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Lots of discussion about self-equalizing systems in which you clip a big loop of something into all the belay points, pull down the sling between the points and tie a whopping great overhand knot with the resulting loops ...
Well it struck me that instead of an overhand knot, why not put the loops through a big format krab and then "flip then over the back" - that is, form a fat lark's foot.
Very fast even with gloves, uses much less sling, and very easy to untie even after loading.
Only obvious disadvantage is that the krab can't be unclipped.
The lark's foot is not the world's best knot, however it seems to me that if one of your points do fail the loop of sling of the failed point will slip a bit under shock loading thus providing a degree of protection.
Anyone have any thoughts on the issue? (Perhaps this is old hat ... ?)
Well it struck me that instead of an overhand knot, why not put the loops through a big format krab and then "flip then over the back" - that is, form a fat lark's foot.
Very fast even with gloves, uses much less sling, and very easy to untie even after loading.
Only obvious disadvantage is that the krab can't be unclipped.
The lark's foot is not the world's best knot, however it seems to me that if one of your points do fail the loop of sling of the failed point will slip a bit under shock loading thus providing a degree of protection.
Anyone have any thoughts on the issue? (Perhaps this is old hat ... ?)
In reply to Gavin Taylor: Couldn't the larks foot slip completely ? If this happened, the effect would be the same as having no knot !
Is the overhand really that hard to undo if you tie it on all strands in one knot?
Is the overhand really that hard to undo if you tie it on all strands in one knot?
In reply to IPPurewater:
Must admit I'd be worried about it slipping, which would lose you the equalisation.
Must admit I'd be worried about it slipping, which would lose you the equalisation.
In reply to IPPurewater:
No - the sling is completely captive in any case.
The overhand is a faff to tie, especially if you have four or more loops, and it requires loads of slack. My system is much sleeker and faster.
I tried the lark's foot in my lounge and I don't see any problems - if it stops snowing I'll try it outside tomorrow.
> (In reply to Gavin Taylor) Couldn't the larks foot slip completely ? If this happened, the effect would be the same as having no knot !
No - the sling is completely captive in any case.
> Is the overhand really that hard to undo if you tie it on all strands in one knot?
The overhand is a faff to tie, especially if you have four or more loops, and it requires loads of slack. My system is much sleeker and faster.
I tried the lark's foot in my lounge and I don't see any problems - if it stops snowing I'll try it outside tomorrow.
In reply to Gavin Taylor:
Interesting idea, but I can't quite visualise it. Will have a play at home later. (Gets me out of painting the loft).
Interesting idea, but I can't quite visualise it. Will have a play at home later. (Gets me out of painting the loft).
In reply to Ridge:
Any slipping only tends to equalize even btter. The big question is when a point fails what happens? I was testing with a thin, new tape sling and it seemed to remain fairly stable, although I got the impression that really heavy loading would cause the failed loop to creep down towards the larks foot, but obviously it would stop when the krab reached the knot. I tried unclipping the krab and helping the the loop to slip through and it was still fine. Effectively every loop is a separate larks foot.
> (In reply to IPPurewater)
>
> Must admit I'd be worried about it slipping, which would lose you the equalisation.
>
> Must admit I'd be worried about it slipping, which would lose you the equalisation.
Any slipping only tends to equalize even btter. The big question is when a point fails what happens? I was testing with a thin, new tape sling and it seemed to remain fairly stable, although I got the impression that really heavy loading would cause the failed loop to creep down towards the larks foot, but obviously it would stop when the krab reached the knot. I tried unclipping the krab and helping the the loop to slip through and it was still fine. Effectively every loop is a separate larks foot.
In reply to Ridge:
Please do - and let me know what you think (seems a bit too good to be true)
> (In reply to Gavin Taylor)
>
> Interesting idea, but I can't quite visualise it. Will have a play at home later. (Gets me out of painting the loft).
>
> Interesting idea, but I can't quite visualise it. Will have a play at home later. (Gets me out of painting the loft).
Please do - and let me know what you think (seems a bit too good to be true)
In reply to Gavin Taylor:
The idea of a loaded knot in a dyneema sling slipping to any great extent scares me a lot. Dyneema melts at about 50 degrees C, and it's quite possible that friction during slipping could generate that sort of temperature. Just a thought...
The idea of a loaded knot in a dyneema sling slipping to any great extent scares me a lot. Dyneema melts at about 50 degrees C, and it's quite possible that friction during slipping could generate that sort of temperature. Just a thought...
In reply to Gavin Taylor:
Having some difficulty in understanding how you form the lark's foot here.
I assume that you have the krab with back bar uppermost and parallel to your body. You then pull the various bights of tape/cord through the krab (rather than clip into it) and then place this loop behind the krab and over the top of the incoming loops which you then pull through and clip into. Is this correct? It is the only way that I can see you forming a lark's foot in this situation.
boB
Having some difficulty in understanding how you form the lark's foot here.
I assume that you have the krab with back bar uppermost and parallel to your body. You then pull the various bights of tape/cord through the krab (rather than clip into it) and then place this loop behind the krab and over the top of the incoming loops which you then pull through and clip into. Is this correct? It is the only way that I can see you forming a lark's foot in this situation.
boB
In reply to Bob:
Not exactly - you could do the same thing with a closed ring instead of a krab - put loops through hole then put loops over ring - very easy but hard to describe.
Think of the old bottle opener figure-of-eight descenders, but flip the loops right over the big ring to form the lark's foot. Try it and you will see it is easy.
> (In reply to Gavin Taylor)
> You then pull the various bights of tape/cord through the krab (rather than clip into it) and then place this loop behind the krab and over the top of the incoming loops which you then pull through and clip into. Is this correct?
>
> You then pull the various bights of tape/cord through the krab (rather than clip into it) and then place this loop behind the krab and over the top of the incoming loops which you then pull through and clip into. Is this correct?
>
Not exactly - you could do the same thing with a closed ring instead of a krab - put loops through hole then put loops over ring - very easy but hard to describe.
Think of the old bottle opener figure-of-eight descenders, but flip the loops right over the big ring to form the lark's foot. Try it and you will see it is easy.
In reply to stuartf:
Indeed - seems pretty stable, as if could maybe slip a couple of cm, but hard to know. Anyone have a test rig handy?
> (In reply to Gavin Taylor)
>
> The idea of a loaded knot in a dyneema sling slipping to any great extent scares me a lot. Dyneema melts at about 50 degrees C, and it's quite possible that friction during slipping could generate that sort of temperature. Just a thought...
>
> The idea of a loaded knot in a dyneema sling slipping to any great extent scares me a lot. Dyneema melts at about 50 degrees C, and it's quite possible that friction during slipping could generate that sort of temperature. Just a thought...
Indeed - seems pretty stable, as if could maybe slip a couple of cm, but hard to know. Anyone have a test rig handy?
In reply to Gavin Taylor: I have tried this with slings and with cordlette,,its an interesting idea but not one i would be happy using at a normal belay,,perhaps it might be better suited to a belay where the belayer is constantly loading the larks footed slings/cordlette,that way there is no chance of the carabiner its all attached to inverting and possibly cross loading.
Its an interesting one Gavin and flies in the face of normal best mountaineering practice.
I have never had any problems with a BFK wether its been used for rigging fixed abseils or top ropes etc.
But... if it was used for equalising some ice screws,which you may not want to fall on ! then what the heck if they go who gives a damn about the larks footed crab
Its an interesting one Gavin and flies in the face of normal best mountaineering practice.
I have never had any problems with a BFK wether its been used for rigging fixed abseils or top ropes etc.
But... if it was used for equalising some ice screws,which you may not want to fall on ! then what the heck if they go who gives a damn about the larks footed crab
In reply to Gavin Taylor:
I'm at work trying this with various lengths of co-axial cable!!
The easiest way to form a Lark's Foot does not require a krab or ring until the final stage. Easiest to describe with a single sling/loop: Create a bight in the sling and let the bight fall over so that you have one half of a four leaf clover - it's obvious when you see it - now clip a krab round the middle two lengths of line/sling and you have a Lark's foot with the advantage that you can still use the krab.
boB
I'm at work trying this with various lengths of co-axial cable!!
The easiest way to form a Lark's Foot does not require a krab or ring until the final stage. Easiest to describe with a single sling/loop: Create a bight in the sling and let the bight fall over so that you have one half of a four leaf clover - it's obvious when you see it - now clip a krab round the middle two lengths of line/sling and you have a Lark's foot with the advantage that you can still use the krab.
boB
In reply to Bob:
True - but a bit confusing with three or four loops together ... my system is very gloves friendly, too
> (In reply to Gavin Taylor)
> The easiest way to form a Lark's Foot does not require a krab or ring until the final stage. Easiest to describe with a single sling/loop: Create a bight in the sling and let the bight fall over so that you have one half of a four leaf clover -
> The easiest way to form a Lark's Foot does not require a krab or ring until the final stage. Easiest to describe with a single sling/loop: Create a bight in the sling and let the bight fall over so that you have one half of a four leaf clover -
True - but a bit confusing with three or four loops together ... my system is very gloves friendly, too
In reply to Gavin Taylor:
Why not do it with a clove hitch through an open screwgate instead,
1) Once the screwgate is done up, there is no chance of the screwgate coming off
2) Not using a lark's foot, which is a kknot to be avoided
Why not do it with a clove hitch through an open screwgate instead,
1) Once the screwgate is done up, there is no chance of the screwgate coming off
2) Not using a lark's foot, which is a kknot to be avoided
In reply to Bob:
Hope it works better than with a phone charger lead and a paperclip...
> (In reply to Gavin Taylor)
>
> I'm at work trying this with various lengths of co-axial cable!!
>
> I'm at work trying this with various lengths of co-axial cable!!
Hope it works better than with a phone charger lead and a paperclip...
In reply to Gavin Taylor:
<pedant>
If you tie an overhand, it will no longer be "self equalising" as the system cannot adjust. In my experience, the above configuration will equalise most of the strands, but not perfectly. It is very difficult to tie the OHK just in the right place.
</pedant>
The magic-X will provide self-equalisation at the risk of extension/shock loading should one of your strands fail.
What you suggest is like a magic X with friction provided by the lark's foot. Any slippage of the larks foot will only serve to equalise the configuration even better. It should eventually lock as a larks foot is a self-tightening knot.
The only issue I have is the low melting point of spectra ( mentioned above). I suspect however, this will not be a problem as the amount of slippage would be minimal. Of course, you could always use perlon/nylon for the belay rig.
An interesting idea with potential.
> Lots of discussion about self-equalizing systems in which you clip a big loop of something into all the belay points, pull down the sling between the points and tie a whopping great overhand knot with the resulting loops ...
<pedant>
If you tie an overhand, it will no longer be "self equalising" as the system cannot adjust. In my experience, the above configuration will equalise most of the strands, but not perfectly. It is very difficult to tie the OHK just in the right place.
</pedant>
>
> Very fast even with gloves, uses much less sling, and very easy to untie even after loading.
> Only obvious disadvantage is that the krab can't be unclipped.
>
> The lark's foot is not the world's best knot, however it seems to me that if one of your points do fail the loop of sling of the failed point will slip a bit under shock loading thus providing a degree of protection.
> Very fast even with gloves, uses much less sling, and very easy to untie even after loading.
> Only obvious disadvantage is that the krab can't be unclipped.
>
> The lark's foot is not the world's best knot, however it seems to me that if one of your points do fail the loop of sling of the failed point will slip a bit under shock loading thus providing a degree of protection.
The magic-X will provide self-equalisation at the risk of extension/shock loading should one of your strands fail.
What you suggest is like a magic X with friction provided by the lark's foot. Any slippage of the larks foot will only serve to equalise the configuration even better. It should eventually lock as a larks foot is a self-tightening knot.
The only issue I have is the low melting point of spectra ( mentioned above). I suspect however, this will not be a problem as the amount of slippage would be minimal. Of course, you could always use perlon/nylon for the belay rig.
An interesting idea with potential.
In reply to chrispowell:
Yes - would be great, but ever tried clove hitching three or four strands simultaneously? Don't think it is practical.
Yes - I was always convinced that lark's feet were bad especially with tape, until I bought a CE safety standard via ferrata kit for my daughter - the whole mess is connected to the sit harness with a sewn sling which is "larked" onto both the shock absorbing plate and the harness!
It's true that in theory the dissipator avoids loads above a certain level, but still ...
In my equalizing system you could use cord - I used that new thin tape which mechanically is less at risk (radiuses of curve and so on) and the knot is very fat, which ought to help. And of course you have a knot for each loop - impossible to break them all, I would say.
> (In reply to Gavin Taylor)
>
> Why not do it with a clove hitch through an open screwgate instead,
>
> Why not do it with a clove hitch through an open screwgate instead,
Yes - would be great, but ever tried clove hitching three or four strands simultaneously? Don't think it is practical.
> 2) Not using a lark's foot, which is a kknot to be avoided
Yes - I was always convinced that lark's feet were bad especially with tape, until I bought a CE safety standard via ferrata kit for my daughter - the whole mess is connected to the sit harness with a sewn sling which is "larked" onto both the shock absorbing plate and the harness!
It's true that in theory the dissipator avoids loads above a certain level, but still ...
In my equalizing system you could use cord - I used that new thin tape which mechanically is less at risk (radiuses of curve and so on) and the knot is very fat, which ought to help. And of course you have a knot for each loop - impossible to break them all, I would say.
In reply to stuartf:
"Dyneema has a melting point between 144 and 152 º C depending on the test method used."
http://www.tote.com.au/dyneema.htm
50ºC would be slightly worrisome
"Dyneema has a melting point between 144 and 152 º C depending on the test method used."
http://www.tote.com.au/dyneema.htm
50ºC would be slightly worrisome
In reply to Gavin Taylor: The other things to look at is what angle the loads are being transmitted from the knot. I don't have anything to practise with here but I seem to remember that it's 90degrees or more from a larks foot which is bad due to the loading on your anchors.
Like I say, nothing to try it on but that's certainly one of the issues I've been told about with using a larks foot in other aplications.
Like I say, nothing to try it on but that's certainly one of the issues I've been told about with using a larks foot in other aplications.
In reply to K9:
That's reassuring - given that it can get up to 40 here on a really hot day!
> (In reply to stuartf)
>
> "Dyneema has a melting point between 144 and 152 º C depending on the test method used."
> http://www.tote.com.au/dyneema.htm
>
> 50ºC would be slightly worrisome
>
> "Dyneema has a melting point between 144 and 152 º C depending on the test method used."
> http://www.tote.com.au/dyneema.htm
>
> 50ºC would be slightly worrisome
That's reassuring - given that it can get up to 40 here on a really hot day!
In reply to K9:
I prefer the "GT equalizer knot"
> (In reply to Gavin Taylor)
>
> Sounds like you've invented the "Gavin Taylor Death Knot".
>
> Sounds like you've invented the "Gavin Taylor Death Knot".
I prefer the "GT equalizer knot"
In reply to Gavin Taylor:
Damn you. Mrs Ridge will kill me when she sees the complete absence of any DIY done tonight..
Right then, big sling, equalise between a few bits of gear as if you're about to do overhand knot.
Feed over back bar of krab, 'flip krab' oooh, big chunky larksfoot!
Slide to one end of krab so it's not cross loaded. OK.
Apply a bit of load and simulate one piece of gear failing..
Seems ok, provided it's loaded when the gear 'fails', there's enough friction in the knot to prevent the sling (dyneema) slipping too much, so no shock loading on the other anchors. In fact it might even decrease the shock.
Hmmmm. You could have something here.
Only reservations would be how it handles in wet and icy conditions, If the krab starts to slide it could unravel. Also if you don't keep tension on the anchors at all times it's a bit prone to slippage so you lose equalisation. Can certainly see the advantage for tying when wearing gloves though.
Damn you. Mrs Ridge will kill me when she sees the complete absence of any DIY done tonight..
Right then, big sling, equalise between a few bits of gear as if you're about to do overhand knot.
Feed over back bar of krab, 'flip krab' oooh, big chunky larksfoot!
Slide to one end of krab so it's not cross loaded. OK.
Apply a bit of load and simulate one piece of gear failing..
Seems ok, provided it's loaded when the gear 'fails', there's enough friction in the knot to prevent the sling (dyneema) slipping too much, so no shock loading on the other anchors. In fact it might even decrease the shock.
Hmmmm. You could have something here.
Only reservations would be how it handles in wet and icy conditions, If the krab starts to slide it could unravel. Also if you don't keep tension on the anchors at all times it's a bit prone to slippage so you lose equalisation. Can certainly see the advantage for tying when wearing gloves though.
In reply to Gavin Taylor:
A lark's foot removes a minimum of around 30% of the strength of the sling. And, I've just ried it and when one anchor fails, the knot wriggles aroung the krab in a way that may well open the gate. And then still might totally unwrap itself. I could go on about the 3 way cross loading when an anchor fails too, but must go for now.
A lark's foot removes a minimum of around 30% of the strength of the sling. And, I've just ried it and when one anchor fails, the knot wriggles aroung the krab in a way that may well open the gate. And then still might totally unwrap itself. I could go on about the 3 way cross loading when an anchor fails too, but must go for now.
In reply to Gavin Taylor:
to the people having problems understanding how to get the larksfoot into the system. I once realised you could make the same thing happen with a fig of 8 and a jammed screwgate on a multi pitch ab. Try this with harness on and FOE attached
1)take a large bight thru the large hole on fig of 8
2) drop the bight over your head and shoulders
3) allow it to come back from under your feet back to the FOE
4)voila. You are attached to the FOE as if you did it the normal way.
The larks foot in the system above is created in the same sort of way.
to the people having problems understanding how to get the larksfoot into the system. I once realised you could make the same thing happen with a fig of 8 and a jammed screwgate on a multi pitch ab. Try this with harness on and FOE attached
1)take a large bight thru the large hole on fig of 8
2) drop the bight over your head and shoulders
3) allow it to come back from under your feet back to the FOE
4)voila. You are attached to the FOE as if you did it the normal way.
The larks foot in the system above is created in the same sort of way.
In reply to Paddy Duncan:
Recent testing into strength of the larksfoot found that (properly loaded)krabs gave way before modern slings. They only got teh slings to break at the knot at significantly lower strains when the system was larksfooted ata n obtuse angle. eg round something really big.
Recent testing into strength of the larksfoot found that (properly loaded)krabs gave way before modern slings. They only got teh slings to break at the knot at significantly lower strains when the system was larksfooted ata n obtuse angle. eg round something really big.
In reply to neil_jj:
So when Gavin states "flip then over the back", he means "flip them over your back"? This means that you need enough rope/sling/cord in the loop to be able to step through which with even moderately spaced gear is going to be unlikely.
boB
So when Gavin states "flip then over the back", he means "flip them over your back"? This means that you need enough rope/sling/cord in the loop to be able to step through which with even moderately spaced gear is going to be unlikely.
boB
In reply to neil_jj:
Help.
I have rope tangled around my arms and dressing gown cord. The FOE is poking me in the kidney, and I'm experiencing problems getting off the bedroom floor.
Stylish idea though.
Help.
I have rope tangled around my arms and dressing gown cord. The FOE is poking me in the kidney, and I'm experiencing problems getting off the bedroom floor.
Stylish idea though.
In reply to Bob: no pull the bight(s) through centre of closed krab. Loop the bight(s) over and end . Then push the end of the bight(s) back to the start of the bight and then clip in.
or you would need a very big sling.
or you would need a very big sling.
In reply to neil_jj:
Got it now, as if you were setting up a fig 8 for an abb but push rope back over end.
Got it now, as if you were setting up a fig 8 for an abb but push rope back over end.
In reply to neil_jj:
Now I've had a bath after my run I have some time to play around with this....
Hold krab horizontally with long axis running away from your body and large radius end away from you. Pass bight of sling through krab and over the near end of krab and pull krab towards you.
boB
Now I've had a bath after my run I have some time to play around with this....
Hold krab horizontally with long axis running away from your body and large radius end away from you. Pass bight of sling through krab and over the near end of krab and pull krab towards you.
boB
In reply to neil_jj:
Can you post a link to any such test results?
Can you post a link to any such test results?
In reply to Gavin Taylor:
Ignoring the melting issues I think this is sound. Just one thought however - something I misunderstood at first. Each loop at the bottom of the sling must have its own larks foot. e.g., using 2 anchors the result should be two larks feet sitting next to each other on the krab with one 'larks toe' from each knot going to each anchor. Friction from the knots should prevent any shock loading in this configuration. However, if the larks foot is formed simultaneously with both loops (i.e., one knot formed of a double thickness strand) the sling is no longer captive and friction in this single knot is all you have should one anchor fail.
On a similar note though if you're only equalising two anchors how about a simple overhand knot around the midpoint in the sling before clipping an end into each anchor. Then, by clipping a krab around this knot the system is equalised (adjustable by moving the overhand knot), redundant and free from extension should one anchor fail.
Any more thoughts anyone?
Ignoring the melting issues I think this is sound. Just one thought however - something I misunderstood at first. Each loop at the bottom of the sling must have its own larks foot. e.g., using 2 anchors the result should be two larks feet sitting next to each other on the krab with one 'larks toe' from each knot going to each anchor. Friction from the knots should prevent any shock loading in this configuration. However, if the larks foot is formed simultaneously with both loops (i.e., one knot formed of a double thickness strand) the sling is no longer captive and friction in this single knot is all you have should one anchor fail.
On a similar note though if you're only equalising two anchors how about a simple overhand knot around the midpoint in the sling before clipping an end into each anchor. Then, by clipping a krab around this knot the system is equalised (adjustable by moving the overhand knot), redundant and free from extension should one anchor fail.
Any more thoughts anyone?
In reply to Gavin Taylor: It sounds good to me - would concur in saying that I would be concerned about cross loading the biner and about knot slippage. Don't feel the weakness of the knot would be an issue as with standard dyneema I would guesstemate from my reading that you would still only drop the strength to a minimum on 15kn which you are never going to acheive under normal circumstances (I think even a fall factor 2 lead fall doesn't reach that). Would like to see some proper tests done on this.
In reply to davewing:
Interesting to hear all the feedback - unfortunately have no time today to follow the thread - I have to go rock climbing (down by lake Garda).
Might test the system ... although I'm still a bit worried about it.
Will try to take a few digi-snaps for anyone who is still confused.
A couple of points about the original idea:
1) I always formed a single big lark's foot with all the loops together, not each one singly, as some seem to think.
2) I noticed last night that if you use this method with just 2 anchors then the sling is not captive (as cited text above correctly notes). The solution is the same as you would normally do to clip a two anchor sling - cross over the sling when clipping the anchors (same principle as crossing a long sling hanging around your chest/shoulder so that the krab doesn't fall off). This makes the sling captive.
> (In reply to Gavin Taylor)
>
> However, if the larks foot is formed simultaneously with both loops (i.e., one knot formed of a double thickness strand) the sling is no longer captive and friction in this single knot is all you have should one anchor fail.
>
>
> However, if the larks foot is formed simultaneously with both loops (i.e., one knot formed of a double thickness strand) the sling is no longer captive and friction in this single knot is all you have should one anchor fail.
>
Interesting to hear all the feedback - unfortunately have no time today to follow the thread - I have to go rock climbing (down by lake Garda).
Might test the system ... although I'm still a bit worried about it.
Will try to take a few digi-snaps for anyone who is still confused.
A couple of points about the original idea:
1) I always formed a single big lark's foot with all the loops together, not each one singly, as some seem to think.
2) I noticed last night that if you use this method with just 2 anchors then the sling is not captive (as cited text above correctly notes). The solution is the same as you would normally do to clip a two anchor sling - cross over the sling when clipping the anchors (same principle as crossing a long sling hanging around your chest/shoulder so that the krab doesn't fall off). This makes the sling captive.
In reply to Gavin Taylor:
A couple of tests confirm that in the case of a two-anchor system, the krab is definitely not captive whether the larksfoots (larksfeet?) are tied as one or individually. Break one anchor and the sling can be wiggled through the system to cause the krab to drop off.
In the case of a three-anchor system, wuth the larksfoots tied as one, breaking one anchor allows the sling to unravel to the point where only one larksfoot remains on the krab (ie one other unravels) and the two remaining anchors are in a simple loop with the krab. This significantly changes the direction of force on the anchors and also means they are not independent.
Having done a few tests, the following general principle seems to emerge: if you can secure the krab to your loops without having to open the gate, then the reverse may also be true. Wouldn't want to hang my life on that, I'm afraid.
Excellent fun, though! Got any more?
A couple of tests confirm that in the case of a two-anchor system, the krab is definitely not captive whether the larksfoots (larksfeet?) are tied as one or individually. Break one anchor and the sling can be wiggled through the system to cause the krab to drop off.
In the case of a three-anchor system, wuth the larksfoots tied as one, breaking one anchor allows the sling to unravel to the point where only one larksfoot remains on the krab (ie one other unravels) and the two remaining anchors are in a simple loop with the krab. This significantly changes the direction of force on the anchors and also means they are not independent.
Having done a few tests, the following general principle seems to emerge: if you can secure the krab to your loops without having to open the gate, then the reverse may also be true. Wouldn't want to hang my life on that, I'm afraid.
Excellent fun, though! Got any more?
In reply to Simon White:
Interestingly I couldn't get this to happen. I ended up with one big larksfoot. When I simulated one of the 3 anchors failing, (with the knot under load), there was enough friction in the knot to hold the loop to the 'failed' anchor in place, with only slight slippage. There was no significant change in the direction of loading on the other anchors.
Good point, but you'd probably have to invert the whole belay or yourself to achieve it.
Seconded!
> (In reply to Gavin Taylor)
>
>
> In the case of a three-anchor system, wuth the larksfoots tied as one, breaking one anchor allows the sling to unravel to the point where only one larksfoot remains on the krab (ie one other unravels) and the two remaining anchors are in a simple loop with the krab. This significantly changes the direction of force on the anchors and also means they are not independent.
>
>
> In the case of a three-anchor system, wuth the larksfoots tied as one, breaking one anchor allows the sling to unravel to the point where only one larksfoot remains on the krab (ie one other unravels) and the two remaining anchors are in a simple loop with the krab. This significantly changes the direction of force on the anchors and also means they are not independent.
Interestingly I couldn't get this to happen. I ended up with one big larksfoot. When I simulated one of the 3 anchors failing, (with the knot under load), there was enough friction in the knot to hold the loop to the 'failed' anchor in place, with only slight slippage. There was no significant change in the direction of loading on the other anchors.
> Having done a few tests, the following general principle seems to emerge: if you can secure the krab to your loops without having to open the gate, then the reverse may also be true. Wouldn't want to hang my life on that, I'm afraid.
Good point, but you'd probably have to invert the whole belay or yourself to achieve it.
> Excellent fun, though! Got any more?
Seconded!
In reply to neil_jj:
Could you give a reference? Didn't I read somewhere recently about it not being as weak as previously thought (Libby Peter's name seems to be associated with the statement in my muddled mind). I've wondered about the quoted weakness of the larksfoot when you consider that it is very similar to an Italian, which we use quite happily.
> (In reply to Paddy Duncan)
>
> Recent testing into strength of the larksfoot found that (properly loaded)krabs gave way before modern slings. They only got teh slings to break at the knot at significantly lower strains when the system was larksfooted ata n obtuse angle. eg round something really big.
>
> Recent testing into strength of the larksfoot found that (properly loaded)krabs gave way before modern slings. They only got teh slings to break at the knot at significantly lower strains when the system was larksfooted ata n obtuse angle. eg round something really big.
Could you give a reference? Didn't I read somewhere recently about it not being as weak as previously thought (Libby Peter's name seems to be associated with the statement in my muddled mind). I've wondered about the quoted weakness of the larksfoot when you consider that it is very similar to an Italian, which we use quite happily.
In reply to Simon White:
I've got one. It's a way of shortening individual slings without using a knot; theoretically better because knots in slings weaken them. It also makes them easily adjustable in length even after you've clipped in.
I didn't make this up, I learned it on an MR training course, but I've never seen it in any books about climbing or anything else, although it wouldn't surprise me if it's used in sailing or the like. I've used it to attach myself to ballast bags and I've discussed it with a guide who thought it seemed OK, but he had never heard of it either. I can see its potential for equalising two slings, but hesitate to recommend a technique with so little pedigree.
So what do you think?
Take the sling and hang from one hand. Put a single twist in the middle of the sling so it forms an 8 shape. Reach through the top loop of the 8 and grab the bottom back part of the sling. Pull it through the top loop, but only part-way, so it forms two loops at the bottom that hang over the middle x. Clip one krab through the two bottom loops and another through the single top one. Voila!
>
> Excellent fun, though! Got any more?
> Excellent fun, though! Got any more?
I've got one. It's a way of shortening individual slings without using a knot; theoretically better because knots in slings weaken them. It also makes them easily adjustable in length even after you've clipped in.
I didn't make this up, I learned it on an MR training course, but I've never seen it in any books about climbing or anything else, although it wouldn't surprise me if it's used in sailing or the like. I've used it to attach myself to ballast bags and I've discussed it with a guide who thought it seemed OK, but he had never heard of it either. I can see its potential for equalising two slings, but hesitate to recommend a technique with so little pedigree.
So what do you think?
Take the sling and hang from one hand. Put a single twist in the middle of the sling so it forms an 8 shape. Reach through the top loop of the 8 and grab the bottom back part of the sling. Pull it through the top loop, but only part-way, so it forms two loops at the bottom that hang over the middle x. Clip one krab through the two bottom loops and another through the single top one. Voila!
In reply to mike swann:
i seem to remember it having something to do with TRoll and / or Plas y Brenin. Can't find any links at the moment though.
i seem to remember it having something to do with TRoll and / or Plas y Brenin. Can't find any links at the moment though.
In reply to Simon White:
I think it is captive if you cross the sling as in my previous post (will have to try again to be sure though)
This seems academic to me - a failed anchor is going to have a krab on it and there is no way that this can get pulled all the way through the knot (or am I missing something?)
Yes - but as soon as you clip onto the krab surely there is no way the knot can come off - you are blocking it.
Thanks for all observations - I'm still not convinced either way - it's just that if it really was safe it would be a real time saver, especially in winter ...
Maybe some minor "tweak" could make it more obviously good ... ?
I'll try and do some tests tomorrow on My crag (BTW didn't have time today - discovered an amazing place though, Nago crag, above Lake Garda - gorgeous in every sense and a bouldering heaven)
> (In reply to Gavin Taylor)
>
> A couple of tests confirm that in the case of a two-anchor system, the krab is definitely not captive
>
> A couple of tests confirm that in the case of a two-anchor system, the krab is definitely not captive
I think it is captive if you cross the sling as in my previous post (will have to try again to be sure though)
> In the case of a three-anchor system, wuth the larksfoots tied as one, breaking one anchor allows the sling to unravel to the point where only one larksfoot remains on the krab
This seems academic to me - a failed anchor is going to have a krab on it and there is no way that this can get pulled all the way through the knot (or am I missing something?)
> Having done a few tests, the following general principle seems to emerge: if you can secure the krab to your loops without having to open the gate, then the reverse may also be true.
Yes - but as soon as you clip onto the krab surely there is no way the knot can come off - you are blocking it.
Thanks for all observations - I'm still not convinced either way - it's just that if it really was safe it would be a real time saver, especially in winter ...
Maybe some minor "tweak" could make it more obviously good ... ?
I'll try and do some tests tomorrow on My crag (BTW didn't have time today - discovered an amazing place though, Nago crag, above Lake Garda - gorgeous in every sense and a bouldering heaven)
In reply to Gavin Taylor:
It's an interesting idea. But perhaps you should check with someone in the business of taking clients out, or people under instruction. Sure someone at PYB or Glenmore would be able to help if you dropped a polite email to an instructor. Have you checked what Nigel Shepherd's books say about it?
If it hasn't been taken up as a good system after all these years, there'll be a good reason.
It's an interesting idea. But perhaps you should check with someone in the business of taking clients out, or people under instruction. Sure someone at PYB or Glenmore would be able to help if you dropped a polite email to an instructor. Have you checked what Nigel Shepherd's books say about it?
If it hasn't been taken up as a good system after all these years, there'll be a good reason.
In reply to AlXN:
like no one having thought of it?
seems to be pretty stable when tied with cord.(7mm)
like no one having thought of it?
seems to be pretty stable when tied with cord.(7mm)
In reply to Dr.Strangeglove:
Indeed. When did they announce that everything that was gong to be invented already had been? About 150 years ago wasn't it?
Ideas and techniques have always steadily changed in climbing and I'm sure they will continue to do so.
Indeed. When did they announce that everything that was gong to be invented already had been? About 150 years ago wasn't it?
Ideas and techniques have always steadily changed in climbing and I'm sure they will continue to do so.
In reply to Dr.Strangeglove:
I take that back, its stable as long as the knot is loaded. even if only one piece of gear survived a fall the knot does not deform significantly. however if the knot is slack and starts to slip down the 'sides' of the krab then it becomes very unstable if some gear fails and can slide with even light loading. this is true when a second krab is clipped into the first (i.e someone tied in)
so probably safe to use on a hanging belay but not so good if you might move around at all/ let any slack into the system.
I take that back, its stable as long as the knot is loaded. even if only one piece of gear survived a fall the knot does not deform significantly. however if the knot is slack and starts to slip down the 'sides' of the krab then it becomes very unstable if some gear fails and can slide with even light loading. this is true when a second krab is clipped into the first (i.e someone tied in)
so probably safe to use on a hanging belay but not so good if you might move around at all/ let any slack into the system.
In reply to Alison Stockwell: Thats a Y hanger,,old school caving technique,,its good though isnt it
In reply to brt: Just get a grab and a sling,follow the instructions and you will end up with one loop of sling at one end, and two loops at the other,,you can then pull said loop/s to adjust the overall length of the sling,,,But if you put a crab onto each of the Two loops formed and pull them apart as if clipping 2 pieces of gear,it will form a Y shape,,its good,but if on leg go's then the shockloading to the other leg is pretty big.It used to be used a lot in caving and a sfar as im aware its acceptable as a way of shortening slings,but not for a Y hanger.
In reply to Dr.Strangeglove:
Nice try, but I think lots of people will have thought of it and rejected it. You really think that people who are totally immersed in guiding, instructing and writing books on these subjects haven't thought of it before?
Possible, but just think how likely that is
Nice try, but I think lots of people will have thought of it and rejected it. You really think that people who are totally immersed in guiding, instructing and writing books on these subjects haven't thought of it before?
Possible, but just think how likely that is
In reply to AlXN:
"What do you call it Ug? A wheel? C'mon if it was any good someone would have invented it by now..."
"What do you call it Ug? A wheel? C'mon if it was any good someone would have invented it by now..."
In reply to AlXN:
Took them a while to come up with the "cordette" idea, and this is a development of that.
In any case, today I rigged the baby up on "my" crag and am even more convinced that it is good.
I took a series of photos for anyone interested - they can be downloaded from:
http://www.webalice.it/cadine/down/Equalizer.zip
(1.8 meg - I left them big for clarity - if somebody really needs a smaller file let me know)
follow the numbering order: first the 3 point set up, easy release by opening Krab, and various simulated failures. I only hung on the krab so there was no shock loading or anything, but it looked pretty convincing to me.
The sequence continues with a two point example crossing the sling (like we always do already - no?)
I was on my own so no shots of me hanging on the runners (not that I hang on runners normally, of course).
I have decded to call the as yet un-named crack "Equalizer crack" (so there, all you doubters!)
I have an old pal who works for the UIAA in Leysin - could ask him I suppose ...
> I think lots of people will have thought of it and rejected it. You really think that people who are totally immersed in guiding, instructing and writing books on these subjects haven't thought of it before?
>
>
Took them a while to come up with the "cordette" idea, and this is a development of that.
In any case, today I rigged the baby up on "my" crag and am even more convinced that it is good.
I took a series of photos for anyone interested - they can be downloaded from:
http://www.webalice.it/cadine/down/Equalizer.zip
(1.8 meg - I left them big for clarity - if somebody really needs a smaller file let me know)
follow the numbering order: first the 3 point set up, easy release by opening Krab, and various simulated failures. I only hung on the krab so there was no shock loading or anything, but it looked pretty convincing to me.
The sequence continues with a two point example crossing the sling (like we always do already - no?)
I was on my own so no shots of me hanging on the runners (not that I hang on runners normally, of course).
I have decded to call the as yet un-named crack "Equalizer crack" (so there, all you doubters!)
I have an old pal who works for the UIAA in Leysin - could ask him I suppose ...
In reply to Alison Stockwell: Oldam MRT weekend at a guess?
In reply to James Thacker:
If you know it you can show me next time, at one of Ian's little soiree's.
Still can't fathom it.
If you know it you can show me next time, at one of Ian's little soiree's.
Still can't fathom it.
In reply to Gavin Taylor:
If for instance after a harsh fall; or after some sort of rescue was performed i.e. rescue loads; the knot cinched up really tightly around the krab, it may be difficult to extract from the sling. One potential drawback.
I don't have a distinct fear of the lark's foot having witnessed some strength tests.
It's worthy of debate and investigation.
If for instance after a harsh fall; or after some sort of rescue was performed i.e. rescue loads; the knot cinched up really tightly around the krab, it may be difficult to extract from the sling. One potential drawback.
I don't have a distinct fear of the lark's foot having witnessed some strength tests.
It's worthy of debate and investigation.
In reply to brt:
I'm sure you are right it being difficult to release - but since this is offered as an alternative to the "normal" elephantine multi-loop overhand knot, it should be easier to untie - what you mention is really an advantage ...
> (In reply to Gavin Taylor)
>
> If for instance after a harsh fall; or after some sort of rescue was performed i.e. rescue loads; the knot cinched up really tightly around the krab, it may be difficult to extract from the sling. One potential drawback.
>
>
> If for instance after a harsh fall; or after some sort of rescue was performed i.e. rescue loads; the knot cinched up really tightly around the krab, it may be difficult to extract from the sling. One potential drawback.
>
I'm sure you are right it being difficult to release - but since this is offered as an alternative to the "normal" elephantine multi-loop overhand knot, it should be easier to untie - what you mention is really an advantage ...
In reply to Gavin Taylor:
The "test" knots were never coming undone. Probably "overloaded" but none the less the tape had to be cut off to retrieve the krab.
I suppose cinching is less likely when more strands of tape are involved i.e. three or more loops rather than two. At least with the looped knot the krab cab taken off afterwards.
Still, it's worth looking at.
The "test" knots were never coming undone. Probably "overloaded" but none the less the tape had to be cut off to retrieve the krab.
I suppose cinching is less likely when more strands of tape are involved i.e. three or more loops rather than two. At least with the looped knot the krab cab taken off afterwards.
Still, it's worth looking at.
In reply to James Thacker:
LOL! Got it in one
> (In reply to Alison Stockwell) Oldam MRT weekend at a guess?
LOL! Got it in one
In reply to AlXN:
> Nice try, but I think lots of people will have thought of it and rejected it. You really think that people who are totally immersed in guiding, instructing and writing books on these subjects haven't thought of it before?
>
I don't agree. I remember when the South African abseil technique first appeared. Individuals may well have thought of it before, but if so it hadn't found its way into the mainstream. In the time I've been climbing I've seen quite few new ideas. >
In reply to Alison Stockwell:
What's that ?
> (In reply to Astral Highway)
> [...]
> the South African abseil technique
> [...]
> the South African abseil technique
What's that ?
In reply to Gavin Taylor:
Classic ab alternative.
Parallel ropes; one either side of waist; cross over at back; both out to front; both through legs (crotch); both around ONE leg brought out to side and front!!!
Classic ab alternative.
Parallel ropes; one either side of waist; cross over at back; both out to front; both through legs (crotch); both around ONE leg brought out to side and front!!!
In reply to Gavin Taylor:
Oh dear. Well, having failed dismally to explain the Oldham adjustable sling shortening technique, I hesitate to try and do the same to anything else.
> (In reply to Alison Stockwell)
>
> What's that ?
>
> What's that ?
Oh dear. Well, having failed dismally to explain the Oldham adjustable sling shortening technique, I hesitate to try and do the same to anything else.
In reply to Alison Stockwell:
Damn right. If I could see the end product I could reverse the procedure.
> (In reply to brt)
>
> Sorry; it's not easy to explain.
>
> Sorry; it's not easy to explain.
Damn right. If I could see the end product I could reverse the procedure.
In reply to brt:
OK; the Oldham adjustable sling shortening technique in three easy steps.
http://www.ascentsofadventure.co.uk/picture_library/Oldham4.jpg
http://www.ascentsofadventure.co.uk/picture_library/Oldham5.jpg
http://www.ascentsofadventure.co.uk/picture_library/Oldham6.jpg
http://www.ascentsofadventure.co.uk/picture_library/Oldham7.jpg
OK; the Oldham adjustable sling shortening technique in three easy steps.
http://www.ascentsofadventure.co.uk/picture_library/Oldham4.jpg
http://www.ascentsofadventure.co.uk/picture_library/Oldham5.jpg
http://www.ascentsofadventure.co.uk/picture_library/Oldham6.jpg
http://www.ascentsofadventure.co.uk/picture_library/Oldham7.jpg
In reply to Alison Stockwell:
Gah! So close. So obvious... when you know how!
If you weren't already taken... etc
Gah! So close. So obvious... when you know how!
If you weren't already taken... etc
In reply to brt:
Hehe.
So, do you like it?
It doesn't seem to slip at all as long as the force is along its length. And yet you don't have to take the krabs off to adjust it?
Hehe.
So, do you like it?
It doesn't seem to slip at all as long as the force is along its length. And yet you don't have to take the krabs off to adjust it?
In reply to Alison Stockwell:
Ever considered a career as a stage conjuror?
Ever considered a career as a stage conjuror?
In reply to karl walton:
I doubt it pays as much as IT work. But you could argue there are similarities.....
> Ever considered a career as a stage conjuror?
I doubt it pays as much as IT work. But you could argue there are similarities.....
In reply to Alison Stockwell:
Yes I'm sure your right.
Well done though, nice knot.
Having said that not entirely sure 'knot' is quite the right term?
Yes I'm sure your right.
Well done though, nice knot.
Having said that not entirely sure 'knot' is quite the right term?
In reply to Gavin Taylor:
looks very nice in you pictures, I probably wil not use it ast is does not replace the overhand in the guiding/ instructing environment a lage loop formed by the O/H knot for two or three krabs and a central cliping point.
THe GTKN does not allow for this and I bet your bottom dollor that whan used in proper climbing with real loads it will fail to hold as demonstrated in you photos - as tape over tape is slippy as is tape around a krab radius.
I shall stay clear of this knot...
looks very nice in you pictures, I probably wil not use it ast is does not replace the overhand in the guiding/ instructing environment a lage loop formed by the O/H knot for two or three krabs and a central cliping point.
THe GTKN does not allow for this and I bet your bottom dollor that whan used in proper climbing with real loads it will fail to hold as demonstrated in you photos - as tape over tape is slippy as is tape around a krab radius.
I shall stay clear of this knot...
In reply to Gavin Taylor:
Don't know why a I haven't thought of this before.
On ice and winter routes I have had occassion to "cats paw" the rope to the krab. In your sling method could you replace the single larks foot with a cats paw i.e. two or more turns?
Could alleviate the potential cicnch problem.
I have come to the conclusion that this may be a solution looking for a problem, but fun all the same.
Don't know why a I haven't thought of this before.
On ice and winter routes I have had occassion to "cats paw" the rope to the krab. In your sling method could you replace the single larks foot with a cats paw i.e. two or more turns?
Could alleviate the potential cicnch problem.
I have come to the conclusion that this may be a solution looking for a problem, but fun all the same.
In reply to Gavin Taylor:
why use a larks foot? I mean it is significantly weakening the sling. it's obviously a lot weaker than your rope now.
Also the idea of the sling slipping on a loaded larks foot does not sound like a good idea to me.
I figure this is a dangerous setup.
why use a larks foot? I mean it is significantly weakening the sling. it's obviously a lot weaker than your rope now.
Also the idea of the sling slipping on a loaded larks foot does not sound like a good idea to me.
I figure this is a dangerous setup.
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