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Chockstone Forum - Climbing Videos

Post links and comments about your favourite climbing flicks

 Page 1 of 2. Messages 1 to 20 | 21 to 23
Author
Crossloading knots
Pok
25/04/2012
10:33:50 PM
So I can't think of when a knot would be subjected to these loads.

But everyone loves a good destruction video.

http://vimeo.com/40767916
patto
25/04/2012
11:18:09 PM
Except of course when one chooses to belay by clipping through the rope loop! ;-)

http://www.chockstone.org/Forum/Forum.asp?Action=DisplayTopic&ForumID=6&MessageID=21432&PagePos=&Sort=&Replies=59&MsgPagePos=0


Thanks for the post!

pmonks
26/04/2012
6:14:40 AM
Cool to see how the rope "unwinds" through the knot. Shame they didn't test the Alpine Butterfly - I've read that it's one of the stronger knots in this scenario.

benjenga
26/04/2012
7:04:04 AM
Good to watch.

ajfclark
26/04/2012
8:06:52 AM
I would've liked to have seen the retraced bowline too.
patto
26/04/2012
9:15:54 AM
On 26/04/2012 pmonks wrote:
>Cool to see how the rope "unwinds" through the knot. Shame they didn't
>test the Alpine Butterfly - I've read that it's one of the stronger knots
>in this scenario.

Are you sure? Alpine butterfly is supposed to be used as a knot on a bight. I've never heard of it being used as a terminating knot. Furthermore given its construction I would have thought that it would roll VERY easily.

phillipivan
26/04/2012
9:41:30 AM
On 25/04/2012 patto wrote:
>Except of course when one chooses to belay by clipping through the rope
>loop! ;-)

Even then, it is not an accurate model or worthwhile test of the system as it is typically loaded.
patto
26/04/2012
10:13:14 AM
On 26/04/2012 phillipivan wrote:
>On 25/04/2012 patto wrote:
>>Except of course when one chooses to belay by clipping through the rope
>>loop! ;-)
>
>Even then, it is not an accurate model or worthwhile test of the system
>as it is typically loaded.

No it isn't at all. However it IS possible that the system could get loaded in a manner similar similar to what is shown here. It is this possibility, even if quite unlikely, that make me suggest that belaying or otherwise attaching anything else to the tie in loop is inadvisable. There are plenty of other options, and choosing one where there is a chance of failure under low loads (even if it is remote) doesn't appeal to me.

phillipivan
26/04/2012
10:31:34 AM
On 26/04/2012 ajfclark wrote:
>I would've liked to have seen the retraced bowline too.

So you have even more reasons for telling me off when I tie in with it?

ajfclark
26/04/2012
10:37:10 AM
Now that I've had a good look at it and realised it's actually a bowline on the bight, I might be a convert...
Richard Delaney
26/04/2012
11:22:44 AM
I've just started doing a bunch of test too:

http://youtu.be/9skZ27YQd1g

this is a tug-of-war between a bowline and a fig-8 on a manky, 20-year-old pice of 9mm BlueWater II+ static rope that's been through lots of canyons.

Richard
Olbert
26/04/2012
2:03:54 PM
On 26/04/2012 Richard Delaney wrote:
>I've just started doing a bunch of test too:
>
>http://youtu.be/9skZ27YQd1g
>
>this is a tug-of-war between a bowline and a fig-8 on a manky, 20-year-old
>pice of 9mm BlueWater II+ static rope that's been through lots of canyons.
>
>Richard

Whats the point?

You test a non-rethreaded bowline against a figure 8 on an old rope. The video shows what the tension at breaking point was, however, this is pretty useless information without more context and analysis.

Where did the rope break?
Did it break because of either of the two knots, or did it break because of some old weakness?
Is this result consistent with expectations? Why/why not?

The other point is, for rock climbing purposes, the breaking strain of a figure 8 against the bowline is pretty useless information even if all the above questions are answered. I think we can all agree that both the bowline and the figure 8 are well strong enough - it is their other characteristics that are of concern to climbers (ease of tying, ease of seeing if it is tied wrong, risk of coming untied unintentionally etc.)

Good that you have got yourself a strain testing device but you should put a bit more effort into testing things that are useful, answering questions people want answered, and making videos that have a bit more useful information in them.
One Day Hero
26/04/2012
2:20:48 PM
Holy shit, that looks like it's in your garage! How much did the rig cost? I'm thinking the price would get you somewhere between an excellent woody, and an excellent overseas climbing holiday........hmmm

phillipivan
26/04/2012
2:21:04 PM
On 26/04/2012 ajfclark wrote:
>Now that I've had a good look at it and realised it's actually a bowline
>on the bight, I might be a convert...

How does that change your fear that it may spontaneously come undone during the most exposed moves of any given route?

IdratherbeclimbingM9
26/04/2012
2:49:51 PM
I found RD's tug of war between knots interesting, though agree with Olbert in the sense that it was largely academic.

I strongly suspect that the rope broke at the Fig 8 knot due to previous wear'n tear at that portion of the rope, and not due to any inherant aspects of the knots involved.
Richard Delaney
26/04/2012
3:13:36 PM
As posted in a previous thread, I've set up a facebook page to discuss a whole lot of tests that we'll be doing in the very near future.
I totally agree that a single test on a manky old piece of rope means nothing - it's just an example/initial run through of the rig on the day it was first set up.

If anyone wants to know more, look for the facebook page 'Rope Test Lab' and sign up if you want.

I will be conducting some very detailed tests for NSW Fire and Rescue in the near future with Bill Proctor and Mikl looking over our shoulders for a bit of scientific advice.

We've also done a few other fun things - like dropping 3 steel and 3 alu biners 250m onto a hard surface - to be pull tested next week.

Again, sorry that it's on Facebook - it's just a very easy way to get stuff out there for the 250 or so people that have signed up so far.

Richard

Richard Delaney
26/04/2012
3:16:46 PM
ODH - yep $10,000 - but we have more than enough work lined up to pay for that and wages... so the rest is for fun.
Olbert - that test was sampled and recorded at 2,000 samples/sec. We can also film things at 400fps - there will be detailed analysis on scientifically valid tests.
One Day Hero
26/04/2012
3:21:10 PM
Ah, if someone is paying you for it, it's sweet!

IdratherbeclimbingM9
26/04/2012
5:01:26 PM
On 26/04/2012 Richard Delaney wrote:
>... so the rest is for fun.


The thread Are expensive ropes better? strikes me that it could be a fun test criteria.

I don't doubt their strength on an individual basis, but if people donated samples of old rope with a brief history of usage, it would be interesting to generally compare the left over strength in the expensive ones vs the cheaper ones.

A side product could be that any data gathered might prompt some of us who still use old ropes to change their habits!
;-)
Olbert
26/04/2012
5:24:40 PM
On 26/04/2012 Richard Delaney wrote:
>ODH - yep $10,000 - but we have more than enough work lined up to pay for
>that and wages... so the rest is for fun.
>Olbert - that test was sampled and recorded at 2,000 samples/sec. We can
>also film things at 400fps - there will be detailed analysis on scientifically
>valid tests.

Fair enough...I guess I jumped the gun. I thought it was a "look at me I've done the same as above" rather than a "I've got some cool stuff, I'm doing some cool tests and this is an example of what it can do".

 Page 1 of 2. Messages 1 to 20 | 21 to 23
There are 23 messages in this topic.

 

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