Dyneema caving ropes

[Wolfo]

Great, comprehensive summary, Alex!

There seems to be a decent selection of "canyoning rope" that uses aramid/aramid-mix materials in the sheath, from 6-9mm.

One could use a fancy-8, or super-munter hitch for descending. I'm not sure what one would use for ascending something smaller than 8mm, as far as I can tell, our typical caving-use toothed ascenders aren't rated for ropes below 8mm. Perhaps they would still work?

You will not use devices like figure-8s or munster hitches in a caving SRT setup. These twist the rope badly, not a good idea if you use alpine rigging and rebelays. It's fine for canyoning where you usually pull the rope after decent but not for technical caving. Adjusted bobbins or racks work fine with these thin lined.

 

[Edz]

There are a few descenders for 5mm ish ropes/cords. The ISC D1 is most similar to a caving descender as it has an opening side plate. There is also an ascender to go with it.
It's only made for specific types of rope although I'm sure it will work on others.

 

[JAshley73]

You will not use devices like figure-8s or munster hitches in a caving SRT setup. These twist the rope badly, not a good idea if you use alpine rigging and rebelays. It's fine for canyoning where you usually pull the rope after decent but not for technical caving. Adjusted bobbins or racks work fine with these thin lined.

Yes, I'm aware. I have not however seen bobbins for use on small diameter ropes. I guess a rack can be made to function with darn-near anything.
(Before we start into battle, let me just say, I'm not too worried about the topic, really.)

I HAVE considered investing in some smaller diameter rope - 8mm or so - for climbing, and for cowstails. (Oh my, another battle indeed!) Mainly for just reduced bulk.

(Though for the little amount of caving I've done this year, it's certainly irrelevant...)

 

[JAshley73]

For future potential:
Current CE certification does not allow for a completely static SRT rope, though as zzzzzzed points out there could always be a future standard. Also, our friends from over the pond don't suffer from this problem, as their much more static polyester ropes lay testament to.

As an american, I admit I'm a little puzzled by this. A favorite over here is Cancord's "Greenline" - a 100% Polyester rope, with less than 1% stretch at 10% of MBS. That equates to around .5% at 300lbs or so... It's not the toughest sheathed rope, but is outstanding for rapelling and climbing on.

 

[JAshley73]

As an american, I admit I'm a little puzzled by this. A favorite over here is Cancord's "Greenline" - a 100% Polyester rope, with less than 1% stretch at 10% of MBS. That equates to around .5% at 300lbs or so... It's not the toughest sheathed rope, but is outstanding for rapelling and climbing on.

Oh, and I forgot (and it's too late to edit...) That stuff is cheap too. 9mm, 10mm, 11mm, are all between 55¢ - 70¢ a foot.

My 300' of 10mm "Greenline" was $180 usd. Equates to 91.4 meters for £134...

 

[JasonC]

Oh, and I forgot (and it's too late to edit...) That stuff is cheap too. 9mm, 10mm, 11mm, are all between 55¢ - 70¢ a foot.

My 300' of 10mm "Greenline" was $180 usd. Equates to 91.4 meters for £134...

So, it's non-bouncing and cheap, so what's wrong with it? I assume there must be some negative if it's not certified in the UK?

 

[AlexR]

If an anchor breaks above you'll probably break your spine.
For IRT rigging that's not too much of an issue, as your anchor breaking generally means you're done for anyway.

I'm not overly familiar with the certification process, but think this stems from the CE EN1891 standard requiring a maximum impact force of 6kN. That's only achievable if you have a certain elasticity in your rope. (or BS EN1891 if you want to be patriotic about it )

I've been sorely tempted to get my mitts on some American ropes to rig a certain dig commute on, it would make the required 250m of ascent much nicer. If your anchors are bomber I really wouldn't be too concerned about shock absorbency of my ropes.

 

[ChrisB]

it's non-bouncing and cheap, so what's wrong with it

It's non-bouncing, and therefore non-shock absorbing. I was about to explain why that's OK for American but not UK ropes but AlexR has done that while I'm writing. They don't use normally use rebelays in America.

 

[JAshley73]

So, it's non-bouncing and cheap, so what's wrong with it? I assume there must be some negative if it's not certified in the UK?

It's 100% polyester, so not the most durable sheath. (We are pretty diligent in padding our ropes for IRT though...) The rope is made in Canada - Not sure what importing into the UK/EU would do to the price...

As far as falling on it - Our cowstail ropes are typically 10%-stretch, plus the knots, and harnesses and body-fat/soft-tissue... Not that I want to take a FF2 on it - nor any fall for that matter. But I don't know if a FF.5 - FF1 would be spine-shattering...?

It is really nice to use though. The 10mm is still slick enough that my 70lb daughter can smoothly rappel on a Petzl-Stop. And it's nice & stiff for climbing.

 

[andrewmcleod]

The EU standard requires, I think, a maximum force of 6kN for a FF0.3 fall (hence 'semi-static' ropes), so a FF2, FF1 or even FF0.5 onto UK/EU ropes will really, really hurt at best. A FF1 fall onto hyperstatic rope is going to be messy (and might even break the rope as the peak force is so high).

It's perfectly possible for a rope with a lower max breaking strength to survive a dynamic drop that a rope with a higher max breaking strength, if the rope with the higher breaking strength is more static.

 

[JoshW]

The EU standard requires, I think, a maximum force of 6kN for a FF0.3 fall

6kN for a fall factor 1

 

[Mark Wright]

The EU standard requires, I think, a maximum force of 6kN for a FF0.3 fall (hence 'semi-static' ropes), so a FF2, FF1 or even FF0.5 onto UK/EU ropes will really, really hurt at best.

In the 80's I did quite a lot of bridge jumping with Badlad and others in the NCC. The ones with the biggest drops I ever did were on Anglesey. One involved a 10m free fall before the 2 x low stretch ropes went tight under the arch of a 5m wide railway bridge. The other was a night time jump off the 12m wide Menai Bridge with 2 x 20m low stretch ropes. I never felt anything other than relief that the ropes hadn't broken.

With low stretch ropes you could sometimes get higher than the bridge deck on the first swing. I remember taking a photograph of the anchors on Monsal Head Viaduct on one such occasion. From the high point you ended up with an even bigger free fall than the original jump and still never felt a thing.

The rope access company that I worked for at the time got the job of installing the steel bars under the arches to stop people jumping off it!

 

[Chocolate fireguard]

They didn't stop people doing it. They just made sure that anybody doing it would be badly hurt.
It was harmless fun before that.
IIRC there was a notice on the wall at the top to tell you the best place to go off so you were midway between pillars.
Although it didn't actually say that.

 

[andrewmcleod]

6kN for a fall factor 1

I've managed to dig up a dodgy PDF version of the EN1891 standard, and I think while the rope must survive 5 FF1 drops with a 100kg mass (80kg for class B), the impact force test is done with FF 0.3.
You use a 2m long lanyard with sewn terminations in both cases, but for the impact force for you only lift the weight up 600mm while for the repeated drop tests you lift it up 2000mm. 600/2000 = 0.3; 2000/2000 = 1.

Petzl real-life testing (i.e. with squidy soft people rather than 100kg steel test masses) got 4kN on a FF1 fall with _dynamic_ rope...

Forces at work in a real fall - Petzl USA

www.petzl.com

 

[JoshW]

I've managed to dig up a dodgy PDF version of the EN1891 standard, and I think while the rope must survive 5 FF1 drops with a 100kg mass (80kg for class B), the impact force test is done with FF 0.3.
You use a 2m long lanyard with sewn terminations in both cases, but for the impact force for you only lift the weight up 600mm while for the repeated drop tests you lift it up 2000mm. 600/2000 = 0.3; 2000/2000 = 1.

Petzl real-life testing (i.e. with squidy soft people rather than 100kg steel test masses) got 4kN on a FF1 fall with _dynamic_ rope...

Forces at work in a real fall - Petzl USA

www.petzl.com

You’re correct, where the hell did I find that other info from