New lowering rope

[bob]

Is that right? 14mm max for use on a porta wrap style capstan?

 

if the bend ratio is less than 4-1 it reduces the strength of the rope

[armchairarborist]

treated ourselves to a new marlow 14mm bull rope last week from jonesie, 50m for just over 100 quid, its ready for a wash already thanks to a nice greasy sycamore and lime in the rain:thumbup: well happy with it..

[educated arborist]

Is that right? 14mm max for use on a porta wrap style capstan?

 

As i tried to explain, this is in order to maintain your rope as the weekest link so look up the break strains of each product, there are some really crappy 16mm lowering lines with low break strains which may be ok but in my experiance any tree surgeon savy enough to be using a capstan probably has a decent lowering line. The MBS of the large ISC capstan (in configuration) is 5T & don't be making the classic mistake of looking at the SWL's without remembering that the SF on the rope is 10-1 whilst on the hardware its 5-1:thumbup1:

 

There is a good reason to maintain your rope, a soft link, as the weakest link as if you ever do overload your system all you may loose is an eye. When you overload hardware it can break the speed of sound & will take no prisoners! I used to have a photo of a cross section of wood which had a distorted karabiner gate a little way in it. The tree had not grown around it but it had been launched an inch into the tree when a near by tree surgeon overloaded his system rigging down a seperate tree:ohmy:

[High Scale]

I got a 60m,14mm, Liros at £1:31per metre.

[nod]

"Don't forget if you goto 16mm double esterlon then you'll need to be running a bollard to maintain your rope as the weakest link. 14mm double esterlon or portland is the MAX you can get away with on the large port-a-wrap aaAND thats only after acounting for loss of strength at rope termination!!!

 

Jonsie & I are soon to launch the Loler UK set deals which shall be available exclusivly from FR Jones each of which couples the technical know how with on the ground concencus & experiance. The set deals will have alot of asociated literature which will be available on-line free to all serving as an educational reference & sort of comparison chart when compiling a rigging kit.

 

I would personally steer clear of portland braid & believe it is a false economy, Double esterlon is stronger, harder wearing & performs better I haven't met any-one who's tried both & bought a second portland You gets what you pay for! "

 

As i tried to explain, this is in order to maintain your rope as the weekest link so look up the break strains of each product, there are some really crappy 16mm lowering lines with low break strains which may be ok but in my experiance any tree surgeon savy enough to be using a capstan probably has a decent lowering line. The MBS of the large ISC capstan (in configuration) is 5T & don't be making the classic mistake of looking at the SWL's without remembering that the SF on the rope is 10-1 whilst on the hardware its 5-1:thumbup1:

 

There is a good reason to maintain your rope, a soft link, as the weakest link as if you ever do overload your system all you may loose is an eye. When you overload hardware it can break the speed of sound & will take no prisoners! I used to have a photo of a cross section of wood which had a distorted karabiner gate a little way in it. The tree had not grown around it but it had been launched an inch into the tree when a near by tree surgeon overloaded his system rigging down a seperate tree:ohmy:

 

 

Hello Mike

 

After the three hours I spent getting frustrated with you on the phone the other week I really cannot believe that you'll go on with this project, guffing people out with half baked facts.

 

You know as well as I do that there is no pulley currently on the arb market that offers a good bend radius at the anchor side of the configuration. Or did you think I was guffing you off?

 

Good luck I'm sure it'll do really well.

Nod

[Andy Collins]

What worries me more than the colour/brand/diameter of my rigging gear, is the complete conflict of opinions between those "in the know" who are selling, and testing, and advising us. Surely the theory is black and white on these matters, and surely it is dangerous when people start moving into the "grey areas", be they retailers or inspectors? Surely you should all be singing from the same hymn sheet?

[Mark Bolam]

Big lump = Big rope

 

That's it, really.

[Lorry thompson]

Works for me mark

[nod]

What worries me more than the colour/brand/diameter of my rigging gear, is the complete conflict of opinions between those "in the know" who are selling, and testing, and advising us. Surely the theory is black and white on these matters, and surely it is dangerous when people start moving into the "grey areas", be they retailers or inspectors? Surely you should all be singing from the same hymn sheet?

 

Hi Andy

 

I think that any grey areas that exist on this topic are generally created due to a lack of effort put into finding out & understanding the interaction between the components that are linked to build a system.

 

If we take it that a bend radius of 4x rope/sling diameter is required to maintain said rope/sling at full strength when connected to a piece of hardware; then surely the next step is to be sure that that radius is not compromised when building a system. Can we then presume that if a compromise takes place, i.e. a lower radius is used as a connection point, the system is flawed. If the system is flawed then surely extensive testing needs to take place before it's fair or right to say that the system in it's entirety will work together?

 

How do climbers/riggers configure their anchor point slings? Or their connection between portawrap & sling at base of the tree? What are the bend radii involved & are these connections in some way compromised? Why do we choose to give a rigging rope the same safety factor as climbing rope? Should cycles to failure come into the topic somewhere? Is rope a tool? Do we use it as a tool? Etc etc!

 

You can see that there are many questions which, I believe, many of us do not ask ourselves when planning systems to use. The reasons for this are many & varied. I think it's quite possible that the grey area is somewhat larger than the black or white that is often sought; & maybe, until the equipment exists that helps remove some of this grey we are left to build the puzzle for ourselves. Maybe, when the pieces of the puzzle are all there for us to put together I think that the grey will still exist. It is in our nature but why not just be honest & see things for what they are?

 

I don't believe that it is for me to give the answers, it is for those interested to decipher & begin to try & understand what it is that's involved. At least that way it no longer exists in the realm of hearsay.

 

Cheers

Nod

 

The straight answer is rarely as straight as one would hope!

[Mark Bolam]

I hear what you're saying Nod.

 

The one thing that can never be accurately quantified is the strength of the tree itself.

 

All of my rigging failures have been anchor points snapping out!

 

I like to think that my rigging kit is now well over-spec for the kind of jobs I tackle. I shudder to think of the size of some of the lumps I have rigged down in the past using a carabiner instead of a pulley. Back when I thought 'Bend Radius' was an Erasure album.

 

Good thread.