static versus dynamic rope

[Plasmech]

Talking about the actual rope itself, not the technique...

In rock climbing, we use two types of rope:

1. Dynamic. This is the rope we climb with. If we fell and a piece of protection, say a camming device inserted into a crack, saves our ass, dynamic rope will stretch, absorbing energy. If it did not do this, a fall from only say 5 feet would snap our back. Dynamic rope decellerates the climber slowly enough so that the g-forces are not fatal

2. Static. Used for rapelling ONLY. No give whatsoever. Using this rope where dynamic rope should have been used will likely be fatal if a fall occurs.

I am surprised I don't see any discussion about the twodifferent kinds of topes on here. The flip line woud certainly be static, but should the secondary tie-in line by dynamic?

 

[md_tree_dood]

Trying pulling yourself up a tree with your rope set 100ft up and see what 200 ft of stretch feels like.

 

[OTG BOSTON]

2. Static. Used for rapelling ONLY. No give whatsoever. Using this rope where dynamic rope should have been used will likely be fatal if a fall occurs.

Try using the search feature on here (static climbing line, static line,etc)

There are many on the market for arborist use, and they actually perform best for ASCENDING not rappelling.. KMII and Snakebite are a couple of examples of arborist static climbing lines.


The new trend is for semi-static lines such as tachyon

 

[fsfcks]

I recently looked up some specs for ropes, and for the ropes I looked up the arborist rope had a significantly lower stretch factor than static climbing rope. That is what makes it ideal for pulling trees.

 

[woodchux]

All arborist ropes are static compared to rock climbing ropes.
Falling is not an option...

 

[squad143]

"2. Static. Used for rapelling ONLY. No give whatsoever."

Actually Static rope do have some stretch. I had the opportunity to do a 1000' rappel (static rope) a few years back and it was quite different feeling a bounce on a static rope when you were getting closer to the bottom.

 

[TheTreeSpyder]

Our lines are especially more static when configured into a doubled line support (of each leg with half loading on it, so less elasticity). The line will be more static close to TIP, then of course too.

When it comes to the loading ranges of rigging, the same lines as single leg support, can yield more dynamics, then the anchors too.

One must ask, if our lines allowed more dynamic/elastic absorbtion, then would the resulting increased falling distance give more chance to slam into something.

 

[Mikecutstrees]

all ropes will stretch, Even braided steel stretches. For the most part when tree climbing our tie in point is above our head and our rope doesn't have much slack. So a long fall really doesn't happen if you climb correctly. Which is different from rock climbing where lead climbers often climb far above their last piece of gear. My wife climbs on rocks so I know a little on the subject. Mike

 

[RedlineIt]

Plasmech,

There is no lead-climbing in Arboriculture. In fact one of the golden rules is: Don't climb above your TIP (Tie-in-point). A lot of the time we are not so much climbing the tree as we are installing a rope and then climbing our ropes. Your can see how dynamic rope would be a disadvantage, no?

Once up to the initial TIP and if further height is desirable, we advance our TIP by lanyarding in, hopefully a bit more overhead, unclipping our rope and tossing over a new TIP and up we go! Repeat as necessary. Hopefully, by this point the tree is branchy enough that we are actually tree-climbing, but if not there are many methods to advance our TIP.

Edit to add: Another big difference from rock climbing, we almost never go on a manned belay. The tree climbing school I attended showed us how this would work, but in the real world, the ground crew is too busy with their own jobs. So tree work is mostly done DdRT or "Doubled dynamic Rope Technique". Do not become confused! This does not mean use of dynamic rope, it means the climbing system is dynamic, ie: the rope goes from climber to TIP, over and back down to climber tied in with a friction hitch. So, when more or less rope is required to move around the tree, the rope is travelling in both directions from climber to TIP and back and is thus "dynamic." Make sense? Knew it would.


RedlineIt

 

[Plasmech]

Plasmech,

There is no lead-climbing in Arboriculture. In fact one of the golden rules is: Don't climb above your TIP (Tie-in-point). A lot of the time we are not so much climbing the tree as we are installing a rope and then climbing our ropes. Your can see how dynamic rope would be a disadvantage, no?

Once up to the initial TIP and if further height is desirable, we advance our TIP by lanyarding in, hopefully a bit more overhead, unclipping our rope and tossing over a new TIP and up we go! Repeat as necessary. Hopefully, by this point the tree is branchy enough that we are actually tree-climbing, but if not there are many methods to advance our TIP.

Edit to add: Another big difference from rock climbing, we almost never go on a manned belay. The tree climbing school I attended showed us how this would work, but in the real world, the ground crew is too busy with their own jobs. So tree work is mostly done DdRT or "Doubled dynamic Rope Technique". Do not become confused! This does not mean use of dynamic rope, it means the climbing system is dynamic, ie: the rope goes from climber to TIP, over and back down to climber tied in with a friction hitch. So, when more or less rope is required to move around the tree, the rope is travelling in both directions from climber to TIP and back and is thus "dynamic." Make sense? Knew it would.


RedlineIt

This reply explains it all, thanks. So basically it is unacceptable to fall more than a couple feet.

In rock climbing on a dynamic rope, a fall of say 40 feet is "common". Well, we sure don't want it to happen every day or even once in a career, but it happens to someone every day somewhere. I hear it's quite an experience if it results in a zipper, that is pieces of protection ripping out on the way down.

I rappeled down my 120 meter dynamic line a couple times. When you get to the bottom, she bounces quite a bit believe me. Wish I had a static rope at the time but even if I did, doubt I would have hauled it to the top just for the ride down.

Anyway, thanks for the replies, makes sense. Static ONLY in for tree work.

 

[rbtree]

I rappeled down my 120 meter dynamic line a couple times. When you get to the bottom, she bounces quite a bit believe me. Wish I had a static rope at the time but even if I did, doubt I would have hauled it to the top just for the ride down.

Anyway, thanks for the replies, makes sense. Static ONLY in for tree work.

I used to do major rock and mt climbing. Prolly rappeled hundreds of pitches. Yup, the lines are stretchy, as in 6-8% under body weight and up to 70% at break.

Full static lines have near zero stretch, as in ~3% at break. These are the expensive ones made from spectra or dyneema. Some static caving, rescue, and rappel lines have a fair bit more stretch than arborist tree climbing lines.

Thus, I call our work and lifelines "semi-static"