Goto Chockstone Home

  Guide
  Gallery
  Tech Tips
  Articles
  Reviews
  Dictionary
  Links
  Forum
  Search
  About

      Sponsored By
      ROCK
   HARDWARE

  Shop

Edelrid: "Ultralight Helmet" (Red) Fits 54 - 60cm Great heavy duty all-rounder. SUPER SPECIAL for a short time only!  $79.00
21% Off

Chockstone Photography Australian Landscape Photography by Michael Boniwell
Australian Landscape Prints





Chockstone Forum - General Discussion

General Climbing Discussion

Author
girth hitch flip vs climber hitch (Tech Tips)

rhinckle
21/06/2005
2:03:28 PM
was playing about with my gear the other day,
trying to remember the 'climber hitch'
and
discovered that if you tie one sling to another with a girth hitch
(larks head knot)(or lark's foot knot according to Karl Lew),
it's possible to flip the hitch from the hitch sling onto the non hitch sling, and achieve a symmetrical knot.
this may or not make sense.

i'll post a pic shortly.

IdratherbeclimbingM9
21/06/2005
2:07:19 PM
... and thus you end up with a Reef Knot joining two loops ...
Some people (me included) have been known to extend* runners by this fashion when they are low on karabiners.
*It works but is not as strong; (at a guess only about a third the rated strength of the weakest sling involved).


>trying to remember the 'climber hitch'
= clove hitch?

rhinckle
21/06/2005
2:36:58 PM
imagine that these telephone cables are slings.


IdratherbeclimbingM9
21/06/2005
2:44:33 PM
>(snip) these telephone cables are slings
Ahh; jiggery pokery & gear freakery.
LOL Love it!
You will make an innovative AID Climber extraordinaire Rhinckle !!

... Spotlight* on Rhinckle; ... c'mon up.
(*or is it just a headtorch shining from high on the late evening wall?).

Definition of a lightweight expedition;
~> using mobiles instead of PSTN (copper wire land-line) phones!!!
(Imagine the drag).

New route description/name;
Copperhead Road morphs to copper-wire (slings) road?

rhinckle
21/06/2005
3:00:53 PM
On 21/06/2005 M8iswhereitsat wrote:
>... and thus you end up with a Reef Knot joining two loops ...
>Some people (me included) have been known to extend* runners by this fashion
>when they are low on karabiners.
>*It works but is not as strong; (at a guess only about a third the rated
>strength of the weakest sling involved).

standard girth hitch reduces strength BY 30% not TO 30%

>>trying to remember the 'climber hitch'
>= clove hitch?

nope: http://www.climerware.com/cknot1.htm

IdratherbeclimbingM9
21/06/2005
3:10:26 PM
>BY 30% not TO 30%
I stand corrected.
Good info Rhinckle.

climbau
22/06/2005
3:22:47 PM
Looks mightily like a square knot to me

IdratherbeclimbingM9
22/06/2005
3:52:52 PM
You are right climbau!

From the Brockhampton Reference book of Knots & Splices:

'The Reef Knot or Square Knot is a classic sailor's knot, used to temporarily shorten a sail or create joints. The reef knot should be used on identical lines and should not be subject to significant strain, otherwise it may slip'.

*It is not dissimilar to the Draw Knot and also the Thief Knot.
*It can be made quick release by passing the bight of the remaining rope through the standing part before tightening.
*It is differentiated from the Granny Knot which does not lie flat when tightened.

Better to use (rhinkle reference) 'Climer Sling Hitch' which only reduces strength by 12% (vs 30% for a Girth Hitch) in nylon to nylon slings and also nylon to spectra slings; but reduces by 21% for spectra to spectra slings.
==================
Post edit for clarification in light of The Good Dr's post below;
The % strengths quoted above are for a minimal number of samples tested, and are indicative only (ie not conclusive). A poorly dressed knot as the Dr points out, is NOT as strong as quoted.



The good Dr
22/06/2005
6:57:38 PM
When looking at the test results (rhinkle ref) remember that the knots would have been laid correctly (ie neatly). This is not easy to do when you are on lead as it requires two hands (possible when aiding, but takes extra time).

A poorly laid knot reduces the rated strength by various amounts, particularly if there is a twist included in the knot.

LittleJames
22/06/2005
8:24:24 PM
On 21/06/2005 M8iswhereitsat wrote:
>~> using mobiles instead of PSTN (copper wire land-line) phones!!!
>(Imagine the drag).

OK, maybe you can answer this (it came up in exam study the other day and I couldn't remember). Does PSTN stand for Plain Simple Telephone Network, or Packet Switched Telephone Network?

The second sounds more likely, but my lecturer swears blind that telephones are circuit switched...

Edit: As I hit OK, I suddenly remembered it was Public Switched Telephone Network. Whoops.

Spanky
23/06/2005
9:47:27 PM
When looking at the photos and further at the url supplied by rhinckle. I was just wondering does anyone know whether there is a best way or better way to sling pro. Whether girth hitching the pro was best, flipping the hitch over as per the photo or doing something totally different as per the 'climbers hitch' when attaching a sling to pro.

Pretty interesting results found by chris!!!

thanks guys...
h.

LittleJames
24/06/2005
1:22:54 AM
On 23/06/2005 Spanky wrote:
>When looking at the photos and further at the url supplied by rhinckle.
>I was just wondering does anyone know whether there is a best way or better
>way to sling pro. Whether girth hitching the pro was best, flipping the
>hitch over as per the photo or doing something totally different as per
>the 'climbers hitch' when attaching a sling to pro.

I'm pretty tired, but if I'm reading that right... You should never, ever sling wired pro just with a sling. Always clip a biner into the pro, and then extend from that biner with a sling (or you could use a quickdraw).

IdratherbeclimbingM9
24/06/2005
8:20:13 AM
I second Little James's comment.
It is a very dangerous practice to sling nylon (etc) directly to wire on pro. In a fall (even a small one), the wire will cut through the nylon like a cheesewire.

>does anyone know whether there is a best way or better way to sling pro.
Yes, with an appropriate length sling connected by karabiner to the pro sling.
If the pro already has a nylon (spectra etc) sling on it and you need to extend it, then its still preferable to use a karabiner.
I regard the 'climer (sic) hitch' as a last resort extension method, for when you need to extend a runner but don't have enough karabiners left on the rack for the purpose.

As an aid climber I can envisage a minority of situations where I would dispense with the karabiner, but here I am talking about 'body-weight only' pieces of pro.
rightarmbad
24/06/2005
11:32:54 PM
just seeing if this works. I have posted 2 replies to this thread and they both seemed to have gone missing. It's happened a couple of times before. Don't know what is happening.
rightarmbad
24/06/2005
11:33:40 PM
Hmmm, works now???

rhinckle
27/06/2005
8:58:38 AM
re: reef knot/square knot
while the end result of the 'telephone cable' method looks like a reef knot, it differs from a reef knot in that there are no 'tails': so the load is spread more evenly, if you see what i mean, and i assume a better strength reduction result than a reef knot.

basically it's just a lot easier to do on lead than the extra complication of the 'climer knot'

i think simple counts for a lot.

IdratherbeclimbingM9
27/06/2005
5:27:06 PM
>i think simple counts for a lot.
I agree.

>there are no 'tails': so the load is spread more evenly
The 'tails' have been used elsewhere (as the loop/s), but the load still concentrates at the 'bight' of rope forming the knot, and in particular the contact points of the two slings.
This is not an even distribution of the load as it only applies to a very small surface area at the contact points. For this reason the strength reduction remains the same (ie by 30%).
Incidentally the contact points/area will change during a load to a greater or lesser degree depending on the type and severity of loading.

There is a lot of academic rationalisation in my thought process (typed below) here.
(In the real world my thoughts would run differently ...?)

* Need to extend sling.

* Evaluate pro.
~> (say) # 9 stopper = rated strength of 10 kN; so 1/3 off sling strength of (say) 22 kN leaves (say) 14 kN strength left in sling
~> 14 kN exceeds 10 (or less) kN so sling extension should be fine.

* Marginal placement? = even less strength of pro; ... sling extension is still fine.

*Facing a big fall on it, or worse still a high fall factor?
~> Better double (or triple) up the pro.
~>Sling extension NOT fine, as it needs to be full strength.
.... double up slings?
.... back off the move??
.... Go for it, but DON'T fall !!!

If you reckon the extra jiggery pokery with the 'climer hitch' is a hassle, then how does this compare to the hassle of doubling up pro?

Even if you use it and have a 12% reduction in strength; how does this compare to the number crunch carried out above.

Climbing is meant to be fun, not maths!
~>I'd double up and also equalise the pro if necessary; use an appropriate runner, then run it out!
If I did not have an appropriate runner and ran it out, I would be fully aware that the last placement was less than full strength ...
... mind games come into play.

The above logic is why double ropes are popular.
A softer catch; and safer if one rope is damaged; and also less drag on gear placements.

There are 17 messages in this topic.

 

Home | Guide | Gallery | Tech Tips | Articles | Reviews | Dictionary | Forum | Links | About | Search
Chockstone Photography | Landscape Photography Australia | Australian Landscape Photography

Please read the full disclaimer before using any information contained on these pages.



Australian Panoramic | Australian Coast | Australian Mountains | Australian Countryside | Australian Waterfalls | Australian Lakes | Australian Cities | Australian Macro | Australian Wildlife
Landscape Photo | Landscape Photography | Landscape Photography Australia | Fine Art Photography | Wilderness Photography | Nature Photo | Australian Landscape Photo | Stock Photography Australia | Landscape Photos | Panoramic Photos | Panoramic Photography Australia | Australian Landscape Photography | Mothers Day Gifts | Gifts for Mothers Day | Mothers Day Gift Ideas | Ideas for Mothers Day | Wedding Gift Ideas | Christmas Gift Ideas | Fathers Day Gifts | Gifts for Fathers Day | Fathers Day Gift Ideas | Ideas for Fathers Day | Landscape Prints | Landscape Poster | Limited Edition Prints | Panoramic Photo | Buy Posters | Poster Prints