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PostPosted: Thu Nov 04, 2010 10:12 am 
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Got a question. When climbing with 1/2 ropes, ideally (and as per the manufacturers instructions) you should be clipping each piece alternating between the 2 ropes. Sometimes this isn't always practical and it makes more sense to clip two (or more) consecutive pieces with the same rope. How serious is this. Ultimately even if doing it alternating correctly only 1 rope is going to hold your fall on your top piece of gear. So how far can you push this?

zb.


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PostPosted: Thu Nov 04, 2010 10:49 am 
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This means you can be clipping one 1/2 rope only, until you are 15m or more off the deck.

I have wondered about this many times, have had many debates about it. But to date have not heard a convincing argument either way, so I took to climbing on 2 x jokers for a while, but am now back on 8.5's again.

Perhaps somebody can enlighten us on the risks and theories of lead falling on 1 x 1/2 rope.


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PostPosted: Thu Nov 04, 2010 10:55 am 
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These ropes are strong, they will not break. You can clip just one and trust it to hold your fall.

If you clip both, you increase the load force on that piece due to less rope stretch.

Once you start splitting ropes, keep them split. By clipping both higher up, you will risk ropes stretching different lengths and causing wear over the carabiner.

If there are sharp edges involved and your gear is bomber, use 2 biners/draws in the same piece!

And this is coming from a "sport climber"...

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PostPosted: Thu Nov 04, 2010 10:59 am 
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Gustav wrote:
These ropes are strong, they will not break. You can clip just one and trust it to hold your fall.

If you clip both, you increase the load force on that piece due to less rope stretch.

Once you start splitting ropes, keep them split. By clipping both higher up, you will risk ropes stretching different lengths and causing wear over the carabiner.

If there are sharp edges involved and your gear is bomber, use 2 biners/draws in the same piece!

And this is coming from a "sport climber"...


Think you missed the question there Gustav, wasn't talking about clipping BOTH ropes into 1 piece of gear (I know thats not good). I was asking about not alternating the ropes between pieces of gear.

zb.


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PostPosted: Thu Nov 04, 2010 11:12 am 
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with half ropes you can clip just one rope the whole way. one half rope will hold a factor two fall many times over so a regular real world fall is totally within the limit.

gustav is not correct about his rationale for clipping both ropes on 1 piece. its fine and doesnt change the loading. the load on the gear is identical (one rope holding 100% of your weight vs two ropes holding 50% - adds up to the same).

the only issue is that if you clip both ropes AFTER you have clipped one rope further down, then the ropes will stretch unevenly and chafe against each other causing some extra wear. but it's minor.
bottom line is that with half ropes you can in effect do what you damn well want and they will be fine.

this is official approved wisdom from BlueWater Ropes btw.


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PostPosted: Thu Nov 04, 2010 11:46 am 
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Quote:
with half ropes you can clip just one rope the whole way. one half rope will hold a factor two fall many times over so a regular real world fall is totally within the limit.

robert is correct here ... <<sorry, start again>>

Robert is correct here.

Quote:
gustav is not correct about his rationale for clipping both ropes on 1 piece. its fine and doesnt change the loading. the load on the gear is identical (one rope holding 100% of your weight vs two ropes holding 50% - adds up to the same).

This means I don't have to be concerned about lessening impact force and I can lead with my static ropes? Thanks for the advice...

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PostPosted: Thu Nov 04, 2010 12:31 pm 
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So following this rational, is it then acceptable to climb sport routes using only 1 x 1/2 rope?


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PostPosted: Thu Nov 04, 2010 12:44 pm 
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robertbreyer wrote:
gustav is not correct about his rationale for clipping both ropes on 1 piece. its fine and doesnt change the loading. the load on the gear is identical (one rope holding 100% of your weight vs two ropes holding 50% - adds up to the same).


....I'm no expert....but my understanding is the gear experiences twice the peak load it would if you used a single.

If you fall on a single rope it takes a certain amount of time to stop you (i.e. decelerate) the force of which is held by the gear. If you have 2 ropes through it the amount of time it takes to stop you is halved, thereby increasing the peak load on the gear. Essentially having 2 dynamic ropes running through 1 point is like having a less dynamic single rope....in this case 2x less dynamic....which means you are heading towards the static end of the spectrum....and we all now what happens to the load on a piece of gear if you fall with static gear!

....that's my understanding....and I'll err on the side of safety in this case.

On a side note....I think its time you buy a big fish scale that we can do some testing at the gym of all these things......MythBusters style.

zb.


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PostPosted: Thu Nov 04, 2010 1:55 pm 
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This one is simple ZA and Gustav are correct and Robert is wrong. :twisted:


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PostPosted: Thu Nov 04, 2010 3:57 pm 
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The question I have then is the following:

Why is it ever necessary to clip both ropes into one piece of gear?

As far as I understand, The only time you need to do this is when you go through a larger traverse of any sort AND you have two followers - one on each rope, to prevent them from swinging too far if they fell on the toprope. Why in any other case would you want to clip both ropes in one piece?

Apart from that I cant think of a reason one would need to clip into both. Apart from mental confidence - which may actually be misplaced!

edit: possible other reason is if there are sharp edges - i.e. where you are concerned that a fall may cut your rope - having a backup?


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PostPosted: Thu Nov 04, 2010 7:22 pm 
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Hi, I have had several discussions about this to myself. Below is the result of one such discussion (me, myself and I). Perhaps the oracles on this forum who I am not worthy of belaying can comment on my reasoning:

Firstly: Everything in trad climbing is about compromises. One of the key reasons for climbing using the half rope technique is to help minimise rope drag. But this comes at the cost (read compromise) of carrying more weight (2 half ropes weighs quite a bit more than one single rope – but not twice as much). There are other reasons too such as a bit more insurance to cope with sharp edges / rope severing incidents (think rock falls or ice climbing with sharp axes and crampons) as well as a potentially lower impact force (think less solid protection).

On trad pitches with significant amounts of zigg-zagging strictly alternating the clipping of half ropes to pro will probably result in greater rope drag and eliminate much of the advantage of using double rope techniques (i.e. you could have just taken a single rope). On traverses and long pitches etc. I therefore find that I inevitably need to clip the same rope two or three times consecutively to minimise rope drag and allow longer pitches to be climbed.

In my layman’s mind the difference in the UIAA standard (see below) between half ropes and single ropes to me translates into a situation were a half rope cannot take the same level of severe fall as a single rope before breaking (however I cannot quantify it in mathematical terms). Hence to my mind you need to clip more conservatively (i.e. frequently) for a half ropes compared to a single rope (at least during the first part of the pitch where a fall combined with gear pulling can more easily generate high fall factors). My interpretation of the standard is also that you absolutely do need two ropes to stop significant falls to offer a similar amount of protection compared to a single rope (if one half rope was sufficient to stop significant falls similar to what a single rope would there would simply be no need for the UIAA to have a separate double rope standard).

Therefore in double rope technique when consecutively clipping only one of the ropes without clipping the other there are a few consequences I try to keep in mind when weighing up the various compromises: 1) I am increasing the distance I fall before the other rope comes into play in stopping the fall (remember half ropes stretch quite a lot, a further fall means a greater chance to hit something on the way down). 2) I am also increasing the potential fall factor on the other rope in case things go really pear shaped (e.g. if your gear pulls on the rope you have been clipping last). 3) When I am clipping in a fashion where one of the roper is ‘simply dragged along’ I need to realise that I am stretching the limits.


My understanding of the UIAA standard for single and half ropes are summarised below but in short the standards are similar but a ‘lesser standard’ holds for half ropes (there are more to it than this of course):
  • Single rope: 80kg load dropped on a rope with a +- 1.8 fall factor must generate a maximum of 12kn impact force plus the rope must have limited stretch and withstand X number of such falls before breaking
  • Half rope: 55kg load dropped on a (single) rope with a +- 1.8 fall factor must generate a maximum of 8kn impact force plus the rope must have limited stretch and withstand X number of such falls before breaking


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PostPosted: Fri Nov 05, 2010 2:35 pm 
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Based on no evidence whatsoever-

Hann

1/2 ropes should be able to be used to sports climb as they can take a number of high factor falls, however they are not designed for sport and will severly limit their life if you are pushing your climbing, ie taking wingers and numerous rests on the rope etc. The chance of a critical fail is much greater. In my opinion the risk to climb a sports climb on a single 1/2 rope is not justifyable.

Gustav

You were alluding to the fact that clipping 2 1/2 ropes through a single piece of protection is comparable to using a static rope. Is it that bad. I was told that you could break your back falling onto a static rope? (although this could have been a newbie scare story)

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PostPosted: Fri Nov 05, 2010 2:55 pm 
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@ Wayne,
Also my opinion only....

I'm of the same opinion.
1/2 ropes are designed to save your life.
Sport ropes are designed to take multiple falls.

Thus, yes, you can safely use a 1/2 rope to sport climb, but have to retire it after the 1st big fall. Ok, maybe 2nd big fall.

I'm also backing Gustav on the clipping.
Think of breaking one match. Then think of breaking 2 matches.
In the same way 2 x 1/2ropes clipped into the same biner will need twice as much force to stretch the same amount, and absorb as much impact.
What I'm saying is you will put 2 x the impact on a piece when clipping 2 ropes.
NEVER DO THIS.

And yes, you probably will break your back, or tear your harness if you take a lead fall on a static.
Remember no or very little force is absorbed, so you may as well hit the ground.
Think of the instance not long ago when a biner was broken in a factor 3 fall..... I can't find the tread, anybody?

As for the traverse clipping:
Remember the second. He/she will take the same pendulum that the leader will take in the event of a fall, only in the opposite direction. Often the leader is the stronger climber, so don't only place gear for the leader. Keep the second in mind when placing traverse gear.


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PostPosted: Fri Nov 05, 2010 4:39 pm 
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and make sure your second has and knows how to use prussiks, that penduleum swing might take them to air/ rock that they can't climb.

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