Author Topic: Soft Links Vs Mallions  (Read 1446 times)

Offline Mike Hopley

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Re: Soft Links Vs Mallions
« Reply #25 on: December 04, 2019, 11:07:42 am »
Thank you, Mike, but I think that I managed to work that out for myself; I was merely making an observation.

Apologies for being patronising -- I was thrown off by the way your comment was phrased. :-[

I get the impression that using bigger / heavier carabiners is still common. For one thing, it's pretty expensive to replace them with a complete set of lighter models.

(I would like a set of snaplinks for rigging with more adventurous companions, but I'm not sure I can justify the expense.)

Offline mikem

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Re: Soft Links Vs Mallions
« Reply #26 on: December 04, 2019, 11:46:40 am »
If you've got mud problems, then Grivel also do these at 39g:
https://www.bananafingers.co.uk/carabiners/grivel/plume-twingate

But maillons still lead on compactness & price (& you don't have to consider cross loading the gate). When comparing weight I guess you'd have to factor in the spanner as well - although it's a lot lighter than pliers for dealing with obstinate screws!

Offline Fulk

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Re: Soft Links Vs Mallions
« Reply #27 on: December 04, 2019, 12:40:39 pm »
Quote
Apologies for being patronising -- I was thrown off by the way your comment was phrased. :-[
No problem – but thanks for apologising.

Offline Pony

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Re: Soft Links Vs Mallions
« Reply #28 on: December 04, 2019, 01:14:06 pm »
Another point in the mallion v krab equation is of course time.
BTW when I said originally about weight savings with alloy krabs I neglected to state they were snap gates.

Offline GT

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Re: Soft Links Vs Mallions
« Reply #29 on: December 04, 2019, 09:20:46 pm »
Off topic a bit but worth considering if you're talking about soft shackles attached to anchors. The attached (hopefully) image tape/sling failed at 7kN

Offline mikem

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Re: Soft Links Vs Mallions
« Reply #30 on: December 04, 2019, 11:34:39 pm »
7kN was I believe the 1 inch tubular sling, others failed at lower loading, but it didn't say whether drop tests (I assume it was) or steadily increasing loads...

From Aussie website, who makes his money doing tests for rope access:
https://www.ropelab.com.au/category/free/articles/

Offline Chocolate fireguard

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Re: Soft Links Vs Mallions
« Reply #31 on: December 05, 2019, 02:28:50 pm »
7kN was I believe the 1 inch tubular sling, others failed at lower loading, but it didn't say whether drop tests (I assume it was) or steadily increasing loads..

I know quite a few people who believe that a (say) 7kN load during a drop test is more likely to break something than a steady 7kN load, but I have yet to hear what I consider to be a convincing explanation of why that should be.

I'm not saying it isn't so - it's just that almost all of the explanations seem to concentrate on the fact that the load is there for a shorter time (it's "impulsive"), without any attempt to say why a load that is there for only a short time should be more damaging than the same load present for longer!

Now, if I heard someone say that some things (like knots?) often show obvious signs of melting at the failure point, and that in a slow steady pull more of the heat generated when the knot tightens escapes, then I might be convinced.

But I can't see that being a big consideration when a sling fails over an edge.
« Last Edit: December 05, 2019, 02:41:58 pm by Chocolate fireguard »

Offline mikem

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Re: Soft Links Vs Mallions
« Reply #32 on: December 05, 2019, 04:17:10 pm »
Not sure, but cavers / climbers are unlikely to create a steady load of that magnitude, but can produce such a shock load.

Offline Topimo

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Re: Soft Links Vs Mallions
« Reply #33 on: December 05, 2019, 05:24:42 pm »
7kN was I believe the 1 inch tubular sling, others failed at lower loading, but it didn't say whether drop tests (I assume it was) or steadily increasing loads..

I know quite a few people who believe that a (say) 7kN load during a drop test is more likely to break something than a steady 7kN load, but I have yet to hear what I consider to be a convincing explanation of why that should be.

I'm not saying it isn't so - it's just that almost all of the explanations seem to concentrate on the fact that the load is there for a shorter time (it's "impulsive"), without any attempt to say why a load that is there for only a short time should be more damaging than the same load present for longer!

Now, if I heard someone say that some things (like knots?) often show obvious signs of melting at the failure point, and that in a slow steady pull more of the heat generated when the knot tightens escapes, then I might be convinced.

But I can't see that being a big consideration when a sling fails over an edge.

Rate of energy dissipation - the material has to deform and convert the kinetic energy into heat which is transferred to the environment and elastic potential energy stored in the material itself, load rates are very important with viscoelastic materials (such as UHMWPE - Dyneema). Load it gradually and the material has time to allow the hydrocarbon chains to align themselves with the tension. Load it rapidly and the stress in the material will be higher, breaking these Van der Waals bonds causing macroscale defects - i.e. cracks, tears, failure.

Offline andrewmc

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Re: Soft Links Vs Mallions
« Reply #34 on: December 06, 2019, 04:04:45 am »
'Full strength' (>20kN) 19g snapgates exist. That's probably hard to beat even with a soft shackle...

If using dyneema you could also tie directly to a resin anchor (since all the common sorts have well rounded edges).

Offline Chocolate fireguard

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Re: Soft Links Vs Mallions
« Reply #35 on: December 06, 2019, 07:20:04 pm »
7kN was I believe the 1 inch tubular sling, others failed at lower loading, but it didn't say whether drop tests (I assume it was) or steadily increasing loads..

I know quite a few people who believe that a (say) 7kN load during a drop test is more likely to break something than a steady 7kN load, but I have yet to hear what I consider to be a convincing explanation of why that should be.

I'm not saying it isn't so - it's just that almost all of the explanations seem to concentrate on the fact that the load is there for a shorter time (it's "impulsive"), without any attempt to say why a load that is there for only a short time should be more damaging than the same load present for longer!

Now, if I heard someone say that some things (like knots?) often show obvious signs of melting at the failure point, and that in a slow steady pull more of the heat generated when the knot tightens escapes, then I might be convinced.

But I can't see that being a big consideration when a sling fails over an edge.

Rate of energy dissipation - the material has to deform and convert the kinetic energy into heat which is transferred to the environment and elastic potential energy stored in the material itself, load rates are very important with viscoelastic materials (such as UHMWPE - Dyneema). Load it gradually and the material has time to allow the hydrocarbon chains to align themselves with the tension. Load it rapidly and the stress in the material will be higher, breaking these Van der Waals bonds causing macroscale defects - i.e. cracks, tears, failure.

Topimo, you have PM.