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Making DRT Easier?

lxskllr

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Playing with the paracord Gary sent me(Thanks!), and was pondering a 2:1 haul system. I might be visualizing it wrong, and it might be overcomplicating things, but do you all think this is worth pursuing? The Mora is a branch, the Swiss army a saddle. The butterfly is a pulley on a prusik, and another pulley is on the moving rope at the saddle. The pen is another prusik for progress capture. Pull the rope, prusik holds, slide moving pulley forward, repeat...

IMG_20200705_163111.jpg
 

lxskllr

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Yea, there's that too. If I did it every day, I'd probably see some progress, but holy hell is it kicking my ass now. Took me forever to get ~15' up the tree Saturday. When the weather cools down, maybe I'll try to get more climbing in for the hell of it.
 

Tree09

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You basically are setting up a 3 to 1 pulling a 2 to 1, giving you a 6 to 1. It's actually used in alpine rescue, i think it's in a book i have on mountaineering. For trees tho, no. Tree climbing is hard work, honestly kinda a young man's game (no offense to the older climbers here that are better than most). It's whipping your ass because you haven't built up the muscles for it, and you don't know what you are doing yet. In time you will start to learn the body positioning to make it easier, won't grab everything and wear yourself out, and know the shortcuts to doing stuff. But from that point and now it's simply learning and work. I'm still definitely learning, as are most, but I'm afraid to say it's kinda just one of those things that only comes from sweat equity. Not too long ago you didn't even understand what the climb line was used for, thinking that everyone just climbed with spurs. Limb walking is also new for you. Just take your time, keep trying, and learn what you need to do in order to have a workable system, whether that's a Blake's or tautline, hitch climber, or srt.

Since you are self taught (i am too), you need to get the proper education materials as well. Jerry's books and dvd series the working climber is an excellent start, as is watching guys where they film themselves as someone else watching, rather than a helmet cam. Helmet cams are awesome for learning cutting in a tree, but leave much to be desired as far as actually moving around the tree and work positioning. Treemuggs and the educated climber have some good stuff geared for teaching, start there.
 

lxskllr

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pulling a 2 to 1
I hear this a bunch, but is it true? Seems to me a vanilla DRT setup is 1:1. Lose a bit to friction, gain a bit from body thrusting, but you're pulling the full weight as I see it.
 

Benjo75

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You're pulling slightly over half your body weight. Depends on friction at the tip. Rings, conduit, nothing. Set up a single line, pretend like you're body thrusting. Try holding your progress with one hand to pretend to advance your hitch. You'll see how much of a mechanical advantage you're getting with Ddrt.
 

lxskllr

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So you're saying the 2:1 comes solely from the body thrust? I suppose I could buy that. It's more than I thought, but it's in the realm of believability.
 

Tree09

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No, it's 2 to 1. Friction makes it less, but it's still 2 to 1. Body thrusting is about the most inefficient way to climb, especially if you don't have correct form. You have to hold your self up by the rope, not fun. I get you thinking that more ma would be better, but it's not. Honestly if you are gonna hip thrust use some arborplex or the like, and run a Blake's hitch. If you want to spend a bit more money and make life easier, get a foot ascender, and maybe even a knee ascender. Have you noticed everyone saying srt is easier on the body, despite the fact that there's no ma? That's because you use your legs, and rid yourself of hip thrusting for the most part.
 

lxskllr

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It's just a direction change, no? Taken to it's logical conclusion, if I looped the rope over enough branches, a hummingbird could fly me up.

edit:
This looks like the simplest mechanical advantage pulley system with two moving parts...



I think I'm missing a moving part with DRT.
 
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DMc

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2:1 and 3:1 systems as used in tree climbing are always confusing when compared to the standard chart.

Your thinking that the branch represents a stationary pulley because it doesn't move, when in fact, with each pull, you are moving closer to it. That changes everything and turns what should be a 1:1 into a 2:1 and a 2:1 into a 3:1.
 

Tree09

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That's a 3 to 1, or a z rig. It's rove (rigged) to disadvantage tho, so it's only doing 2. Since you act as the winch, and the weight, a doubled line is 2 to 1.
 

Bermy

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If you throw in a couple of progress capture prussiks that's what we call a 'Z Rig'. 3:1
 

Bermy

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In my transition from DdRT (MRS) to SRT I used the Hitch Climber system, was so much easier than Blakes split tail, your body position start to move from the mostly horizontal body thrust... to being a bit more upright as you tend to pull slack from above a HC system and it self tends to a degree. Then I added a foot ascender to help the load on my arms...makes you a bit more upright...then the switch to SRT where you are basically standing vertically on your rope.
 

lxskllr

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Hmm.... I'm not getting it. Pulley systems are kinda voodoo to me anyway. I'm gonna have to think on this awhile.

edit:
I have a tension handle somewhere. Not sure what weight it goes to, but if it were sufficient, I could setup a test system to prove it to myself. Run the line through a top pulley to minimize friction, sit down in the saddle, and just pull. See how much weight it is.
 
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Marc-Antoine

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edit, I didn't look the vids before my answer, but I keep it as is.
It's just a direction change, no?
No. That would be the case if you are on the ground trying to lift a load with just a rope and an hanging pulley. Your force/weight counterbalances the load. 1:1
It's different in the tree, as you are the load. It's called a closed system. Basically, pretending that we consider only the tensioned part of the rope (cutting out the slack part), both ends of the rope are holding you. So each end sustains half your weight. What you do is shortening the rope on one side, but you are still hanging on the both ends of the rope, either pulling with your arms or staying as is on the prussik/ascender. Half of you counterbalances half of you, or half of you lifts the other half. So it's 1 (you) lifted by 0.5, aka 2:1 to simplify. Actually you needs a good amount more than the half due to the friction of the rope on the bark, but adding a pulley brings it closer to the physical principle.

Ditch the body trusting. It uses only one ascender point on the rope. You have to jerk up yourself to reduce most of your weight (like jumping with no bearing point under your feet) and count on your arm's speed to take out the slack in the quarter of a second before your weight is fully seated again. Adding just a foot ascender is life changing (second choice with an hand ascender, adding both tends toward a pleasure !). That brings a second ascender point alternating with the first one. Exactly like a farm jack with it's two pins.

Ddrt seems the less tiring because it needs the less force to lift yourself. A foot ascender and a pulley at the anchor make it "almost" easy. Actually, it's very good for the short distances (small trees and local moves in the canopy for the bigger ones). Beginning the training of your body and enhancing its strength is less a hard step with ddrt. What's hard on the body is the number of movements involved in the long ascents: like you just climb two trees instead of one.

The energy loss in your muscles is the main point. If you can reduce the movements, you reduce the loss, more efficient and less tiring.

Srt needs to lift your full weight, so it's hard (and asks for more working out), but you do it only half as much as ddrt. So, globally, you save on the energy spent.
 
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lxskllr

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I'll checkout those videos tonight Ben!

Thanks Marc. Your choice of words got everything to align right in my head. I get it now, and it makes sense to me :^)

I started this thread after contemplating some kind of hitch tender, and browsing supply stores for pulleys and such. Looking at pulleys, I thought "Well why not a haul system?". I'm trying to keep my gear fairly minimal. Both due to cost, and the elegance of simplicity. I need to think it all over a bit, and figure out where I'm going with this. I want to fully explore minimalism before I start throwing a bunch of gear at the problem. I'm definitely gonna make time this fall for practice climbing. Doing it a handful of times per year isn't cutting it, both in fitness, and confidence. No solution other than just doing it...
 

DMc

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... Srt needs to lift your full weight, so it's hard (and asks for more working out), but you do it only half as much as ddrt. So, globally, you save on the energy spent.
Nice useful post, as usual, Marc. I would like to expand a bit on your last sentence though.

While at first glance the lack of mechanical advantage in an SRT system would indicate increased climbing effort, the opposite is true.

As it is discussed on this forum, SRT is a leg powered technique, so right from the start you will be using what you use every day for movement, your legs.

There will be more power transfered and less loss of energy within the system. While movement powered by arm and upper body strength feels and works well when needed, mechanical advantage when using leg power will waist energy. Think of pedaling a bicycle on the flat in a very high gear. Your legs are going like crazy but your not getting anywhere.

Our legs are strong and can handle movement loading better than our arms.
 

Marc-Antoine

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I see no contradiction here and agree.
I spoke about the force needed (with the same use of the body, beside the rope configuration), while the "effort" would include many parameters like force, energy loss, over-run (actual speed over the average useful speed which the system was designed for)..., in other words I'd call it the strain on the body to get the real outpout.
Every actuator is designed for a relatively narrow working domain combining force, speed, frequency, relaxing time ... Arms and legs aren't any different and each have their favorite working zone. They can match on some points for the outpout (force x speed), but the global effort asked can't be the same because of their design. Working with both in their own domain is the best.
For me and my body, the leg power is mandatory in srt, usefull in ddrt, and wasteful in a 3:1 system (similar with your pedaling "in the void").
 
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