Author Topic: Making cowstails.. Rope age question  (Read 1632 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. 

Offline mikem

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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?

Offline mikem

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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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Offline mikem

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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. 

 

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