Soft Links Vs Mallions

[topcat]

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

 

[Mark Wright]

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

 

[Fulk]

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.

 

[Mike Hopley]

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.

 

[Fulk]

Thank you, Mike, but I think that I managed to work that out for myself; I was merely making an observation.

 

[Mike Hopley]

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.)

 

[mikem]

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!

 

[Fulk]

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

No problem ? but thanks for apologising.

 

[Pony]

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.

 

[GT]

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

 

[mikem]

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/

 

[Chocolate fireguard]

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.

 

[mikem]

Not sure, but cavers / climbers are unlikely to create a steady load of that magnitude, but can produce such a shock load.

 

[Tommy]

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.

 

[andrewmcleod]

'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).

 

[Chocolate fireguard]

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.

 

[caver63751]

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)

 

[Ian Ball]

screw link every time 

 

[pwhole]

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?

 

[langcliffe]

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!