True Double Rope

G

Ghivelder

I’m starting this thread as a continuation of other discussions about backing up a double ascender on a doubled rope.
I was never satisfied with placing a friction hitch above the ascenders as it increases friction in a significant way, so I finally came up with a very simple idea which I will call “True Double Rope” or “TDR”. First of all, it must be said that is meant for footlockers. So, if you aren’t one, forget about it. But if you are a footlock lover (like I am), it gives you the opportunity to use always the same ascent techniche even in those trees where making a throw for a doubled rope it’s just not possible. The only real disadvantage is that one needs a very long access line (preferably 10 or 11mm of diameter).
This is how it works:
1. Throw the weight as for SRT. No need to have the ropes parallel. Yes, the branch will be doubled loaded, but that’s rarely a problem. I’ve always considered SRT rope installation to be safer than doubled rope regardless of the double loading. I think that branch failure can happen to an experienced (and prudent) climber only in the presence of an invisible defect, so it’s preferable to double load a branch that has many back-ups (other lower branches) than trusting one’s life to a single one.
2. Now tie your access line (which must be a bit over thrice the height of the limb) to the throw line and start pulling it up. When it has gone over the access limb and down a few feet, stop!
3. Take the tail of the access line which is down on the ground and tie it with a blake’s or other knot to the access line which is coming down from the tree. One can also use a separate line - which can be half the lengh of the first one – instead of folding in the tail of the same one. It makes no difference.
4. Resume pulling down the throw line. The blake’s will start going up with a “second” rope. Pull till the blake’s touches the limb (consider that the line will go a bit down when the system is loaded) and tie up the single line to the base of the tree.
5. Voilà! You have easilly installed a TDR system in which both ascenders are independent and it might take you a few seconds even to notice it if one of the two fails. No need to back it up with a friction hitch.
I’ve been using this for a few months now and find it just perfect. That doesn’t mean I don’t use doubled rope anymore, but if I can’t isolate the rope over a single limb or feel like having the extra safety, I go for TDR.
I’m attaching a horrible digital drawing to give an idea. To make it simpler, it’s drawn as if one used two separate access lines.
It’s very simple, but somehow difficult to explain. Try it and let me know what you think…

Sergio
 
Sergio,

TDR is a good option for people who like the feel of the two ropes. Also, like we've talked about, having the two ropes adds a level of safety.

The one item that I question is the use of a sliding friction hitch to attach the two ropes. Why not use some kind of bend? There are many to choose from so I won't get bogged down in defining one single bend. If the TDR rope were pulled over a limb there is the chance that the limb will push the SFH back down the rope.

Tom
 
You are perfectly right Tom.
For months I've used TDR on my climbing courses and since the trees were wide and clean the blake's worked fine. Just last week When I really needed TDR at work, the hitch got tangled at several branches and I made a mess.
I thought about you...

Sergio
 
Poster: Tom_Dunlap
Subject: Re: True Double Rope

>the hitch got tangled at several branches and I made a >mess. That's what saws and knives are for :)


Is that like "I made a mess of myself"
Or
" a mess of the ropes?"
Or
"A mess of the tree?
 
I guess "a mess of the ropes" would be the answer. A fork caught the hitch and made it slide down the main rope so that there wasn't enough double rope to go up with.
What kind of knot would you use? Sheet bend?

Sergio
 
Ghiv- good idea! Ive always had reserves about footlocking up doubled rope without a backup. Correct me if Im wrong here but in your technique basically you are attaching a 2nd line to the working end of an installed srt line, thus the working end has 2 lines 1 for each ascender, and there is no need for a back up hitch because each leg of the line is static so the back up is the neighboring ascender?!
thinking outside of the box, again very good idea!!
I like it.
because both ends of the line are static, the use of a foot ascender(pantin) would also be more efficient.
 
Errrr...maybe an inline-directional figure 8 or an alpine butterfly for the mainline, and then figure 8 in the second line....
I'm not a footlocker, so it seems to me you could just ascend using SRT. Is it possible to ascend on a single rope footlocking?
 
Single rope footlocking works. Most of the time I find it easier. With DRT the two ropes flutter sometimes.

A sheet bend could be used but the tail would need to be tied off with a double fisherman's or other solid knot. Sheet bend is not a reliable knot if both ropes are the same size.

A butterfly could be tied and then another hitch tied into the eye. This seems kind of clumsy though.

Brion Toss recommends the Straight bend for security.

Tom
 
One is sometimes better than two!

Sometimes when I am footlocking on a line that is doubled over a branch, my feet will lock one of the lines, but the other will just slip. Instead of pushing me up, I go nowhere and one end of the rope goes up as my feet pull the other end down.
This just can't happen if you're only using one line!
Maybe I just need to get some different boots with a less prominent arch.

love
nick
 
Re: One is sometimes better than two!

Nick wrote:
>Sometimes when I am footlocking on a line that is doubled >over a branch, my feet will lock one of the lines, but the >other will just slip. Instead of pushing me up, I go >nowhere and one end of the rope goes up as my feet pull >the other end down.
---
Is that as dangerous as it sounds?
 
"Sheet bend is not a reliable knot if both ropes are the same size"
Why not? Isn't the Sheet bend a bowline using two ropes?
And what is a "Straight bend"? (I'm sorry, I'm not english speaking...)

Sergio
 
Here's what Brion Toss wrote in his book, Knots by Chapman's Nautical Guides.

Single Sheet Bend

This is the basic utility bend. It holds well in Manila and hemp, but can slip in synthetics, particularly braided constructions.
The technique shown here is one evolved by weavers to repair broken threads in their looms. It is the fastest way to thei the SSB, and it's alos a way that guarantees the ends will finish on the same side of the standing part. Tied by other methods, there's a fifty-fifty chance that the ends will be diagonally opposed, resulting in a less secure knot.

IN the illustration, the end of the bight and the end of the bent rope are both onthe same side of thier respecetive lines.

This is what he writes about the Double Sheet Bend:

For joining togeher stiff,slick synthetic line, or jsut to be extra safe, we use the DSB. It is much more slip-reessitant than the Single, and lamost as quick to tie. Just be sure that the second turn goes BELOW the first. Unlike the Single, this knot cannot be drawn up properly just by pulling on the ends; take the time to work the slack out before putting this or any other Bend to use.
The DSB is the only Bend to use when joining lines of dissimilar size, or when one line is condsiderably stiffer or slicker that the other. The smaller, more supple, and/or slicker line makes the turns. The largeer, stiffer, and/or less slick line only needs to make a U-tunr to finsish the knot.

This is a good knot website:

http://www.earlham.edu/~peters/knotlink.htm


or these:
http://huizen.dds.nl/~erpprs/kne/kroot.htm

http://webshirt.com/IGKT/


If in doubt, tie backups with the ends. My feeling obout knots is that one should be chosen that functions on it's own, without adding layers of backups.

Tom
 
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