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Comments sought on natural anchor design


pmonks

31-Jul-2012
2:15:01 PM

On 31/07/2012 One Day Hero wrote:
>I use an old climbing rope for this sort of nonsense

As do I - a 10.5mm Mammut Flash that took very few lead falls while in service.

>the stretch doesn't matter because I pad the top edge

Whereas I get the anchor point for the dynamic rope over the tope edge so I don't have to worry about it rubbing over the top edge at all. Of course I still I have to pad the anchor rope (which is an 11mm static).

>If I owned a static I'd be happy to use that too, would just
>pay a little more attention to not letting slack build up.

I wouldn't. Burns said it pretty well: "The best-laid schemes o' mice an' men / Gang aft agley / and at that point you'd better have / a farkin' good backup plan in place!" (or words to that effect).

PDRM

31-Jul-2012
2:42:00 PM

On 31/07/2012 pmonks wrote:
>On 31/07/2012 PDRM wrote:
>>What weird looking rock. Looks like crazy paving.
>
>It's granite, but did look weird from a distance - I actually thought
>it looked a bit like old-skool reinforced concrete! Shame the inclusions
>didn't actually form features - the slab was a lot blanker than it looked
>(as is usually the case for granite, I've found!).
>
>This is one of the top roping areas at Donner Pass near Lake Tahoe, fwiw.

Doesn't look like granite. Looks sedimentary.

Was in SF two weeks ago. Back again end Aug probably. Buy you a beer? Bring sticky shoes?

P


pmonks

31-Jul-2012
2:49:14 PM

On 31/07/2012 PDRM wrote:
>Doesn't look like granite. Looks sedimentary.

Yeah. That area has experienced a fair bit of volcanism and it might be related to that. Some great geology in the saddle between Mt Donner (granite) and Mt Judah (volcanic crap) - you can clearly see the contact point!

>Was in SF two weeks ago. Back again end Aug probably. Buy you a beer?
>Bring sticky shoes?

Yes and yes! Wanna hit Glen Park again? Or maybe something a bit further afield? I'll bring my static to belay you with, if you'd like! ;-)

uwhp510

31-Jul-2012
5:13:42 PM

On 26/07/2012 pmonks wrote:
>even short slumps on a static rope can generate dangerous
>loads on your body and the anchors.

Care to explain why, if this is the case, static ropes don't explode from being abseiled on in non-ideal situations (canyons/caves and the like where slumps or even GASP short falls are common)? Or jumared up (which involves bouncing up and down, which is surely comparable to "slumping" in a loading sense)? Or used as a backup for Industrial Rope Access work, where they're expected to hold a fall, should the main line fail?

ps. Some other questions for extra credit:

What is the loading increase between a 50cm fall and a 1m slump?
Does the above have anything to do with micro-fractures?
How many kilo-newtons does a 10kN shock load produce?


muki

31-Jul-2012
7:22:33 PM

>On 26/07/2012 pmonks wrote:
>>even short slumps on a static rope can generate dangerous
>>loads on your body and the anchors.

well this comment is prety uninformed if you think about all the climbing gyms worldwide that run top ropes for beginners using static rope systems pete !

calling BS because you want to protect beginners while admitting you've only been doing solo set ups for less than a year is also a bit comical, I first used a static toprope self belay over twenty years ago, and made some mistakes that I can now identify using hindsight, but am now using that personal experience when discussing this here.
One of the main dangers is if they were to make the mistakes you yourself say you made on the slab in a previous post, ie slack rope being allowed to enter the system.
Anyway I'm not saying I only use static systems, and am in no way dogmatic about this, done correctly this system is safe either way, while done incorrectly, as in your egsamplers of mistakes made recently, then a dynamic rope is no gaurantee of safety, no matter how much cotton wool you try to wrap yourself in pete.
Ultimatley knowledge is key to doing things right, so discussion is very helpfull for those who are unaware of potential dangers, discussion like this, just try not to talk in black and white, in absolutes, until perhaps you have a bit more understanding or knowledge of what it is your talking about, knowledge gleaned not just from your personal opinion after reading some stuff or doing it for such a short time, but actual real world experience.


pmonks

1-Aug-2012
12:54:37 AM

On 31/07/2012 muki wrote:
>well this comment is prety uninformed if you think about all the climbing
>gyms worldwide that run top ropes for beginners using static rope systems

I have never seen a climbing gym that used static rope for the main climbing rope, and I've been in quite a few gyms in my time, in quite a few countries. I wouldn't climb on a static rope in a gym either.

>calling BS because you want to protect beginners while admitting you've
>only been doing solo set ups for less than a year is also a bit comical,

FYI I've been climbing for almost 20 years, and was caving and (to a lesser degree) canyoning for another 10 years or so before that - it's only top rope soloing that I'm new to.

I'm finding it rather strange that you're not asking about the anchors - should I assume you think they're irrelevant, or that you're actually human and made the (understandable) mistake of overlooking other potential problem areas? I think we probably agree that the quality (or not) of the anchors would be a factor in whether the energy dissipation differences between a static and a dynamic rope might contribute to an overall system failure.

>One of the main dangers is if they were to make the mistakes you yourself
>say you made on the slab in a previous post, ie slack rope being allowed
>to enter the system.

Sure, but you're still missing the point that the dynamic rope gave me a wider margin of error in that situation than a static rope would have.

At the risk of repeating myself: this isn't a single variable game, and the more variables you can stack in your favour (particularly when you're learning something new, as I am right now), the better. It's not going to make things 100% safe, but improving the margin by any amount is worthwhile.

PDRM

1-Aug-2012
9:37:22 AM

I've seen static self top rope systems rigged with screamers in the anchors.

P


muki

1-Aug-2012
9:55:30 AM

On 1/08/2012 PDRM wrote:
>I've seen static self top rope systems rigged with screamers in the anchors.
>
>P
seeing how you and Pmonks are buddies, it must have been his anchor, he was saying that the more cotton wool he can wrap around himself the better, to allow for all his errors.

I probably don't need to talk about the anchor becase it's the same anchor as any other top anchor,perhaps more padding if unatended and the ropes run accross the edge but I talked about that earlier.
I have used screamers on solo lead climbing anchors, and also other types of energy disipation tactics, like counterwieght anchors to replicate a dynamic belay for thin gear leads on solo systems, but thats a different topic for another day.

One Day Hero

1-Aug-2012
10:14:00 AM

On 1/08/2012 pmonks wrote:
>
>I'm finding it rather strange that you're not asking about the anchors
>- should I assume you think they're irrelevant, or that you're actually
>human and made the (understandable) mistake of overlooking other potential
>problem areas? I think we probably agree that the quality (or not) of
>the anchors would be a factor in whether the energy dissipation differences
>between a static and a dynamic rope might contribute to an overall system
>failure.
>

Pmonks, you seem like a nice bloke and I don't really want to join in on the feeding frenzy........but you're in a hole and it would probably be best to put the shovel down :)

It's just toproping mate. If you're worried about the anchors blowing, you're doing it wrong. If you're getting piles of slack building up, you're doing it wrong. If it gets at all sketchy, you're doing it wrong. It really is ok to use a static (as long as you're doing it right), but no one is forcing you to use one if you don't want.

The only thing I really worry about, on the odd occasion I do this crap, is forgetting to engage the cam on my mini-traxion. I've done that once, but had a backup prussic so I think it would have turned out ok anyway. That, and padding the edge properly. Once you have those things sorted, it should be an order of magnitude safer than proper climbing. The anchors are always bomber, or you have no business even being at the cliff, right?


IdratherbeclimbingM9

1-Aug-2012
11:54:23 AM

On 28/07/2012 IdratherbeclimbingM9 wrote:
>On 27/07/2012 One Day Hero wrote:
>>Don't forget that static ropes are still almost half as stretchy as dynamic
>ones,
>
>?
>I haven't looked up the stats recently but I thought 11 mm statics generally
>have less than 2% stretch under bodyweight, while equivalent diameter dynamics
>typically have 8% to 10% under similar loading.

I did some homework...
A Table containing dynamic rope stretch figures.

... but Their static ropes list doesn’t include that elongation figure!

Bluewater 10.5 mm static has @ 300 lbf 3.8% elongation according to their website

Note that approx 176 lb is closer to the UIAA std 80 kg static elongation test! ... so 2% is likely to be a nearer to real figure for comparison...


muki

1-Aug-2012
12:30:21 PM

on rapell when in decent and a sudden halt is made to downward progress loadings can easily increase to 300 lbf if the rapeller is 100 kgs or so.
good to see your researching/cross linking skils are still sharp as.


pmonks

2-Aug-2012
12:31:14 AM

On 1/08/2012 One Day Hero wrote:
>It's just toproping mate. If you're worried about the anchors blowing,
>you're doing it wrong. If you're getting piles of slack building up, you're
>doing it wrong. If it gets at all sketchy, you're doing it wrong. It really
>is ok to use a static (as long as you're doing it right), but no one is
>forcing you to use one if you don't want.

Shit happens. A dynamic rope (amongst other things) makes it more likely that, should some kind of shit happen, you'll be able to nervously laughing about it with your mates at the pub that evening.

There are 52 messages in this topic.