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Overhand Knot (on the bight) in Cows Tails.

wellyjen

Active member
What's the current thinking on these? They were always shown as an option for making cows tails, for example in Marbach & Tourte's Alpine Caving Techniques. Is this still the case, or are they now discouraged? I'm often out of touch with the state of the art. For attachment to a D Maillon, or other central attachment point on the harness, or as an alternative to a barrel knot for a carabiner, at the end of a long, or short cowstail? They use a lot less rope than a figure 8 on the bight. Only going to be subjected to a static load of one caver, unless they stop a fall, in which case they should be replaced after.
Good? bad? You're going to die?
Jen
 
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Pete K

Well-known member
For the central knot on the cowstails - totally fine IMO. There are of course slightly stronger knots out there, but that is irrelevant if cowstails are used correctly and never subjected to more than hanging on, or a FF1 at the absolute worst. Overhands on the end with a sufficient tail (+10cm) would do, but they don't keep your krabs nicely orientated like a barrel/scaffold knot does. Easer to inspect and undo though I guess.
Main thing with any cowstail knots is to slacken them off and re-tie periodically. That's where most of the shock absorption comes from, not the dynamic rope. Rock hard knots are not great.
 

Bob Mehew

Active member
One significant factor in a rope stopping your fall is the peak force you sustain. Too high a peak force and you don't walk away! A major contributor to reducing the peak force is the choice of knot. Work by two organisations show overhand knots are worse compared to figure of eight or barrel, see page 6 to 8 in Speleology 12 (assuming you have BCRA membership - else PM me with a email address). Overhand knots are worse at being undone compared to figure of eight for a given drop; not sure about barrel knot status.

Oh and not just periodically, relax and redress all the knots in your cows tail after each use. Even just repeated hanging on a rope / knot will tighten it and reduce it's ability to absorb the energy in the drop whist minimising the peak force.
 

pwhole

Well-known member
I always have two overhands on my d-ring, mirrored for neatness, and forming a very small loop with a krab as a third cowstail. Three-turn barrel knots on the ends. This uses exactly 3.5m of rope to do, but it's served me well, and I loosen the knots after every trip whilst they're still wet, and periodically take them off and give them a good wash in soapy water, to get rid of any embedded dirt - they're much easier and limper afterwards. Now I only have the current set left though - I have two 23m lengths of Mammut Super Dry (orange), but they're meant to be for bolt-climbing belays, so I'm reluctant to chop those down any more! Anyone know where this can be bought off a reel, rather than buying a full hank from a climbing shop?
 

tim.rose2

Active member
I always have two overhands on my d-ring, mirrored for neatness, and forming a very small loop with a krab as a third cowstail. Three-turn barrel knots on the ends. This uses exactly 3.5m of rope to do, but it's served me well, and I loosen the knots after every trip whilst they're still wet, and periodically take them off and give them a good wash in soapy water, to get rid of any embedded dirt - they're much easier and limper afterwards. Now I only have the current set left though - I have two 23m lengths of Mammut Super Dry (orange), but they're meant to be for bolt-climbing belays, so I'm reluctant to chop those down any more! Anyone know where this can be bought off a reel, rather than buying a full hank from a climbing shop?

Not exactly what you're looking for but I've bought this from up&under for cowtails...
 

Cantclimbtom

Active member
I always have two overhands on my d-ring, mirrored for neatness, and forming a very small loop with a krab as a third cowstail. Three-turn barrel knots on the ends. This uses exactly 3.5m of rope to do, but it's served me well, and I loosen the knots after every trip whilst they're still wet, and periodically take them off and give them a good wash in soapy water, to get rid of any embedded dirt - they're much easier and limper afterwards. Now I only have the current set left though - I have two 23m lengths of Mammut Super Dry (orange), but they're meant to be for bolt-climbing belays, so I'm reluctant to chop those down any more! Anyone know where this can be bought off a reel, rather than buying a full hank from a climbing shop?
They sell dynamic rope per metre. Helpful and reliable company
 

wellyjen

Active member
Thanks for the replies folks. Especially from Pete K and Bob Mehew. The Speleology article was an interesting read.
I'll be sticking with an overhand knot for the harness connection. Have been loosening, or retieing and dressing the knots on a fairly regular basis for a long while, just to clear the mud out when washing cowstails, but will be upping this to after every SRT trip.
 

Pete K

Well-known member
Anyone know where this can be bought off a reel, rather than buying a full hank from a climbing shop?
I usually have a 10 metres or so of new stuff in the van. I sell it to the Welsh instructors at £2pm as they also struggle to find it locally. I tend to buy a 20m rope from Decathlon once a year and chop it down on demand. Not sure what I have in but give me a shout next time we pass.
 
Always used barrel knots on the carabiners myself... If you want a great tip on tieing lengths Adam Evans has a good method on Youtube for getting lengths tuned to you. I know some of the technical merits have been discussed before (pre-tighten knots etc.) but often the consensus is mixed, so I am suggesting his method of tieing the rope lengths more than the smaller details he provides.

 

pwhole

Well-known member
I usually have a 10 metres or so of new stuff in the van. I sell it to the Welsh instructors at £2pm as they also struggle to find it locally. I tend to buy a 20m rope from Decathlon once a year and chop it down on demand. Not sure what I have in but give me a shout next time we pass.
I may do that - to be honest I just bought a 60m originally from Go Outdoors as it was on a ridiculous offer, and cut off 14m for four sets of cowstails and that gave me two 23ms which s about right for most bolt climbs I might undertake.

I just noticed they're currently doing this offer on Edelweiss Dry - and they're literally 2 minutes from my place:

https://www.gooutdoors.co.uk/15904839/edelweiss-10mm-flight-2-dry-x-60m-15904839
 

mikem

Well-known member
There are shops in North & South Wales that sell offcuts of rope (mostly climbing) - maybe mid Wales you'd struggle...
 

JasonC

Active member
An interesting thread, which has caused me to check my cowstails - and re-tie them - which I was not in the habit of doing...

But it led me to wonder - how often has anyone actually taken a fall onto their cowstails? Obviously I don't count their use in standard (or even non-standard) SRT manoeuvres, or even deliberate falls to test kit - I mean actual situations where a cowstail failure would have led to a potentially injurious fall.
Never happened to me, or in my presence, but then I'm very much a part-time caver. What about you hard cases?
 

cap n chris

Well-known member
An interesting thread, which has caused me to check my cowstails - and re-tie them - which I was not in the habit of doing...

But it led me to wonder - how often has anyone actually taken a fall onto their cowstails? Obviously I don't count their use in standard (or even non-standard) SRT manoeuvres, or even deliberate falls to test kit - I mean actual situations where a cowstail failure would have led to a potentially injurious fall.
Never happened to me, or in my presence, but then I'm very much a part-time caver. What about you hard cases?
I have witnessed it first hand, fall factor probably 1.3. CTs were freshly tied prior to the trip. All worked perfectly. No problem.
 

cap n chris

Well-known member
To be fair, though, it is exceptionally rare, FWIW my single observation of a fall into CTs is just once out of a combined log of SRT type trips involving in excess of 5,000 person visits. Perhaps even edging towards 10k.
 

Ian Ball

Well-known member
I've fallen onto cowstails, it's a once in a caving career experience I hope to say, Im positive it took at least a week for the slack in the rigging and cowstails to be taken up, lots of time to wonder if I had clipped it properly.

I replaced them with shorter ones by a fair few cms after that and added a twist gate rather than snap. The cowstails were new so they were re purposed as a foot loop till I decided something less stretchy was needed.
 
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andrewmcleod

Well-known member
I was free-climbing some wide passage thing in Eurospeleo 2018 (in Austria) because we were being led round a round-trip the 'other' way, and the rope we needed to get up was tied up at the top of the passage (only maybe 4/5m up)... I had got high enough to clip the rope, then proceeded higher and slipped off. There was enough rope and knots above me that it wasn't particularly dramatic for me though (slightly more for the onlookers).
 
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