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beansnugget
Mar 7, 2010, 6:58 AM
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What's the difference between a dynamic belay and a static belay?
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uni_jim
Mar 7, 2010, 7:23 AM
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most of the time when people talk about a dynamic belay, they mean to say that the belyer is actively doing something to a) soften the catch or b) shorten the fall.
to sften the catch, most belayers will allow the rope to pull them up/towards the cliff, legthening the catch time, and providing a softer catch. Allowing the rope to slip through the belay device before catching the climber will have the same effect.
to shorten a fall, a belayer may take in rope as the climber falls, run away from the cliff to take slack out of the system, or jump from a belay stance to achieve the same goal. This increases the load on the gear, and is a technique saved for when the climber is in a situation that may result in a ground fall.
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beansnugget
Mar 7, 2010, 7:47 AM
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uni_jim wrote: most of the time when people talk about a dynamic belay, they mean to say that the belyer is actively doing something to a) soften the catch or b) shorten the fall. to sften the catch, most belayers will allow the rope to pull them up/towards the cliff, legthening the catch time, and providing a softer catch. Allowing the rope to slip through the belay device before catching the climber will have the same effect. to shorten a fall, a belayer may take in rope as the climber falls, run away from the cliff to take slack out of the system, or jump from a belay stance to achieve the same goal. This increases the load on the gear, and is a technique saved for when the climber is in a situation that may result in a ground fall.
Great, thanks!
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jt512
Mar 7, 2010, 5:24 PM
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uni_jim wrote: most of the time when people talk about a dynamic belay, they mean to say that the belyer is actively doing something to a) soften the catch or b) shorten the fall.
That is dangerous misinformation. A dynamic belay softens the catch. Shortening the fall is something else.
Jay
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davidnn5
Mar 7, 2010, 6:59 PM
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jt512 wrote: uni_jim wrote: most of the time when people talk about a dynamic belay, they mean to say that the belyer is actively doing something to a) soften the catch or b) shorten the fall. That is dangerous misinformation. A dynamic belay softens the catch. Shortening the fall is something else. Jay
JT up to his old tricks again! He said very specifically when you might shorten a fall (if the climber is in danger of a ground fall). I'm sure there's more you can add that will help the OP understand the difference...
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majid_sabet
Mar 7, 2010, 7:22 PM
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according to a report I posed in the LAB, dynamic belay does not do much.
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jt512
Mar 7, 2010, 8:16 PM
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davidnn5 wrote: jt512 wrote: uni_jim wrote: most of the time when people talk about a dynamic belay, they mean to say that the belyer is actively doing something to a) soften the catch or b) shorten the fall. That is dangerous misinformation. A dynamic belay softens the catch. Shortening the fall is something else. Jay JT up to his old tricks again! He said very specifically when you might shorten a fall (if the climber is in danger of a ground fall). I'm sure there's more you can add that will help the OP understand the difference...
The point is that shortening a fall is not dynamic belaying. If I ask a partner for a dynamic belay, I expect to get a soft catch, not slammed into the wall.
Dangerous misinformation, like I said.
Jay
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jt512
Mar 7, 2010, 8:26 PM
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mturner wrote: majid_sabet wrote: according to a report I posed in the LAB, dynamic belay does not do much. I can't even begin to understand what this statement means. 
What it means is clear. It's wrong, but it's clear.
Jay
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mturner
Mar 7, 2010, 8:56 PM
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jt512 wrote: mturner wrote: majid_sabet wrote: according to a report I posed in the LAB, dynamic belay does not do much. I can't even begin to understand what this statement means. What it means is clear. It's wrong, but it's clear. Jay
I'll give you that. I guess usually you expect to see some follow up to a blanket statement like that
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I_do
Mar 8, 2010, 11:28 AM
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mturner wrote: jt512 wrote: mturner wrote: majid_sabet wrote: according to a report I posed in the LAB, dynamic belay does not do much. I can't even begin to understand what this statement means. What it means is clear. It's wrong, but it's clear. Jay I'll give you that. I guess usually you expect to see some follow up to a blanket statement like that
You don't know Majid's m.o. very well do you?
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USnavy
Mar 8, 2010, 1:18 PM
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majid_sabet wrote: according to a report I posed in the LAB, dynamic belay does not do much.
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jbro_135
Mar 8, 2010, 1:42 PM
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Well I think it's ok that Majid's statement is astronomically incorrect because we're discussing rock climbing, not astronomy!
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greatview
Mar 8, 2010, 2:05 PM
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according to thinking, oberservation and tests etc. my conclusion is: it does not matter.
looking at the how much rope runs through the top carabiner during a fall and how much anyone is ever able to actively feed during a sportsclimbfall to soften a fall, those 10cm of "soft catching" dont do anything but distract the belayer from catching.
thats my opinion however, just think about it long enough. ever since i always use the grigri (or of course with doubleropes on alpine climbs a reverso)
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jbro_135
Mar 8, 2010, 2:19 PM
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uni_jim wrote: most of the time when people talk about a dynamic belay, they mean to say that the belyer is actively doing something to a) soften the catch or b) shorten the fall. to sften the catch, most belayers will allow the rope to pull them up/towards the cliff, legthening the catch time, and providing a softer catch. Allowing the rope to slip through the belay device before catching the climber will have the same effect.
Just a note, I think it's important to clarify what is meant by letting the rope slip through the belay device. How do people typically go about this? Personally, I like to hold the rope with two hands, slide my right hand down to a position about an arm or two of slack down the rope, and gradually increase the braking pressure as i let the slack out during the fall. I don't feel comfortable letting the rope slip through my hand while the climber is falling, as this could potentially cause a loss of control in case of a twist in the rope or something. Losing control of the rope is not particularly likely in this case, since we are much more likely to err on the side of braking too strongly, but I prefer to keep a solid grip the entire time.
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I_do
Mar 8, 2010, 2:32 PM
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greatview wrote: according to thinking, oberservation and tests etc. my conclusion is: it does not matter. looking at the how much rope runs through the top carabiner during a fall and how much anyone is ever able to actively feed during a sportsclimbfall to soften a fall, those 10cm of "soft catching" dont do anything but distract the belayer from catching. thats my opinion however, just think about it long enough. ever since i always use the grigri (or of course with doubleropes on alpine climbs a reverso)
Obviously your observations are not consitent with reality. Just yesterday my belayer was op in the air by two meters, having started a meter or 2 away from the wall that means travel of almost three meters. Not 10 cm. I think this is quite typical. Although I'm heavy for a climber. But when I caught her I was also up at least a meter.
My opinion is that you don't know how to give a dynamic belay with a gri-gri, while it's really not that hard, just jump into it dude. Try it and report back about 10cm.
Or as Jt512 would put it;
Please don;t belay me.
(copyright infringement? FTW)
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greatview
Mar 8, 2010, 2:48 PM
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hm, of course you get lifted but thats not what I thought was discussed here. as far as i understood (sorry if my english wasnt sufficient for that) the soft belay is given by letting rope run through the belay device during a fall. the lifting happens anyway and is not an active way of providing a soft belay, which, in my opinion, can not be "given" as the amount of rope possibly added to the rope that stretches and therefore reducing the fall factor is too minimal to provide any benefit larger than just locking down and not beeing distracted by feeding rope during the fall of the leader.
i hope my statment is clearer now.
edit:
and I largely doubt anyone can jump at the exact moment of the shockload. just imagine: leader shouts -> hold tight, im falling. -> you jump -> he still struggels -> jump again -> he almost falls -> jump again -> he falls -> jump again -> he was already hanging.
just doesnt work, maybe i dont climb enough, but it didnt work as far as i experienced.
edit:
spälling
(This post was edited by greatview on Mar 8, 2010, 2:56 PM)
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mturner
Mar 8, 2010, 2:56 PM
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greatview wrote: maybe i dont climb enough
ding ding ding winner winner chicken dinner
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I_do
Mar 8, 2010, 2:58 PM
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greatview wrote: hm, of course you get lifted but thats not what I thought was discussed here. as far as i understood (sorry if my english wasnt sufficient for that) the soft belay is given by letting rope run through the belay device during a fall. the lifting happens anyway and is not an active way of providing a soft belay, which, in my opinion, can not be "given" as the amount of rope possibly added to the rope that stretches and therefore reducing the fall factor is too minimal to provide any benefit larger than just locking down and not beeing distracted by feeding rope during the fall a leader. i hope my statment is clearer now. edit: and I largely doubt anyone can jump at the exact moment of the shockload. just imagine: leader shouts -> hold tight, im falling. -> you jump -> he still struggels -> jump again -> he almost falls -> jump again -> he falls -> jump again -> he was already hanging. just doesnt work, maybe i dont climb enough, but i didnt work as far as i experienced.
Aaah yeah so where having a partial communications problem.
With any tube style delay it's very well possible to let an armslenght of rope slip through the device when your leader falls.
If I don't activly jump I'm going nowhere as I generally outweigh my climber by 40-50 pounds. Just watch your climber and if she falls give into it. It does make a hughe difference.
I suggest you experiment with it a bit more, it's really not hard to do and makes a massive difference from the climbers point of view.
Personally it's not distracting for me to let a foot or two slip through it's become second nature.
Bottom line, we can discuss this over the internet all we want but anyone who experimented with dynamic belays will tell you they do help.
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greatview
Mar 8, 2010, 3:15 PM
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all right, I get what you mean now.
But Im still not convinced ... having belayed real light and real heavy persons, everyone got lifted once in a while depending on the fall. me wheighting 65kg i already lifted climbers with 100kg easily, just a matter of how deep you fall.
and in the case of rope of the length of an arm makes a difference in reducing the fall factor significantly (my 10cm, let it be half a meter), I would rather not let out rope because there's so little out i wouldnt risk giving out any more.
you must have great handforce by the way, a tuber kind of device still needs about 300N of holding force of your hand (we measured) in a hard fall, a force i'm already really unhappy with by just holding, let alone letting it slip without gloves will for sure burn my hand. therefore i just lock up and get lifted.
edit: faulty unit, see next comment
(This post was edited by greatview on Mar 8, 2010, 3:35 PM)
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I_do
Mar 8, 2010, 3:19 PM
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greatview wrote: all right, I get what you mean now. But Im still not convinced ... having belayed real light and real heavy persons, everyone got lifted once in a while depending on the fall. me wheighting 65kg i already lifted climbers with 100kg easily, just a matter of how deep you fall. and in the case of rope of the length of an arm makes a difference in reducing the fall factor significantly (my 10cm, let it be half a meter), I would rather not let out rope because there's so little out i wouldnt risk giving out any more. you must have great handforce by the way, a tuber kind of device still needs about 300kN of holding force of your hand (we measured) in a hard fall, a force i'm already really unhappy with by just holding, let alone letting it slip without gloves will for sure burn my hand. therefore i just lock up and get lifted.
I'm not letting rope slip through my hand, I let the rope slip through the device.
300KN of force? I think you can use that to crush rocks dude! You're way off.
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greatview
Mar 8, 2010, 3:34 PM
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yes, you are right there ... sorry. wanted to write 300N, still a lot to hold with a hand and a skinny rope 
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uni_jim
Mar 8, 2010, 4:54 PM
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jt512 wrote: davidnn5 wrote: jt512 wrote: uni_jim wrote: most of the time when people talk about a dynamic belay, they mean to say that the belyer is actively doing something to a) soften the catch or b) shorten the fall. That is dangerous misinformation. A dynamic belay softens the catch. Shortening the fall is something else. Jay JT up to his old tricks again! He said very specifically when you might shorten a fall (if the climber is in danger of a ground fall). I'm sure there's more you can add that will help the OP understand the difference... The point is that shortening a fall is not dynamic belaying. If I ask a partner for a dynamic belay, I expect to get a soft catch, not slammed into the wall. Dangerous misinformation, like I said. Jay
I don't think it is "dangerous misinformation," but perhaps you have a better term for reelin' in the slack? An active belay, perhaps?
And I didn't tell the OP to try to go shatter everyone's ankles, nor am I in the habit of doing so myself. I stated that there is a situation where it is an appropriate technique to use to prevent a ground fall.
Anyway, my interpretation of a "dynamic belay" has always been that the belayer feeds or takes slack during the fall/catch to provide the safest outcome possible. Most of the time (especially for sport climbers and on vertical to overhanging terrain) it will mean softening the catch.
That has just been the way I have always undestood the term.
go climb a rock.
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. Fun to know how much force it takes though! 
1
