Using single line technique for more than ascent

Re: Using single line technique for more than asce

I'd be sorry to see the friction hitch go by the wayside. I use them now and then, just to keep in practice, and demonstrate how climbers of yesteryear once did it.


"They called this little number a Blake's. And they actually got tree work done climbing on this thing."
 
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...Keeping in mind I plan on getting a Rig to use in a RADS system because I can recognise its attributes for my intended use, I do not think an argument based on which one uses the least support gear is viable.

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I hope we're not arguing. I think discussions like this are beneficial. It helps every one see potentials of climbing systems.

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...But a young and strong climber needs nothing more than the Uni on a tether to enter and work a tree. So that would win the "least support gear contest" but does not address if it is the best tool for the job at hand or the person doing the work.

Dave

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You see Dave that's exactly what I'm talking about. Tell me how a young, strong climber would climb with nothing but a Unicender and a tether. A tether to what BTW?

I presume you mean a tether to that upper ascender, don't they have to buy that? Isn't that a significant piece of gear?

And, the ONLY way they can climb on that is in a sit-stand mode - they cannot ropewalk with just the Unicender and the upper ascender.

Let's check the list and I won't even list costs:

Unicender:
1- Unicender
2- Tether
3- upper ascender
4- foot loop
5- chest/shoulder strap

RADS:
1- upper ascender
2- Grigri
3- $12 pulley
4- foot loop
5- optional tether

I don't use the tether, but some do so I included it.

What do I get for the exact same number of gear requirements with the RADS?

1:1 on the legs, 3:1 on the arms; stand-alone climbing with the arms only even if there are no limbs to put the feet on. Knee relief. Instant escapability?: it has to be setup correctly but requires no additional gear. Limb walking with no changes, additions whatsoever. Tail tending - built in. return from limb walking: tail tending pulls toward you rather than away from you and it's built in - requires no changes, modification, re-arrangements.

What about the Unicender - with only the gear listed? 1:1 on the legs in a sit-stand only mode - rope walking not possible without adding gear - a Pantin and a chest strap/harness. Hands only climbing would be quite difficult as the climber's arms would have to lift his full weight each stroke. Escapability: that upper ascender has to be disconnected or the tether to it has to be disconnected. Tail tending - self-tending. Returning from a limb walk: a little bit more involved tail tending.

Again, I certainly don't mean to be or even sound argumentative, but I am trying to disclose all the gear requrements of each system.

A lot of claims have been made about the Unicender, all of which are true, but they don't fully disclose everything. Just like, 'a young climber can climb with nothing but the Unicender'. That's simply inaccurate; at least one ascender is also needed and some kind of chest strap.

And again, nothing at all against the Unicender, I realize it's a fine versatile piece of gear, but it does have some competition.

Also, to reiterate, a lot of this doesn't even matter. Once a compact, electric personal ascending/descending device is available and affordable, and that looks to be just around the corner, none of this will matter anyway.
 
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... Has anyone here ever even heard of a failure in TIP?

If you are pruning, what kind of forces can get generated by a handsaw cut... if you are using a chainsaw, you should have a second TIP anyhow..


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Didn't Mark Bridge (or one of the Treemagineer guys) fall only a few feet when his SRT TIP failed and he hit the ground breaking ankles?

And I've seen some extreme forces being generated from a handsaw pull, definately enough to shear a tensioned static line quickly.

And lastly, I don't think that Ddrt can be considered "halved" compared to Srt. I mean in ddrt the rope is up over the tip and back to climber. Depending on how close the climber is to the TIP, it seems that the distance can vary comparitively.
 
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... Has anyone here ever even heard of a failure in TIP?

If you are pruning, what kind of forces can get generated by a handsaw cut... if you are using a chainsaw, you should have a second TIP anyhow..


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Didn't Mark Bridge (or one of the Treemagineer guys) fall only a few feet when his SRT TIP failed and he hit the ground breaking ankles?

And I've seen some extreme forces being generated from a handsaw pull, definately enough to shear a tensioned static line quickly.

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WOW! Scary stuff!

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And lastly, I don't think that Ddrt can be considered "halved" compared to Srt. I mean in ddrt the rope is up over the tip and back to climber. Depending on how close the climber is to the TIP, it seems that the distance can vary comparitively.

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First let's be very careful what we are saying. If you have a doubled rope over a limb and both sides come back down and attach to the climber, as in DdRT, that configuration will be twice as 'stiff' for a shock load as a single rope cinched to the limb and climber. Here's why.

Let's say we have 10' of rope that stretches 6" with a 200 lb climber on it. If we suspend the climber on one piece of 10' rope cinched to a limb, how much stretch would we get? Six inches.

If we suspend the man with two 10' pieces of the rope how much stretch will we get? Well each strand has half the climber's weight, so each rope would only stretch half as much as a single rope. So the total stretch would be 3".

But what we've been talking about is a ground anchored rope. This is a different thing entirely. If the climber is the same ten feet below the TIP and the TIP is 50' above the ground anchor, how much rope is between the climber and the anchor? 50' from the anchor point to the TIP and 10 more feet back down to the climber. For the moment, assuming negligible friction over the limb, how much stretch would we get? We defined the rope as stretching 6" for every 10' with a 200 lb load. Since we have 60' of rope, we'd have 3 feet of stretch!

That same principle comes into play for shock loading. There's just more rope to absorb the shock, or more rope to stretch.
 
Since rigging/climbing loads are always in flux it's easier to speak of finites. Halving loads is easier to say than going into the minutiae all over again. The concept of halving and doubling is what I am getting after.

To learn about this...get a fish scale, shoelace, tiny pully and a small water bottle. run through the variables...you'll be able to scale things up. Then, change the shoelace to some thing more dynamic like elastic shock cord.

If I wanted to all I would need is the Uni attached directly to my bridge, or even a biner/link to change the phase of the connection. Then, footlock up. I 've done this without a bungee neck strap and the Uni does tend to stay in line. At least with my TreeFlex and a short bridge. No changeover to come down, no extra gear.
 
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I hope we're not arguing. I think discussions like this are beneficial. It helps every one see potentials of climbing systems.

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...But a young and strong climber needs nothing more than the Uni on a tether to enter and work a tree. So that would win the "least support gear contest" but does not address if it is the best tool for the job at hand or the person doing the work.Dave

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You see Dave that's exactly what I'm talking about. Tell me how a young, strong climber would climb with nothing but a Unicender and a tether. A tether to what BTW?

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I love discussing climbing with people that are interested as it has been such a large part of my life, and I continually search for personal improvement. So keep the questions coming.

The Unicender can work SRT in a stand alone fashion by attaching the tether to your saddle.(see attachment) Like I said this will work for the young and strong that prefer a minimalist approach. For ascent you foot lock the tail and then clip the Uni close in for work positioning.

I would have loved to have had one in my 20's.

Dave
 

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Again, it can be done, but how many actually do that? SRT footlocking is not something everyone can do - I can't. Even what little success I've had SRT footlocking, it's exhausting.

So to me, what we're now claiming is that SRT foot locking with a Unicender is an efficient way to climb. It's interesting that neither Tom or Dave actually do this simply because it's too hard and takes too much energy.

And, that young guy is still expending more energy that he needs to or should. And, let us not forget why most of us don't use that method - we got older - which unfortunately, is what we're doing everyday.

But, conceding that it is possible, although the practicality and efficiency is debatable, I'm 64 years old and still climbing on a RADS and haven't had to add any gear to compensate for age. I seriously doubt there are any 64 year olds SRT footlocking on a Unicender, and in reality, I bet not many young guys are either, and if they are, they probably won't long.

My left knee is showing some signs of stress. Just imagine what I'd be experiencing after years of full body loading on each knee in a ropewalker.

Which brings us back to 'practical' climbing with the Unicender. For practical climbing, the upper ascender is gonna be needed and the gear list for the Unicender and RADS are the same number of pieces.
 
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That's sweet Dave! Do you climb with a static or climb line when climbing with the Uni in that fashion?

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Arbor Master 13mm works best for me. Do make note, I will demo this method but I do not work with it. I like all my little climbing crutches.

Dave
 
My point is "the best" climbing system depends on what you want or need. Picking out or expounding on certain attributes may have little relevance if they are not what you need.

Dave
 
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...If the climber is the same ten feet below the TIP and the TIP is 50' above the ground anchor, how much rope is between the climber and the anchor? 50' from the anchor point to the TIP and 10 more feet back down to the climber. For the moment, assuming negligible friction over the limb, how much stretch would we get?...
That same principle comes into play for shock loading. There's just more rope to absorb the shock, or more rope to stretch.

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We know the friction isn't negligible, and I can tell you roughly what it is! I've measured it several times and it comes out pretty close to 2:1. What I mean is this: when a downward moving load is causing the rope to slide across the TIP, that rope leg has twice the tension of the anchor leg. That 50' of rope acts more like 25'

You can imagine a situation in which a climber comes to rest with the forces on the two legs of his/her rope in a 2:1 ratio. The total downward load on the limb is then 1.5 times the climber's weight, not 2X. Where did the rest go? It is still there, in the form of torque on the limb. Whether the limb likes that better than straight downward force I have no idea. These are just amusing quibbles, but rock climbers actually pay atention to the friction at their highest protection point. It makes the long leg of rope down to their belayer much less effective at absorbing the shock of a fall.
 
I am completely, completely sold on working the tree SRT. I cant imagine doing things the old way anymore. The Fate system of climbing is very cheap and riggable in a lot of ways. Climbing SRT is not inherently gear intensive. The basic components can be a hitch and a Fate; or a heat sink.

http://www.youtube.com/watch?v=XyXwrXgN0qw

(i really need to revise this video because a lot has changed now) ie. subsitute Kong robot and a lot more simplified ascent.

I remember listening to Tom Dunlap in 2002 Detroit TCIA talk about how the future of climbing was SRT and double rope would be a thing of the past. to me he is absolutely right. I dead wooded 9 oaks with out touching the ground a few weeks ago. Dont mean to boast.. or yes i do. My point being this would not have been possible with me in DDRT, I just don't see it. And definitely not in the easy time it took me.

It would have involved numerous complicated redirects, stuck lines And not being able to get to the tippy tips of the limbs. I was not a shabby climber dDRT but i know I am countless times more effective and fast with a single line. A good groundperson who can safely connect and reconnect you to the ground is the only thing needed to traverse through the canopy.

The ground line can be set strategically away from cutting action. sometimes it is threaded around the outside of the canopy and tied to a remote tree. the forces become so spread out that even if one limb where to break, you are redirected. this of course takes strategy but I feel safer and I can achieve far far better tie in points than in dDRT. TIPs that are backed up by the tree itself. In a removal, a simple runing bowline is all you need for a tie in point. My friction savers are feeling neglected. Srt simplifies so much about climbing.

I have a feeling that all these different tools for SRT don't really make a big difference. because you are receiving such a big benefit from being srt in the first place. So discussing whatever tool you use to achieve working SRT just becomes like comparing a swabish to a distal or a VT. Kind of fun to talk about but its really whatever floats your boat.

the last climber I trained, I trained dDRT. she is comfortable with it now and is somewhat reluctant to change. The next climber, I will teach SRT first. dDRT as something you can also do in case of emergency. But I want him to be comfortable with the more productive climbing method first.
 
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...We know the friction isn't negligible, and I can tell you roughly what it is! I've measured it several times and it comes out pretty close to 2:1. What I mean is this: when a downward moving load is causing the rope to slide across the TIP, that rope leg has twice the tension of the anchor leg. That 50' of rope acts more like 25'

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I've measured it too. However, it is difficult to measure the actual friction because dynamic friction is always less than static.

No, friction across the TIP isn't negligible, but it's a lot easier to explain the concept without friction. I didn't go back and read my post, but I may have not followed up with the friction in play.

Friction can vary significantly depending on the type of tree, the type of rope, surface moisture or dryness and even the temperature of the tree, so it'd be difficult to assign a single number to all trees and rope combinations. Plus the dynamic friction may very well be dynamic itself. I.e. as the rope heats and polishes the tree with friction, the friction may go down significantly.

The point is however, not to determine a specific friction for all rope/tree combinations, but to explain how a ground anchor will always provide more stretch and hence shock absorption than a DdRT or cinched limb setting.
 
After all of this discussion I've forgotten about one of the best parts of a ground anchor SRT system.

Rescue!

If a climber needed to be lowered the rescue would be expedited by having the anchor rigged already. Sure, the climber could have a lanyard on or be incapacitated. In that case a rescue climber would have to ascend. But, a belayer on the ground could lower the victim which allows the rescue climber to take care of patient care.

This is a foundation point that I have incorporated in SRT from close to the beginning. So far, knock on wood, I haven't needed a rescue. But, if I did I'm much more accessible to rescue with a ground anchor than in a DdRT system.

With that in mind the issue of a two person rescue on a TIP must be considered.
 
Great point Tom , even if his line was anchored to the base of the tree you could set a base sling and transfer him over to lower the injured climber down. With DDrt, you need to ascend to the injured climber and then bring him down, which takes more time...

X-man O.G.
 
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Ron, I in a way see your point about the days are numbered on manual climbing. The way I like to look at it is, that it all comes down to education.

If a new climber is taught how to climb from scratch ( one harrnes and one rope for ascending and descending) then once that climber mastered that he/she is taught a new hitch and knot. In this manner of learning there is a span of control. I always cringe inside when I see a new climber starting with a new device and not a simple hitch, knot and harrnes. Plus it will give the new climber an appreciation of climbing and a feel for how systems will act in diffrent situations.

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Amen to that!!!!
 
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My point is "the best" climbing system depends on what you want or need. Picking out or expounding on certain attributes may have little relevance if they are not what you need.

Dave

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You mean like saying a Unicender is all one needs to climb with?

I knew this would eventually happen. If we compare something to something else long enough, e.g. RADS and Unicender, it is inevitable that the impression will be made that we am 'pushing' the one and possibly that we are 'anti' the other. And that's not true nor what we want to happen at all.

I think what happens in these discussions, one says their system will do X and I come back and say my system will too, it sometimes infers that I'm puttin' down the other guy's system and that's not the case at all.

OTOH, it would appear that a RADS, carefully set up, has some advantages, and can do or provide some things many had no idea could be done with a RADS. That shouldn't imply anything about the Uni.

And since this is a thread about SRT, it seems appropriate to discuss the attributes of SRT systems and RADS is just one of them.
 
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Keeping in mind I plan on getting a Rig to use in a RADS system because I can recognise its attributes for my intended use, I do not think an argument based on which one uses the least support gear is viable. Dave

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Ron, I hope I was not giving the impression that the Unicender was all you need to climb SRT. I was just describing what it does or doesn't need in the way of support gear dependent on the purpose and person.

I actually like and use RADS and see a Rig as being a superior design for this application as I mentioned above.

Dave
 
OK,
I wasn't thinking about all the added line on the standing end... That said... I'd still like to see some scicene done using a real tree, and real climbing line... I think there may be some false assumptions presented here.. related to rope elasticity etc.. Does rope really stretch twice as much with twice the weight or half as much with half the weight? And does twice the stretch reduce shock loads by half or more? And how much does the friction at th TIP effect the stretch in the line on small branch unions? That is the only time it really matters as no large branch union is going to fail, right?

another question that comes to mind is in what scenarios can TIP failures be expected... How much shock load can be expected in tree climbing? I never climb with much slack in my system. So what else could cause shock loads? perhaps a large limb or wood catching the climbing line... if it is that big a piece, I'll cut it with a chainsaw, which means two tie-ins....

So in reality.. that is: real world climbing scenarios, where do you worry about TIP failure? I was setting a friction saver in a white pine, my first climb of the year, and wanted to get as high as possible, so I could shape the top of the tree. I had no concern about shock loading... my only concern was side loading during limb walks. In that scenario, I would have felt a lot safer using SRT, knowing that should the TIP fail, I'd only fall a few feet, til the next limb down caught the line.. Either way the only difference would be about 2', so I picked the lower TIP and went to work DdRT.

I agree with Tom, that the idea that SRT is more dangerous cause of added force on the TIP is bogus... Generally tree climbers are pretty set in their ways and will use any excuse to keep doing things the same old way, rather than admit they are too lazy or comfortable to bother learning something new. Kudos to all those that go to the time and trouble to pioneer new methods and equipment..
 
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