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Hi everyone,
I'm confused about when it is and isn't safe to use a larks hitch. For example say you have put a sling around a small tree for a belay and used a larks hitch, is that a safe use? Another is example is connecting a few slings together to extend a belay, is it safe to use a larks hitch between the slings?
Thanks for any advice.
I'm confused about when it is and isn't safe to use a larks hitch. For example say you have put a sling around a small tree for a belay and used a larks hitch, is that a safe use? Another is example is connecting a few slings together to extend a belay, is it safe to use a larks hitch between the slings?
Thanks for any advice.
In reply to Greasy Prusiks:
"Safe" or not all depends on how much it's going to be loaded. The more relevant question is whether there's a better/stronger option. For slings in the uses you've described, yes, I generally find that there's a better option.
Clove hitches around stakes.
No hitch or knot needed at all for most items you might sling.
Joining slings best done with a krab but rarely necessary anyway.
"Safe" or not all depends on how much it's going to be loaded. The more relevant question is whether there's a better/stronger option. For slings in the uses you've described, yes, I generally find that there's a better option.
Clove hitches around stakes.
No hitch or knot needed at all for most items you might sling.
Joining slings best done with a krab but rarely necessary anyway.
4
In reply to Greasy Prusiks:
Lark's foot knots weaken the anchor (because of the large angles the rope or sling turns - similar to using slings connected together with a large angle). The general rule of thumb is a lark's foot is half as strong as the sling used to make it. So long as you're aware of this and take the reduced strength into account then its fine.
I regularly use a larks foot to connect to trees - normally because doubling the sling around the tree wouldn't be as satisfactory (eg you need the extra length or you need to prevent the sling from slipping).
For a regular sling the strength of the lark's foot is still really high but using something weaker (6mm cord) as a single anchor or attacheing at a wide angle to to other anchors etc is probably something you should avoid if possible. Also lark's footing slings together weakens the chain especially dissimilar slings (eg dyneema vs nylon) as the thinner sling can cut through the thicker (ideally here use a carabiner to link).
In the context of an earlier post talking about lark's footing to a stake vs using a clove hitch then use the clove hitch with the knot around the back - it will grip the stake better than the lark's foot and not significantly weaken the sling (it is not normally possible to do this with a tree).
All that said if you're descending in a hurry from manky pegs in an alpine situation this is probably the least of your worries.
Lark's foot knots weaken the anchor (because of the large angles the rope or sling turns - similar to using slings connected together with a large angle). The general rule of thumb is a lark's foot is half as strong as the sling used to make it. So long as you're aware of this and take the reduced strength into account then its fine.
I regularly use a larks foot to connect to trees - normally because doubling the sling around the tree wouldn't be as satisfactory (eg you need the extra length or you need to prevent the sling from slipping).
For a regular sling the strength of the lark's foot is still really high but using something weaker (6mm cord) as a single anchor or attacheing at a wide angle to to other anchors etc is probably something you should avoid if possible. Also lark's footing slings together weakens the chain especially dissimilar slings (eg dyneema vs nylon) as the thinner sling can cut through the thicker (ideally here use a carabiner to link).
In the context of an earlier post talking about lark's footing to a stake vs using a clove hitch then use the clove hitch with the knot around the back - it will grip the stake better than the lark's foot and not significantly weaken the sling (it is not normally possible to do this with a tree).
All that said if you're descending in a hurry from manky pegs in an alpine situation this is probably the least of your worries.
9
In reply to Greasy Prusiks:
As I understand the way a larks foot is potentially dangerous is if the larks foot is around anything and the loop can move against the two strands and potentially wear through the sling (slings have very low melting points).
As I understand the way a larks foot is potentially dangerous is if the larks foot is around anything and the loop can move against the two strands and potentially wear through the sling (slings have very low melting points).
1
In reply to Greasy Prusiks:
It depends...
If you're using nylon slings and there's no chance of shock loading them then it may be less than ideal but not unsafe. On the other hand if there's a chance of shock loading a Dynema sling that is knotted or hitched directly to itself or another sling then there's a definite risk, Dynema has a very low melting point and textile on Dynema friction as the hitch or knot tightens can markedly reduce the load required to induce failure.
If you do have to use a lark's foot/ girth hitch, rather than a clove hitch when slinging a tree or fence post then an extra wrap around the post reduces the force transmitted to the hitch. I had to do this last week, the fence post I was using had wire mesh attached so I couldn't drop the sling over the top, normally I would just pass the sling behind the post and connect both ends with a screwgate but I wanted as much length as possible to reduce the angle to the other anchor so used a girth hitch with an extra turn.
Here's a thread illustrating why shock loading slings is bad:
http://www.ukclimbing.com/forums/t.php?t=256487
And here's the DMM video about breaking slings:
http://dmmclimbing.com/knowledge/how-to-break-nylon-dyneema-slings/
It depends...
If you're using nylon slings and there's no chance of shock loading them then it may be less than ideal but not unsafe. On the other hand if there's a chance of shock loading a Dynema sling that is knotted or hitched directly to itself or another sling then there's a definite risk, Dynema has a very low melting point and textile on Dynema friction as the hitch or knot tightens can markedly reduce the load required to induce failure.
If you do have to use a lark's foot/ girth hitch, rather than a clove hitch when slinging a tree or fence post then an extra wrap around the post reduces the force transmitted to the hitch. I had to do this last week, the fence post I was using had wire mesh attached so I couldn't drop the sling over the top, normally I would just pass the sling behind the post and connect both ends with a screwgate but I wanted as much length as possible to reduce the angle to the other anchor so used a girth hitch with an extra turn.
Here's a thread illustrating why shock loading slings is bad:
http://www.ukclimbing.com/forums/t.php?t=256487
And here's the DMM video about breaking slings:
http://dmmclimbing.com/knowledge/how-to-break-nylon-dyneema-slings/
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In reply to Greasy Prusiks:
Half the sling strength in general is 11kN. You'd be going some to generate that sort of force, close to gear breaking also- DMM nuts are 12kN max. If you manage to do a 11kN fall I think a sling snapping will be one of many many issues you're facing as you would of had an absolutely massive serious fall. Shock loading is a bit of an imagined issue in my opinion, something to be aware of but something you would have to be very stupid to do
Half the sling strength in general is 11kN. You'd be going some to generate that sort of force, close to gear breaking also- DMM nuts are 12kN max. If you manage to do a 11kN fall I think a sling snapping will be one of many many issues you're facing as you would of had an absolutely massive serious fall. Shock loading is a bit of an imagined issue in my opinion, something to be aware of but something you would have to be very stupid to do
Post edited at 11:04
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In reply to Greasy Prusiks:
How safe is safe?
It's not the strongest possible way to connect slings but it's pretty strong (it's basically a reef knot that can't slip or fall apart when used to join like sized thin tapes). It may or may not be the strongest option when slinging a tree, that depends to some extent on the sling length and the angles formed when the tape comes back to the krab. You can get a detrimental 3-way load on the krab with tape that's too short, in that case the larksfoot is likely the better option. One data sheet I got with modern 6mm (so unusually thin) slings suggests 16kN for a larksfoot on a solid bar (branch, krab, round stake etc). Much weaker than the base sling but still stronger than say a well placed nut which most would trust implicitly as one half of a belay.
I use them quite freely and I doubt it's likely to be the thing that kills me.
jk
> I'm confused about when it is and isn't safe to use a larks hitch.
How safe is safe?
It's not the strongest possible way to connect slings but it's pretty strong (it's basically a reef knot that can't slip or fall apart when used to join like sized thin tapes). It may or may not be the strongest option when slinging a tree, that depends to some extent on the sling length and the angles formed when the tape comes back to the krab. You can get a detrimental 3-way load on the krab with tape that's too short, in that case the larksfoot is likely the better option. One data sheet I got with modern 6mm (so unusually thin) slings suggests 16kN for a larksfoot on a solid bar (branch, krab, round stake etc). Much weaker than the base sling but still stronger than say a well placed nut which most would trust implicitly as one half of a belay.
I use them quite freely and I doubt it's likely to be the thing that kills me.
jk
8
In reply to Greasy Prusiks:
Larks foot can be a useful tool. Its a bit weaker than other knots but not actually that much weaker. One bonus is if connecting to an anchor that may not be 100%, like a small tree or say fence post that may not be 100%, as its a very grabby knot and will probably remain attached even if the anchor partially gives. Another good time to use it is around large trees to avoid three way loading a biner, in this case I suspect its very strong as the friction around the tree will stop the hitch getting loaded too much, in this case you should make sure the end you clip is not getting snagged in to an angle by the loop you threaded through as this weakens it. Personally I'm weary of joining slings together with a larks foot as accidents have occurred, it appears its likely not a problem if the slings are similar in width and material and you don't expect the slings to need to hold a massive fall. If you are worried about this and have no biners left a basket hitch is stronger.
Larks foot can be a useful tool. Its a bit weaker than other knots but not actually that much weaker. One bonus is if connecting to an anchor that may not be 100%, like a small tree or say fence post that may not be 100%, as its a very grabby knot and will probably remain attached even if the anchor partially gives. Another good time to use it is around large trees to avoid three way loading a biner, in this case I suspect its very strong as the friction around the tree will stop the hitch getting loaded too much, in this case you should make sure the end you clip is not getting snagged in to an angle by the loop you threaded through as this weakens it. Personally I'm weary of joining slings together with a larks foot as accidents have occurred, it appears its likely not a problem if the slings are similar in width and material and you don't expect the slings to need to hold a massive fall. If you are worried about this and have no biners left a basket hitch is stronger.
1
In reply to Greasy Prusiks:
Good question, I was just considering asking something similar myself based on the previous thread!
When at Harrison rocks, top roping is the only ascent allowed and they give you rings at the top. I always tie a sling to the ring using a lark's foot, then a krab on the sling with the rope through. Is this safe enough?
I guess I should really be doubling the sling through the ring and not tying it?
I doubt the forces involved in top roping (using a dynamic rope) would be anywhere near sufficient to be a problem?
Good question, I was just considering asking something similar myself based on the previous thread!
When at Harrison rocks, top roping is the only ascent allowed and they give you rings at the top. I always tie a sling to the ring using a lark's foot, then a krab on the sling with the rope through. Is this safe enough?
I guess I should really be doubling the sling through the ring and not tying it?
I doubt the forces involved in top roping (using a dynamic rope) would be anywhere near sufficient to be a problem?
Post edited at 11:25
In reply to Greasy Prusiks:
I use the larksfoot freely except in threads generally, where I want the load to distribute on both sides of the thread, where in my mind, a larksfoot loads a thread disproportionately to the one side. but always tend to clove hitch onto stakes, especially with rope. Big loop of a fig of 8 on a bight clove hitched on a stake is beautiful!
I use the larksfoot freely except in threads generally, where I want the load to distribute on both sides of the thread, where in my mind, a larksfoot loads a thread disproportionately to the one side. but always tend to clove hitch onto stakes, especially with rope. Big loop of a fig of 8 on a bight clove hitched on a stake is beautiful!
In reply to Greasy Prusiks:
Thanks for the replies everyone.
Another example I've been thinking about is top roping with beginners. I have always larks hitched a tree then larks hitched a couple of slings together to extend the anchor over the cliff edge so I can top rope from the bottom of the crag. Is there a better way of doing that?
Thanks for the replies everyone.
Another example I've been thinking about is top roping with beginners. I have always larks hitched a tree then larks hitched a couple of slings together to extend the anchor over the cliff edge so I can top rope from the bottom of the crag. Is there a better way of doing that?
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In reply to Greasy Prusiks:
The more important DMM video:
http://dmmclimbing.com/knowledge/improvisation-larks-foot-or-basket-hitch-v...
The more important DMM video:
http://dmmclimbing.com/knowledge/improvisation-larks-foot-or-basket-hitch-v...
1
In reply to Greasy Prusiks:
Interesting research here - http://blackdiamondequipment.com/en_GB/qc-lab-connecting-two-slings-togethe...
The 'girth hitch / lark's foot' doesn't get such a bad press in the States.
> Hi everyone,
> Another is example is connecting a few slings together to extend a belay, is it safe to use a larks hitch between the slings?
Interesting research here - http://blackdiamondequipment.com/en_GB/qc-lab-connecting-two-slings-togethe...
The 'girth hitch / lark's foot' doesn't get such a bad press in the States.
In reply to Andy Say:
Indeed . In days gone by, when people used to tie their own slings and quick draws, you used a tape knot. If you even out a larks foot between two slings so that it looks like the 'strop bend' in the BD paper, it is essentially the same as a tape knot, which has been tested times beyond number. I have no problemm with this.
If you put a sling around a big tree, just arrange it so that there is minimum bend in the side that takes the load - as above, friction will do the work. I still prefer to clip the two ends together though.
Around stakes, I prefer clove hitches.
Indeed . In days gone by, when people used to tie their own slings and quick draws, you used a tape knot. If you even out a larks foot between two slings so that it looks like the 'strop bend' in the BD paper, it is essentially the same as a tape knot, which has been tested times beyond number. I have no problemm with this.
If you put a sling around a big tree, just arrange it so that there is minimum bend in the side that takes the load - as above, friction will do the work. I still prefer to clip the two ends together though.
Around stakes, I prefer clove hitches.
In reply to Greasy Prusiks:
The main reason I tend to use the lark's foot on (large) trees & threads rather than simply clipping both ends of the sling is to prevent a three-way loading on the carabiner. Obviously the length of the sling and size of the tree is going to determine how important this is, but certainly if the angle between the legs of the sling is more than about 30 degrees I'd prefer a lark's foot.
The main reason I tend to use the lark's foot on (large) trees & threads rather than simply clipping both ends of the sling is to prevent a three-way loading on the carabiner. Obviously the length of the sling and size of the tree is going to determine how important this is, but certainly if the angle between the legs of the sling is more than about 30 degrees I'd prefer a lark's foot.
1
In reply to Greasy Prusiks:
I use a lark's foot to attach a sling to something where it might otherwise blow/fall off e.g. the big sticky out bits on Outward Bound, Haytor. It's better to attach two slings with a carabiner if that carabiner is not being badly loaded over an edge or similar, but it's not exactly the end of the world. If your belay system is completely dependent on a single larks-footed pair of slings not failing or similar, perhaps it would be better to add some redundancy rather than worrying about the exact strength of a single component. Long (2.4m or 4m) slings are nice for getting two independent strands round larger objects (using a knot, just wrapping the sling round twice or passing it around the back and clipping doesn't count!).
I use a lark's foot to attach a sling to something where it might otherwise blow/fall off e.g. the big sticky out bits on Outward Bound, Haytor. It's better to attach two slings with a carabiner if that carabiner is not being badly loaded over an edge or similar, but it's not exactly the end of the world. If your belay system is completely dependent on a single larks-footed pair of slings not failing or similar, perhaps it would be better to add some redundancy rather than worrying about the exact strength of a single component. Long (2.4m or 4m) slings are nice for getting two independent strands round larger objects (using a knot, just wrapping the sling round twice or passing it around the back and clipping doesn't count!).
In reply to Greasy Prusiks:
There was a guy that was only body weighting two larks footed slings (strop bend IIRC) of somewhat different diameters and somehow one managed to saw through the other, it occurred slowly over a period of a day or twos use. Personally I wouldn't do this for top roping with multiple falls, especially if failure would mean complete failure of the system and if the slings aren't pretty similar.
There was a guy that was only body weighting two larks footed slings (strop bend IIRC) of somewhat different diameters and somehow one managed to saw through the other, it occurred slowly over a period of a day or twos use. Personally I wouldn't do this for top roping with multiple falls, especially if failure would mean complete failure of the system and if the slings aren't pretty similar.
Post edited at 19:00
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In reply to Greasy Prusiks:
It weakens the sling yes, but like all things if you know the pros and cons you can make an educated decision on its use. I used it the other day for example because the sling wouldn't have reached the rest of my anchor otherwise. Basket hitching uses up so much of the sling that larks footing is often the only way unless you always carry cord with you. As others have said, 11kn is about a tonne of force, I'd be more concerned about your back than the sling in that scenario... That being said - if you can basket hitch, then do it.
It weakens the sling yes, but like all things if you know the pros and cons you can make an educated decision on its use. I used it the other day for example because the sling wouldn't have reached the rest of my anchor otherwise. Basket hitching uses up so much of the sling that larks footing is often the only way unless you always carry cord with you. As others have said, 11kn is about a tonne of force, I'd be more concerned about your back than the sling in that scenario... That being said - if you can basket hitch, then do it.
1
In reply to Greasy Prusiks:
AFAIK it's about the angle, so if it's around a big tree it doesn't weaken the sling much. If it's a very tight angle (e.g. around a crab) then it can halve the strength of the sling.
Is that dangerous, well it depends on if you need 24Kn or if 12Kn is fine...
AFAIK it's about the angle, so if it's around a big tree it doesn't weaken the sling much. If it's a very tight angle (e.g. around a crab) then it can halve the strength of the sling.
Is that dangerous, well it depends on if you need 24Kn or if 12Kn is fine...
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In reply to CurlyStevo:
Any chance of a URL to the story, please? Thanks
> There was a guy that was only body weighting two larks footed slings (strop bend IIRC) of somewhat different diameters and somehow one managed to saw through the other, it occurred slowly over a period of a day or twos use. Personally I wouldn't do this for top roping with multiple falls, especially if failure would mean complete failure of the system and if the slings aren't pretty similar.
Any chance of a URL to the story, please? Thanks
In reply to Greasy Prusiks:
http://www.chauvinguides.com/Anchoring.PDF Crap pictures but written well
http://www.chauvinguides.com/Anchoring.PDF Crap pictures but written well
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In reply to Greasy Prusiks:
Lark's foot is not generally the strongest way to use a sling, and so is not best practice; however, as others have said above, it will often be acceptably strong.
Climbers who always lark's foot slings, as their default procedure, even when a stronger option is no extra hassle, worry me, I must confess. It seems a bit lazy, or like they've just switched off their brain, or something .....
> I'm confused about when it is and isn't safe to use a larks hitch.
Lark's foot is not generally the strongest way to use a sling, and so is not best practice; however, as others have said above, it will often be acceptably strong.
Climbers who always lark's foot slings, as their default procedure, even when a stronger option is no extra hassle, worry me, I must confess. It seems a bit lazy, or like they've just switched off their brain, or something .....
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