arm breaker
Well-Known Member
I’m not super interested in dealing with a chess harness. It seems like a lot of the “rope walking” demonstrations suggest thats they way to go.
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SRT Climbing
- Thread starter jakhammer
- Start date
It's a matter of priorities. Hunters climbing say 20 ft once a day are going to have a different set of priorities than arborists or recreational tree climbers climbing higher and more frequently (and not caring about noise). If you're in reasonable shape, I'd favor simplicity over "ease of climbing".
arm breaker
Well-Known Member
Yes, let me be clear. I am saying if it takes the extra gear to do the walking style techniques then I am not interested in making the switch from the hand ascender, safeguard, footloop SRT method more common to hunters.
Bango Skank
Active Member
- Joined
- Nov 1, 2020
- Messages
- 177
The chest harness is just for pulling/tending the device and keeping more upright with a little less strain on the lower abdominal muscles and can ascend hands free. Totally optional.
I got a better one now, but I used a beer knotted piece of tubular webbing with a carabiner for a while. I’ve always been spooked about anything around my neck, but some arborists use a neck tether to tend their device, and a lot of folks put their lanyard/LB over their shoulder and clip it back on the saddle and use that to tend it.
Basal anchors eliminate the need for retrieval lines, easy peasy.
I love SRT for working and rec climbing, but after watching some vids, the one stick with aiders method looks pretty damn efficient for most trees. I’d like to try that sometime, looks fun. Looks cost effective too. Even a good RopeWrench setup with a HitchClimber pulley is gonna set one back at least 200$.
I got a better one now, but I used a beer knotted piece of tubular webbing with a carabiner for a while. I’ve always been spooked about anything around my neck, but some arborists use a neck tether to tend their device, and a lot of folks put their lanyard/LB over their shoulder and clip it back on the saddle and use that to tend it.
Basal anchors eliminate the need for retrieval lines, easy peasy.
I love SRT for working and rec climbing, but after watching some vids, the one stick with aiders method looks pretty damn efficient for most trees. I’d like to try that sometime, looks fun. Looks cost effective too. Even a good RopeWrench setup with a HitchClimber pulley is gonna set one back at least 200$.
On the flip side, basal anchors require a branch to take MORE than your weight in load, while you can set a girth-hitch canopy anchor over a twig.
If the rope is around the trunk a twig will probably stop it from sliding, perhaps this is what you meant, not advisable to use just a twig for life support.
Yes, the twig is sufficient to support a throw line and set up a girth hitch with your main rope around the trunk of the tree, and your life support is the girth hitch around the trunk (and make damn sure it's good and tight). Vs a basal anchor is 2x your bodyweight applied to whatever limb you're over (minus friction).
You end up with a heavier load on a branch that you can't inspect preclimb with a basal anchor.
Can you explain this? I've seen it mentioned before, but I can not wrap my head around why a basal anchor causes more weight on the limb than a canopy anchor.
If the limb was a perfect pulley, your body weight load would go up the rope, around the pulley, and down to the base anchor. So both strands of the rope would be loaded with your body weight, and both pulling down on the branch. It's a 2x mechanical advantage.
- Joined
- Oct 14, 2014
- Messages
- 1,451
Many climbers will opt to use their linesman belt(lanyard) over their shoulder to tend device up the rope. It doesn't need to be a separate piece of equipment and I have used the chest strap on the JX3 at times. I also use my SRT chest harness as my recliner strap in my configuration.
Not sure what you mean by last sentence?
The 2X mechanical advantage refers to a pull of 2x being exerted on the load with a 1X pull force.
Here is is a nice video that starts out with an upside down SRT RADS type system.
i think the confusion is coming in to play because i think we're confusing the physics. once your body weight is off the ground, it can only exert 1 body weight (times gravity) worth of force (well technically you could bounce your body downward while hanging to increase the force by using inertia to supplement gravity briefly but that's not what we're talking about here). the tree limb experiences the same force regardless of how many ropes are supporting the weight, or what's done with the tag end, the only thing that can increase that load once the climber is off the ground is if the tag end is also pulled/has a force applied. fixing it to an anchor does not impart load, it enables the single climber load to be split over the up rope and the down rope (the fixed anchor also experiences one climber x gravity load, minus friction). as far as the limb is concerned, the weight never changes, and gravity never changes, so the force on the limb is the same. the 2x mechanical advantage of the pulley pertains to the effort or force needed to lift a weight against the force of gravity (effort of the climber is halved if we ignore friction), however the pulley itself experiences the same load. fixing one end of the rope to the tree and hanging off the other is no different than hanging off both ends, or girth hitching to the limb and hanging off of that. the limb still only has one person hanging on it.
i'm not doing a good job explaining, just watch this: load doesn't change, rope tension and force do.
the key difference is 2x mechanical advantage means both strands of the rope are loaded with HALF your body weight.
The rope is over a branch and tied to the climber, someone else takes the free and lifts the climber. The climber is two hundred pounds, the person lifting uses two hundred pounds of force for lifting, both legs of rope have two hundred pounds now, add those together for the total load at the anchor point.
Again the rope is over the branch tied to climber, but this time the climber lifts himself, now the two hundred pounds is shared by the two sections of rope, and the load at the anchor point is only the weight of the climber.
Again the rope is over the branch tied to climber, but this time the climber lifts himself, now the two hundred pounds is shared by the two sections of rope, and the load at the anchor point is only the weight of the climber.
Nope.
You are hanging on 1 rope strand. Rope tension is your body weight. This is fixed - you are exerting a force equal to your body weight on the rope.
when you are hanging on one strand, and pulling on the other the pulley at the top is not a multiplier. it is a redirect. the tension is halved between the strands if you pull on both (or the laod hangs from both. it remains constant if one end is fixed (anywhere except the laod) and you "pull" (meaning gravity is pulling the climber) on the other end.
think of it this way: lets say there's a branch that you KNOW (somehow) can hold 300 lbs. you're 200 lbs for this exercise. you tie a rope to the branch and hang on it, the branch has a 200 lb weight hanging on it, it does not break.
now you take a rope, loop it over, and hang on both ends. each rope has 100 lbs worth of tension (because they're each carrying half of the load) , but the branch is still only holding up one 200 lb person. the load on the branch (pulley) doesn't change, the load/tension on the rope does.
now take one end of that rope and tie it to the ground/trunk. hang from the other end. the branch STILL only has one 200 lb person hanging off of it. the tension is not halved, but the load on the pulley is also NOT increased. this is basically the same thing as tying the rope to the branch itself.
now add as many ropes as you want, the branch still only has one perosn hanging on it. you won't break the branch until the weight of the ropes exceeds 300 lbs. you need to add pulleys- if you add them to the climber(moving) you decrease the rope tension, decrease the effort to pull and INCREASE the amount of rope pull needed to have the same height increase, the load on the branch never changes.
gravity is gravity, it doesn't matter how many ropes you pull down with, if you/the load is in the air. tying off the tag end doesn't increase the load. it can't.
now, if you have another pulley, and you attach THAT to the ground, have climber in the air on one end and pull on the other THEN you're imparting mechanical advantage to the branch because both pulleys are fixed fixing the end of the rope doesn't do the same thing as this.
This is a simple pulley system so the load at the branch is 2x the weight of the climber if you use a base tie off on the rope. People that are saying the force can only be the weight of the climber are ignoring the pulley effect. It took me a while to understand this and I am a professional scientist. Once you get it, you will.
Take the case of a canopy anchor. The 200 lb climber is hanging from one side of the rope. The other side of the rope goes around the branch to a loop. This side of the line also has 200 lb tension on it. The rope going around the branch can now squeeze the branch with a force of 400 lbs but wood is strong enough to resist this. The extra force is being directed into the branch and not down. The climbers weight of 200 lbs is all the force that is directed down. The other 200 lb is squeezing the branch. That is all it takes to understand this supposed paradox.
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Please understand that I have taught courses on this at the university level. Long enough ago that I might misuse a word here and there...but not long enough ago that I'm going to get it wrong. I'm not full of crap.
You are hanging from 1 strand. It is supporting your entire weight. If we neglect friction on the branch for now (and obviously there's a lot of friction), that same tension exists along the entire length of the rope - right down to where it's anchored.
AT THE BRANCH, you have the branch (or "pulley") reaction force opposing the downward forces from the tension in EACH rope. Body force x2.
Using your example, in the case where you have 100 lbs on each end of the rope...if you remove one of the weights and tie off instead, the load on the pulley would not change. It would still be 200 pounds. Tying off does not "increase the load" or decrease it. It keeps it the same.
no need to throw around credentials, we're all random people on the internet here.
if you hang 200 lbs from a tree branch, it will always be 200 lbs no matter how many stands of rope are holding it there, the more rope, the easier job for each rope. the branch does not receive additional force if you tie the tag end off. the ROPE has full tension along its length if tied off, half tension if both ends go to the climber. the BRANCH still is only holding 200 lb up in the air either way. the tied off end is exerting 0 force. the climber is the only end that exerts force. typing off to a fixed point after looping over the branch is the exact same thing as tying off TO the branch. the branch still is only holding one person's weight.