Light rigging/lowering line

Tom Dunlap

Tom Dunlap

Here from the beginning
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Retired in Minneapolis
At the present time almost all of the crews use True Blue as their light, general duty lowering line. The rope has some assets that make it a good choice. Personally, I'm not a fan of the rope except for the color, it's the best color of any rope :)

What rope is being used for small work? What reasons can you give for choosing any particular rope?

One idea is to use half inch double braid or one of the 'climbing' ropes in place of True Blue. How do they hold up to abuse and occasional natural crotch rigging? Cost/durablity?
 
I use Arborplex cause it is cheap, or old climb lines. For light rigging, a retired climb line is just fine.....both 12 and 16 strand hold up fine for natural crotch rigging, as long as loads are light. I save my 1/2 inch double braid for use with blocks, to make it last, and as it is rated at close to 10k, for heavier work.

I'm into my 32nd year of tree work and have never used True Blue...
 
Hi Tom

I used to use True Blue as a light rigging line. But its too heavy when natural crotch rigging (tends to pull itself out of the crotch before you can flick it down when setting from a distance).

I also had my eyes opened when I tested that rope after five years of (periodic when training) climbing use:

We cut it into lengths and tied a scaffold knot (sliding double barrelly my wotsit thingy) in both ends and pulled it on the test rig:

Broke at 983Kg /forum/images/graemlins/bigeyes.gif

http://www.treemettlenexus.com/pdfs/FrictionHitchCompilation.pdf

(page 85 of 96)

We did two other straight line tests with bowlines v sliding doubley barrelly me wotsit thingys. The SDBMWT(?!) won. The BS was similar.

This isn't slagging off the True Blue. /forum/images/graemlins/rolleyes.gif I expect many other single braids would have tested lower over that time. TB is a quality 100% polyester line.

It is used to discourage climbers from using their retired single braid climbing lines as rigging lines. Save them for tying down loads on the truck. Single braid rigging ropes are prone to losing a lot of strength in a short space of time.

The option for me for a light rigging rope is a 12 strand single braid: Its light, strong (verstile with other systems), abrasion resistant, cheap and can be run through a portawrap, Muenter hitch and fig 8 without too much hockling (lowering devices of choice for light rigging). Yale XTC 12 is a good example.

This makes it replaceable before it becomes risky from age (50% strength reduction after as little as two years - depends on the safety factor applied how risky this might be. If its 20:1, shouldn't be a worry).

The lightest line I use for topping down used to be a 12mm double braid. I'm thinking of replacing this with 13mm 5000Kg BS edelrid power static dry (rescue kernmantel). Its a softer lay low stretch kernmantel thats stretchier than most and knots well. This is the system that gets the most wear on a daily basis. Kernmantels have been shown to resist strength loss from UV and internal and external abrasion for upto 15 years (caving and industrial low stretch KM). This way, I don't have to worry about premature ageing of the rope and associated strength loss over 5 years. I'll just cut off the ends when they show excessive wear from knotting (buy a longer rope).

Depends how you run your accounts and design and replace your riging kits I guess, and how many staff are likey to cut through it on its 2nd day out (It always seems to happen...!? /forum/images/graemlins/bangtard.gif /forum/images/graemlins/furious3.gif ).

Not relevant to this discussion, but I'm gonna replace the 16mm polyester double braid with nylon for topping down.
 
For light natual crotch rigging 3 strand is a good choice. Super durable and low cost and lower surface friction. We also use retired climbing lines for light stuff.
 
Can't beat 1/2" 3 strand for natural crotch rigging. It's durable, inexpensive and doesn't loose strength running over tree crotches (double braid will). We shy away from using climbing lines as lowering lines so no one grabs the wrong line. When running a lowering line through a block and down to a friction device, we use double braids. Have a 1/2" Amsteel 2 for GRCS use.
 
I am a huge fan of All Gear's 1/2" Husky double braid for light rigging. You can't beat the price on it and it is rated to 9500 lbs. This is also what I use to anchor off my pulley for climbing. If I am rigging through a natural crotch I tend to use Blue Streak due to its strength and wear resistance.
 
a side note to the above post:

The rope I use for anchoring my pulley is a seperate line than I use for rigging. Much like everyone else I try my best to avoid using any rigging line for climbing applications or any climbing line for rigging applications.
 
Tru-Blue is OK for a lowering line, but it is stretchy if your working in close quarters, which is why I only like to use it for pulling over trees or spars.

Ever since we started using double braids I have been a big fan of using it for all of our lowering needs. We use blocks and pulleys about half the time and natural crotches the rest of the time. I like using the double braids because it gives me some piece of mind when not on the job and don't have to worry about having a rope overloaded, my guys are not experts in rigging but do have a lot of common sense about do's and don'ts when it comes to shock loading, a good strong rope on the job is just a little extra added insurance for me. I usually replace our lowering ropes long before they should be, age and strength loss usually are not a big issue.

I have never used a 3 strand, how well does it hold a knot??

Are there different types of 3 strand ?? The 3 strand I see in the hardware store seem like it would be a hard stiff rope to work with.

Larry
 
When I worked for myself it was occasionaly a retired climbing line for pulls and real light rigging. Primarily 1/2" dbl braid.

At work we have 3-strand and an Arborplex. I dislike the 3-strand more than the AP.

Just wondering and not critizing, does the 3-strand really have less friction? Isn't the amount of friction the same just concentrated to the smaller surface area? Maybe this should be a different thread to avoid hijacking this one.
 
I use tree master three strand primarily because it works well in the rope puller.
When I get the GRCS I'll be looking for something different, maybe a Double Braid.
I have Stable Braid now but just use it for block slings.
 
Larry, New England Ropes has Safety Blue 3 strand (which is what we use), Samson Rope Technologies has Tree Master (harder lay than Safety Blue, therefore longer break in period). We have used both, but most, if not all, of the climbers prefer SB 3 strand.
Eric, I would think that 3 strand would have less friction because there is less surface contact. If you look at a cross section of both, you will see what I mean.
Brendon, most arborist double braids (polyester/polyester) share the load 50/50. 50% cover to 50% core. Other blends will be different; polyester cover/spectra, technora, vectran, etc. core. When runnng a double braid thru a natural crotch, the cover will take most of the load, because it is in direct contact with the surface. The core will "slide" thru the cover strands. When running over an arborist block, the pulley turns with the rope, causing the cover/core to share the load. Hope this helps.
 
[ QUOTE ]
Eric, I would think that 3 strand would have less friction because there is less surface contact. If you look at a cross section of both, you will see what I mean.


[/ QUOTE ]

Norm, I completely understand what you are saying about less surface contact but isn't the amount of friction constant regardless of the surface area?

I'm certainty not an expert in physics and there are others here that know more than I do. I'll try to do my best and try to explain my thoughts.

If natural crotch rigging a 100 # branch there will be X amount of friction at the crotch/rope union. The amount of friction would remain the same regardless of the rope construction or does the rope construction change the amount of friction.

I'll use this example because the "Pine Heads" spend way more time therorizing about friction than we ever will.
In building pinewood derby cars friction is the enemy. One of the main areas worked on is the axle/wheel interface. Many studies/experiments have been done in this area. One common idea is to cut groves in the axle (nail)with the idea that it would reduce friction by reducing surface area. Most of the guys concluded that it was no faster because the friction remained the same. Thge surface area was reduced but the amount of friction remains the same and is not transfered to the smaller amount of surface area.
 
Double braid isn't recommended for natural crotch rigging - heavier, picks easily, generally more expensive and the sheath and core slip where it contacts the branch creating a weakness (too much friction of the sheath on the crotch while the core does the work).

Which are some of the reasons not to use it as a climbing line too.
 
[ QUOTE ]
Double braid isn't recommended for natural crotch rigging - heavier, picks easily, generally more expensive and the sheath and core slip where it contacts the branch creating a weakness (too much friction of the sheath on the crotch while the core does the work).

Which are some of the reasons not to use it as a climbing line too.

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Which is exactly why you should use pulleys not only for rigging but for climbing as well. Using a natural crotch makes it difficult to accurately measure the amount of friction you will have on the line at any one time. The heat caused will definitely damage the rope used and all ropes regardless of construction have the chance to pick if running over bark.

Rigging off of pulleys will certainly require your crew to learn how to manage the lack of friction up top, but the end result will be a ground guy that has much, much more control over the rigged out piece, longer lasting rigging lines, and less question as to how the rigged piece will react when cut.

Climbing off of pulleys will take time to get used to as well. We usually learn to climb by positioning ourselves with the help of friction from the crotch. Doing so without friction works a bit differently , but is much better once you are used to it. Setting up a pulley to climb on can be as simple as rigging one from the ground (anchored pulley), or installing one once in the tree (rope guide, etc.) The benefits gained include less rope wear and MUCH less wear on the body.

I prefer to use double braid lines for climbing, but I do my best to avoid using them in natural crotches. Of coarse I do my best to avoid climbing on natural crotches anyway.
 
I don't exactly disagree with you there Rich. Here are some other reasons though:

Double braids are too soft for effective ascender safety in SRT (check what ropes were used in the tests).

Double braids that don't pass EN1891 Type A dont have sufficient energy absorption for a factor 1 fall in SRT (may cause ascender/rope damage or failure)with a 100kg mass.

Double Braids that don't pass Type A, don't have sufficient energy absorption to mitigate 10-12kN forces from a Ddrt factor 1 fall.

Some double braids pass Type B, but this test is for an 80kg mass, 18kN Tensile spliced, 12kN knotted. 80kg is not typical of most tree climbers with equipment. Remember we have no back up.

I'd recommend any climber avoid double braids that don't pass EN1891 Type A, for climbing - There are many safer Type A alternatives. And pulleys/false crotches aren't always practicable in climbing or rigging. /forum/images/graemlins/cool.gif
 
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