Rigging line advice - cable vs. rope?

[IllinoisJim]

I have limited experience with rigging and have been planning to put together a speedline and light, fast winch for moving 200 lb. blocks of wood up steep hillsides. I started thinking steel cable but am now thinking rope may be easier to handle and setup. The stationary support line will have about 1200 lbs of tension max and the winch line less than 200 lbs. At these loads I am thinking I should be able to avoid brace lines as the anchor points will be in 12"+ trees and only up to about 15 feet up. Need about 250' of line for longest runs. Was thinking 1/4 and 3/16 cable. Cable is cheaper but kinking issues and attachment to trees will be more trouble. With cable I need straps, clevis for tree anchors to avoid tree damage. For end anchors I thought I could move the end fittings by using "twin base" clips to prevent cable damage but still a lot of work to move the rigging. Not sure twin clips are even available in these small cable sizes. If I understand correctly rope is often just tied around the anchor trees making setup much easier.

For these loads 1/8" amsteel is the cheapest I have found that meets the load requirements (2300 lb breaking strength) for the winch line (about $.40/ft). (discoverd it was available in small sizes when I stumbled across wakeboarding winches) For the mainline I am having a bit more trouble finding a low cost line. Wesspurr has 3/8" Tenex TEC line for $.40/foot and gives what looks like a reasonable safety factor (breaking strength 6100 lb). But I did notice a note that it is "susceptible to plucking and abrasion if it is run over the bark of a tree".

How do Amsteel, Tenex TEC, and other lines compare in terms of wear resistance in this type of use? Other factors I may have overlooked? This will get somewhat limited use so wear resistance and ease of use need to considered but balanced against cost...

Looking for advice and comments from those with more experience.

 

[treeslayer]

are you going to tie to the load, and then drag it up the hill, putting the rope in contact with the ground?

rope will not suffer that abuse well. dirt, water, mud, etc..... have you thought about a high line, with or without a pulley? run a tensioned static line (cable), and use the rope to pull the load up, supported by the high line. kinda like they do on ax men, without all the elaborate equipment.

A basic idea, needs to be adapted to your actual situation. post some diagrams or pics, I have done a lot of ravine clearing, as have many others. we can offer our methods for your scrutiny. RBTree has one of the best setups I've seen, numerous pulleys, and a GRCS with a big drill motor to spin it. now there are faster ways to do it, but its whatever is financially practical..........

 

[Sirpouralot]

Rope vs Cable

Hi we are Tree service in Michigan and we use a Rope now that holds up rather well and is stronger than Steel Cable. It is very expensive and still would not work as well in the application that you would be using it in. We are using the new rope for our Winch on our Chipper and it is way nicer than using cable. The cable tends to fray and then it sticks you when you are handling it. We put a nylon sleeve over the last 10 feet of the rope to protect it from abrasion. This is normally the part of the rope that will be used to anchor and would receive the most wear. The rope is holding up better than cable for us, is stronger and never cuts your hands. We still use cable for our Crane and have not tried the new rope, so I can't comment on that.

The only problem with the Cable in your situation, is that when you are done at the end of the day you just can't fold it up like a rope. You have to have a way of managing and storing the cable. If you can work that out, then Cable is going to be the best option. If you are using a winch then your problem is solved.

 

[rbtree]

Dan, a spectra line won't sag, as there's no stretch.

Thanks, slayer.

Here's a pic--dragging brush up a steep hillside. Available anchor points weren't very high. Traveling block on tight high line. Chain saw winch employed. In order to keep high line tight, we ran the pull line through the traveling block and then to the load, which allowed it to be winched right up to the pulley. This required a back line to hold the pulley in place until the loads were pulled up to the pulley. Then the back line was released. Labor intensive. Took three guys.

 

[IllinoisJim]

rope vs. cable

Treeslayer,

A static highline is exactly what I am planning. A pulley carriage will run on that and be pulled up with a winch (actually an old rototiller with a spool fitted). The rope will not be running on the ground. 15' may not seem like much lift but that is on the edge of 80' deep ravines with 30 degree and more (mostly more!) slopes. I planned some sag in the line to keep the tension on the main line reasonably low while keeping things off the ground. I have done some calculations of the worst case forces - 1200 lbs. Also will be limiting the size of load.

I planned to build a simple carriage with 2 pulleys riding on the main line. The winch line would go through another pulley on the carriage and then down to a pulley with hook to attach the load and them back to the carriage. I also planned to have hooks on the carriage to attach the load so it stays suspended. I won't be raising or lowering the main line - or at least hadn't planned to. I can post a sketch later.

So should I use cable or rope for the highline? I am now thinking rope would be much easier to handle and worth the extra cost. Then the question is which rope will do the job for the least cost...

Any links to the RBtree setup? Sounds interesting...

 

[ddhlakebound]

I have done some calculations of the worst case forces - 1200 lbs. Also will be limiting the size of load.

If you're figuring 1200 lbs as the max force you're going to create, then you need to be working off a safety factor. Also keep in mind that knots greatly reduce tensile strength, and that sometimes the calculations of a "max load" are off by enough to create difficulties. If you go at/just above what you think you'll need, it'll be no time at all before wear and tear/cycles to failure causes a problem. 10:1 is a good safety factor, and what I and probably most others here were taught to use for treework.

Looking at the Sherril rigging rope chart, I'd suggest that you take a look at the 5/8" super braid w/ 15.6k tensile (low stretch) or the 9/16" stable braid @13.3k tensile (moderate stretch). The 5/8 super is about $1.20/ft, and the stable braid is right around $1.00/ft.

Any attachment slings and hardware should be rated higher than the rope you're using. If you have a failure, you want it to be in the rope. Flying biners and hardware are sorta like bullets.

Good luck, work safe.

 

[ddhlakebound]

Dan, a spectra line won't sag, as there's no stretch.

Thanks, slayer.

Here's a pic--dragging brush up a steep hillside. Available anchor points weren't very high. Traveling block on tight high line. Chain saw winch employed. In order to keep high line tight, we ran the pull line through the traveling block and then to the load, which allowed it to be winched right up to the pulley. This required a back line to hold the pulley in place until the loads were pulled up to the pulley. Then the back line was released. Labor intensive. Took three guys.

Nice setup there RB. You say it was labor intensive?

I'm wondering how many guys it would have taken to drag it up by hand in the same time...

So you had the static highline, then brought the load up to the pulley with a lifting line, clipped it to the pulley on the highline, then released the lift line, is that right?

 

[pdqdl]

If cheap is most important, then the high line should be done with a wire rope. Hard to work with, but strong and durable. You could use 7-strand, for an even reduced expense and increased aggravation.

Amsteel rope is perfect for that application, but pretty pricey. Consider that it will have many other uses when you are done, and that moving the rig around will be much more tedious with wire rope.

I wouldn't use a standard arborist rope in that application unless you could live with all the extra stretch. You will really need to pull a stretchy rope TIGHT to keep the sag at an acceptable limit. All the pulleys and hardware will need to be bigger and heavier ($$) to fit the larger rope, too.

Tenex is a great rope, and stands up pretty well to abrasion. Loose weave allows easy splicing and snags on branches easy. Amsteel is almost as tough as nails (literally), but don't get it hot, as it melts very easily. 3/8ths amsteel has a breaking strenght of around 19k, with very little stretch. Probably costs near $2.00/ft !

 

[treeslayer]

Treeslayer,
So should I use cable or rope for the highline? I am now thinking rope would be much easier to handle and worth the extra cost. Then the question is which rope will do the job for the least cost...

AMSTEEL.

Any links to the RBtree setup? Sounds interesting...

on the bottom of his posts, click on "my online photos".

Where in Illinois? I'm in the Mchenry/Lake county area, PM me and we can trade #'s.

 

[treeslayer]

The math says that with no sag the load on the anchor points would be infinite.

:agree2:

everything sags, to some degree. add some cheap rope stretch, you got a problem. I've seen a speedline rig go bad, and wipe out a deck.
I am only concerned with the rope coming in contact with the ground, not too worried about the loads dragging, you can't hurt dirt.

 

[pdqdl]

You can sure tear hell out of the understory plants growing on the dirt. Then you start an endless cycle of bare earth leading to increased erosion, leading to more groundcover being destroyed, leading to more erosion...

Sometimes it pays to take care of the dirt, as well as the trees.

 

[rbtree]

It seems to me with a 'high line' that is only 15ft. off of the ground that rope sag in the middle is going to have the load dragging the ground. When you tension between two fixed points and place a load in the middle very large forces can be generated.

I'll try again, Dan. With a spectra line, 15 feet of elevation should be enough, depending on the length of run. Get it snug enough to keep the load off the ground and you're good to go. With that amount of slack, there'll be no problem overloading anchor points, if they're beefy enough relative to the loads. Back guying them will solve any possible overload scenario.

 

[rbtree]

Mt comments in bold

If cheap is most important, then the high line should be done with a wire rope. Hard to work with, but strong and durable. too bulky, heavy, and slow to deal with, typically

I wouldn't use a standard arborist rope in that application unless you could live with all the extra stretch. You will really need to pull a stretchy rope TIGHT to keep the sag at an acceptable limit. Most arb lines only stretch 2-5% at 10-20% of tensile. That's not an issue.

Tenex is a great rope, and stands up pretty well to abrasion. and quite low stretch 3/8ths amsteel has a breaking strenght of around 19k, with very little stretch. Probably costs near $2.00/ft !

Not to me. My source, got me 1/2 inch spectra for $1.50 a foot....You're referring to Amsteel Blue, which is stronger and pricier than plain spectra....

If anyone really wants some spectra, get hold of me. I'll sell 300 feet of that reel, or can get rope from my bud. Or you can go direct, as they now have a site. Ask for Ben...tell him Rog sent ya

www.dantrawl.com

 

[rbtree]

Nice setup there RB. You say it was labor intensive?

I'm wondering how many guys it would have taken to drag it up by hand in the same time...

So you had the static highline, then brought the load up to the pulley with a lifting line, clipped it to the pulley on the highline, then released the lift line, is that right?

Required three folks...plus me when I lost* the camera..

Slope was about 30 degrees.....woulda taken a monthasundays to get it up...there were stairs off to the side....

The yarding line was run off a high tied pulley, and through the traveling pulley to the load. As it was being winched it eventually came up against the pulley....to keep it from dragging along the ground at first, we had a back line run through a friction device to keep the pulley in place. then we were able to slowly release the back friction device, until the load stayed locked against the pulley.

*= put it away.....

 

[pdqdl]

How to rig with ropes rather than cables

I was trolling extra files on my hard drive, consolidating information, and tripped over this little file.

It fits this thread rather nicely, essentially a "How-to" for this topic.

Dang! it won't load. Google... First try!

http://www.orosha.org/pdf/grants/osu/rigandopguide.pdf

 

[IllinoisJim]

Thanks for all the good feedback.

pdqdl, VERY good link!
I noticed most of the line was wrapped directly on the trees but had seen something somewhere about canvas wrap for protection of the line or possibly protection of the tree. I did see one place that showed fire hose and I happen to have a few scraps of that. Is there a need for protection and, if so, what to use?

treeslayer, I am in southern part of the state, near St. Louis. Looks like we are at opposite ends of the state.

What is the difference between Amsteel BLUE and plain Amsteel. Looks like the blue has slightly higher cost and load rating. What else?

The comment about the line being rated less than hardware has me wondering about blocks and such. Makes sense but hard to find a rope block that is rated at more than the line unless it is huge and expensive. Any reason a wire rope block shouldn't be used with rope (Amsteel or otherwise...)? How much more should the hardware be rated for?

 

[pdqdl]

Wire rope blocks rated for the same weight will not be cheap, either.

 

[IllinoisJim]

rope vs. cable

How about this?

http://cgi.ebay.com/ebaymotors/20K-...802205QQptZMotorsQ5fATVQ5fPartsQ5fAccessories

20k winch block, 1/2" line, $30 delivered.

I am not sure if that is a working rating or a breaking strength. Looks like 20k is the strongest I could find in this construction and low price. Above that the prices shoot up.

This wouldn't be 2x stronger than the line for 3/8 amsteel. But I think this is over 4x what I could pull (Kubota L3600). Since the block gives 2x that would leave a 2x rating. Tell me if this sounds reasonable. I know I started thread with the highline setup but it would be great if I could also use the line with a few blocks for a bit of pulling too.

 

[pdqdl]

No pictures, no description, no sale!

How would you know what you are buying?

 

[treeslayer]

These work well, and can be procured from any tow truck supply outfit.

This site shows sizing and ratings.
http://www.truckntow.com/showproduct.aspx?productid=10653