SRT/Rope Wrench Safety Advice

[ClimbMIT]

Okay, I have been really excited about using my Rope Wrench for access and pruning as well. I like the fact how your climbing hitch will not bind going around multiple crotches. I haven't played with it much though. I have read a lot of threads about the static ropes not designed for fall arrest and climbing line not designed for ascending, Rope Wrench threads and videos, rope options for SRT, really great information! What I was wondering is what kind of force is created on the rope each time you redirect your line? Does this create more stress and weight to the climbing line with each redirect? Also this seems like it would create a lot of wear on the rope. I want to utilize these new tools I just want to make sure that I understand the risk factors and know how to apply proper technique with this equipment.

Thanks!

 

[Carburetorless]

Okay, I have been really excited about using my Rope Wrench for access and pruning as well. I like the fact how your climbing hitch will not bind going around multiple crotches. I haven't played with it much though.

I can't comment on the Rope Wrench, I've never used one.

I have read a lot of threads about the static ropes not designed for fall arrest and climbing line not designed for ascending, Rope Wrench threads and videos, rope options for SRT, really great information!

You don't fall while tree climbing(at least you're not supposed to), and you never use a dynamic(rock climbing line) for tree climbing, they're used to arrest falls while rock climbing.

You could a dynamic rope for rigging to absorb the shock load of a limb being lowered onto it, but you don't want to climb on one.

What I was wondering is what kind of force is created on the rope each time you redirect your line? Does this create more stress and weight to the climbing line with each redirect?

If you place a rope around a limb or anything else, and pass it back down the other side at 180 degrees, and apply a load to one side, you will double that load on the line.

If you do that over multiple limbs, you will apply that force to multiple places on the rope; However, you won't be increasing the initial load.

If you place the rope around a limb or whatever at 120 degrees or less you only put a force equal to the load on the part of the rope that's over the limb.

Something else you may not know, when you put a rope over something at 180 degrees only half of the rope is supporting the load, since ropes are designed to have strength along their length, when you bend the rope around a limb the inside of the rope becomes compressed, while only the outside of the rope is pulled by the load. So your ropes strength is reduced by half when you put it around an anchor point at 180 degrees.

Also this seems like it would create a lot of wear on the rope. I want to utilize these new tools I just want to make sure that I understand the risk factors and know how to apply proper technique with this equipment.

Thanks!

Arborist ropes are pretty tough, but not indestructible. Examine your ropes before and after every use to check for signs of wear or damage. If it doesn't look safe replace it.

 

[VA-Sawyer]

Carb,
So many of your statements about rope loads are wrong that I don't know where to begin.

A rope going up one side of a branch and back down the other does not increase the load on the rope, but it does increase the load on the branch supporting the rope.

A rope doesn't lose 1/2 of its strength going over a branch due to compression on the inside! In fact the strength loss is very minor if the diameter of the pulley/branch is at least 4 times the diameter of the rope.

There is nothing magical about the 120 degree angle on rope loads!

You really need to get a clue about physics before trying to tell others about rope loads.
Rick

 

[Iustinian]

Bend ratio is the term that comes to mind.

HSA Rigging Report..." Rope Bend Ratio 7.3.4 When rope passes over an object (e.g. branch or pulley) the bend generated in the rope will result in uneven loading of the threads of the rope. The fibers on the inside of the bend will be compressed, and therefore they cannot participate in carrying the load in the same way as they would if the rope were straight..." ETC, which most know. Then the report quotes Blair, 1999 "Working rope over too small a sheave or tying off to an undersized bollard, for example, can cause both internal and external fibre fatigue and abrasion, creating potential for failure."

If your rope is hung on a branch that is 4x's greater than the diameter of the rope itself, then it will generally be accepted to be a sufficient bend ratio so as not to alter the strength of the rope in that situation.

I agree: if you secure the standing part of the rope to the trunk, and do an srt ascent on the working end of the rope -- the branch will have to support 2x's the weight applied to the working end of the rope, that is double the climber's loaded weight, gear and all.

 

[Carburetorless]

Carb,
So many of your statements about rope loads are wrong that I don't know where to begin.

A rope going up one side of a branch and back down the other does not increase the load on the rope, but it does increase the load on the branch supporting the rope.

A rope doesn't lose 1/2 of its strength going over a branch due to compression on the inside! In fact the strength loss is very minor if the diameter of the pulley/branch is at least 4 times the diameter of the rope.

There is nothing magical about the 120 degree angle on rope loads!

You really need to get a clue about physics before trying to tell others about rope loads.
Rick

A rope's strength is along it's length when it's being pulled on, if you bend that rope at 180 degrees there is only about half the rope being pulled on, so yes it does lose half it's strength.

Stop being a keyboard jockey.

 

[VA-Sawyer]

No it doesn't ! You might just do a little reading on the subject before saying such dumb stuff.

As for being a keyboard jockey....... I'm just trying to keep folks from getting injured or killed by WRONG infomation.
Rick

Dang! Del beat me to it.

 

[ClimbMIT]

Thanks for the responses! I am going to read up on some of the rope dynamics.I figured this thread might get a good debate going. I am not taking any advice for granted. I am teaching myself these techniques that I watch videos on. So I take it seriously. Low and slow for now. When I get better. I will have to make a video of me climbing SRT and Rope Wrench. Then you guys will be like, " what the hell is he doing?! " or hopefully say, " Nice Video and technique"

 

[Carburetorless]

No it doesn't ! You might just do a little reading on the subject before saying such dumb stuff.

As for being a keyboard jockey....... I'm just trying to keep folks from getting injured or killed by WRONG infomation.
Rick

Dang! Del beat me to it.

So your telling them that their rope is stronger than it actually is will keep them safer?

Oh, my bad.:msp_confused:

 

[tree md]

So your telling them that their rope is stronger than it actually is will keep them safer?

Oh, my bad.:msp_confused:

You're wrong man. You need to go back and hit the books.

 

[tree md]

And just so you know, I was unclear on that a few years ago myself. And was told so here. Same discussion. I had to research it to be sure for myself.

 

[VA-Sawyer]

I think we may be wasting our time trying to educate a 'clueless carb'.

Hey Clueless, have you ever seen the results of a splice test in a pulling machine ? The eye of the rope splice is bent 180 degrees over a pin at each end and then pulled to failure. I have never seen one break where it bent over the pin. They often fail at the end of the inserted tail which is straight.
Try explaining that with your 1/2 strength when bent 180 degrees crap.

Bad infomation is BAD no matter which side of the equation it falls on.

Rick

 

[Bomber]

I file Carbs advice in the same class as FTA and AA.

 

[VA-Sawyer]

It's bad to use the 'troll' word when not sure but I've felt 'trolled' right from the start with him.


He was giving clues when he posted about dropping his srt line......going on about never DbRT'ing and never learning how to hip thrust. IMO, he's making it up for entertainment purposes and we are his entertainment, Keyboard Jockey.

Del_,
I haven't responded to his stuff before, but he was so wrong on this thread, I felt I had to in the name of safety. And just for the record...I can't hip thrust for beans.

Bomber, Ok, I got it now. CC,AA and FTA.

Rick

 

[Iustinian]

I think we may be wasting our time trying to educate a 'clueless carb'.

Hey Clueless, have you ever seen the results of a splice test in a pulling machine ? The eye of the rope splice is bent 180 degrees over a pin at each end and then pulled to failure. I have never seen one break where it bent over the pin. They often fail at the end of the inserted tail which is straight.
Try explaining that with your 1/2 strength when bent 180 degrees crap.

Bad infomation is BAD no matter which side of the equation it falls on.

Rick

yea, absolutely correct. At one time Samson's (for those that don't know, the manufacturer of many quality rigging ropes lol) recommendations were a 8:1 bend ratio for load bearing applications, but allowed a 3:1 for pin termination.

And carb-less -- you would be correct with the assumption that the rope is bent at 180 to the extent that it has been pinched; HOWEVER, it can be safely used during 180 degree turn, provided that the bend ratio is 4:1, that is, the bend occurs at a place (like in a properly selected pulley, or even a branch) if the turn provides at least the prescibed bend ratio.

 

[VA-Sawyer]

Actually, climbers hang every day on ropes using less than a 4 to 1 bend radius. A knot on a biner and through the rings of a friction saver are just two that come to mind.
Rick

 

[tree md]

I use biners and friction savers as little as I can get away with on my climbing line. I find that the bend radius is harder on my ropes than natural crotch. Don't get me wrong, I'll throw a FC on a limb for a redirect when I need to but I have found that the FS and biners make my PI milk and I don't like that.

 

[VA-Sawyer]

I agree. I also climb on Hi-vy and use a spliced eye and that leather bark saver. Haven't had any milking issues.
Rick

 

[Iustinian]

I've been using this as a redirect (for drt climbs) for awhile. The double pulley allows the rope to run past itself side by side without ever locking off, which has happened to me using redirects before -- avoiding that once was worth the extra $35 for the pulley. Plus it has a permanent spot on the gear racks on the back of my harness.

 

[ClimbMIT]

I agree. I also climb on Hi-vy and use a spliced eye and that leather bark saver. Haven't had any milking issues.
Rick

Thanks Sawyer, I appreciate your feedback along with Del. Do you use your leather bark saver for SRT on your highest tie in point?

 

[VA-Sawyer]

I try to. It is always on my rope, so if I can easily get it over the TIP I will do so. However, as there is little rope movement on SRT, I don't fret too much if it is being a PITA. Sometimes I go up SRT and then change over and position the leather where I want it at that time.
Rick