Author Topic: Making cowstails.. Rope age question  (Read 1597 times)

Offline benshannon

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Making cowstails.. Rope age question
« on: September 24, 2020, 07:37:39 pm »
I want to make some cowstails and I have a climbing rope in the loft that I haven't used for ~10years. It never took a big fall, but I appreciate I shouldn't use it for climbing anymore, would it be OK as cows tails or is there an age of rope that you should not use despite it not having much use over its life?

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Making cowstails.. Rope age question
« on: September 24, 2020, 07:37:39 pm »
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Offline langcliffe

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Re: Making cowstails.. Rope age question
« Reply #1 on: September 24, 2020, 07:42:37 pm »
It's the sort of stuff that I make mine of!

Offline ChrisJC

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Re: Making cowstails.. Rope age question
« Reply #2 on: September 24, 2020, 07:56:08 pm »
Given you can buy brand new rope for £2/meter, why faff about with some dodgy old baler twine?

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Offline Ian Ball

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Re: Making cowstails.. Rope age question
« Reply #3 on: September 24, 2020, 08:01:35 pm »
Personally I would say don't fall on it and you'll be fine.

Offline langcliffe

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Re: Making cowstails.. Rope age question
« Reply #4 on: September 24, 2020, 08:06:20 pm »
why faff about with some dodgy old baler twine?

???? - Beale say 15 years, and that will be conservative.

Offline Cripplecreeker

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Re: Making cowstails.. Rope age question
« Reply #5 on: September 24, 2020, 08:12:42 pm »
Climbing rope does not degrade with time alone (certainly not 10 years). Some good advice here: https://www.theuiaa.org/documents/safety/Recommendations_Standard_101_BMC.pdf

Offline Cap'n Chris

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Re: Making cowstails.. Rope age question
« Reply #6 on: September 24, 2020, 08:41:45 pm »
Obviously you're insane. Your safety connectors are your principal life saving PPE. Price for your life?

Offline badger

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Re: Making cowstails.. Rope age question
« Reply #7 on: September 24, 2020, 09:18:03 pm »
for the sake of £5.00 why would you risk your life on old rope even if you believe it is in good condition. And regardless to the condition of my cows tails still look good, I change them regularly. And I thought beal rope as 10 years from start of use, but can be kept upto to 5 years after manufacture before use.

Offline Mike Hopley

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Re: Making cowstails.. Rope age question
« Reply #8 on: September 24, 2020, 09:24:36 pm »
If the rope should not be used for climbing, then it should not be used for cowstails either.

Aging of ropes is a debatable subject, but the manufacturers' recommendations are clear. Nowadays they typically state a maximum lifespan of 10 years, starting from the first use. That assumes the rope is lightly and occasionally used and in good condition.

They also normally say that an unused rope may be kept in storage for an additional 5 years, so potentially up to 15 years total if stored correctly for 5 years before its first use.

These recommendations are no doubt quite conservative. It's up to you! Personally, I like to have complete faith in my SRT kit.

Offline Bob Mehew

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Re: Making cowstails.. Rope age question
« Reply #9 on: September 24, 2020, 09:25:11 pm »
Little falls deposit a surprising amount of energy into a short length of rope and with bits of ironmongery even more than in a big fall.  (See note 5 at the bottom of page 6 in https://british-caving.org.uk/wiki3/lib/exe/fetch.php?media=rope_testing:lanyard_tests_v6.pdf )  As Badger says, for £6 ready made why take the risk?

And always relax the knots after very trip.  Even just hanging on a cows tail tightens them and increases the shock loading if you do fall.

Offline Mike Hopley

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Re: Making cowstails.. Rope age question
« Reply #10 on: September 24, 2020, 09:30:49 pm »
And always relax the knots after very trip.  Even just hanging on a cows tail tightens them and increases the shock loading if you do fall.

This advice seems highly impractical if you do much SRT, especially if you're using 9mm rope for your cowstails.

I also don't think it's supported by the evidence. Those oft-referenced lanyard tests found acceptable peak forces in heavily-used cowstails, provided they were made from knotted dynamic rope (manufactured cowstails fared rather badly).

Once sufficiently tightened, it may actually be worse to undo knots. This has been noted in some ropework texts if I recall correctly (Life on a Line?).

Offline Bob Mehew

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Re: Making cowstails.. Rope age question
« Reply #11 on: September 24, 2020, 10:09:56 pm »
I also don't think it's supported by the evidence.
Sorry I am way behind publishing it but as a taster, data for 10mm dynamic on brand new rope.  Long is the 75cm tail and short is the 35cm tail.  6kN is the treshold for injury used in the standards.

And by the way I did not say undo the knots, I said RELAX them - a world of difference. 

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Re: Making cowstails.. Rope age question
« Reply #12 on: September 24, 2020, 10:31:33 pm »
In most situations, tight knots won't break, but they will transmit more force to your body.

Offline Mike Hopley

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Re: Making cowstails.. Rope age question
« Reply #13 on: September 24, 2020, 11:02:29 pm »
There will be a huge difference between knot tightness following a severe fall, and just during normal use.

If you take a really heavy fall onto your cowstails, the safest thing to do is probably cutting new ones from any spare rope you have (like the end of the pitch rope). Failing that, you could try "relaxing" them, though it may prove difficult!

Repeatedly taking factor 1 falls onto your cowstails does not seem like a good idea.

Offline Ian Ball

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Re: Making cowstails.. Rope age question
« Reply #14 on: September 24, 2020, 11:10:59 pm »
Cowstails out of semi-static? better than shockloaded dynamic?

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Re: Making cowstails.. Rope age question
« Reply #15 on: September 25, 2020, 05:31:08 am »
That does depend what you are using them for, & how badly you shock loaded them, but not for normal caving...

Offline Cap'n Chris

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Re: Making cowstails.. Rope age question
« Reply #16 on: September 25, 2020, 07:16:41 am »
And always relax the knots after very trip.  Even just hanging on a cows tail tightens them and increases the shock loading if you do fall.

This advice seems highly impractical if you do much SRT, especially if you're using 9mm rope for your cowstails.

You quickly get used to it. We've been untieing and retieing safety connectors twice a day, most days, for four years, multiple sets, based on the BCA advisory notification online. Insurers spot this kind of thing.

Offline benshannon

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Re: Making cowstails.. Rope age question
« Reply #17 on: September 25, 2020, 07:53:54 am »
Thanks for the info guys. I'll buy some new rope. Just seems a shame to have a nearly immaculate rope going to waste. Ah well.

Offline Pete K

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Re: Making cowstails.. Rope age question
« Reply #18 on: September 25, 2020, 08:01:30 am »
Your local climbing wall may have a recycling bin for it. It might end up as a dog lead, door mat or some other item instead of heading to landfill.

Offline Cripplecreeker

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Re: Making cowstails.. Rope age question
« Reply #19 on: September 25, 2020, 08:08:19 am »
Thanks for the info guys. I'll buy some new rope. Just seems a shame to have a nearly immaculate rope going to waste. Ah well.

The downside of asking for technical advice on an Internet forum...

Offline ChrisJC

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Re: Making cowstails.. Rope age question
« Reply #20 on: September 25, 2020, 08:09:41 am »
The downside of asking for technical advice on an Internet forum...

And on the upside - he might live to ask another technical question.

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Re: Making cowstails.. Rope age question
« Reply #21 on: September 25, 2020, 08:53:42 am »
No climbing rope has ever broken, unless it was already damaged or subjected to forces that would have broken you. The problem with old (& wet) ropes is they have less stretch left, so transfer more of the force of a fall to your body - this is even more important in cowstails than a climbing rope, as large forces are applied to a very short section. If your only use of cowstails is on sections where they are stopping you going over an edge, then they are unlikely to be subjected to those kind of forces. If you might end up above your anchor point, with a possibility of freefall, then you want the best that you can get.

Offline PaulW

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Re: Making cowstails.. Rope age question
« Reply #22 on: September 25, 2020, 11:07:12 am »
why faff about with some dodgy old baler twine?

???? - Beale say 15 years, and that will be conservative.

If Beale still say '15 yearss' that's a max of 5 years in storage and then 10years once it goes into use

Offline Mike Hopley

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Re: Making cowstails.. Rope age question
« Reply #23 on: September 25, 2020, 11:16:13 am »
Cowstails out of semi-static? better than shockloaded dynamic?

Yes, if the dynamic took a heavy shock-load. Much of the "cushioning" comes from the knots tightening, rather than the rope stretching over such a short length (compared to the length of the fall).

To be clear, a shock-loaded dynamic rope would be much better as a climbing rope than a new semi-static (which is just dangerous).

A factor 1+ fall in caving should be extremely rare. A bit like in Via Ferrata: the equipment is only designed to take one really serious fall, to save your life. If you keep falling on Via Ferrata, you shouldn't be doing it.
« Last Edit: September 25, 2020, 11:25:18 am by Mike Hopley »

Offline Bob Mehew

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Re: Making cowstails.. Rope age question
« Reply #24 on: September 25, 2020, 11:33:26 am »
There will be a huge difference between knot tightness following a severe fall, and just during normal use.

Even 'heavy loadings' will take up the 'slack' in the knots and increase the peak force seen by your body.  Hence the advice to relax the knots after each trip.    (The smallest drop in my graph was only 40cm.)

If you take a really heavy fall onto your cowstails, the safest thing to do is probably cutting new ones from any spare rope you have (like the end of the pitch rope). Failing that, you could try "relaxing" them, though it may prove difficult!

I suggest the rule of thumb is if you can't relax the knot, then replace the cow's tail. 

Offline pwhole

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Re: Making cowstails.. Rope age question
« Reply #25 on: September 25, 2020, 11:44:53 am »
Thanks for the info guys. I'll buy some new rope. Just seems a shame to have a nearly immaculate rope going to waste. Ah well.

You could spend an afternoon with Lily Ardor (what a wonderful name). It might not be as soft and gentle as hers, but might make a good changing 'rug' ;)


Offline Mike Hopley

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Re: Making cowstails.. Rope age question
« Reply #26 on: September 25, 2020, 01:45:12 pm »
Even 'heavy loadings' will take up the 'slack' in the knots and increase the peak force seen by your body.

Sure, but by how much?

You could make the same argument about anything. Even a single use of a rope will make it weaker, therefore replace all your ropes after every trip. Also replace your harness.

My cowstails are pretty tight even when new, because I want secure knots, and I don't want them to change length more than needed. Relaxing the knots could easily take 10 -- 30 minutes even with a spanner.

I've never met anyone who actually does this, and I think it's unnecessary perfectionism. Focus on things that make a relevant difference.

Offline Kenilworth

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Re: Making cowstails.. Rope age question
« Reply #27 on: September 25, 2020, 03:34:58 pm »
Obviously you're insane. Your safety connectors are your principal life saving PPE. Price for your life?

Not picking on Chris specifically since several people have made a similar comment, and since it always gets made every time these topics come up, but this is a bad argument. The money cost has nothing to do with anything. Is the cost of shiny new cowstails the appropriate money value of a life? 

I personally like to use things that will work, if I have them, rather than get more things. If a piece of safety equipment is safe enough, it does not need to be safer. We could increase potential safety factors (and cost) indefinitely with zero practical improvement.

There should be data available to answer the original question. I have read a lot of pull and drop test data on ropes and knots of various types and ages. Anymore I perform my own testing if I'm in doubt, which was interesting in the case of my hand sewn harness made from old van seat belts, or the emergency harness idea utilizing a cord through the crotch of some blue jeans.

Offline benshannon

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Re: Making cowstails.. Rope age question
« Reply #28 on: September 25, 2020, 03:51:28 pm »
Exactly, it wasn't a "I don't want to spend money" question. More, that I have a rope that I don't use anymore because my climbing partner moved away and now I am bouldering almost exclusively and thought I could repurpose the rope for cows tails as I assumed they would take less force than a fall. I didn't realise this thread would incite such emotions in some people

Online cavemanmike

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Re: Making cowstails.. Rope age question
« Reply #29 on: September 25, 2020, 04:25:52 pm »
you should'nt be falling on your cowstails anyway so an old(ish) climbing rope would be ok in my eyes.

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Re: Making cowstails.. Rope age question
« Reply #30 on: September 25, 2020, 07:01:57 pm »
The problem is that there isn't any empirical data, because so many factors are involved. Bob's chart is as near as you can get to an answer, but as Mike Hopley suggests, secure knots is more important than badly tied ones "coz you relaxed them a bit too much"...

Offline Bob Mehew

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Re: Making cowstails.. Rope age question
« Reply #31 on: September 25, 2020, 08:01:58 pm »
... secure knots is more important than badly tied ones "coz you relaxed them a bit too much"...
Again this is slightly misrepresenting what I mean by relaxing a knot.  In the two sets of 3 0.1FF drops shown, the samples extended by 3 and 5cm which came out of the knots.  In the five sets of 3 FF1.0 drops it was 16cm, that is the cows tail lengthened from 37cm to 53cm!  I predict more will come out if I had kept going as it is only when the peak forces are up around 10kN does the overall sample length stop extending.  (Sorry I am not in a position to do that test as yet.)  To spell out the point I am trying to make:

after a trip, unpick the knot so that you can move each part of the rope within the knot with respect to the bit next to it and then retension it as normal

There is no need to completely untie the knot and I am not suggesting you leave the knot not tensioned.  I am also assuming you have enough of a tail on the knot so it won't pull out because of a drop.

What I am asking you to do is to return each knot to the same condition it was before you went caving.  It is that simple.  That way you better protect your back.

Offline Chocolate fireguard

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Re: Making cowstails.. Rope age question
« Reply #32 on: September 25, 2020, 08:16:05 pm »
It does seem a shame to throw the rope away, but I assume you are only thinking about getting one set of cowstails from it and dumping the rest?
If it was my rope and I was as confident of its past history as you are then I would use it for cowstails.

I remember seeing some of my old 9mm semi static pitch rope, with perhaps 10 years hard use and another 5 years in a bag in the cellar, drop tested (probably FF1 80kg) and surviving at least 1 drop.
So you could cut the rest of your rope into 10 or 15m lengths for use on those short pitches or handline climbs that sometimes use up and waste longer ropes, and where the extra bounce isn't excessive.

Or you could compromise, buy new cowstails and use the whole rope for that.

Offline Cripplecreeker

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Re: Making cowstails.. Rope age question
« Reply #33 on: September 25, 2020, 08:30:27 pm »
I’m not sure that empirical data is really required. In the millions of hours that have now been spent by users of rope cows tails (for caving and industry), is there any instances of people being injured because their cows tails had lost/reduced their shock absorbing capacity? Not that I know of. In the very long list of things that can kill/injure you caving, this has got to be pretty much at the bottom. It’s good practice to undo the knots in your cowstails occasionally to check for damage though.

To me, the key questions are: was the rope in a fit condition to be used for cows tails before it went into storage? And, was it stored well (not too hot, no possibility of chemical contamination). If the answer to both is yes, then why not?

Ropes deteriorate through use rather than age:

https://www.theuiaa.org/documents/safety/About_Ageing_of_Climbing_Ropes.pdf



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Re: Making cowstails.. Rope age question
« Reply #34 on: September 25, 2020, 08:48:40 pm »
The empirical data is mainly required to cut down the online arguments that benshannon was commenting on!

Very few people have actually experienced a proper fall onto cowstails, as we do our best to avoid it.

Offline Cripplecreeker

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Re: Making cowstails.. Rope age question
« Reply #35 on: September 25, 2020, 08:58:15 pm »
 ;D I’m not sure anything will cut down the number of arguments on UK caving. Who would have thought the number of entrances to a cave in South Wales could cause so many posts.

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Re: Making cowstails.. Rope age question
« Reply #36 on: September 29, 2020, 09:06:21 am »
It does seem a shame to throw the rope away, but I assume you are only thinking about getting one set of cowstails from it and dumping the rest?
If it was my rope and I was as confident of its past history as you are then I would use it for cowstails.

I remember seeing some of my old 9mm semi static pitch rope, with perhaps 10 years hard use and another 5 years in a bag in the cellar, drop tested (probably FF1 80kg) and surviving at least 1 drop.
So you could cut the rest of your rope into 10 or 15m lengths for use on those short pitches or handline climbs that sometimes use up and waste longer ropes, and where the extra bounce isn't excessive.

Or you could compromise, buy new cowstails and use the whole rope for that.

I've often seen this sort of advice and I've never really understood it. My old rope feels dangerous, so I'll make it shorter and then it'll be fine because a 10m pitch doesn't feel as bad. If there's even the slightest chance that a rope would fail on a 30m pitch, then it's the same chance on a 10m pitch? And I don't want to fall 'even' 5m!

Handline is perhaps a different use case but even there the rope will be supporting my whole bodyweight.
If the world didn't suck, we'd all fall off.

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Re: Making cowstails.. Rope age question
« Reply #37 on: September 29, 2020, 10:10:02 am »
Modern ropes don't just break. It's a climbing rope, which may have lost some of its elasticity, so no longer as good to take a lead fall on (which is also what cowstails have to deal with) - it will still stretch on long pitches, which is annoying when prussiking, but less noticeable over short distances. Even if your anchor fails there is no way you will create a factor 2 fall on standard SRT, whereas it is possible to get more than that on a cowstail.

Offline Ian Ball

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Re: Making cowstails.. Rope age question
« Reply #38 on: September 29, 2020, 10:21:54 am »
If you're total bodyweight is on a handline you must be dangling no?

To be honest I really think that age is not a barrier to rope strength.  It is made of nylon which is hardy stuff.  Ropes used to be 3 years use, then 5 years use, now 5 years storage and 10 years use, ever increasing safety as datasets are compiled giving a greater proof of longevity?  A brand new never used rope left in the sun will scare me more than an old rope I'd looked after.  An old rope someone else had looked after for my cowstails I wouldn't be keen on.

With regard to using old rope for a short pitch.  My personal view is that it 'feels' less risky but also that cutting an old rope down is more to remove damage sections and the ends where the majority of the knotting happens rather than saying a short pitch is less dangerous than a long one.



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Re: Making cowstails.. Rope age question
« Reply #39 on: September 29, 2020, 10:38:00 am »
If you're on one marginal foothold, then the majority of your weight can be (whilst you're stepping the other foot up) - it still ain't gonna break under these sorts of forces!

Age just means the cumulative effects of UV etc are likely to be greater.

& the short lengths was more about reducing the bounce, because it's a dynamic rope.

Offline andrewmc

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Re: Making cowstails.. Rope age question
« Reply #40 on: September 29, 2020, 12:39:23 pm »
If the exact details of forces on cowstails with tight knots/loose knots/rope diameter etc. were that critical, then rather than arguing about small differences we should just be using shock-absorbing lanyards.

But we don't, because we don't need to, and it's a faff.

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Re: Making cowstails.. Rope age question
« Reply #41 on: September 29, 2020, 02:12:17 pm »
Bob's chart on previous page shows that for factor 1 & 1.25 falls on both short or long cowstails, the third drop hits about 1.5 times the peak force of the first drop, so it is significant, but we don't know how much of that is due to tightening of the knots & how much to damage of the internal structure of the rope. Fortunately it's very rare to actually subject a cowstail to a "clean" drop in use.

 

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