UKC

Simple question, and I'm pretty sure what the answer would be, but I'd be intrigued to know why ...

Would an normal ascender/ ropeman work on a steel cable? And would it be advisable?

Talk science to me ...

In reply to JoeCoxson:
At a guess I'd say no as an ascender requires compression of the rope to provide the friction (think free body diagram) which you wouldn't really get on a steel cable.

EDIT: And by compression I mean lateral compression in the locality of the cam.

In reply to JoeCoxson:

It might, depending on the specific ascender, the size of the cable etc.. And no, it probably wouldn't be a good idea.

Many ascenders have a toothed cam, and get their initial grip by pushing their pointy little teeth in between the fibres of the sheath of the rope. They're unlikely to penetrate a steel rope the same way.

Then there's the question of friction - most ascenders squeeze the rope between the body of the device and a cam, deforming the rope a little bit and creating friction to hold it in place. There's likely to be a lot less friction between steel (especially greasy steel) and aluminium than between a somewhat squashed nylon rope and aluminium.

If you were looking to ascend a steel rope you'd probably be better off using prusik loops.

There are various devices out there designed for pulling steel ropes with (for example for handling the conductors when hanging up electricity lines). Many of those are a little bit like ascenders.
<quick google>
I have one of these kicking about somewhere: http://www.amazon.co.uk/Klein-1604-20L-Havens-Grip/dp/B0002RI512
"Havens Grip" is a mistake btw, it's a Haven Grip (singular).

There's no spring in one of those (so it only grips while it's actually loaded), but if you were daft enough to try using one as an ascender, you could modify it by simply putting an elastic band around it.

Out of interest, why do you ask?

Yeah, that makes sense really, the limited deformation would mean the camming never produces enough friction to firmly grip. Do you reckon prusiks would be better? I guess fabric on metal is preferable to metal on metal, but you loose the mechanical camming.

It started as a general wondering how mechanics and such safely climb structures with a wire running up the side of the ladderway- I guess a Haven grip could be used there?

In reply to JoeCoxson:

They have inertia-locking reels which run on a cable attached to the side of the structure being climbed, such as 'ladderlatch'.

In reply to JoeCoxson:

http://www.radiostructures.com/images/uploads/latchwaysfallattach.jpg

In reply to JoeCoxson:


Either that or a similar system to via ferrata I would guess.

In reply to crayefish:

Both are used - scaffolding hooks which are clipped on the rungs of the ladder as you climb, with the inertia device clipped to your harness going up/down as you go.

In reply to JoeCoxson:


That's a different thing entirely to ascending the wire itself. More like a top-rope self belay type shenanigans. You wouldn't really want to use a prusik for that, and it's *definitely* not something you'd want to do with something like a Haven Grip either.

There are various proprietary systems on the market for fall-arrest when people are climbing ladders and wotnot at work. Many of them are based on some kind of grab/chuck type device running on a rail or up & down a steel rope.

If there's a ladder in some kind of industrial setting with a steel rope in place beside it, chances are it's one of those. (In which case there will be a device out there somewhere specifically designed to be used with it.)

Eg: http://www.unilinesafety.com/product-sectors/vertical-systems/cabloc/

In reply to JoeCoxson:

Skylotec make a fall arrest device for VF cables, but I don't know if it will work as an ascender as such.