Author Topic: Soft Links Vs Mallions  (Read 13074 times)

Offline Topimo

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Soft Links Vs Mallions
« on: December 02, 2019, 09:10:42 pm »
In paragliding and also kite boarding (I believe), many modern setups eschew metal connectors between the harness and glider in favour of softlinks. Every gram counts and it seems the fabrics used are reaching a practical limit in terms of g/m^2 so manufacturers are looking elsewhere to save weight.

E.g. https://flybubble.com/shop/accessories/hardware/soft-links

Might such a connection be useful for extreme alpine cave rigging, where the benefits would potentially multiply far beyond 2 connection points to tens or hundereds?

Clearly fabric to fabric friction may be a concern, I highlight that such connections are used for reserve parachute bridle connections, though o-rings are used to keep things snug to limit shock loads, but these can be high g scenarios.

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Soft Links Vs Mallions
« on: December 02, 2019, 09:10:42 pm »
Warmbac

Offline Bob Mehew

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Re: Soft Links Vs Mallions
« Reply #1 on: December 02, 2019, 09:34:19 pm »
Some work is being done on the concept but nothing as yet to report.  We are however extending the capability of the Bradford's rope test rig kit to cope with the higher shock loads involved, as well as figuring out how to get useful answers.  Like most rope work, the initial 'suck see' gave a spectrum of results, though they did not rule the concept out.   

Online Benfool

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Re: Soft Links Vs Mallions
« Reply #2 on: December 02, 2019, 09:54:25 pm »
Something similar is already being used. AS hangers.....

https://starlessriver.com/shop/rigging_and_bolting/amarrage_souple

B

Offline Topimo

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Re: Soft Links Vs Mallions
« Reply #3 on: December 03, 2019, 07:24:07 am »
Something similar is already being used. AS hangers.....

https://starlessriver.com/shop/rigging_and_bolting/amarrage_souple

B

Ah yes, I did think of the AS hangers but I thought they were to be used with metal connectors to the rope, thus only saving the weigh of the rope loops in the rigging.

I didn't realise they were intended to be tied direct. Cool! I've just had a quick flick through the section on their use in Alpine Caving Techniques.

Offline AlexR

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Re: Soft Links Vs Mallions
« Reply #4 on: December 03, 2019, 08:46:52 am »
Funny you should mention it now, I brought the idea to Bob a couple of months ago. Soft shackles are now fairly widely used in marine (sport) applications, and spreading. As he said, we've been testing samples/ concepts, inc. soft shackles. There are certain issues, especially when it comes to sharp edges.

Before you go and tie one/ buy one to use for caving, I should warn you that the spread of breaking strengths is considerable. There are also a wide variety of tying variations, with breaking strengths varying from 80-230% of single line strength.

Offline Topimo

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Re: Soft Links Vs Mallions
« Reply #5 on: December 03, 2019, 09:41:35 am »
Sounds good Alex, I'm interested to hear how you get on.

Offline Pony

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Re: Soft Links Vs Mallions
« Reply #6 on: December 03, 2019, 10:32:07 am »
Been used in slack lining for some time, and in the Yosemite situation, as well as playing in the park. Check out How Not To Slackline on YouTube. Everything from construction to destruction, it was these guys who got me going "Hmm, I wonder..."

Offline Mike Hopley

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Re: Soft Links Vs Mallions
« Reply #7 on: December 03, 2019, 10:35:21 am »
Rigging with 5mm dyneema cord and AS is a long-established practice. Plenty of testing has been done if you're prepared to look beyond the end of our collective noses.

See the EFS Technical Guide for an explanation of modern practice. For testing and additional safety considerations, see these EFS tests on dyneema.

I use dyneema all the time, and AS rarely. Obligatory disclaimer: like anything else, dyneema must be understood to be safe. There are some rules of use. Read the books.

Dyneema cord is essentially just a better sling in every way. A good length is about 3 metres of cord. Tie the sling fresh every time (using a figure-8 in expansion with 15cm+ tails), giving you exactly the length you want. Untie it when derigging. For very long slings, make a longer piece of cord by tying the ends together.

AS are very versatile, but obviously not much use on a resin-anchored route! Advantages include light weight, ability to extend straight over a rub point (unless it's a razor blade!), and ability to be used safely with any anchor placement (even in the ceiling). I would describe these anchors as specialist, whereas dyneema cord itself is more generally useful.

When using AS, the general idea is to tie in directly to the rope. However, depending on the method chosen, this can "throttle" the knot loop and make it quite difficult for people to clip their cowstail in. It's good to understand the multiple options for tying, but also consider using a few carabiners to make life less awkward.

Quote
I've just had a quick flick through the section on their use in Alpine Caving Techniques.

Note that things have moved on since the days of Alpine Caving Techniques -- there are safer and more efficient rigging options (see the EFS Technical Guide).

Offline MJenkinson

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Re: Soft Links Vs Mallions
« Reply #8 on: December 03, 2019, 10:56:19 am »
I've come across a rope rigged down Gavel on soft links (short braided lengths with a "monkey's fist" passed through a loop).  So someone is using them.

Online MarkS

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Re: Soft Links Vs Mallions
« Reply #9 on: December 03, 2019, 11:26:48 am »
I think they are also widely used in sailing.

We have pondered soft links/shackles for unavoidable fixed rigging in Rowter. There are about 30 anchors on pitches that cannot be accessed from above, and long-term choices seem to be stainless maillons ($$!) or some sort of dyneema connectors.

Online Benfool

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Re: Soft Links Vs Mallions
« Reply #10 on: December 03, 2019, 11:27:09 am »
Matt, that could be a well known dales diver, who was diving at the bottom for a while.

When he leaves caves rigged, he often does it "Russian Style" where you leave the rope in, but remove all the metalwork - replacing it with short loops of rope which you use to tie the rigging into the bolts. When you return, you replace each loop with a krab, meaning you dont need to rerig the cave. Means that people dont rob your krabs and avoids galvanic corrosion.

He did the same in Brownhill for a long period.

B

Online Mark Wright

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Re: Soft Links Vs Mallions
« Reply #11 on: December 03, 2019, 11:41:31 am »
There are certain issues, especially when it comes to sharp edges.

I work in the Superyacht industry and soft shackles are common for many applications. I witnessed a load test of a £1M tender last year and the soft shackle snapped over a sharp edge inside the tender. It only dropped 2m but the tender had to be replaced at £1M.

Liros is probably the most common make in the yachting industry but they aren’t certified for man-riding and usually carry no EN certification or even have a CE mark so you can never be sure of the QA systems in operation at the factories where they are manufactured.

I use the paragliding ones in the original post on my paraglider.

Mark

Offline Pony

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Re: Soft Links Vs Mallions
« Reply #12 on: December 03, 2019, 03:10:42 pm »
Another consideration is what are you wanting to gain?
For instance this year I've changed over from steel mallions to alloy krabs, because (a) less weight and (b) I can afford them. With soft shackles the cost will probably be just under a mallion, weight deffinately so, though that said I wouldn't want to rig Juniper Gulf traverse with them.

Online Mark Wright

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Re: Soft Links Vs Mallions
« Reply #13 on: December 03, 2019, 04:51:25 pm »
I’m not sure about the weight benefit of a typical alloy carabiner over a 7mm long M/R. I would have thought the carabiner was heavier? M/Rs are a lot less bulky than carabiners.
As for the price benefit of a soft shackle, I don’t think there is one. The soft shackles on the paragliding site that Topimo mentions are £10.00. The Liros soft shackles are 
nearly twice the price, though they are primarily used for yachting which generally significantly increases the prices of things.

Mark

Offline langcliffe

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Re: Soft Links Vs Mallions
« Reply #14 on: December 03, 2019, 04:57:32 pm »
I’m not sure about the weight benefit of a typical alloy carabiner over a 7mm long M/R. I would have thought the carabiner was heavier? M/Rs are a lot less bulky than carabiners.

The main advantage of carabiners is that when one gets to a certain age, they are easier to handle with arthritic fingers! I don't have the finger strength for stiff maillons any more.

Offline Topimo

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Re: Soft Links Vs Mallions
« Reply #15 on: December 03, 2019, 05:11:53 pm »
As for the price benefit of a soft shackle, I don’t think there is one. The soft shackles on the paragliding site that Topimo mentions are £10.00. The Liros soft shackles are 
nearly twice the price, though they are primarily used for yachting which generally significantly increases the prices of things.

Mark

Paragliding gear is another victim of poor economies of scale and some willingness to spend. The cheapest helmets are 3 times the price of a ski helmet despite being basically the same...

Offline Topimo

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Re: Soft Links Vs Mallions
« Reply #16 on: December 03, 2019, 05:14:08 pm »
The main advantage of carabiners is that when one gets to a certain age, they are easier to handle with arthritic fingers! I don't have the finger strength for stiff maillons any more.

Another is the idiot and abuse proofness. Bloody rusty bent gritty mallions... Much better to have a nice screwgate imo.

Offline Fulk

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Re: Soft Links Vs Mallions
« Reply #17 on: December 03, 2019, 05:28:18 pm »
Quote
I’m not sure about the weight benefit of a typical alloy carabiner over a 7mm long M/R. I would have thought the carabiner was heavier?

I just weighed 2 dozen maillon rapides and 2 dozen assorted alloy screw-gate krabs – the former weighed 3 lb 2.75 oz (1439 g), the latter
2 lb 14.75 oz (1325 g), so the karabiners are ~8% lighter. (Well, someone had to  :))

Offline Mike Hopley

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Re: Soft Links Vs Mallions
« Reply #18 on: December 03, 2019, 06:06:57 pm »
I’m not sure about the weight benefit of a typical alloy carabiner over a 7mm long M/R. I would have thought the carabiner was heavier?

Steel 7mm maillons are 60 grams. Some screwgate carabiners are heavier, some lighter. I use Edelrid Pure Screws, which are 43 grams. The main reason for using them is better handling than a maillon.

For the bold/rational/demented (delete according to preference), snapgates are even lighter and nicer to use. Camp Nano 22 is my favourite ultra-light carabiner (22 grams).
 
Aluminium maillons are also available, such as the Petzl Speedy (23 grams). These are less strong, though still strong enough for caving if used appropriately.

Offline topcat

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Re: Soft Links Vs Mallions
« Reply #19 on: December 03, 2019, 06:29:04 pm »
I’m not sure about the weight benefit of a typical alloy carabiner over a 7mm long M/R. I would have thought the carabiner was heavier? M/Rs are a lot less bulky than carabiners.

Going from memory ...7mms long maillon 72g and my rigging screwgates 38g.   And so much faster and easier.

I keep a few maillons for surface rigging.  And use soft rigging where possible.

Offline topcat

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Re: Soft Links Vs Mallions
« Reply #20 on: December 03, 2019, 06:33:48 pm »
Ok, poor memory.

I have now weighed them.

Maillon 60g
Grivel plume screwgate 37g.     Almost half the weight and four times faster.

No brainer.

TC

Online Mark Wright

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Re: Soft Links Vs Mallions
« Reply #21 on: December 03, 2019, 06:56:49 pm »
I have to say I’m surprised at the weight difference. The only crabs I’ve ever weighed  were the sideways walking variety.

As Topcat and others say, carabiners are a lot more practical and easier to clip to rigging anchors and easier to clip cows tails to when passing, e.g. re-belays.

I don’t usually worry about the weight as I usually get somebody else in the party to carry them!!

Mark

Offline Fulk

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Re: Soft Links Vs Mallions
« Reply #22 on: December 03, 2019, 07:30:15 pm »
Hmmm . . . we seem to agree that the 7-mm MRs weigh ~60 g, but my krabs seem to be significantly heavier – at ~55 g – than the others mentioned here.

Offline Mike Hopley

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Re: Soft Links Vs Mallions
« Reply #23 on: December 03, 2019, 11:56:49 pm »
Hmmm . . . we seem to agree that the 7-mm MRs weigh ~60 g, but my krabs seem to be significantly heavier – at ~55 g – than the others mentioned here.

That's because 7-mm long-opening MRs have exactly one design, whereas there are countless designs for carabiners. Bigger ones are obviously heavier, and newer designs use I-beam construction to reduce the volume of metal while retaining strength.

Offline Fulk

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Re: Soft Links Vs Mallions
« Reply #24 on: December 04, 2019, 09:01:48 am »
Thank you, Mike, but I think that I managed to work that out for myself; I was merely making an observation.

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.)

Online 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

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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 »

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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.

Offline caver63751

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Re: Soft Links Vs Mallions
« Reply #36 on: December 23, 2019, 04:16:57 am »
Pertaining to the potential application Topimo mentioned of remote/deep caves, I've recently done a comparison of connector types. I realize prices may be different in the UK—I included them here for the sake of comparison. I intentionally omitted the Petzl Speedy due to high cost ($10 USD for me). Also of note, there are other non-locking carabiners in the 20-25 g range that may cost less than the Edelrid Nineteen G, which is currently the lightest on the market if I'm not mistaken.

screw link, stainless steel, 6mm, wide opening (from Zoron Manufacturing; we tested N=3 to ultimate tensile strength of ~40 kN)
41 g
$2.53 USD (quantity discount)

carabiner, Cypher Firefly II, screw gate
42 g
$4.29 USD (pro discount through distributor)

carabiner, Edelrid Nineteen G, non-locking
19 g
$7.50 USD (no discount for me)

cord, Beal Pure Dyneema, 120 cm (120 cm seems to be a good length for attaching to standard or AS hangers)
18 g
$3.24 USD (pro discount through distributor)

Offline Ian Ball

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Re: Soft Links Vs Mallions
« Reply #37 on: December 23, 2019, 10:24:29 am »
screw link every time   ;)

Offline pwhole

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Re: Soft Links Vs Mallions
« Reply #38 on: December 23, 2019, 02:45:29 pm »

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 remember at school bending bars of McCowan's Highland Toffee slowly (and eventually stretching them out), but you could still snap them if you moved your hand quickly enough. Are the two issues related perchance? As in there's a threshold velocity that suddenly overcomes structural stability? ;)

Offline langcliffe

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Re: Soft Links Vs Mallions
« Reply #39 on: December 23, 2019, 03:03:38 pm »
screw link every time   ;)

You won't be saying that at my age when your fingers don't work as well as they used to!

Offline Ian Ball

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Re: Soft Links Vs Mallions
« Reply #40 on: December 23, 2019, 05:11:31 pm »
screw link every time   ;)

You won't be saying that at my age when your fingers don't work as well as they used to!

 :thumbsup:  spanner to the rescue.

Offline Mike Hopley

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Re: Soft Links Vs Mallions
« Reply #41 on: December 23, 2019, 06:27:04 pm »
Also of note, there are other non-locking carabiners in the 20-25 g range that may cost less than the Edelrid Nineteen G, which is currently the lightest on the market if I'm not mistaken.

I think the 19g is a bit too small for rigging. For another ~3 grams, you can get something more practical (Camp Nano 22).

In their "current" book, the French Caving School even mention rigging with carabiners that are not full strength -- i.e. strong accessory carabiners like this one. This now seems a little mad, given that we have full-strength carabiners that are lighter and cost about the same.

Offline andrewmc

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Re: Soft Links Vs Mallions
« Reply #42 on: December 24, 2019, 10:38:56 am »
If you were feeling really ballsy, you could rig on DMM XSRE snapgates, rated to 4kN and only 8g :p

It's probably worth remembering though that rope is about 50g a metre so you can save more by making sure you have the right length ropes... Even making loops larger than they need to be will add extra weight.

Offline JB

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Re: Soft Links Vs Mallions
« Reply #43 on: December 26, 2019, 08:14:05 am »
Interesting topic. Looking at how you tie those things in and faff about trying to tighten elastic o-rings over them they’re not for me. Cold hands and gloves could put a stop to your trip I would think.

Like lots of people i’m sure I’m after ease of use, versatility and strength so prefer to use full strength screwgate karabiners (if you end up with two people on a rope for some reason proper karabiners reassuring).

Offline Ian Ball

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Re: Soft Links Vs Mallions
« Reply #44 on: December 26, 2019, 12:44:16 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/

Nice website  :thumbsup:

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Re: Soft Links Vs Mallions
« Reply #45 on: December 26, 2019, 04:40:53 pm »

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 remember at school bending bars of McCowan's Highland Toffee slowly (and eventually stretching them out), but you could still snap them if you moved your hand quickly enough. Are the two issues related perchance? As in there's a threshold velocity that suddenly overcomes structural stability? ;)

A big difference is heat, at least in rope if you do a drop test you can melt knots especially ones that are not set well as it tightens suddenly. At speed ropes rub on each other without having time to dissipate the heat where as a slow pull would set the knot and even though the same amount of friction/energy is generated it will dissipate slower.

The same issue could be seen if you were testing a descender etc.

I would guess the same could happen in other materials at a more molecular level? but i'm not a physicist and am happy to be corrected.

Offline Chocolate fireguard

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Re: Soft Links Vs Mallions
« Reply #46 on: December 26, 2019, 09:43:08 pm »

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 remember at school bending bars of McCowan's Highland Toffee slowly (and eventually stretching them out), but you could still snap them if you moved your hand quickly enough. Are the two issues related perchance? As in there's a threshold velocity that suddenly overcomes structural stability? ;)

Sorry, I just saw this post.

I think what you’re describing is called strain rate dependence.

Over the last few years, whenever I remember, I have been looking for information on it and nylon, but without much success.

It seems that many (most?) materials exhibit it, but not significantly under the conditions of temperature and strain rate components are designed for. I have found a few mentions that some physical properties of polymers are sensitive to strain rates, but no actual figures that can be applied to ropes.

Strain is the change in a dimension (length in our case) divided by the original dimension.  The average strain rate is that strain divided by the time taken.

A drop test to break on a new 1m length of caving rope will produce a rope stretch of perhaps 30% and take perhaps 200 milliseconds as the knots tighten. That gives a strain rate of 0.3/0.2, or 1.5 per second.

So we are talking about strain rates of “a few per second” for a dynamic test and possibly “a few hundredths per second” for a slow stretch. This difference of a couple of orders of magnitude is important for a toffee bar or a piece of silly putty, but I haven’t found anybody who has done work on nylon at these rates.

Bearing in mind that the break happens in the knot, that a knot will convert several hundred Joules of energy to heat and that after a drop test it is not remarkable to find  the broken end of rope showing signs of melting (and sometimes stuck to another part of the sample), it would surprise me if the time for the heat to spread throughout the knot during a test was not important.

Not much of this would apply to a sewn sling failing over an edge.

Any info on strain rate measurements on nylon will be gratefully received.

 

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