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 Page 2 of 2. Messages 1 to 20 | 21 to 27
Author
top rope soloing

IdratherbeclimbingM9
29-Jun-2007
8:40:59 AM
On 28/06/2007 Ronny wrote:
>Not sure if that's quite right.
>
>Unaltered, rope won't run through the gri gri as you climb up. So you
>have to climb a bit, pull rope through, climb a bit more. As I understand
>the gri gri alteration method, you cut away part (a pretty useless part)
>of the casing, so that rope runs straighter. Then by holding it upright,
>rather than hanging down from the harness, the rope runs straight and will
>slide through as you climb up. And when you fall it just locks off like
>normal.
>
>Then again I could be wrong.

What you say is correct Ronny, though imo it is all matters of degree, and to that extent I think we are largely saying the same thing. My reply was focussed on the orientation aspect rather than the modification aspect.
Both issues need consideration by the prospective soloer for their specific needs.

For clarification I don't own or use a gri gri, ... but did my homework before investing in a Silent Partner.
>>Unaltered, rope won't run through the gri gri as you climb up.
It will (with difficulty), if the orientation is better, but I decided it was a hassle I could do without.
The orientation also helps minimising delay? in device grabbing rope in the event of a fall. Prolly only an issue in awkward falls that have a high rotational aspect??
... none of which are a particular issue when climbing a slightly weighted pre-set toprope.
:)

Eduardo Slabofvic
29-Jun-2007
4:02:07 PM
On 29/06/2007 Macciza wrote:
>Shunts also have real issues - don't use them for soloing

Apart from the two rope vs. single rope issue with the shunt, what are it's limitations/issues?

(Please note this is not a personal challenge, just interested in what you know).

Macciza
29-Jun-2007
9:13:31 PM
From various resources reports etc
The small size of the 'cam' can lead to heating and sliding/glazing instead of grabbing
The casing is known to deform in high factor falls and to slice the rope along it's length
Braking disabled by grabbing the device
Disengagement from rope when falling onto knots in the rope

Never used one - checked them out along with other options
Done quite a bit of aid and free (lead and toprope) soloing
In general my comment relate to serious coloing where you are committed to the climbing and will be
taking uncontrolled falls (if at all) as opposed to just dicking about on a rope . . .


Ronny
1-Jul-2007
7:12:49 PM
On 28/06/2007 bomber pro wrote:

>have teeth, a lot of people
>don't like using these in the false belief that the teeth will strip the
>mantle off the rope, this can only
>happen if the unit is shock loaded, or not on a chest harness, so don't
>shock load it!, ie a lead fall
>generates such loads, so weight the bottom of the rope and that can't
>happen, you will only a slump
>onto an ascender that is right there with you.
>

Hey Bomb,

How far do you reckon you have to fall to cause a problem like this? I"ve always soloed with a petzl ascender, and have often done it with just a screwgate through the top hole (the one above the clamp) just into my belay loop. It means no chest harnes needed as the biner pulls the device up the rope. I know this isn't the safest method, but the ascender does lock like this, and I only tend to do it on easy ground. But it does mean that if you fell unexpectedly you'd fall about a foot or so before it took up.

My thinking is that this is probably ok for th odd bit of climbing on easy ground - but am no so sure any more.

James

muki
1-Jul-2007
9:41:49 PM
The real danger's for you are 1. A cross loaded aluminium biner (failure at much lower loadings),2. a
side torqued rope (definately not the way to use that particular model)3. And using your method, rope
damage if a foot hold blows or hold breaks (this still happens on "easy ground") but not rope failure,
depending on the Kn of the fall and the diameter of the rope, usually you just get damage on the side
of the rope that the teeth are on, complete sheath failure is very rare and needs other factors like
weakening from extreem cold or an alraedy weakened mantle in that particular area of rope that gets
hammered by the fall, one meter is enough to create damage, thats just 500mm of slack once you fall
past it.
My advise is to use a steel "D" shaped malion to connect the bottom of the unit to the harnness, and
use a biner (snap link) to attach the top to a sling around your shoulders to keep it upright, also weight
the bottom of the rope enough so that it stays down and does'nt ride up with you and create a shock
load potential, use beefy diameter ropes eg 10.5/11mm, and try to get a devise that does'nt hurt the
ropes at all, Petzle microscender is the buisness(used with an oval steel malion), and a shunt is ok on
double ropes.
In high access work it's the only back up to any accident on your main working lines, and only ever on
a single static rope, with the small amount of dynamic lanyard doing all the shock absorbtion.
I,ve had a fall where a welder cut my anchor by accident when some sparks caught alight and melted
my primary anchors, the shunt was about level with my ankles and three feet away, no glazing or any
other sign that the shunt had affected the rope in any way, other than some deformation at the grab
point, but that was able to be worked out of the rope when I got down again.
Took a while to get my heart out of my throat, those unexpected falls are the pits, but it was all good
when I got another line sent down.
Have a think about it, and make good decisions, you might have used up some of your nine lives
already.

Macciza
1-Jul-2007
10:05:44 PM
Type B - Ascenders are generally body-loaded, toothed-cam devices. They are designed to grab
immediately and avoid any loss of height - the only way they can absorb force is through stretch of the
rope or slippage of the sheath if, or rather when, the sheath severs and eventually bunches on the
core. (Tie a good knot in the end to avoid rope de-sheathing.
Standard minimum static strength is 4kN
Dynamic load test - 100kg, 1m Fall, FF - 1 : results in sheath stripping between 4.5 to 6.5 kN

Type A - Backup devices are basically work positioning/fall arrest devices. These are designed to
absorb force by slipping/sliding along the sheath - Most do so in the 3 - 6 kN range with slippage of 50
to 150 cm (These are inversely proportional - more slippage = less force) Petzl Microscender fits this
range. Maximum device strength (ie stuck on a knot) is over 12kN.
Dynamic load test - 100kg with FF 2 : results in device sliding and 3 - 6kN impact force.

The Shunt slips at ~2.5kN and can slide >2m It has also been known to snag and with the higher
impact force to sever the sheath . The corner of the frame routinely damages the sheath as it slips
and when the device is blocked by a knot the frame can bend and release the rope as low as 6kN

In summary - Don't use Toothed ascenders or Shunts if you are doing any serious top-rope soloing . . .
On absolutely easy ground - be very careful, avoid dynamic loading , be extra careful near the anchors
as there is very little rope to absorb fall force (like a heavy slump) and basically don't fall . . .

These figures are from investigative reports into PPE used in Rope Access - I did not make them up.

rod
2-Jul-2007
10:33:18 PM
On 1/07/2007 Macciza wrote:
>Type B - Ascenders are generally body-loaded, toothed-cam devices. They
>are designed to grab
>immediately and avoid any loss of height - the only way they can absorb
>force is through stretch of the
>rope or slippage of the sheath if, or rather when, the sheath severs and
>eventually bunches on the
>core. (Tie a good knot in the end to avoid rope de-sheathing.
>Standard minimum static strength is 4kN
>Dynamic load test - 100kg, 1m Fall, FF - 1 : results in sheath stripping
>between 4.5 to 6.5 kN
>
>Type A - Backup devices are basically work positioning/fall arrest devices.
>These are designed to
>absorb force by slipping/sliding along the sheath - Most do so in the
>3 - 6 kN range with slippage of 50
>to 150 cm (These are inversely proportional - more slippage = less force)
>Petzl Microscender fits this
>range. Maximum device strength (ie stuck on a knot) is over 12kN.
>Dynamic load test - 100kg with FF 2 : results in device sliding and 3
>- 6kN impact force.
>
>The Shunt slips at ~2.5kN and can slide >2m It has also been known to
>snag and with the higher
>impact force to sever the sheath . The corner of the frame routinely damages
>the sheath as it slips
>and when the device is blocked by a knot the frame can bend and release
>the rope as low as 6kN
>
>In summary - Don't use Toothed ascenders or Shunts if you are doing any
>serious top-rope soloing . . .
>On absolutely easy ground - be very careful, avoid dynamic loading , be
>extra careful near the anchors
>as there is very little rope to absorb fall force (like a heavy slump)
>and basically don't fall . . .
>
>These figures are from investigative reports into PPE used in Rope Access
>- I did not make them up.
>
>


macciza: can you clarify what you mean in the summary component regarding "serious" vs "easy ground". in my experience, the issues are slack build up and ensuring a teethed ascender stays correctly aligned in a fall. personally, i find its easier to avoid these situations on vertical to slightly overhanging routes because the rope stays better aligned in falls and the pack weight at the end of the rope works better. situations i avoid are low angle "easy" routes, moves which are dramatically away from the natural fall line and as you suggest, routes wherein i have high potential for falling close to the anchors. i'm on the petzl basic rigged similarly to BP's suggestion in the preceding post.

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