, but sometimes i just dont practice them if I see no foreseeable use for them with what I do. But you are right, everyone should have a wide range of hitches and knots in their bag of tricks. I know the munters hitch, played with it a few times, but really havent used it. some people rappel short distances with it right?

clove hitch, well that one doesnt move at all right? Thanks for helping.

[chh]

Right chad. Clove hitch doesn't move, nor is it releasable but is one I use a lot in climbing. Not as much in caving. The munter is typically used to rappel or to belay a leader or second. In caving the mule knot/hitch is very helpful for small party rescue or what I've heard referred to as "rescue" rigging - i.e. rigging drops with the capability to lower. You'll have to refer to Scott for that particular nomenclature though, or maybe one of the other NCRC types
The munter/mule has a lot of uses in other venues as well. There's a lot of info out there on the web I'm sure. Probably best to find someone to show you the nuances though. Definitely a tool I think everyone in the vertical world should be able to use with ease whether for caves, rock, ice, trees, industrial etc... But everyone has their favorite tools. This is one that I reach for on a fairly regular basis. To each thier own.

[Amazingracer]

Was this by chance the trip that LJ and Andrea Tognetti were on? And bill Putnam? IE the pics that bill posted?

Nope. We were out a week or two before Bill. It was just myself and four other Georgia Tech cavers.

[ian mckenzie]

If I understand your scenario correctly, I think I would have used a butterfly rather than an in-line eight. The butterfly is easier to adjust for length, easier to untie after loading, will tend to tighten in a load-equalizing direction, and has some shock-absorbing qualities. It is also a knot that is designed to be loaded in three directions.