Jammer safety leash

[Neil B]

i have it set uo so the croll just touches the bottom of the jammer handle even when fully standing.

Yeah - I was going to say. That's how I have my rig set up too, so there shouldn't be any chance of the croll ever interfering with the hand jammer. Though in most of the 'text books' the consensus seems to be that the croll should be exactly level with the hand jammer when standing in the footloop.

 

[mudman]

Carry a prusik loop that you can install above the jammers and just long enough to allow you to stand in when done so.
Also handy in a variety of other situations as well.

 

[Johnny]

I have never experienced this problem. My jammer never goes that close to my croll. Has this got anything to do with how high the croll sits on your body?
I try to keep mine as low as possable, I use a petzle Avanti harness ( not the one with the matal central connections) which helps this. See the thread on Harnesses.
The accepted wisdom seems to be that the lower the croll the more efficient the prussiking.
Does this problem occur particularly with the Fractio harness which has a high croll mounting position?

 

[paul]

I have never experienced this problem. My jammer never goes that close to my croll. Has this got anything to do with how high the croll sits on your body?

I think the critical factor is the length of your foot loop(s).

Obviously, if you were to push your top jammer to as far up as your arm length (and safety loop length) allow, then stand up in you foot loop, the distance your croll will travel depends on the length of the foot loop. If you stand up and still have say 10cm between the jammers, you could have gained those extra 10 cm if the jammers were closer together.

The closer the 2 jammers come together, the more distance you will climb with each stand/sit cycle and hence be more efficient.

 

[Johnny]

Paul, you are right. You obviously want to push the jammer as high as you can to get the stroke length but there is no point having your foot loop any longer than the distance between your reach and fully bent leg, otherwise your leg is not fully bent and you limit your stroke.
The point is, when your legs(s) are straight, they are straight and where your croll ends up relative to your jammer depends on how high on your body it is mounted.
The lower the position of your croll the greater the window of adjustment for the position of your hand jammer.
If your croll is too high then you can get a situation where, with your footloop optimised to your reach/leg length, the croll and jammer clash. To avoid this you will have to stop the standing stroke before you are upright, thus limiting the stroke and the efficiency.
:!: It's a hard thing to explain :!:

 

[SamT]

I think people have slightly mis understood the problem.

In the photo, the croll and the RH jammer have come together and are positioned so that the mechanism to release the cam is not accessible rendering the caver stuck on the rope.

Solution - move the hand jammer up a bit, then both units can be removed (if so desired).

The only instance I can see this causing a problem is where the top jammer is right up against a knot (this can sometimes be a problem in itself and hence it is always a consious move to stop my hand jammer 1 inch away from the knot), then the croll has come right up behind it. Quite unlikely. But I do sometimes jump a bit when I arrive at a rebelay to get the croll higher which can make life easier on the rebelay.

The photo does not suggest any problem 'during' prussiking or with efficiency etc, it only suggests that you could get stuck without access to the release mechanism for the cam

You should always be able move the hand jammer up a bit to gain access to the cams. Using a LH jammer should prevent the possibility of this happening.

 

[Johnny]

But I do sometimes jump a bit when I arrive at a rebelay to get the croll higher which can make life easier on the rebelay.

Us short arses sometimes have to improvise

I am still right though :!: :wink:

 

[SamT]

Dont worry - I know what you mean.

 

[Ann]

I think people have slightly mis understood the problem.

In the photo, the croll and the RH jammer have come together and are positioned so that the mechanism to release the cam is not accessible rendering the caver stuck on the rope.

Solution - move the hand jammer up a bit, then both units can be removed (if so desired).

You should always be able move the hand jammer up a bit to gain access to the cams. Using a LH jammer should prevent the possibility of this happening.

I think my problem was a variation on this theme. My croll was actually stuck in the handle of the jammer thus making it impossible to move the jammer up. Presume this problem could also happen with a left handled jammer.
Thanks for all the tips I will try a few adjustments. My croll does seem to sit fairly high up on my chest although I use the same harness as Johnny. May be because I am a short arse :!: :!:

 

[Ann]

Ann - DCRO will rescue you, although we may laugh at you first

It's a long way to come for a laugh :!: I was up in North Yorkshire when it happened

 

[paul]

Ann - DCRO will rescue you, although we may laugh at you first

It's a long way to come for a laugh :!: I was up in North Yorkshire when it happened

Well next time take some photos and post them here and save us the drive!

 

[JB]

I know this is slightly off topic but does anyone on here not use a dedicated jammer safety leash but just clip their long cowstail into the crab on the bottom of the upper jammer? This is the method recommended in Alpine Caving Techniques and I've been doing it for a while. Everyone else seems to have a dedicated safety leash and I'd be interested to know why.

I can see...

Advantages

Leaves you two cowstails available for traversing off the pitch head without dismantling your ascending system.

Disadvantages

More cluttered Central Maillon.

I'd be particularly interested if anyone can think of any specific situations where I'm likely to have a problem using my system.

Ta.

 

[dunc]

I use a piece of 9mm for the job, so it doesn't weigh that much extra and doesn't in my eyes cause to much mess for the central maillon. It's the way I was taught and it's the way I've stuck with.

Disadvantages

With jammer on rope you only have one cowstail (a short one) - which could make life more awkward in some places(like as you say, pitch heads/traverses). Not so much a problem in caves with a horizontal/vertical mix but in some pots it would be a faff to keep clipping/unclipping the jammer.

There would appear to be a small possibility of dropping the jammer - ie. it's not attatched to anything unless you have the cowstail attatched - obviously attatching the tail before unclipping jammer from harness would help matters, but the potential is there.. Lets say you were mid descent and have a problem, you need to change over - unless you clipped the cowstail to jammer at the pitch head after you had finished with them on traverse etc then you have to do it mid pitch, which is probably where the greatest potential for losing it exists - more so I would have thought if it was a small/tight pitch with not much room for movement.

Not often used in descent but, at a hanging rebelay - you hang from short cowstail with long cowstail on rope you just came down with descender reattatched you need to take weight of short tail.. It might not happen often but you need to use jammer to get weight off short cowstail - thus you need to remove your backup cowstail to use it.. Which means your only backup is then a jammer which if you had made an error in threading the descender (ok, this is rare but the potential does exist for it to happen) then your backup is the jammer which is not recommended for a shock loading.

 

[GSR]

with long cowstail as your safety you don't really have the option of adjusting your system with your safety leash and footloop so that they're running through the krab attached to your jammer. each step down is also hoisting you up - giving you massive mechanical advantage but taking you only half the distance upwards.

admittedly you only need to do this about once every 23 blue moons but i never like ruling out options.

 

[Stu]

I know the (unlikely in real life) rescue situation can't be ruled out. With a seperate safety line you have all the advantages of a second long cowstail and you can haul your buddy's ass out of a cave if/when they mess up. Always been taught that self rescue where possible is a top priority. The Alpine book is good, though I think their is a danger of picking out certain things and not really considering them. Lightweight is all very good but does it save that much. If weight is a real concern they also show a nifty way of rigging on a semi larksfoot aramgement, on snaps and on 8mm rope! Pays your money really.