# Lowering wood with bull rope



## TreeandLand (Dec 24, 2010)

I have only used 16 strand climbing line for my rigging up to this point. 
This line has been used a lot though, and is looking worn, so I decided to retire it from any heavy pieces.
I bought 600' of 9/16" bull rope from Bailey's and plan to cut a 200' piece to use for rigging. I'm a little nervous about the first time we try it though, because the climbing line always had that stretch in it to soften the impact of a heavy peice. If the groundman doesn't let the line run, am I in danger of breaking the hardware and jarring my teeth out when it shock-loads?


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## sgreanbeans (Dec 24, 2010)

As long as you stay under the WLL of each piece in the system, you should be OK. Read up on Dynamic loading and cycle to life on the rope, each time it takes a hit, one more nail in the coffin. Let it run as much as possible, even if a little bit, it will soften the blow. Its not a bad idea to practice "letting it run" with your ground guy. On easy tree's that you can bomb, rig it instead, good time to try the risky stuff, don't wait until yur over a hot tub and have to. Buy "The Art and Science of Practical Rigging" by ArborMaster, good read and will help you greatly.


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## squad143 (Dec 24, 2010)

Rig smaller pieces until your groundie gets the feel for the new rope and then work your way up to bigger chunks.


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## the Aerialist (Dec 24, 2010)

*What are you gonna tie it to?*

I just bought a stainless steel Porta-Wrap and it recently arrived, what a slick piece of gear! I clicked through the Sherrill Tree link from this site to help support it, and you should too. It's on sale right now for $120, the same price as the regular steel was. A great bargain when you consider the difference.

I also have an aluminium one which dissipates heat better and is less than half the weight, but in some gear the weight is worth it.


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## TreeandLand (Dec 24, 2010)

TreeCo said:


> No need to be nervous if you've got much experience using 1/2 inch rope. You're not going to notice much difference between the two.



My new rope is "stable braid", doesn't that stretch much less than climbing line? I'm glad to hear you say that I won't notice much difference. After all, I want less stretch in the line so I can control tops when working close to a house.
I will be sure to practice with this rope on less risky trees.


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## TreeandLand (Dec 24, 2010)

Aerial Arborist said:


> I just bought a stainless steel Porta-Wrap and it recently arrived, what a slick piece of gear! I clicked through the Sherrill Tree link from this site to help support it, and you should too. It's on sale right now for $120, the same price as the regular steel was. A great bargain when you consider the difference.
> 
> I also have an aluminium one which dissipates heat better and is less than half the weight, but in some gear the weight is worth it.



AA, we use a steel porta-wrap that was given to me by another arborist. It was made for him by a welder....it seems pretty rugged and is the same size as the medium porty that Sherrill Tree sells. (they claim you can use 9/16" rope with it, so I hope they're right). We attach the porta-wrap to the base of the trunk with a tenex whoopie sling, and use a smaller whoopie sling for the block up in the tree. 
What size rigging line do you use? This new bull rope is by Yale Cordage and has an average breaking strength of 15,000 lbs. Way better than my old climbing line.


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## the Aerialist (Dec 24, 2010)

*Lowering Line ...*

I've been using 1/2 " bluestreak with my aluminum Porty, but I wanted to get something heavier for heavier wood. I do have a 3 strand 3/4' bull rope, but it is not recommended (3 strand) for Porta-Wraps.

I'm thinking of 9/16 or 5/8 12 strand but I'm open to suggestions.


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## tree MDS (Dec 24, 2010)

TreeandLand said:


> AA, we use a steel porta-wrap that was given to me by another arborist. It was made for him by a welder....it seems pretty rugged and is the same size as the medium porty that Sherrill Tree sells. (they claim you can use 9/16" rope with it, so I hope they're right). We attach the porta-wrap to the base of the trunk with a tenex whoopie sling, and use a smaller whoopie sling for the block up in the tree.
> What size rigging line do you use? This new bull rope is by Yale Cordage and has an average breaking strength of 15,000 lbs. Way better than my old climbing line.



I have the large and mid size steel portys. I dont use the mid size much, but it seems to me the last time I did, my 9/16 didnt seem run too smoothly through it (you have to remember that thats max rope size for the mid), a wrap seemed to be more than with the big one.. Probably something to do with bend radius or something. I could be mistaken though..


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## TreeandLand (Dec 28, 2010)

Aerial Arborist said:


> I've been using 1/2 " bluestreak with my aluminum Porty, but I wanted to get something heavier for heavier wood. I do have a 3 strand 3/4' bull rope, but it is not recommended (3 strand) for Porta-Wraps.
> 
> I'm thinking of 9/16 or 5/8 12 strand but I'm open to suggestions.



AA, I've heard good things about 12 strand but haven't used it. I'll try and let you know how my 9/16" bull rope works out. It's double braided....I don't know how many strands.


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## Capt. Blye (Dec 29, 2010)

*Never took calculus*

What is the formula used when determining shock load? For the sake of discussion, a 500# log falling 3' vs 6' or does no such rule of thumb for the industry exist? I know wwl and let lines run when applicable, however, knowing the fomula and calculating prior to the cut would reduce some of the sweat in the tree I expieriance over property.


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## Blakesmaster (Dec 29, 2010)

Capt. Blye said:


> What is the formula used when determining shock load? For the sake of discussion, a 500# log falling 3' vs 6' or does no such rule of thumb for the industry exist? I know wwl and let lines run when applicable, however, knowing the fomula and calculating prior to the cut would reduce some of the sweat in the tree I expieriance over property.


 
That's a damn good question. There's a coupla guys with good math skills on this site that might be able to speculate. I'm not one of them.


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## ropensaddle (Dec 29, 2010)

Vector,force,weight,friction,energy,acceleration,anchor forces are all used in the calculation.


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## Mike Cantolina (Dec 29, 2010)

Capt. Blye said:


> What is the formula used when determining shock load? For the sake of discussion, a 500# log falling 3' vs 6' or does no such rule of thumb for the industry exist? I know wwl and let lines run when applicable, however, knowing the fomula and calculating prior to the cut would reduce some of the sweat in the tree I expieriance over property.


 
This software can be very helpful:

http://www.sherrilltree.com/Professional-Gear/Videos_3/Rigging-Software-v-10-1176

I have it and used to use it a lot. I don't need to as much anymore.


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## ropensaddle (Dec 29, 2010)

I chose to keep it a little on the small side in weight and limit drop all I can,too many times we are nearing potential failures of our gear through kinetic energy. Math is not my strongest virtue yet lol so I err on the cautious side. I used to do wild stuff but I have broke ropes and got lucky a time or two and decided smaller or even chucking a better result.


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## TreeClimber57 (Dec 29, 2010)

Capt. Blye said:


> What is the formula used when determining shock load? For the sake of discussion, a 500# log falling 3' vs 6' or does no such rule of thumb for the industry exist? I know wwl and let lines run when applicable, however, knowing the fomula and calculating prior to the cut would reduce some of the sweat in the tree I expieriance over property.


 
Making one think.. and not sure if I can get this 100% correct or not, digging out my old notes so will try. But am missing some info.. to get accurate need specs on the rope (amount of stretch, etc).. 

But lets plug in some #s and see how it goes.. feel free to point out where I make errors 

Now my formulas all are in metric, not sure if what the other formulas are .. so will play it by ear.

500 lbs is around 227 kg.. and we will call 3 ft as 1 m.

227 kg dropped 1 m is traveling at 4.4 m/s at place of stop. This equates to around 2225 J of energy (rounding here).

Now if the rope stretches .1 m or 10 cm (not sure how much it would realistically be).. then this means that there is an impact of around 22,000 N or 4,400 lbs of force.

That same 227 kg dropped 6 ft or 2 m would be traveling at around 6 m/s and have around 4450 J of energy.

If we have the same .1 m stretch (again not sure how realistic this is), then we have 44,500 J of energy or 8,900 lbs of force. With more J of energy, I expect the stretch would really be slightly more but not sure how much.

BUT if I recall correctly the rope stretch changes based upon mass and energy.. so the amount changes here.

Also dynamic rope, again if I remember correctly, looses it stretch rather quickly when used in heavy dynamic loading situations and each drop will be different loading due to the change in stretch of rope.

Now don't use the #s above for anything serious.. as too much guess in the #s .. 

Now as it falls farther, it will be dropping faster.. 4 m would be dropping almost 9 m/s and would be around 17,000 lbs of force... and 10 m would be up to 14 m/s and 45,000 lbs of force.

Keep in mind the block at top, if the rope is going straight up and back down (at 180 degrees) is handling twice the stated load .. so at 1 m the block would have around 8,800 lbs of force.. As that angle decreases so does the impact on the block. I think 120 degrees would half that load as I recall..

Think this is right but been a long time since I did this stuff.

This is also taking some very simple concepts, and ruling out any friction, etc.. if using porty there is also some slippage as rope tightens (no matter how hard you try there will be some with this amount of impact).. and depending on wraps on porty and how much you letting it run.. will dramatically impact that force actually experienced.

Bottom line, you get into big #s very fast.. and we were taught to apply the following:
10:1 safety factor on all ropes
7:1 on slings
5:1 on steel hardware

Some apply the 10:1 for everything.. so this could be a point of discussion and may be controlled by WSIB or similar rules in your area (so be aware).


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## Mike Cantolina (Dec 29, 2010)

The stretch in the rope will vary with the amount of rope in the system. (above and below the rigging)

3 foot drop







6 foot drop






From the software linked to earlier


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## Capt. Blye (Dec 29, 2010)

*Insightful with practcality*

Thanks for response on the Q. I will research this a bit more. Sometimes the ground crew isn't expierianced enough to take the proper amount of wraps to let run or the owner wants the BF Cherry over his pool brought down in 8 footers. I use 5/8 stable braid for big stuff but I occasionally wonder if were using strong enough line. I should be able to figure it out with the info provided here. Thanks again


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## ropensaddle (Dec 29, 2010)

Capt. Blye said:


> Thanks for response on the Q. I will research this a bit more. Sometimes the ground crew isn't expierianced enough to take the proper amount of wraps to let run or the owner wants the BF Cherry over his pool brought down in 8 footers. I use 5/8 stable braid for big stuff but I occasionally wonder if were using strong enough line. I should be able to figure it out with the info provided here. Thanks again


 
I use 3/4 stable braid, there is times I believe it is not enough. 8 foot stick of cherry if 20 inch in dia is near 800 lbs. Its easy to see how 800 lbs changed from potential energy and then kinetic and not allowed to run can easily get past the design factor if not actual breaking strength. I wont attempt it no more too many chances for damage and injury. I have seen ropes bind in the bollard and normally groundies don't get it. They get scared they are not going to be able to stop it and end up either completely stopping or coming to a quick stop with little run. The best groundie is an older climber imho.


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## TreeClimber57 (Dec 30, 2010)

Mike Cantolina said:


> The stretch in the rope will vary with the amount of rope in the system. (above and below the rigging)
> 
> 3 foot drop
> 
> ...


 
Correct!!

Which is why the first piece, and last piece typically show the greatest loads. Top being because it is usually bigger and falls farther, the bottom because it can be large, but also because rope is shortest. At least that is what the formulas always show. Realistically the formulas we were given years ago, were designed to get the concept of shock load into your head, they were not designed to use manually in field. With computers and software today, that is actually possible I guess.

As you mentioned, the brand of rope, type of rope, diameter of rope, age of rope, if wet or dry.. just about anything can impact the ability of rope to stretch and absorb some of the energy.

I will take a look at software Rope.. thanks.. I never really spend much time doing calculations, when you have done it for a while you know what works or what has worked in past.


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## TreeClimber57 (Dec 30, 2010)

Mike Cantolina said:


> The stretch in the rope will vary with the amount of rope in the system. (above and below the rigging)
> 
> 3 foot drop
> 
> ...


 
This is actually more accurate for day to day work, as it is taking in to consideration factors like how far up the wood the rigging is attached, length of rope under rigging point - from block to porty, length of rope from block to wood, type of knot used, and type/size of rope. All factors that impact the stretch of rope and ability to absorb shock.

Would be interesting to see how that 12 ft of rope after rigging point will impact the numbers.


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## TreeClimber57 (Dec 30, 2010)

ropensaddle said:


> The best groundie is an older climber imho.



Agreed.. 

They know what is going on and why, they can anticipate things that could or will happen, they THINK.. 

And, in an emergency many of them could still climb up (maybe with spurs) and help out.


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## TreeClimber57 (Dec 30, 2010)

ropensaddle said:


> 8 foot stick of cherry if 20 inch in dia is near 800 lbs.



A lot of new or younger climbers have trouble estimating the actual weight of any wood.. I have a chart around somewhere but I can not find a soft copy of it right now.

Part of battle is understanding the weight of block, then getting the concept of what that would change into energy wise during a shock load in rigging.


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## ropensaddle (Dec 30, 2010)

TreeClimber57 said:


> A lot of new or younger climbers have trouble estimating the actual weight of any wood.. I have a chart around somewhere but I can not find a soft copy of it right now.
> 
> Part of battle is understanding the weight of block, then getting the concept of what that would change into energy wise during a shock load in rigging.


 
Yes I have green wood chart so it is easy for approximate weight. It starts as potential energy the turns kinetic and has gravity bearing on it at 32 foot per second per second before run turns it into friction. I understand the principals but have forgotten the math! I learned without any of the formula's but am sure I have put many ropes past the wll. I am a bit more careful now and just use a ten times rule 800 = 8000 with some run.


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## sgreanbeans (Jan 1, 2011)

Mike Cantolina said:


> This software can be very helpful:
> 
> Rigging Software v 1.0 : SherrillTree Tree Care Equipment
> 
> I have it and used to use it a lot. I don't need to as much anymore.



I like that! Put it on yur laptop and take wit ya?
I can do the math in my head, have been doing it for along time too, but that program is neat, I gunna get me won does! Anything from ArborMaster is pretty good, have learned a lot from those 2!


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## sgreanbeans (Jan 1, 2011)

TreeClimber57 said:


> Agreed..
> 
> They know what is going on and why, they can anticipate things that could or will happen, they THINK..
> 
> And, in an emergency many of them could still climb up (maybe with spurs) and help out.


 
I have been grounding for my climber, he is loving it. Don't have to explain what he is doing, no talk, just hand signals. I am having a blast! Teaching the yunging the "ropes", pun intended! He is still a little nervous on the bigins, but getting better everyday, his timing is pretty good, doing a good job of getting it away from my climber. Its fun showing them the tricks and watching for that point of enlightenment, you get a look from them that tells you the bulb over their head is on! " oh that's cool, show me again!"


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## rarefish383 (Jan 2, 2011)

ropensaddle said:


> I use 3/4 stable braid, there is times I believe it is not enough. 8 foot stick of cherry if 20 inch in dia is near 800 lbs. Its easy to see how 800 lbs changed from potential energy and then kinetic and not allowed to run can easily get past the design factor if not actual breaking strength. I wont attempt it no more too many chances for damage and injury. I have seen ropes bind in the bollard and normally groundies don't get it. They get scared they are not going to be able to stop it and end up either completely stopping or coming to a quick stop with little run. The best groundie is an older climber imho.



I agree, it's great to work with another climber running your ropes. We were a small Co and were lucky enough to have a pretty good work force to draw from. Many guys floated around from Co to Co and were known, with good or bad reps. We'd cherry pick the good guys. A groundie would probably be on the crew a year before he was allowed to do any real tricky roping. I also started when we were using manilla or hemp rope, and porta wraps were a thing of the future. When I retired we were using New England Rope exclusively. We used 5/8 and 3/4 braid bull line. All of our rigging was through crotches and wraps on trees. I don't remember ever breaking any braid, I do remember poppin big old manilla. Another thing we had to think about were the crotches. A crotch could often fail long before the rope, and we didn't want to burn the bark/cambium. If I had to work with a newbie I would take partial raps in the tree to control the fall in case he froze up. Either leave a foot or two loop in front of my notch or a loose wrap leading into the crotch. There's a lot you can do up in the tree to set up the rope man in case he doesn't quite know what you want. If you're both new and inexperienced expect lots of loose teath and buckin bronco rides, Joe.


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## TreeClimber57 (Jan 3, 2011)

rarefish383 said:


> ]I also started when we were using manilla or hemp rope, and porta wraps were a thing of the future.



Yep, we used manilla until the 80's.. still have a couple of rolls of it in shop. Thinking back, a lot has changed in 20-30 years.


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## eye.heart.trees (Nov 5, 2019)

Sorry to resurrect this but it's just so on-point with the thread I *would've* made on this topic!



TreeClimber57 said:


> Correct!!
> 
> Which is why the first piece, and last piece typically show the greatest loads. Top being because it is usually bigger and falls farther, the bottom because it can be large, but also because rope is shortest. At least that is what the formulas always show. Realistically the formulas we were given years ago, were designed to get the concept of shock load into your head, they were not designed to use manually in field. With computers and software today, that is actually possible I guess.
> 
> ...



Any links you have for understanding things would be incredibly useful, have been having a helluva time trying to select bull line for my new "heavy duty" rigging setup, my contention/problem is that I look at 90% of the ropes marketed, see ~1-2% elasticity, and think "that's dangerously static, shock-loads could shatter that surprisingly easily"

Our rigging lines are more static than our climb lines....wth?!? People recognize the difference between static/tensile strengths and dynamic strengths enough to know that, despite an impressive STATIC strength, the 0.5% elasticity of dyneema('amsteel') makes it useless for rigging-lines or rigging-slings....was face-palming so hard when watching a video where a guy describes how he broke his ~3/8" or 1/2" amsteel sling and his response was to get 3/4" or 1" amsteel, as-if upping the STATIC capacity of the line somehow meant it'd be better for the dynamic forces experienced when "shock loaded".

These lines are marketed for rigging which INHERENTLY includes 'shock loading' (vague term....'dynamic loading' is inherent to the downward control, with ropes, of a piece of wood you've just cut. Doesn't matter how skilled the groundie is, hell even having a positive-line-angle from the rigging-anchor to the piece to negate hard dynamic forces['shock loading'] doesn't mean you've got 0 dynamic force it just greatly minimizes it, but being able to tie&lift a branch to cut it, then lower it gently, is obviously something that's nice-when-possible but more often than not is NOT the way to properly rig something) So, if they're for rigging, how come they're so damn static?

Looks like Yale's 3% polydyne is a great step forward (surprised double esterlon still sells, cannot even come up with a use-case where you'd want it over polydyne, yet it's still sold and actually sometimes more-expensively than the polydyne!), then Sterling comes out with Atlas which is **50%** more elastic than the next-stretchiest rope (4.5%, compared to polydyne's 3%) and, no shock (lol, punny) to me, that line is getting incredibly popular. 

What I cannot reconcile is "Why, after decades of doing this type of production, why aren't the elasticity #'s of these bull lines dialed-in yet?" I mean, I'd bet $$$ all day long that if I got a retailer's catalogue from 10yrs in the future, I'd bet any amount of $$ that the average elasticity of the bull lines will be greater than it is today. That said, the 1.1% elasticity "Stable Braid" line is incredibly popular, I look at it and am blown away that anybody would choose it for rigging, I understand using it for winching/liftting/hauling/mech-advantage setups but for routine-rigging IE what we'd use these ropes for 95% of the time, the "SWL/WLL" concept IS UTTERLY FLAWED!!

People say "Oh, this rope's STATIC strength is 10k, ergo I'm being conservative by keeping my loads under 1k", these SWL's/WLL's ignore dynamic conditions / the shock-absorption-capacity of the ropes, it seems so clearly-misguided to me that I'm genuinely unable to figure it out (IE I'd expect that anyone looking for a bull line would say "atlas or polydyne, nothing else" yet the stiff samson stable braid is incredibly popular!)

This video by Yale is fantastic (though it makes me wonder why their most-elastic line is still just 3%), shows the same force (a 220lbs load taking a 6' free fall, equating to 1,400lbs dynamic force when it hits that 6') on two ropes, one is a 20k ABS sling-type rope (ultrex or yalex, their version of what samson calls 'tenex') and the other is a 6k ABS climb-line (XTC), it's a great illustration of just how important this static-versus-dynamic concept is as the 20k ABS line snaps on the first try, while the 6k ABS line can take the load over&over..... Video is on the bottom of their article here: http://www.yalecordage.com/featured-industries/arborculture/dynamic-energy-arborist-rope

I'm not ordering anymore of the 1.5% yalex/tenex slings, a sling should be more-capable than the bull-line it supports, **IMO** this doesn't just mean a thicker line (if using identical cordage construction) but also means it'd be optimal to have slightly different cordage IE more-elastic, I want my anchor-slings to be at least 20% stronger than what I'll be using the line for, so if it were static-only (generally inapplicable to our purposes) then I'd want a 12k sling supporting anchorage for my 10k line. For our uses, I'd apply the same logic only I'd add that, if my bull line were 3%, I'd like 3.25% on the sling -- the strength of ropes when it comes to dynamic loads is a function of many things but length-of-line to take the shock is an important variable, so given that the slings have such short lengths they necessitate being a higher elasticity line to have the same relative shock-mitigation that a more-static, but longer length, line of bull rope had!

I'd probably be choosing Atlas if Yale made it, however I'm a Yale supporter and their Polydyne is the 2nd-best specs (on-paper, 2nd to Atlas) on the market, was planning to get like 40' of Yalex with the polydyne to make slings but am now thinking I'm just going to order a longer spool of polydyne and make my slings from that (*NOTE*- I'd only be using 'basket configuation' type slings IE no chokers, this means I'm using both legs of the sling therefore it's stronger than single-line usage, so I do get the stronger-than-rig-line attribute here anyways) 

~~~~~~~~~

Would love anyone's thoughts, especially recommendations on choosing between the 5/8" (19k ABS wtih 3% elast.), or the 3/4" (26k ABS with 3% elasticity), polydyne!! I'd been thinking the 3/4" would be overkill, but with 5/8" being 19k ABS, and reading someone in this thread saying they felt their 3/4" stable braid was insufficient (that 3/4" has static-strength equivalent to a 5/8" polydyne cord), has me of two minds.....on one hand, I think "well, if their ~20k line was Poly instead of SB, the nearly 3X more elastic polydyne would be fine for them", making me think to get 5/8".....the other part of me thinks "it's a bit more expensive, and heavier, but 3/4" polydyne seems about the best on the market, you could do double-safebloc-rigging with the stuff, when in-doubt go for redundancy/overkill!" --- would love to hear thoughts, I've gotta place this order by the weekend I've researched long enough now, am awaiting replies to a physics thread on this subject as well as a couple more rope-manufacturer replies (emails) to really get this, but honestly when considering the guy who said he felttt his 3/4" stable braid (1.1% elasticitty!) felt insufficient for him, I have to wonder if he'd had the 5/8" poly instead (same tensile but triple the elasticity/shock-absorpttion-capacity) whether he'd still have felt the same....I know I'd take ***1/2"*** polydyne over 3/4" stable braid, I know that my STATIC capacity would only be 50% of the Stable Braid but if you factor in the elasticity/shock-absorpttion of the line it becomes clear you can snub higher loads with the 1/2" polydyne than you could with **3/4"** of the ever-popular Stable Braid! (again please watch video at end of the Yale ^ link I posted....that 20k ultrex line that snapped was a 0.5% elasticity line so it snapped *despite* its 20k *static* ABS while the 6k ABS XTC line around 1.6% elasticity, IMO that's still super-static at 1.6% but it still handled that dynamic load like a champ while the stiffer line snapped, I'm just astounded that sub-2% lines are used ANYWHERE in a rigging setup whether as bull-line, slings or anything, they've got no business being around dynamic loading!!!


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## eye.heart.trees (Nov 5, 2019)

ropensaddle said:


> Yes I have green wood chart so it is easy for approximate weight. It starts as potential energy the turns kinetic and has gravity bearing on it at 32 foot per second per second before run turns it into friction. I understand the principals but have forgotten the math! I learned without any of the formula's but am sure I have put many ropes past the wll. I am a bit more careful now and just use a ten times rule 800 = 8000 with some run.



I'm surprised to hear that people have trouble estimating, it's never going to be perfect but it's literally just "width, height, wood-weight" (if someone's field-rigging without a green-weights list then they're either a vet who's beyond needing it, or they're ignorant and liable to hurt themselves/others/property) My problem is this whole concept of using STATIC strengths as the baseline-figure for our DYNAMIC loading calculations (dynamic loading is like 99% of the uses these ropes get, yet industry-norm is to focus on STATIC numbers....an ignorant person could be forgiven for thinking they were OK to drop a 1k log, after 3' of free-fall, because they were using 3/4" amsteel.....made-up #'s but you get the point, amsteel/dyneema snaps under dynamic loading it's for static use only, but our general approach would put amsteel as a viable contender when it simply is not)

You mention you learned without any of the formulas, so want to ask you, and anyone reading: _*Does anybody have any formulas for calculating things here??*_ I'm unable to find my scrap paper that had this amazing formula that accounted for rope-length in the system, elasticity etc, am dying to re-find this formula but *any* formulas would be useful!!!

PS-- does anyone think I'm shooting myself in the foot getting a 150' length of bull line? My current line (1/2") isn't even a full 100' as I've made a sling from it, and never once have I found I needed a longer line, so am thinking 150' is plenty for me....but then I glance at my new x-kit (rigging anchors for directing the line all over, meaning it won't be that short trunk-to-anchor-to-load that I currently do, will need an extra 5-30' of redirect length through the canopy, would love to hear people's thoughts on this!!!)


[AWESOME username/handle btw!!!!!]


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## eye.heart.trees (Nov 5, 2019)

sgreanbeans said:


> I have been grounding for my climber, he is loving it. Don't have to explain what he is doing, no talk, just hand signals.


Silly Q but you didn't happen to find any guidelines for hand signals did you? I use walkie-talkies when needed but was recently thinking "Damn, with as few as like 5 hand-signals, I could have a rigging-sign-language method of communication with my groundsman!!", in hearing/reading your post here ^ I'm totally sold on the idea now and'll be trying to come-up with a good system / 'language', any&all specifics you could share would be greatly appreciated so I'm not 'rebuilding the wheel' that you've started


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## ropensaddle (Nov 5, 2019)

eye.heart.trees said:


> I'm surprised to hear that people have trouble estimating, it's never going to be perfect but it's literally just "width, height, wood-weight" (if someone's field-rigging without a green-weights list then they're either a vet who's beyond needing it, or they're ignorant and liable to hurt themselves/others/property) My problem is this whole concept of using STATIC strengths as the baseline-figure for our DYNAMIC loading calculations (dynamic loading is like 99% of the uses these ropes get, yet industry-norm is to focus on STATIC numbers....an ignorant person could be forgiven for thinking they were OK to drop a 1k log, after 3' of free-fall, because they were using 3/4" amsteel.....made-up #'s but you get the point, amsteel/dyneema snaps under dynamic loading it's for static use only, but our general approach would put amsteel as a viable contender when it simply is not)
> 
> You mention you learned without any of the formulas, so want to ask you, and anyone reading: _*Does anybody have any formulas for calculating things here??*_ I'm unable to find my scrap paper that had this amazing formula that accounted for rope-length in the system, elasticity etc, am dying to re-find this formula but *any* formulas would be useful!!!
> 
> ...


The vet thingy does apply to me but then it doesn't as well. I have been in trees since 1982 my go to formula was cut it smaller for a good part of my mid career and especially after I was buying my ropes lol. I have dumped big stuff onto 3/4 double braid but the older I get the more careful I've become. As for production many times its faster to cut stuff smaller in my experience than to rig for very large gear testing loads. It also many times requires a seasoned groundsman to pull off big loads successful without jarring me around up there. I prefer to speedline now a day to get the mess clear of my decent but to tell the truth my career has taken a different path the last two years and I climb less and less as a result.


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