Friction hitch/split tail, what diameter ?

[Ollybean]

I have seen conflicting info on the size needed for making friction hitch rope lengths.

Some say about 70% of the climbing rope diameter and others that they are the same size as the climbing rope.

I have been using my home made 7mm dia on a 10.5mm climbing rope and they hold well, but are they strong enough ? Most of the commercial ones advertised are 8mm and over.

[Lukey-Loki]

All depends what friction hitch you use. And even then different combinations will behave differently.

 

From a health and safety point of view believe fiction cord should be a minimum of 8mm.

Is your home made stuff rated?

[Ollybean]

The rope I have been using is rated stuff from a climbing shop. Not an arborist supplier though so does it make a difference.

[Billbigtree]

If its a climbing rope like rock climbing its the wrong rope you need arborist rope mate.

[agrimog]

how can a climbing rope be the wrong rope?, its all made in the same factories with the same materials, supose youll be saying rescue ropes are the wrong kind next

[Coletti]

Hate to sound like a boff but didn't do my climbing ticket overly long ago and was told that legislation states that for use by an arborist min diameter rope is 10mm and min diameter friction chord is 8mm

 

 

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[agrimog]

how can there be legislation for some thing that isnt covered by law, only a H&S advisory paper, sorry about that

[sammym]

how can a climbing rope be the wrong rope?, its all made in the same factories with the same materials, supose youll be saying rescue ropes are the wrong kind next

 

As someone who does rock climbing and who used to climb trees. Put simply, rock climbing rope is more stretchy. It's resigned so that you fall and the rope absorbs the energy rather than breaking your back... When climbing a tree your prussic (insert fancy bit of kit) is not meant to have much/any slack in the system.

 

Try hip thrusting up a tree with rock climbing rope. You will be bouncing all day long.

 

There may be other differences.

[Lukey-Loki]

From an HSE perspective if you're using rock climbing rope for tree climbing, you're using the wrong rope. It will certainly hold your weight but I don't think it's designed to withstand the friction that arb rope goes through.

 

For recreational climbing, as long as you keep a keen eye on its condition it's probably fine. You may find arb rope and arb friction rope perform better though and also give you more peace of mind.

[Rupe]

Its nothing to do with withstanding friction, its the stretch in the rope that a problem.

 

Rock rock is dynamic so it is designed to absorb falls. We are not allowed to fall becuase we use work positioning, so you need a nearly static/minimal stretch rope for work positioning.

 

Rockclimbers will say you need a prussik diameter of less than 70% of the rope but thats because they would use prussiks on a single line for emergency ascents only. James Bond used his bootlaces on one film, and thats fine as a last resort!

 

But we use the rope differently, doubled into a loop, so the weight on the hitch is less and you dont have to have such small diameter cord, and with some hitches likes blakes you can use the same diameter cord as the rope.

 

But you simply cant use rock climbing rope for tree work. Not so much because of any industrty best practice or "rules" of any kind, its simply too stretchy so when you pull yourselk from a to b you are pulling the stretch out of the rope before you go anywhere which is pointless, inefficient and will sap your energy.