Loopies, whoopies, ultras etc

[Joe Newton]

19 minutes ago, peds said:

As you say, they are all called "static", but are in fact "semi-static" as they do inevitably stretch a bit, unless they are a genuine zero-stretch cord made of kevlar or aramid or something. 

 

With that in mind... is there anything to be said for using a truly dynamic rope, like wot rock climbers use, for catching big falls, when you switch to negative rigging? "Dynamic" ropes can have something like 15%, 20%, anywhere up to 40% stretch... which does of course soften the blow on the anchor and is kinder to the system on the whole.

The problem with using a "dynamic" rope (lets assume it's been tested against the correct standard for rigging operations) is that when theres not much room to let a piece run, that stretch goes against you. Its why we use more static ropes for rigging and try and keep the force to the rigging point to a minimum via dynamic lowering techniques, i.e letting the piece run. 

6 minutes ago, AHPP said:

 

There's static and static. Double braid like Sirius is stretchier than dyneema like arborWINCH (both Teufelberger).

I'm aware this is academic. Nobody's going to snatch anything big on arborWINCH. Just curious if it was mentioned.

To the best of my knowledge, arborist rigging line will be tested against a different EN standard than winch lines, which need to have very low elongation.

 

I could dig out my LOLER handbook but it won't be this evening I'm afraid.

 

Different rope materials have different properties too. Dyneema has very low elongation under load, as well as being very light for its high breaking strength. It doesn't resist abrasion or UV degradation well though, and wouldn't have a great cycles- to- failure rate for repeated shock loading. 

[AHPP]

At your leisure and convenience.

[Joe Newton]

Correction, Dyneema isn't bad for UV, I might've been thinking of Technora. Another UHMWPE fibre.

 

Dyneema has a very low melting point, which makes it unsuitable for rigging due to the heat generated through friction based braking systems like bollards etc. 

[AHPP]

It's often sheathed. How good is the heat insulation from that do you think?

[Joe Newton]

I can't answer that.

 

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Here's an interesting link on the required standard for low stretch ropes like the ones we use. It states a minimum melting point considerably higher than that of dyneema (around 145°)

[Rich Rule]

1 hour ago, peds said:

 

 

With that in mind... is there anything to be said for using a truly dynamic rope, like wot rock climbers use, for catching big falls, when you switch to negative rigging? "Dynamic" ropes can have something like 15%, 20%, anywhere up to 40% stretch... which does of course soften the blow on the anchor and is kinder to the system on the whole.

 

Id say one word - No.

 

Abojt 20 years ago I was rigging down a Lombardy Pop over an aspestos roofed garage.

 

we rigging a lump which the inexperience grounds guy let run but stopped in what he thought was time.  The rope stretched out, smashed a hole in the roof, bounced back up the geezer on the tag line tried to pull like mad and it stretched again and smashed another hole and then recoiled again and smashed a third hole in the roof.

 

So again I would say no to using Rick climbing ropes for rigging.

 

 

[AHPP]

Polyester melts at 295 degrees celsius and you can do that glazing it on a bollard. Christ.

Edited Saturday at 18:37 by AHPP

[Joe Newton]

8 minutes ago, Rich Rule said:

 

Id say one word - No.

 

Abojt 20 years ago I was rigging down a Lombardy Pop over an aspestos roofed garage.

 

we rigging a lump which the inexperience grounds guy let run but stopped in what he thought was time.  The rope stretched out, smashed a hole in the roof, bounced back up the geezer on the tag line tried to pull like mad and it stretched again and smashed another hole and then recoiled again and smashed a third hole in the roof.

 

So again I would say no to using Rick climbing ropes for rigging.

 

 

I was trying to recall who told me that anecdote many years ago!

[AHPP]

22 hours ago, Mick Dempsey said:

 

 

The real hero of this thread has been overlooked since page two btw. Pikey or not, that works.

Edited Sunday at 09:58 by AHPP

[Mark Bolam]

Alex, as I told you, that’s what I did with my crappy Stein floating bollard about 12 years ago.