# Friction hitch on double rope



## rmihalek (Sep 6, 2006)

Does anyone know of a friction hitch that can be used to descend a double rope? I'm not refering to a Blake's hitch (or the equivalent) used in DdRT, but a hitch that can be tied around both strands of, say, a half inch climbing line and then used to descend with.


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## Kneejerk Bombas (Sep 6, 2006)

For footlocking a doubled rope, guys use a prussic, but more for locking off if you fall. With all your weight on a single rope (or single set of ropes) a friction hitch will lock off like mad. If you do get it to slide, the friction will be very hard on the rope (can you say burn) as well as very hard to smoothly control.
A standard climbing system gives you a 2 to 1 advantage, which takes at least half the load off your hitch, and even more than half if you have friction at the TIP (like with a natural crotch).


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## squisher (Sep 6, 2006)

what sort of application were you thinking of that for or were you just wondering if it's possible? Standard I think would be to use a descending device like a figure eight and back it up with a prussic.


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## rmihalek (Sep 6, 2006)

Basically, is there a knot equivalent of a figure 8. Ekka showed how he has his climbers set up a false crotch with a figure 8 so if the guys hit a bees nest or something while they're on spikes up in the tree, they can descend quickly on the 8. (He called it absail or something like that.)

I was just wondering if there's a knot that can do the same. Maybe a Klemheist might work?


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## Tom Dunlap (Sep 6, 2006)

Any of the usual friction hitches will work. You'll have to take the time to test the many combinations to see how each works though. If you used a doulbed half inch rope you should start experimenting with the same rope tied using a friction hitch.

But...why???

You can abseil, rap, rappel, descend... using a Munter on a large diameter HMS biner.


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## rmihalek (Sep 6, 2006)

I tried a Klemheist hitch today and it worked great. The cord got pretty hot, but my descent was very controllable. Next up is trying a Munter on a carabiner. It's more for just seeing what different things work. The Munter is on my list of things to practice with for sure.

Thanks to all.


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## Tree Machine (Sep 11, 2006)

I would recommend looking places other than a friction hitch. Having tried that, and having used mechanical pieces like an ATC or similar tube device, or even the big ring from a friction saver, there are many easy-to-learn and inexpensive ways to descend down a static doubled line.

A Munter will work, but it'll twist your rope. Works OK with SRT, but static doubled rope and 13mm line, you'll wanbt a fairly big biner, or a locking scaffold hook (a really big caribiner). A figure 8 also has the problem of twisting your rope. 

With most belay devices, the predominant friction control comes from the passing of the rope through the piece. The remainder comes from your hand. Whereas with a friction hitch, you let go to stay suspended. With most devices you set up a soft lock, or a hard lock to stay suspended; a secondary point of friction equal to or greater than what your belay hand was providing.

Spare yourself the agony and skip the Prussik altogether. Mike says


Mike Maas said:


> For footlocking a doubled rope, guys use a prussic


I've seen this in footlocking competitions, but nowhere else. If they're using it in the field they're stuck in time and need to move on to something that allows smoother, fully controllable friction. There are literally hundreds of better options.


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## PUclimber (Sep 11, 2006)

*Prussic or kleimhiest backed up with figure 8*

The prussic locks up so bad due to the friction that is placed on it. By running a second point of friction such as a figure 8 below it takes some of the friction off it and is able to slide. Also you work the tree off the double rope? Most just use this as a way of accessing the canopy.


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## TheTreeSpyder (Sep 11, 2006)

PU Cllimber's strategy works if line between hitch and device is kept tight i think. Hitch around both legs of line at once limits how close you can safely get to support / TIP by ~5x the horisontal diameter of the support; or the tension of the spread on the lines can pull hitch open.

The mechanics of load friction on a hitch descending while grabbing all support legs is different than that of a friction hitch grabbing 1 of 2 legs of support.

Most obvious is that all your weight instead of at most half is on the sliding friction of the hitch; then less than that for the participle of friction at support. But the real kicker i believe, is that if you have 2 legs of support and are riding a friction hitch down on one leg; the other leg automatically takes your weight. i think this is analogous to if the friction hitch leg of support was stretching or failing, the other leg automatically takes the loading. So in DdRT the sliding friction hitch might unload to 20# or less. That is lots less friction descending in this DdRT example than in SRT or your pro-posed DRT(?) with a friction hitch. IMLHO; after lots of experimentation; descending on a friction hitch not in DdRT is beyond the design scope and safety of a friction hitch.

Fig. 8's and Muenters with gloved back up hand can work; the metal device not wearing the same as a hitch and acting as a heat (draining) sink too. Aluminum dissipating heat faster than steel, but then too you can get burnt easier on the non-friction side of device then too. Spiraling can be a problem. It is best if the line is completely free of spirals to start; line barely reaches ground so it can let spirals venture off/ not be trapped by weight of line after hitting ground. And also if the line on the Bitters side of device is held to be inline with/ not bent perpendicular to the line on the Standing Part side of device. Muenter is typically harder on line by the sharper bend and rope grinding against self when moving.


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## Tree Machine (Sep 12, 2006)

From Mihalek's question what I hear is that he's found that ascending 1:1 on a doubled line is more efficient; about twice as fast and easier because you have half the number of footlocks as with a traditional 2:1 system to get up there, and many find footlocking two lines with your feet easier than footlocking a single line. He's found the advantage there pretty obvious. This is DdRT vs DbRT.

Once up in the tree, you flipline in and pull the end of your rope up and fashion a traditional friction hitch which, depending on how high up you are can cost you quite a bit of time in getting the rope up there and configuring your hitch.

The question (in my own words) asks, is there a way to safely attach to the doubled line as it stands in front of you and move on to treecare working off these parallel lines.

The answer is a definite yes. The method works identically to SRT; you just treat the two lines as if they were one. Both ends are on the ground and both lines are not moving, relative to the tie-in point. It is a 1:1 abseil where 100% of your friction is created and controlled in front of you and eliminates the need for a friction saver as there is only the weight of you, your gear and your rope on the crotch. The rope presses down on the tree, but does not slide over the area.

There's a number of advantages in speed, efficiency, minimizing gear and lessened rope wear in approaching ascent / descent in this manner. Ya just gotta figure out how to do it.

Since the thread is about using a friction hitch on this 1:1 system, I'll step out. I might use a friction hitch to back up the friction controller, but I wouldn't use the friction hitch AS the friction controller. This doesn't mean it's not possible, but the alternatives to a friction hitch are easy and inexpensive. The hardest part is the shift in mindset.


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## rmihalek (Sep 12, 2006)

I learned pretty quickly from watching Moss demonstrate SRT at the inaugural Boston Tree climb how efficient the 1:1 ascending systems are. I'm still in the DdRT mode, but may switch to SRT for getting into the canopy and then switch to DdRT for moving around once aloft.

This issue of descending on a doubled rope came up when I saw Ekka's video of how they set up a false crotch when doing takedowns (on spikes) so that if a hazard is encountered, the climber can get down fast on the rope with an 8 versus having to spike down. I was wondering if such an emergency descent could be done without a Figure 8 by using some kind of knot combination.

As I mentioned, I tried a Klemheist hitch on a doubled rope and it worked pretty well for a short descent. I stopped descending when I let go and was able to start descending again by applying pressure to the top wrap of the hitch. I'll need to try it on a longer descent to see if it continues to perform well. The cord got pretty hot on the short descent.


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## OTG BOSTON (Sep 12, 2006)

I was always told that the Kleimheist was not suitable for decending. It seems as though the friction you experienced prooves it.

I was in a huge Oak tree at a Mass. Arborists Arborday event the first year I started climbing. An old timer asked if I needed help (it was pretty obvious I wasn't making it down in time for lunch). He had me place a line for him and footlocked with a traditional two wrap prussic made from 1/2 line. Pruned his way up and around, and descended the same way.

In my limited comp. experience we footlocked(timed footlock event) up with either a three wrap prussic or a kleimheist (no mechanical ascenders) and descended on a fig 8. I have to believe if it were O.K. to descend on the prussic they would have asked us to, to speed up the event.


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## Tree Machine (Sep 12, 2006)

rmihalek said:


> I'm still in the DdRT mode, but may switch to SRT for getting into the canopy and then switch to DdRT for moving around once aloft.


This would require the person on the ground to untie your base anchor, and then you haul one end of the rope up and tie and set the hitch. This will work, but takes two persons and a lot of extra motion for this one-person task that can be simplified quite a bit.

What are you using for ascent, Mihalek? In having asked about descending a doubled line, I assume you're ascending, 1:1 up a doubled line and that pretty much means dual ascenders. Is this right?

Ascending 1:1 up a doubled line as compared to ascending 1:1 up a single line is really very similar.


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## TheTreeSpyder (Sep 12, 2006)

SRT gets more elasticity/bounce from the line; than DdRT. DRT gives less elasticity/ bounce to fight when walking up the line, like DdRT. i imagine someone can get to the beat right to use the bounce to throw into next lift; but not me, so the elasticity totally works against me, adding distance to climb etc.

Without Base Anchor; i can SRT up to TIP, secure with lanyard and untie running Bowline, retie in for DdRT. Alternatively have rigging line or other line krab-bed to Running Bowline of lifeline higher than you will need to climb. Do a few cuts on way up, secure self with lanyard (sometimes with a sling too, even if sling support is not totally support worthy, bug just stabilizing or more comfy to lean against etc.), and use rigging line to remotely pull Running Bowline open and bring to you. Retie in for DdRT around that same support; and have rigging line too. Without caring it up, ready to usewith load or have stuff pulled back up . 

i like Pantin and can feel slip of the line when just stepping on one side with it in DRT.


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## PUclimber (Sep 12, 2006)

Tree Machine said:


> This would require the person on the ground to untie your base anchor, and then you haul one end of the rope up and tie and set the hitch. This will work, but takes two persons and a lot of extra motion for this one-person task that can be simplified quite a bit.
> 
> What are you using for ascent, Mihalek? In having asked about descending a doubled line, I assume you're ascending, 1:1 up a doubled line and that pretty much means dual ascenders. Is this right?
> 
> Ascending 1:1 up a doubled line as compared to ascending 1:1 up a single line is really very similar.


You don't have to have someone untie your rope going up single line. You can tie a running bowline if you isolate the limb but you have to go all the way up to that tie in point to untie to get switch over to your drt. This is an okay practice or you can tie off to the base climb up the tree with an extra line and then run drt off a pulley or something attached to a friction hitch where you can work the tree all the way down and then untie from the base of the tree and drop all your equipment out of the tree. This is also helpful in case of an emergency where you have no one else that can climb if you use a belay device or a friction device such as a portawrap then you can be lowered from the ground if you have enough rope on the other end.


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## Tree Machine (Sep 13, 2006)

TheTreeSpyder said:


> SRT gets more elasticity/bounce from the line; than DdRT. DRT gives less elasticity/ bounce to fight when walking up the line, like DdRT. i imagine someone can get to the beat right to use the bounce to throw into next lift; but not me, so the elasticity totally works against me, adding distance to climb etc.


Agreed. I used to favor 13mm stable braid for years, because the bounce was nil. Then the 11 mm stuff came on the market, Velocity being relatively low stretch. MK3, a 11 mm static line is sweet in overcoming rope bounce. Stable braid, I've learned since then, can be special ordered in 11 mm. Very nice.








TheTreeSpyder said:


> Alternatively have rigging line or other line krab-bed to Running Bowline of lifeline higher than you will need to climb. Do a few cuts on way up, secure self with lanyard and use rigging line to remotely pull Running Bowline open and bring to you.


Nice nugget there, Spidey. That's a good one.


PUclimber said:


> This is also helpful in case of an emergency where you have no one else that can climb if you use a belay device or a friction device such as a portawrap then you can be lowered from the ground if you have enough rope on the other end.


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## rmihalek (Sep 13, 2006)

I'm doing all climbing with DdRT for now. I was experimenting with friction hitches using a doubled rope through a false crotch that I made with webbing slings and a carabiner. I will probably eventually purchase a figure 8 and a steel ring friction saver to make a false crotch with but wanted to see if I could get something to work with the gear I already had.


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## SuperDIYer (Sep 13, 2006)

*Hey Tree Machine - Cross Loaded Biener?*

Pardon me for being picky here, but the biner anchoring your Gri-Gri looks cross-loaded (slightly) by the large leather ends on your sling. I see that its a locking biener, but is this a concern at all?

Thanks
jtz


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## PUclimber (Sep 13, 2006)

TM,
That was the set up I was talking about as far as accessing the canopy but you can back up the ascender with a vt on top of that run a carabiner through the eyes and through the hole in the top of your ascender and have a pulley running off that carabiner with your drt system running off the pulley so you can work the tree drt after you get to your canopy or tie in point. So this way you've got a floating anchor point in the tree on your rope. You have to back it up though by tying a slip not below your ascender and clipping a carabiner though the slip not.


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## Tree Machine (Sep 13, 2006)

SuperDIYer said:


> Pardon me for being picky here, but the biner anchoring your Gri-Gri looks cross-loaded (slightly) by the large leather ends on your sling. I see that its a locking biener, but is this a concern at all?
> 
> Thanks
> jtz


That's a good eye, Super. I suppose I should have snugged the one eye over the other eye and dressed it a little better. Still, crossloading needs to be looked at from the standpoint of forces, and where those forces are on the biner. With those eyes, they are distributing, or spreading out the load across the top of the caribiner (it was positioned upside down). The forces are still vertical, the caribiner being pulled lengthwise, parallel to the spine. Crossloading, or sideloading as it sometimes referred, is when forces are applied perpendicular to the axis of the spine.

Anyway, the magnitude of force on the biner is approximately equal to my weight, 165 lbs or 0.73 Kn. This is a 50 Kn triple lock, hardly worrisome. The focus, when setting this rig, was to make sure the eyes didn't interfere with the gate. 

I looked up 'crossloading' in the ISA glossary of arboricultural terms and it's not in there. It was a good question, Super, off the subject, but so was the picture. Normally I anchor using the rope, no slings, and sink two biners, positioned opposite and gates opposed where one of the biners is a triple locker. This particular day I was trying out a brand new 200 foot MK-3 and had a ground guy so I set up a rescue rig. That was also the only time I've ever used that giant blue strap.


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## Tree Machine (Sep 13, 2006)

I enjoy seeing stuff like Tod's floating false crotch. I really try to keep the complexity of the climbing system minimized, straight-forward and swift in setup. Tod's rig has lots of parts and pieces and stuff going on. Fascinating.

Back to Mihalek's original question, and the reason I've hung with this thread is because the the basic system he described, ascending two parallel lines and abseiling down those same dual lines is how I've done it my entire climbing career. This doubled rope technique (D*b*RT) is a 1:1 system which made more sense to me than the 2:1 DdRT. As mentioned earlier the 1:1 DbRT is very similar, almost identical in ascent, as SRT, so moving on to SRT was no stretch. DbRT is still my preferred method, only because it's faster than SRT in that you don't have to take the time to anchor to the base of the tree. If I can isolate the limb or crotch and successfully trace the line back parallel, I climb DbRT. If the trace is taking any time at all, I let the bag drop straight down, anchor it, and climb SRT. It just doesn't matter. They're both 1:1 systems. The rope at the crotch does not move, so there's no friction there, no need for a false crotch. Friction control is on two lines or one line, but handling the friction is very, very much the same whichever way you go.


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## Tom Dunlap (Sep 14, 2006)

TM,

Don't confuse the lingo...DdRT is 'doubled'...

If you want to use D[bee]RT to signify another concept, come up with another name that is significantly different. 

The advantage of using agreed upon acronyms is that it makes writing much easier. Your DbRT is so much like SRT that very few people would understand.


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## Tree Machine (Sep 14, 2006)

As I understand it, both DdRT and DbRT are both doubled rope systems. DdRT is the system, traditional tail around standing, or split-tail where the 2:1 mechanics pulls the rope over the tie-in point as you ascend or descend.

DbRT is also a doubled rope system but is 1:1, you're working your way up and down two parallel lines and they dont move back and forth over the tie-in while ascending or descending. The lines don't move vertically relative to one another. Both ends stay on the ground and the rope sits stationary at the tie-in point.

DRT is *double* rope technique where you are using two seperate ropes. Each of those two can be any one or combination of the three techniques.

I'm not crazy about the nomenclature either, find it confusing which one is the d and which one is the b. I've seen DbRT names _static_ doubled rope, but that can be confused as using a traditional arbo system using a static (as opposed to semi-static or dynamic) rope.


The techniques are distinctly different and I usually describe what I'm talking about in words or pics for the clarification. The thread here is is titled 'Friction hitch on a double rope' but by the opening question it's clear that Mihalek meant to write 'Friction hitch on a _doubled_ rope'.

We hashed out the nomenclature in a thread two or three years ago as to which was the b and which was the d. Still, I'd like to see the techniques renamed for the sake of clarification, like stationary doubled rope or 1:1 doubled.


Tom said:


> Your DbRT is so much like SRT that very few people would understand.


That's exactly my point. They ARE almost identical. Other than the base anchoring of the SRT line, you are either ascending/descending one line or two.

What do you think, Tom?


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## PUclimber (Sep 14, 2006)

TM, 
Look at the sherrilltree catalog. Ddrt is the doubled roped technique which is your 1:1 system. There is no Dbrt unless you have something that no one knows about. The Drt is just the double rope technique using the 2:1 system. From what i know Tom is a wise man and knows his stuff and this point there is no arguing that the man is right.


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## TheTreeSpyder (Sep 14, 2006)

Ummmmmmmmm with all due refverance to Tom; i believe other disciplines look at DRT as 2 seperate lines of support in a failsafe fashion; mostly of different elasticity ranges too. Somewhere's along the way; the tree sector etc. seems to have taken the same accronym for a single line doubled over a support to form a retrievable SRT. 

So that in our DRT line isn't anchored at ground (inducing double loading of support and more line elasticity by length and tensile both); nor choked remotely to support/ TIP(that gives no double loading of support and higher elasticity than DRT by tensile). Our DRT is retrieveable and gives less elasticity; like our DdRT. Only our DRT would be 1:1 like SRT; DdRT giving 2:1 potential.


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## Tree Machine (Sep 15, 2006)

TM, 
Look at the sherrilltree catalog. [/QUOTE]The Master Catalog, Fall/Winter of _Ascend_? Ddrt is the doubled roped technique which is your 1:1 system. The Drt is just the double rope technique using the 2:1 system. From what i know Tom is a wise man and knows his stuff and this point there is no arguing that the man is right.[/QUOTE]No one's arguing. This isn't stuff I made up. The delineations are from a thread years ago in the Rocky J Squirrel era. 

The Sherrill Master Catalog doesn't describe anywhere how to descend down a doubled line as asked in the opening question. The DdRT page 46 shows only ascenders, dual ascenders and marbar for going up a doubled line. The following page shows the figure 8's. The eared rescuescender will allow abseiling down a doubled rope, but the catalog shows the 8 set up for SRT. *Coming down a doubled stationary line is not described in the Sherrill Catalog*. It never has. Good catch, but does that mean it _doesn't exist_, or that I'm making it up?


> There is no Dbrt unless you have something that no one knows about.


 This is not my original stuff, so I can't accept credit for it. 

Very few descend a doubled stationary line, I'm becoming more aware of that as time goes on. But I don't have something no one knows about. 1:1 descent down a doubled rope is what this thread asks about, so at least one other arborist has pondered the question. I just chose to travel down that road and have been climbing regularly in this unheard of style for better than 13 years. It would take a lot of convincing that no none else knows about it. It's been discussed through the years. Few climb it probably because it's not in the Sherrill Catalog. 1:1 descent has a number of advantages. If you can go up 1:1, why not come down 1:1. This is what the question asked, though he wanted to know if you could do it using a friction hitch. This is cool. We're staying on topic.


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## rmihalek (Sep 15, 2006)

Yeah, I realize now that I used the incorrect terminology when posing the original question. I meant to ask about descending on a doubled rope (i.e descending on a rope that goes up and over an anchor point, coming back down with the two standing parts running parallel to each other all the way to the ground).

I'm still waiting on the chance to try descending on a doubled rope for a good distance. I tried the "low and slow" descent with a Klemheist hitch and it worked okay. What I want to do now is establish two TIPs, one with my usual DdRT set up and then a second, lower TIP on a doubled rope with a Klemheist hitch. The higher DdRT will be my backup in case I burn through the Klemheist or something else fails. Maybe I'll get a hank of that Bee-Line friction cord before I try this...

TM, you haven't mentioned yet how you descend on a doubled rope.:help:


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## Tree Machine (Sep 15, 2006)

rmihalek said:


> TM, you haven't mentioned yet how you descend on a doubled rope.:help:


How do I descend? Isn't it obvious??? You put on your bedroom slippers and sing the Periodic Chart of the Elements.



Duhhh


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## PUclimber (Sep 15, 2006)

TM,
The big thing then is where did you get D*B*RT. We see the Drt and the Ddrt but everyone is trying to figure out where the B comes from.


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## Tree Machine (Sep 15, 2006)

First, it's D*b*RT, small b. A thread three or four years ago. Tom was part of it, John Paul Sanborn. There were plenty others, too.

A quick use of the *search function* (which you apparently didn't do) of just the acronym *DbRT* shows 39 threads with a combined total # of views at 164,632. I was not even part of some of those threads.

I've done your research for you. Mebbe you should read through those and re-open some for debate.


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## rmihalek (Sep 19, 2006)

The video is nice, but there's not enough detail of the set up. What kind of knot do you have your left hand on? What are you running the rope through on your saddle?


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## Tree Machine (Sep 19, 2006)

No, it's not an 8. 

Figure 8's, used in a traditional manner, will twist your rope, not acceptable if there are better alternatives. The Petzl Pirhana is a well-designed aluminum 8 with horns. I have one, but never use it. It'll twist rope also.

I much prefer to interface rope with steel, without any twisting.


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## Tree Machine (Sep 19, 2006)

I use fairly simple stuff. I'll have to think back of what I was using that day. No pat pending. Not using anything that's not already out there, just might be using some of it in unique ways. 


It varys quite a bit what I'll apply to a single or doubed stationary line. Either way, the device has to handle either the single rope, or the doubled rope identically. In the 11 mm world, a lot of stuff opens up to you. So very many pieces to try, so little time.


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## Tree Machine (Sep 19, 2006)

TreeCo said:


> I love the weightless feeling of a fast repel but I don't do it often. Mostly I go slow and enjoy the view.


Going off my porch in house slippers was not a _fast_ rappell.



What were you using, or thinking of using to descend Mihalek?


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## Tree Machine (Sep 19, 2006)

On a 2:1 system, twice as much rope goes through the hitch as in 1:1, plus you have additional friction over the limb or through a friction saver. You get heat and wear

Friction can be increased by increasing the force of pressure on the rope, or by distributing lesser force(s) over a greater surface area. A friction hitch is coering maximal surface area. A device is concentrating all friction on a specific, single place along the single or doubled line. A good piece will allow you 100% precision control over the friction with as minimal an effort as it takes.


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## TheTreeSpyder (Sep 19, 2006)

*Some thoughts:*

Friction is a help on hold and descending/ hold or extension on jig; only fight it on ascending/ compressing rig. 

Hanging still on DdRT is a 1:1 though; your weight pulls down on 2 lines that are pulling up on your weight; 1:1. 2:1 comes in like when you pull on 1 leg of line with effort; that causes 2 pulls on you as load. Just like pulling 1 leg of line that laces thru a pulley on load; the 1 pull of effort gives 2 pulls on Load. Or, if you grabbed both legs of line at oncet and climbed up; you would be pulling down on 2 legs of line that were holding you up for a 1:1. 

Too much friction can melt a cord; i think there are more stories of this in rescue/ mountain SRT with someone trying to force descent on friction hitch. i stick with my model that friction hitches slide on descent in DdRT; because sliding the hitch is really lengthening that supporting leg of line; and just like 2 separate legs of support on a load; if one stretches or starts to fail, the other takes the load automatically. This automatic shift of load to the nonstretching leg of line terminating on saddle; unloads the friction hitch instantaneously; allowing slide. So at this point, there is lots less than half load on friction hitch; or i could descend on same gear in SRT as JP on DdRT. Figured that out and tested with scales after searching long and hard for friction hitch to descend on in SRT. SRT or DRT does not offer the system of support another leg of support to carry the load as hitch slides; so doesn't work; hitch clamps tighter(as system tries to effect support), overheats cord etc. So, i can't use same gear setup to descend in SRT as someone 2x as heavy/ but only half loaded hitch in DdRT; the mechanix are much different than than just the 'obvious' 2:1.

All friction counts; and adds up to load + descending rate etc. Friction at hitch and feet is nicer on ascending; because you have to fight the remote friction at support; but can relieve friction load on feet and hitch and move forward as needed. One catch on descending is, that less friction allows less support; that allows you to descend faster; that causes more friction(so increase in speed or weight also gives increase in friction)!

Friction spread out/ apart on descending like so much on support, so much on hitch and so much on feets etc.(to add up to support - your movement); give a break between friction points for cooling down, rather than concentrating all friction to build in just one point like just at friction hitch with pulley as support or several friction points instead of just one on lowering loads keeps line cooler etc. IMLHO.

i don't like coiling on Fig.8's and muenters; but think it seems Natural to hold brake hand/Bitters(line part after friction device) at 90 degrees/perpendicular to support/Standing Part (line part before friction device); and this gives more coiling i think. Holding brake hand/ Bitters inline/180 from support line/ Standing Part gives less coiling.

Friction is inevitable in DdRT for it is a simple machine; each force conversion thru a machine must have some inefficiency/ tax on force at exchange; or there would be a perpetual motion machine. These energies are neither created nor destroyed just recycled/ altered into another energy form; like the evil that wouldn't die in the Denzel Washington movie (appropriately named for my purposes) "Fallen"! The heat byproduct from the friction inefficiency is energy released to atmosphere; in partial exchange/ balance for all the sun/heat energy reigning down as part of this far reaching energy is neither created or destroyed principal!

A rose is a rose by any other name; just let me know what you call it! Many times i could not take credit as idiot nor genius; but as thief; when using 'new terms' / acronyms taken from other places and disciplines. Why re-invent the doughnut or wheel or whatever ya call it?! Peace!


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## rmihalek (Sep 20, 2006)

TM, I was hoping that there was some type of friction hitch that could be used on a doubled rope that would work just like a Blake's on DdRT. I like the feature that when you let go of the Blake's, you stop. The thing that gets me about descending on a 8, is that you don't have that feature. You need to tie a hard lock to stop descending.

Was TreeCo correct when he said there is no knot in your left hand when you were descending off your porch in that video clip? If so, then you're just relying on this mysterious device on your saddle for which you can't/won't name for us?


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## Tree Machine (Sep 20, 2006)

No, I just am trying to recall what I had up there.

As far as a friction hitch, I suppose something is possible, but we need to talk about heat.

Spidey started us on this, others have made mention, but let's look at heat real close, look at it in the practical perspective of the scope of our work, and keep heat generation in the realm of the tree, not recreational trees like redwoods and sequois, but all other trees that we climb and care for.

Heat and friction and ropes, and mass and gravity. Those are the ingredients for a good climb. Friction is required for us to overcome the effects of gravity which pull us down in an accelerating manner unless we apply an outside force, a pressure on the rope, an amount of pressure equal to, and opposite the force of gravity.

How the pressure is applied is, I think, is what's keeping this thread alive.


Using a traditional friction hitch, or a tress cord, or a split tail, you are depending on a maximal area of two opposing surfaces to create enough friction. Each wind picks up it's share of the work, and of the heat. The more wraps, the more distributed the heat dissipation. Heat concentrates in the friction hitch, not so much the rope. Heat and friction eat these friction hitches and they need to be replaced from time to time, and the performance changes as the hitch wears. Rope-on-rope friction.

With a device, you get the same friction, equal and opposite the force of gravity, sufficient to keep your (m)ass from hitting the grass.  
Only this time, you're going from a widely distributed friction force of light pressure (hitch system) to a finely positioned, stronger pressure (metal pieces). _The friction is the same. The heat generated is the same_, just enough to oppose the force of gravity. The friction is accomplished by different means, that's all this discussion is about.

The 1:1 system may seem a challenge for many of you, but that is only because the limitations of the friction hitch do not allow it's practical use on a doubled, or a single 1:1 line.


Before I go any further I just want you to know that I love and enjoy the friction hitches. To adapt to mechanical methods does not mean giving up friction hitches. It's not an either / or. It's adopting different methods to be better all-around climbers. This talk of mechanical devices in tree care shouldn't insult your manhood. 1:1 systems do not have to replace the 2:1. It's just that in the climbing world about us, nobody climbs as much as the Arborist. We should be more skilled than any of the other climbing trades by the sheer number of hours we are actually climbing and using ropes. Besides, we know the friction hitch systems, which other climbing industries will probably never know. We need to keep friction hitches alive as part of our overall industry identity.

By stretchin our skill base just a bit, we can explore the ways of other climbing disciplines in ways they can't ours. They use devices, and generally 11 mm rope for which most pieces are designed. We've been in the 11 mm era for about three years now, but as an industry, we've only begun to explore mechanical devices.... well actually, as a group, I don't think that trend has even begun yet.

Mebbe it never will. Conventional ways, the tried, the true, the tested, they never go away. Friction hitches will always be unique to our discipline and should be preserved.


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## TheTreeSpyder (Sep 20, 2006)

A difference in heat is also that the metal devices act as a heat sink; to drain heat away from production site on rope somewhat; especially aluminum. Whereas, a cord as a friction device tends to insulate/ hold the built up heat in one place/ while more is being produced in that same place.

The lower loading by half load on DdRT(compaired to SRT\DRT); then relieved as other leg of line terminating at saddle takes load; gives lots less friction thereby heat. But; if you can still be burnt or burn cord with that; just imagine the friction/ heat of cord fully loaded/ with no possible relief in 1:1 methods of no separate helper line to automatically carry loading(per previously dis-cussed model) when hitch tries to slide/ you force slide in SRT/DRT!


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## Tree Machine (Sep 21, 2006)

Well-said, My Spidey. Looking more precicely at how friction is generated and where the friction is created allows us to know where the heat is being generated and then dissipated.

Spideys point about a metal piece acting as a heat sink, and cord-on-rope insulating and building up heat before it is lost is true. Heat has to follow certain laws of physics and for us to know just a touch about that can help us understand better what's happening right in front of us.

Heat flows spontaneously from an area of high heat, to an area of low heat, not the other way around. Things are not 'cooled', things lose heat. We see our weather as getting cooler overnight, but more accurately, the earth and air are losing heat as it flows spontaneously to cooler places in the atmosphere.

All that aside and getting back to a specific place on a rope, where there is pressure being applied to oppose the effects of gravity you are changing energy from one form to another; your downward motion, being stopped by pressure on a line from an outside force known as friction converts _kinetic energy_ (the energy of the motion of mass) into heat. If you weigh 75 Kg (168#), you're on rope, you go from a hanging stop, drop down 1 meter and come to a complete stop, you have created a specific amount of heat, which will move from the area of high heat to the area of lesser heat spontaneously. If you weigh 100 Kg (224#) and do the identical same thing, it takes additional friction, additional opposing force because the mass of the object is bigger. This makes sense, without understanding the details.

Lighter guys make less friction overall, but light or heavy, something still has to be done with the heat.

If you create friction in different places, the heat is split up, create all the friction in one place, you get all the heat in one place. Increasing the surface area over which the rope passes will increase the placement and distribution of the heat over a bigger area; no 'hotspots'.

At this point we can talk about a couple classes of friction pieces called _belay devices_ and _rappel devices_ and how that applies practically to the treeguy as to which is which and why that's important to know.


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## Tree Machine (Sep 21, 2006)

Before we go any further, does this Jive with everybody? I mean, if I am full of crap, please call me out. If you're freaked out about this talk of using metal pieces in treecare, or you're just very intimidated by it, by all means, step up and tell us why. We can use this as group counseling.

I think, though, as you understand the dynamic of friction generation and heat transfer you'll get very clear on what the device is doing for you.




Questions?


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## squisher (Sep 21, 2006)

Keep going very intriguing and interesting. One of the best threads going right now.


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## OTG BOSTON (Sep 21, 2006)

Tree Machine said:


> Before we go any further, does this Jive with everybody? I mean, if I am full of crap, please call me out. If you're freaked out about this talk of using metal pieces in treecare, or you're just very intimidated by it, by all means, step up and tell us why. We can use this as group counseling.
> 
> I think, though, as you understand the dynamic of friction generation and heat transfer you'll get very clear on what the device is doing for you.
> 
> ...



TMI---not that you all haven't made valid points. 

Bob's original question was if anybody was using a friction hitch on a double rope. My answer, NO, however I did see an oldtimer use a traditional two wrap prussic(half inch line) on a doubled half in. line.

Then I think the question changed to are there any other devices that can be used? I don't know of any.

Bob, correct me if I'm wrong but you used my double ascender at the climb event we did, and all you want to know is if there is a device that can go up like the ascender AND lower you safely to the ground, without changing hardware.

Having said all this: I  am easily confused so please continue


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## Tree Machine (Sep 22, 2006)

> Bob's original question was if anybody was using a friction hitch on a double rope.


First, he meant to say 'doubled'. Bob went on to ask 'is there a friction hitch that will go down a stationary, doubled line' and that he has ascended on dual, and was wondering if, rather than pull the tail up and fashion a traditional 2:1 DdRT, could he just go _onto_ the dual line and descend it. That was the question. He was just asking if it could be done on a friction hitch.


"No" was the quick answer to that and our talks of heat generation and friction can help better understand the 'why?'. Excess wear and tear, and poor overall performance.


> I did see an oldtimer use a traditional two wrap prussic(half inch line) on a doubled half in. line.


And how fluidly was he moving about the crown with his chainsaw, pole pruner, two silkys and a rack of slings and biners? If he can't move through the crown with tools and get his job done, the technique is useless in commercial treecare. 100% total control of the friction using minimum effort is not achievable with a two-wrap prussik.


> Bob, correct me if I'm wrong but you used my double ascender at the climb event we did, and all you want to know is if there is a device that can go up like the ascender AND lower you safely to the ground, without changing hardware.


You're talking about an all-in-one unit. That's called the unicender. If there were a miracle device out there that was rock-solid in it's ascent & descent capabilities, a one-piece, do-it-all device, I think you would have heard about it. It's not out there, but maybe some day it will be.

For now, we have awesome ascenders that ascend like there was no tomorrow. It is what they were designed and intended to do. There are lots of models to choose from, even titanium. It's very efficient which is why we use ascenders in the first place. 100% control of ascent. We have ascending covered. 

Descending on dual, now we get back to the question and keep this train on track.


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## rmihalek (Sep 22, 2006)

OTG, I vaguely recall your climbing rig but not accurately enough to expound on its virtues. One thing I was saying to Moss when discussing the next Boston Rec climb was that I wanted to try your system out some more. I seem to recall that I could just climb the rope hand-over-hand and if some one was holding the running end, the hitch would self feed and I could zoom right up the rope.

TM, I have no problem using a metal device for self belay when descending. Does anyone know if such a device is made that can be used on a doubled rope and has a "let-go-and-stop" safety feature similar to a Blake's Hitch on DdRT?

I guess what I'll eventually end up doing is ascending with SRT and then switch to DdRT for moving about the tree and a self-belay descent.


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## TheTreeSpyder (Sep 22, 2006)

i think in general; hardware you can descend on you can't use as safety to ascend on; because you can place pressure below the device to lift self or device fights you. grabbing higher than device; rope won't pull through device.

Similarly, holding a line tight below someone, can make it easier to ascend with software (hitch); but impossible with descending hardware (fig. 8, Muenter);as one of the defining characteristics of the 2 strategy types.

More and more examination has all ways brought me back to more respect for each system; in it's own specialty; including our hitches on DdRT; in their correct place/ setting. Especially when i tried to find a similar ascend/ descend hitch/hardware to work as well in SRT/DRT/DbRT 1:1 strategies as cleanly as our handed down DdRT(besides it's particular flavour of 'faults'/ tradeoffs).

Friction is how it these machines all work to support; but as a double edged sword of it's own yin/yang tradeoffs; also what we fight in these devices.


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## jefflovstrom (Sep 22, 2006)

I cannot believe this is still going on.
Jeff Lovstrom


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## squisher (Sep 23, 2006)

C'mon man it was just started on the sixth that's not that long. Isn't this what it's all about sharing thoughts, theorys, and experiences with different gear and techniques. I mean what else are climbers going to talk about.


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## Tree Machine (Sep 23, 2006)

Jeff, we're just getting warmed up.

Of the hundreds of threads, only a handful are about climbing, I mean, _climbing._ This is commercial treecare, meaning we get paid for what we do. The forum is called Commercial Tree Care and* Climbing*. The thread, right here, right now, climbing. This is highly focussed, specific to one little-used rope method and we're about to fully describe it as it applies to professional tree climbing. This is as climbing as it gets.

Coming down a dual line has been lightly gone over at Arboristsite for just over 4 years. This is the furthest we've gotten yet.


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## OTG BOSTON (Sep 25, 2006)

rmihalek said:


> OTG, I vaguely recall your climbing rig but not accurately enough to expound on its virtues. One thing I was saying to Moss when discussing the next Boston Rec climb was that I wanted to try your system out some more. I seem to recall that I could just climb the rope hand-over-hand and if some one was holding the running end, the hitch would self feed and I could zoom right up the rope.
> 
> TM, I have no problem using a metal device for self belay when descending. Does anyone know if such a device is made that can be used on a doubled rope and has a "let-go-and-stop" safety feature similar to a Blake's Hitch on DdRT?
> 
> I guess what I'll eventually end up doing is ascending with SRT and then switch to DdRT for moving about the tree and a self-belay descent.



That is a schwabish prussic with a micro pulley---very simple rig. I thought you were referring to the doubled ascender I have for footlocking.

Using both is probably the way to go!!!!!!!!


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## Tree Machine (Sep 25, 2006)

Please describe with a picture if possible. Arboristsite visitors just love pictures.


A picture of friction is a toughie. Friction is a force, like magnetism, gravity, elesticity. You can't see the force itself, which makes it a little harder to understand. But you can experience the effects of the force, and you generate heat as a by-product.



Controlling friction, therefore, is controlling heat, meaning the less friction overall you apply to the hitch or device, the less wear and tear on all parts of the system. Highly accurate application of either lower-pressure, distributed friction or higher pressure, concentrated friction. In the dual-line setup we are talking about with the two lines, each line need only pick up 50% of the friction duty. The pressure really isn't all that great. The friction, by design, is being spread over a more distributed area. How you climb and how heavy you are will dictate how much friction and wear you are creating.


The design of the device may keep ropes seperated (maybe by just a couple millimeters), OR the design of the device (or your unique use of it) may cross the rope over itself creating a 2-part friction system in one.

The simplest sub-family in the world of mechanical pieces uses simply rope-on-metal.


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## SRT-Tech (Oct 11, 2006)

TreeCo said:


> We are pretty much in 100% agreement on this subject. I would like to point out that all of the friction at one point does generate quite a bit of heat too. I've heard stories of long, fast descents......that when brought to a stop..... the device has melted the climbing rope...resulting in a fall.
> 
> I've never known someone this has happened to but it does sound plausible, or it could be an urban legend.




Its called _"rope lubricated rappel causing uncontrolled descent"_, common with rappel racks on LONG DROP (200 - 3000 foot rappells on big walls). basically the rappel rack (on long drops) CANNOT dissipate the heat (caused by friction) fast enough, which causes the rope to get glazed, then you descend faster, then the rope and rappel rack heats up even hotter melting the rope, which in turn further lubricates the rack with hot melted nylon, until you simply cannot control the rappel anymore and you slide at high speeds into the ground. Often time the rappel rack and the base of the big wall/cliff will be covered in orange sized globs of melted rope. 

when you suddenly stop a rappel, the heat buildup in the device is CONCENTRATED on one tiny spot of the rope (around 2 - 5 mm), thats why in some cases it will suddenly melt thru (if the heat on the rappel device is hot enough). That is why it is better to COMPLETE your rappel to ground, then keep pulling rope thru your device to prevent hotspotting.

Now if you think this _("rope lubricated rappel causing uncontrolled descent")_ is possible in in tree climbing, think again.....we are NOT descending LONG DISTANCES or descending LONG ENOUGH to create excessive heat!!!!! . We are descending maybe at the most 200 feet, if that. There WILL be some heat from friction, but not enought to cause the treeclimber to enter that "rope lubricated hiway of death". 

ON ROPE goes into more detail about this, but we as treeclimbers really dont need to worry about it.


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## Tree Machine (Oct 12, 2006)

Thanks for that, SRT Tech. Another note to add to the friction / heating scenario is that the heavier the climber, the more the friction (as well as tension on the rope). I am in agreement with you that "rope lubricated rappel causing uncontrolled descent" is very, very unlikely in tree climbing. Possibly in recreational where the highest trees are often the goal or inexperienced yahoo demons showing off, rather than paying attention to their safety.

I attended a presentation last year at our monthly caving meeting. One of the members had had been out to a national park and rappelled down the face of a monlithic boulder called Half Dome. It was shaped like half a boulder, but had the size of a mountain. It was a very, very long drop, a good chunk of the day just coming down a rope. The presenter said he could sense the heat building up to dangerous levels and used his water bottle, drenching the rack to pull off more heat. It's probably a good thing he did. Those oblivious to the heat generation will be the ones lying next to the gobs of melted plastic.

Over the last 14 years I have used a lot of different devices and all the friction hitches ever covered here at Arboristsite. Close attention is paid to heat, friction, wear on the device/hitch/tress cord and the wear on the rope, as well as how tight a bend on the rope as it passes over a device at the point of friction knowing that the tighter the bend, the more stresses on the fibers and weakening of the rope at that point.

A parallel doubled rope takes 1/2 the friction per line. Additionally, if the friction center utilized both rope-on-metal friction as well as rope-on-rope friction, as well as control friction from your hand, the heat is distributed around and shared to a good degree. Any heat generated _into the rope itself_ is left behind (above), sparing the device from the full amount of heat buildup. Personally, I like a setup that distributes the heat around in this way, rope-on-rope and rope-on-metal. Most devices, however, take the entirety of the friction (pure rope-on-metal). Some will be absorbed by the rope, but rope doesn't absorb heat well (unless it's wet).

Thanks again, SRT. I would encourage everyone, however, to be aware and be in understanding of what is going on. A simple, non-scientific way to measure the heat generated after a long descent or a really fast descent is to touch the device. If you want even more accurate non-scientific measurement, purse your lips right up to it without actually touching. If you do this 50 or a hundred times you get a very good idea of the level of heat you're generating. Like SRT says,


> we as tree cimbers really don't need to worry about it.


 As far as the use of devices on a doubled parallel line, it's more important to apply the rope within the device correctly, to be certain how much hand-control it takes to slow or stop, and where are your positions for soft lock / hard lock. Each device is unique, even within the same class of devices. Each class works on the same principal, but it is the finer nuances of it's performance that will determine precisely how it is used.


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## Tree Machine (Oct 12, 2006)

The next very important point (before we actually go into specific doubled rope descent devices) is the difference between two similar terms.

The terms are *Rappel* (or abseil) and *self-belay*. Anyone wanna take a stab at how these are different?


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