Knots in slings for chocks - are the old ways still best?

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 MisterPiggy 03 Jan 2022

Since the 80s when I started climbing (now known as  trad. climbing) I've been tying my chocks into accessory cord or dynamic rope for the whoppers using a double fishermen's knot.

I bought five new-ish chocks of eBay last week and as I have long since lost my notes on how much cord/rope is used up by each knot, was carefully disassembling the previous owner's slings, measuring as I went.

So far, so good. Then suddenly it hit me: I was untying reef knots ..! What ..?! Judging by the state of the chocks and the slings, this guy must've been climbing for years on these knots. He had fastened the dangly ends of the knots with bandage, and it didn't look like these ends had ever slipped.

So my musing is: Are reef knots OK to use in cord/rope slings, with dangly ends taped off; or are double fishermen's, with tied off dangly ends, the only really 'safe' method?

Just musing...

Happy New Year to all

In reply to MisterPiggy:

Reef knots are plenty strong enough but have a habit of working themselves loose. With the tails taped to the live strands I reckon this wouldn't be a problem. If you're looking to use less cord a simple overhand with a couple of inches of tail would probably do just fine as well.

13
 Root1 03 Jan 2022
In reply to MisterPiggy:

I use dyneema cord with a triple fishermans. Overhand or reef knots sound a bit dodgy to me.

In reply to Root1:

Overhand knots have their uses in climbing, but there is a strong case for banning reef knots completely. (Good for conjuring tricks, though, when you want a knot to disappear instantaneously!)

6
 beardy mike 03 Jan 2022
In reply to pancakeandchips:

Ringbend/water knot/tape knot please, not overhand. An overhand is a dreadful idea. 

4
 petegunn 03 Jan 2022
In reply to MisterPiggy:

Most of my old sling ones are tied with a water knott which although they dont come undone easily, they do look a bit like a reef knott at a glance.

 wbo2 03 Jan 2022
In reply to beardy mike:

Whys that Mike? Strength reduction. 

I've always used double fisherman's... the beauty of the reef knot, that it loosens so easily,  is not a strength here .

 beardy mike 03 Jan 2022
In reply to wbo2:

An overhand rolls, a ringbend/whatever you call it doesnt due to the symmetric topology of the knot. Unless you have long tails, an overhand can fail at low loads because when it's tied and loaded offset it is reasonably unstable. Stable enough to abseil on, but not stable enough to load with a proper fall. I wasn't commenting on a reef knot, personally it wouldn't be my preference for this application but I doubt you'd die as long as you made sure the knot was well dressed and you provided some method of loosening prevention. The double fisherman, well its just safe as houses...

 spragglerocks 04 Jan 2022
In reply to MisterPiggy:

I've just replaced all the cord on my hexes. Needle sports have some useful info on length required and type of tape ' they also sell it pre cut. 

https://www.needlesports.com/Catalogue/Climbing-Running/Rock-Trad-Climbing/...

Also provide a useful list of climbing knots....no mention of the reef knot.

https://www.needlesports.com/Information/Need-Advice/Knots-for-Climbers

I used double fisherman's for mine. 

In reply to beardy mike:

> An overhand rolls, a ringbend/whatever you call it doesnt due to the symmetric topology of the knot. Unless you have long tails, an overhand can fail at low loads because when it's tied and loaded offset it is reasonably unstable. Stable enough to abseil on, but not stable enough to load with a proper fall. I wasn't commenting on a reef knot, personally it wouldn't be my preference for this application but I doubt you'd die as long as you made sure the knot was well dressed and you provided some method of loosening prevention. The double fisherman, well its just safe as houses...

It would roll if tied 'side on' but you wouldn't tie it like that on a chock you'd tie it 'in line' by reversing one through the other.

2
 MischaHY 04 Jan 2022
In reply to wbo2:

For anyone wondering how bad overhands are for this purpose - some years ago when less informed I used them on my skyhooks. After doing some fall testing I discovered rather quickly why it's a poor choice:

Fall 1 (0.5m above): held fine.

Fall 2 (1.5m above): held fine. 

Fall 3 (2m above): mahoooooooooooosive whipper onto the bomber nest below, much confusion all round. The skyhook is nowhere to be seen. The quickdraw however is nestled on my rope quite devoid of tape or hook. Upon climbing back up I found the skyhook still firmly lodged in place with the knotless tape flapping limply in the breeze. The takeaway was that hooks are actually pretty bomber but overhands not so much (in this context). 

 deepsoup 04 Jan 2022
In reply to spragglerocks:

> Also provide a useful list of climbing knots....no mention of the reef knot.

Nor an overhand to be fair. 

Before the overhand largely took over though, the main use for a reef knot was in the middle of a double fishermans to prevent it from nipping up tight and being difficult to untie after an abseil.

 GrahamD 04 Jan 2022
In reply to John Stainforth:

> Overhand knots have their uses in climbing, but there is a strong case for banning reef knots completely. (Good for conjuring tricks, though, when you want a knot to disappear instantaneously!)

Most people tie their shoes with a reef knot variant.

 beardy mike 04 Jan 2022
In reply to DubyaJamesDubya:

That's not an overhand, that's a Ringbend. A Ringbend IS an overhand which joins two end  tied in line. By definition though an overhand is the knot you tie for abseiling from. I see many threads tied  that way in Europe and always spend the time to retire them as a ring bend, the difference in strength is huge...

Infact I even tie on with a ringbend as it has loop strength (like a bowline) when compared to an overhand or an 8 on the bight. 

Post edited at 09:41
 beardy mike 04 Jan 2022
In reply to beardy mike:

Damned autocorrect, typing on my phone!

 Martin Hore 04 Jan 2022
In reply to beardy mike:

I'm a bit confused here. What is it that makes the overhand knot tied "offset" safe for joining abseil ropes but not for other uses? I would have thought that forces approaching those involved in the falls described by MishaHY above could potentially arise when abseiling in certain circumstances eg "sagging" back onto a slack abseil rope rope after problem sorting close to the top (with less rope in play), or taking a big swing from a diagonal line. Also wouldn't the "unrolling" of the knot be more likely to happen with the constant bouncing involved in abseiling (particularly when abseiling on  wet ropes)?

I always now abseil using the offset overhand knot with long tails having switched from the double fisherman's 15 or 20 years ago on advice from many others that it helped prevent the rope snagging when retrieving. It now seems to be normal practice. I'm quite surprised to learn that it might fail so readily if subject to slightly stronger forces. 

Martin

 deepsoup 04 Jan 2022
In reply to Martin Hore:

> I always now abseil using the offset overhand knot with long tails..

Just ignoring the 'forces' thing for now; the long tails are essential.  Nobody wants big long tails like that flapping about on half a dozen pieces of racked gear.

1
 oldie 04 Jan 2022
In reply to Martin Hore:

There may be some confusion in this thread as some people may be describing knots in tape ( material is also a factor esp nylon vs dyneema) and some describing knots in cord or rope.

 Tom Valentine 04 Jan 2022
In reply to MisterPiggy:

I don't know how old you mean - I tied my first sling in 1967 and a double fisherman's was the only accepted way in those days (as far as I know)

In reply to GrahamD:

> Most people tie their shoes with a reef knot variant.

So do I. I double tie them, and still they occasionally come undone - the last time was yesterday. But that use of the reef knot doesn't kill me.

I was talking climbing.

Post edited at 10:37
In reply to Martin Hore:

> I'm a bit confused here. What is it that makes the overhand knot tied "offset" safe for joining abseil ropes but not for other uses? I would have thought that forces approaching those involved in the falls described by MishaHY above could potentially arise when abseiling in certain circumstances eg "sagging" back onto a slack abseil rope rope after problem sorting close to the top (with less rope in play), or taking a big swing from a diagonal line. Also wouldn't the "unrolling" of the knot be more likely to happen with the constant bouncing involved in abseiling (particularly when abseiling on  wet ropes)?

> I always now abseil using the offset overhand knot with long tails having switched from the double fisherman's 15 or 20 years ago on advice from many others that it helped prevent the rope snagging when retrieving. It now seems to be normal practice. I'm quite surprised to learn that it might fail so readily if subject to slightly stronger forces. 

> Martin

Explains it all here with testing too:

https://www.needlesports.com/Information/Need-Advice/Abseil-Knots

 deepsoup 04 Jan 2022
In reply to oldie:

> There may be some confusion in this thread as some people may be describing knots in tape ( material is also a factor esp nylon vs dyneema) and some describing knots in cord or rope.

There is only one knot for tape isn't there? 

Nylon tape that is.  No sane person has ever tried to make a sling by knotting a piece of dyneema tape.  Though, thinking on, maybe the previous owner of the OP's new old formerly reef-knotted hexes had a few.

 Martin Hore 04 Jan 2022
In reply to DubyaJamesDubya:

Thank you James - a useful and authoritative link.

I should have said that I always use the double version when abseiling, with long tails. I'll continue to do so.

Martin

 wercat 04 Jan 2022
In reply to GrahamD:

I only found out a few weeks ago that I have been tying my laces since primary school (1960 ish) wrongly.  Possibly because I seemed incapable of learning it properly at that time.  Seems to have been a version of a granny knot.  I've corrected this by reversing the initial polarity of the crossing of the laces which is definitely easier than butterfingers on the later bit.

Post edited at 12:28
 wercat 04 Jan 2022
In reply to John Stainforth:

could do if a winter boot came unfastened on steep ice!

 beardy mike 04 Jan 2022
In reply to Martin Hore:

What makes it OK is that abseiling a relatively low force, even with bouncing, in combination with long tails, dressing the knot well and cinching it up tight before loading it. A fall is in the range of 4kN minimum, 7 in a large fall and potentially up to around 10 if you really go for it. An abseil will be maybe up to 2kN(guess) and I seem to remember offset overhand roll around 3-4kN, ie not really sufficient for a fall, but plenty for an abseil. I'm sure Jim Titt would be able to correct me on precise numbers...

 GrahamD 04 Jan 2022
In reply to beardy mike:

I'd have thought (intuitively- dangerous,  I know) that the issue of an overhand for gear cord is the fact that the tight radius lowers the breaking point of the cord ?

In extremis I'll still use an overhand to tie off threads when these have to be tied one handed, though.

 oldie 04 Jan 2022
In reply to deepsoup:

> There is only one knot for tape isn't there? 

> Nylon tape that is.  No sane person has ever tried to make a sling by knotting a piece of dyneema tape.  Though, thinking on, maybe the previous owner of the OP's new old formerly reef-knotted hexes had a few.

True. I think the triple fishermans is a supposedly stronger and slips less than the tape knot but isn't much used as its bulkier. Probably most people use sewn slings now and perhaps tape knots are mainly used for tat for abbing. Obviously one can use knots in dyneema slings that aren't for joining the ends eg master point when belaying, half knot for shortening a sling. I think its OK to use a triple fishermans for dyneema cord or rope.

 oldie 04 Jan 2022
In reply to deepsoup:

> There is only one knot for tape isn't there? 

> Nylon tape that is.  No sane person has ever tried to make a sling by knotting a piece of dyneema tape.  Though, thinking on, maybe the previous owner of the OP's new old formerly reef-knotted hexes had a few.

True. I think the triple fishermans is a supposedly stronger and slips less than the tape knot but isn't much used as its bulkier. Probably most people use sewn slings now and perhaps tape knots are mainly used for tat for abbing. Obviously one can use knots in dyneema tape slings that aren't for joining the ends eg master point when belaying, half knot for shortening a sling. I think its OK to use a triple fishermans for dyneema cord or rope.

 deepsoup 04 Jan 2022
In reply to oldie:

> I think the triple fishermans is a supposedly stronger and slips less than the tape knot but isn't much used as its bulkier.

Ah, yes.  I was thinking tape knot obvs (ie: nicely dressed 'flat' water knot/ring bend), but you're quite right - a triple fisherman's is stronger and more reliable in tape.  Not that anyone used it to make a sling back in the day (only slightly before my time) as far as I know..

I had a little rummage for a link and this is interesting:
https://dmmclimbing.com/Knowledge/March-2012/Knotting-Dyneema

> Obviously one can use knots in dyneema slings that aren't for joining the ends eg master point when belaying, half knot for shortening a sling.

That would be an ecumenical matter.  I'm not so sure it is obvious that one can - at best I think that's a definite maybe!

As I understand it the issue is that the stuff is so slippery that a knot can tighten up much more under load than nylon, and forcing to bend around a smaller radius reduces the strength more than forcing it around a bigger one.  Also that it has a lower melting point, so the heat generated as the knot tightens can be more dangerous.

Here's a semi-relevant link again:
https://dmmwales.com/knowledge/june-2010/how-to-break-nylon-dyneema%C2%AE-s...

 oldie 04 Jan 2022
In reply to deepsoup:

>RE: Obviously one can use knots in dyneema slings that aren't for joining the ends eg master point when belaying, half knot for shortening a sling. <  >That would be an ecumenical matter.  I'm not so sure it is obvious that one can - at best I think that's a definite maybe! <

Thanks for the links. It seems to be generally accepted that one can use Dyneema slings with overhands or other knots to equalize at a master point. After all surely that would be a main reason for having a 240cm sling?

Here's one demonstration by a british mountain guide.  youtube.com/watch?v=-SBNp3VaMXI&

Personally I still use a system based on clipping into a couple of bights of rope.

 deepsoup 04 Jan 2022
In reply to oldie:

> It seems to be generally accepted that one can use Dyneema slings with overhands or other knots to equalize at a master point.

Yep, I think you're right. 

It just occurred to me that I'm pretty sure I still have an enormous skinny dyneema sling kicking about somewhere (4m I think) intended to be used as a cordlette.  I bought it thinking it would be useful but never did use it much.

 beardy mike 04 Jan 2022
In reply to oldie:

What we are talking about here is a different use of the knot, we are talking about joining 2 ends of an open piece of tape rather than for making a loop in a closed tape. The danger of using an overhand where there are ends is the knot rolling underload as the knot is offset to the load. A fisherman's cinches down tighter when used in this application, and with dyneema, the extra sliperiness exacerbates any slippage, hence the triple fisherman requirement.

 CantClimbTom 05 Jan 2022
In reply to MisterPiggy:

IMHO any further debate on knots should be split into 2 different categories

1) rope, cord, tape that is *not* dynema (or equivalent). To be honest on this debate I'm a bit Meh... because most sensible choices will work for this

2) Anything made from dynema (or equivalent). Dynema is very slippery and knots can work loose and/or slip under load. Even double fisherman may not be good in some cases and triple is needed. For all the strength advantage of dynema it's a matter of opinion if it is a net benefit to use in knotted/tied nuts

 Root1 05 Jan 2022
In reply to John Stainforth:

> Overhand knots have their uses in climbing, but there is a strong case for banning reef knots completely. (Good for conjuring tricks, though, when you want a knot to disappear instantaneously!)

Yes. I use two overhand knots for tying abseil ropes together, but would never use that for putting a rope on a hex or the like.

 oldie 05 Jan 2022
In reply to beardy mike:

As mentioned again in a post below yours I think there is some possible confusion (for me anyway) in this thread between knots for cord/rope and ones for tape...I did mention in one reply that  I thought some knots could be used in tape but only where it was not for joining ends. Your post implies (to me at least!) that a triple fisherman is OK to join the ends of dyneema tape. I've previously thought, perhaps wrongly, that no knot is OK for joining dyneema tape though the triple fisherman is Ok for joining dyneema cord. 

 deepsoup 05 Jan 2022
In reply to oldie:

>  I've previously thought, perhaps wrongly, that no knot is OK for joining dyneema tape though the triple fisherman is Ok for joining dyneema cord. 

I thought the same, but there's some info in the first DMM article I posted a link to up thread to suggest that it could be ok.  (Not that I'm about to try it.)

Ah.  That's interesting - the link doesn't work now.  (Did it work yesterday?  I thought so but not sure now.)  I think it's because UKC has stripped the "®" off the end of the URL.  I'll try again:
https://dmmclimbing.com/Knowledge/March-2012/Knotting-Dyneema®

 oldie 05 Jan 2022
In reply to deepsoup:

Thanks. I do note that the link says its possible to join Dyneema tape with a knot, but then "Overall, we should stress that we strongly recommend that you do not construct your own Dyneema® slings by tying lengths of loose Dyneema® tape together. " 

I remember reading an entry in a hut logbook in pre sewn sling days describing how the writer rested back on a nylon tape sling (on Vember?) and to his horror saw an end slowly slipping through the knot and then he was falling etc ".

Post edited at 15:26
 LastBoyScout 05 Jan 2022
In reply to DubyaJamesDubya:

Yes - the water knot and overhand are basically the same knot, but with the working ends and tails opposed.

I used water knots for tying tape into my larger hexes and then stitched the ends.

 johncook 05 Jan 2022
In reply to pancakeandchips:

I use reef knots to join two ropes for abbing. The tails are then tied with fishermens knots. If the reef knot slips, the fishermens holds. Reefs have a habit of coming loose. Fishermens are a bugger to untie after loading. The combination of the two gives a secure, low profile knot than can be easily untied after use. I wouldn't use a reef for slings because of the tendency to come loose!

 johncook 05 Jan 2022
In reply to DubyaJamesDubya:

That sounds like a water knot/tape knot. Very different to an overhand, both in strength and resistance to rolling of cross loaded!

 BenSA 05 Jan 2022
In reply to LastBoyScout:

out of interest how do you go about stitching open slings? (dont think I would trust my own stitching from reading up the thread and hearing stories of people falling!

Ive got some hexes that I am going to resling, but was going to go with cord and a triple fishermans. Its a shame wild country dont replace hex slings anymore. 

 LastBoyScout 05 Jan 2022
In reply to BenSA:

> out of interest, how do you go about stitching open slings? (don't think I would trust my own stitching from reading up the thread and hearing stories of people falling!

Once I've tied a water knot in the tape, I just put a few stitches into the tails - they're not load bearing, but makes it obvious if the knot has slipped in any way.

> I've got some hexes that I am going to resling, but was going to go with cord and a triple fishermans. It's a shame wild country don't replace hex slings anymore.

On large hexes, try and tie the fishermans/water knot inside the hex.

One option, depending on the size of the holes in the hex, is to thread a narrow sling through and clip through both ends (also works for re-slinging old cams). Has potential for getting it wrong and that could be nasty, but some tape by the krab should prevent issues.

 BenSA 05 Jan 2022
In reply to LastBoyScout:

Thanks, might look into your last suggestion. 


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