UKC

Any suggestions for a belay/abseil device for use with 2 skinny ropes? Never had any difficulty until a recent ab back down an overhanging route on a couple of 8.3mm ropes. My Black Diamond ATC XP didn't create enough friction. Abing back down was much more scary than the route. Thinking of a Mammut Smart Alpine for skinny ropes. Any comments anyone?

In reply to chrisfrugill:

Add another locking crab to increase the friction. Jim Titt posted some figures on another post recently

In reply to chrisfrugill:

Prussiks are kind off a must. Would have been scary without. I ab off of my meteor 8.3 halfs with an ATC XP and dont find it bad at all. Even had to ab off of just one of my halfs once with the XP. I was glad I had prussiks but would never ab without them.

In reply to chrisfrugill:

Mussolini hitch?

In reply to chrisfrugill:

Don't know if you do this already, but extending your device (rather than clipping it directly to the harness belay loop) gives you extra friction, because you get closer to a 180 degree bend in the brake strand as it exits the device. Rapping with an extended device also makes it more comfortable to use both hands for braking. Finally, with an extended device, you can (if necessary in mid-rappel) increase friction substantially with the following trick requiring two free carabiners:

Clip Carabiner #1 to the tether loop that holds your belay device, and clip Carabiner #2 to your harness belay loop.

Clip the brake strand through Carabiner #2 and then up to and through Carabiner #1 (and then of course back down to your brake hand). This will give lots more friction.

An advantage of the mid-rappel installation is you can begin the rappel without extra friction, benefiting from the rope weight, and later increase the friction substantially when there is less of an assist from rope weight. A disadvantage is that it can be hard to rig this if your backup prussik is mounted low down on the leg loop (where it shouldn't be anyway with the extended device method). If the prussik is on the harness belay loop, it won't interfere with the rigging steps.

Of course, there are also some more primitive ways to increase friction during the rappel. You can pass the break strand around behind your back and so essentially add a waist belay to the process of creating rappel friction. Or you can take a half-turn of the break strand around your thigh, but this is more painful and more awkward as well.

Once the first person down has noted friction problems, they should provide the support of a "fireman's belay" to subsequent party members.

In reply to chrisfrugill:
I use a reverso, found it fine on my 7.8mm ropes, but I think most belay devices will be fine with the right set-up. As has been recommended in previous posts, it is good practice to use a sling so the belay device is higher up, and always use a prussik below the belay device, I attach this to my leg loop.

In reply to chrisfrugill:

DMM Pivot and 8.1mm Beal Icelines (brand new, by the way) works like a charm.

In reply to paul_in_cumbria:


This will do the trick, very easy, very quick

In reply to chrisfrugill:

I have used a DMM Bugette on my Mammut Phoenix 8.00mm ropes for the last 5 years-perfect piece of kit which I cannot recommend highly enough. This device will cover 7.5mm-9.5mm though I have only used it on my 8mms.

In reply to chrisfrugill:
I use Mammut Phoenix ropes with the DMM Reverso 3 and 4 , and carry a DMM Bugette as a spare, all work perfectly well with these excellent ropes. Going to try the DMM Pivot out soon,
Agree with the sling tip, handy .

In reply to chrisfrugill:

Add karabiners as required.

It´s worth pointing out if you can´t reasonably abseil on a rope/device combination the chances of stopping a good fall are minimal.

With skinny ropes the whole issue is a bit confusing, the shape of the rope entry into the Vee slots is critical and some ropes bite better in than others especially at the lower hand force used for abseiling. I get more braking force at low levels from 7.8´s than 8.5´s for example.
The nose providing the release hole on guide plates seems to make matters worse but I haven´t got round to testing these at abseiling loads.

In reply to jimtitt:


I was thinking exactly this thought, too. If you can't hold body weight on an abseil, how the heck do you expect to catch a fall with this device-rope combination, especially a leader fall? Especially if catching it on only one strand? (Which would be half the friction of a double-strand abseil.)

In reply to dagibbs:


One naturally has measured this as well
When only one strand is loaded of the pair then the braking force you can achieve is around 35% less than if the pair are equally loaded. You are actually better off letting go of the unloaded strand and just gripping the loaded one but in practice this may be problematic

In reply to jimtitt:


Jim, any chance of some data on this with skinny ropes? For some reason it just feels like a single skinny rope will be impossible to hold, whereas adding in the other rope increases the diameter in the hand and gives one something to hold against, if that makes sense.

In reply to chrisfrugill:
Is yr xp old? Check the breaking cleats aren't overly worn. A couple of things to note - if you are struggling to safely ab then I doubt you'll be able to hold a whipper. The ATC XP guide has different shaped cleats I find it grabbier and higher friction. If the ropes are new and / or dry treated they will be harder to hold falls. You may want to consider a specialist skinny rope device like a bugette although I normally only advice that for 8mm and below.

In reply to Ann S:


I take most the manufacturers rope diameters for belay devices with a pinch of salt - normally they say they will go to a lower diameter than they safely will. However a bugette with anything over 8.5mm is not going to happen. Even 8.5mm is hard work unless they are brand new and then it's still not as slick as you'd like.

In reply to David Coley:


A fairly unpleasant test to do, repeatedly pulling until the rope slides through the hand reduces ones enthusiasm!
ATC XP/9mm rope. One of a pair loaded 193kg, single strand 242kg, loaded equally 293kg.
Reverso³/9mm rope. One of a pair loaded 148kg, single strand 194g, loaded equally 240kg.

In reply to CurlyStevo:

I use my bugette regularly with my 9.5mm Mammut Infinity. For lead climbing and abseiling. I'd still be stuck on top of the Inn Pinn if what you say were true. And of course it works a treat with my 8mm skinny halves.

In reply to BnB:
Odd, I find it far too grabby for pleasant use on my 8.5 mammut genesis (and other 8.5mm ropes I've tried) and have failed to do abseils multiple times on single ropes as they just wouldn't fit in!

I have noticed before that the actual width and compressibility (and also flex) varies a lot between different ropes of the same width. The infinity is a light 9.5 mm with a lot of flex.

Anyway I stand corrected, lets just say the bugette only reliably works well with used ropes under 8.5mm but you may find it is ok above that.

In reply to jimtitt:



ahh but that doesn't prove that just holding the single strand gives more breaking power than holding it as one of a pair (when only that strand is loaded)

In reply to CurlyStevo:

It may just be the flexibility of the Infinity. I've yet to use single rope that I preferred to it. And mine has had a full life too.

In reply to jimtitt:




Thanks

In reply to chrisfrugill:


Some photos here: http://people.bath.ac.uk/dac33/high/10GettingBackDown.htm#addingfriction

In reply to CurlyStevo:


Indeed, I think with my weight of 8st I would have a hard job shoving 9.5mm through a Bugette on abseil!!

In reply to chrisfrugill:

I got a DMM bug because I wasn't happy belaying skinny ropes on an ATC. That was back in the days before super skinny ropes - so I guess the Bugette is what you'd want for them.

I've never noticed a problem abseiling, but I've always had the device extended from my harness, and a Prusik, so wouldn't expect to have, IYSWIM?

In reply to CurlyStevo:


"One of a pair loaded 193kg, single strand 242kg,"

Do you generally suffer from reading comprehension problems? It´s spelt braking not breaking by the way.

In reply to chrisfrugill:

I'm surprised. I've used a variety of skinnies with an ATC XP over the years, including Beal Ice Lines, and I have found the friction sufficient. For routine abseils I normally don't extend the ATC, and I use a prussic on my leg loop; in this case I find the toothed side of the ATC provides too much friction, so I use the smooth side. Occasionally I don't back up my abseil, but would still almost always use the untoothed side (unless, perhaps, on some free-hanging monstrosity). The toothed side can provide a rather jerky abseil, I've found.

In reply to chrisfrugill:

The Edelrid MicroJul is the way to go for skinny ropes. It can be oriented in two ways for rappelling to adjust friction and the (semi) auto-lock mode feels very safe and smooth when combined with a crab lever - there are a couple of excellent videos demonstrating the device. https://www.youtube.com/results?search_query=edelrid+microjul

BTW I would question the wisdom of adding crabs to increase friction - typically I've used an additional crab to push the ropes AWAy from the belay/rappel device thus reducing friction - unless I'm reading that technique wrong I'd be wary of that.

Either way get yourself a MicroJul

In reply to Wild Isle:

Add the second karabiner loose and you decrease the friction, clip two identical karabiners into the belay loop and the friction increases.