/ Abseiling with DMM pivot

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bedspring on 10 Jul 2017
Been doing a bit of abbing off routes and not very happy with the DMM pivot. I find it very grabby/jerky, particularly in the the first 10 or 20``feet or so. Is there a better device or am I doing something wrong. I orientate it to abb as I would to belay and belay direct of my loop as do like to keep things ultra simple. We use 8.5mm or 9mm ropes. Thanks for any help.
ChrisH89 - on 10 Jul 2017
In reply to bedspring:

I use my Pivot regularly to abseil with no issues, unless the rope is particularly thick and/or wet which I find always makes abseiling a pain.

Two things that might make it easier. Firstly, try abseiling in the low friction mode i.e. with the grooves on the top rather than the bottom. I weigh about 70kg-ish and find that if I abseil in high friction mode it's much more difficult, especially on less than vertical abseils. Secondly, try extending the abseil plate using a sling larks footed to your belay loop and with a knot tied about at about 20cm to use as a shelf (I like the Edelrid amarid slings for this as the knots are much easier to undo after loading) . This allows you to have your prussik on your belay loop rather than leg loop and makes feeding rope through the belay plate easier, among other advantages. I know you say you prefer ultra simple, but this is a commonly used abseil technique that in most situations is better than using belay loop and leg loop for plate/prussik respectively.
superturbo - on 10 Jul 2017
In reply to bedspring:

I was having the same issue until I turned it around, so the ropes are running through the smooth side of the device. I attach the screwgate to a sling then prussik on a legloop. Works much better.
Jim Walton on 10 Jul 2017
In reply to bedspring:
Like others said, try extending your belay plate away from your harness. This can be done with a sling larks footed to your harness witha overhand knot tied in it about 30cm from the harness (a Beal Dynaloop is dynamic as opposed to nylon or dynemma which are static and Dynemma slings are a pig to undue the knot once it's been loaded).

Also, what karabiner do you use to attach your belay plate? I have found an Oval shaped carabiner (a Type X if you will) to be the smothest of all. D Shape (a Type B if you will) seems to be the worst for creating jerkyness, HMS Carabiners with a solid round bar are ok but not as smooth as an oval.
Post edited at 15:07
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bedspring on 10 Jul 2017
In reply to bedspring:

Cheers for the replies. I use the DMM Rhino Krab that came with the device so I may try a rounder profile one. I will try reversing the device. Though I appreciate extending the belay I would rather not do this as it is one more link in a chain and I strongly believe in KISS, Keep It Simple Stupid
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Jim Walton on 10 Jul 2017
In reply to bedspring:

The dissadvantage of not extending the belay device is that you have to then clip the prussik (if you use one) to your leg loop to prevent it fouling the abseil device. This always seems a strange choice to me as the harness was designed for you to hang in if the point of connection linked both the waist and the leg loops together.

I recommend you try hanging off just your leg loop (with perhaps a safety rope as well!!), let go of the abseil rope and just hang as you would if unconsious the result is you being turned upside down with all your weight supported by one leg loop. Not ideal.

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bedspring on 10 Jul 2017
In reply to Jim Walton:

I do use a prussick and I agree the leg loop is an odd thing. I am in this instance talking about abbing off big routes that often have equipped abbs and belays so I use a Beal Dynaconnexion so I could experiment with the nearer loop and a round profiled krab I have for belaying off. http://www.beal-planet.com/2014/img/photos-produits/Longe-Dynaconnexion.jpg But I do not like making changes to my system.
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Jack B on 10 Jul 2017
In reply to bedspring:

I also don't like the abseil device on belay loop and prussic on leg loop arrangement. When initially trying it out, I found that if I lent back and lifted my knee, then the prussic could make it up to the ab device. The ab device then stopped the prussic from locking off, and the top strand of the prussic guided the rope into the ab device so it didn't lock either. Now, it probably depends a lot on harness size, prussic length, and choice of ab device, but I certainly didn't feel like it would reliably lock off if I was unconscious. I settled on extending the ab device with a sling, and put the prussic on the belay loop.
andyjohnson0 - on 10 Jul 2017
In reply to Jim Walton:
> I recommend you try hanging off just your leg loop (with perhaps a safety rope as well!!), let go of the abseil rope and just hang as you would if unconsious the result is you being turned upside down with all your weight supported by one leg loop. Not ideal.

I see you're an MIA, so I'm sure your knowledge is much more extensive than mine, but I don't understand how an unconscious climber could realistically end-up hanging from their leg loop while abseiling. I suppose if the abseil device, krab, or extender failed then this could happen, but thats a catastrophic failure and the prussik isn't intended to back that up. What am I missing?
Post edited at 16:45
GridNorth - on 10 Jul 2017
In reply to bedspring:

I got into the habit of extending the device away from the harness many years ago out of necessity because I had a BD harness with plastic buckles securing the leg loops. I soon discovered however that it made abseiling much easier and more controllable with the added advantage that on multiple abseils I could also use it to secure myself to the anchors very quickly. I've used this method ever since.

Al
Greasy Prusiks on 10 Jul 2017
In reply to bedspring:

I use a pivot without any issues. What are you comparing it to?
Mattilda on 10 Jul 2017
In reply to bedspring:

Haven't had a problem with mine, seems pretty spangly, very well thought out and engineered. Prefer it to an atc which is a bit too slick for me. Do use it with a sling from my belay loop. Not sure if this makes any difference, but if you use a double sling with a knot in it (horror of horrors,) you can also use it as a lanyard to clip to you anchor safely above the belay device (making sure no slack in the system).

One other thing to check is the carabiner used. Seems that the plate type belay devices seem to work better with carabiners with less curved top bars like the rhino, new petzl Attache etc, probably very wrong here but wonder if tube type (atc) work better with more rounded hms types? (and would an offset d bunch up the ropes?)
rgold - on 10 Jul 2017
In reply to bedspring:

Here are things that will help the binding issue:

1. Try a rounder carabiner
2. Try low-friction mode.
3. Try using two carabiners, but with the second one NOT clipped to the belay loop.

Extending the rappel is the best and safest way to employ an autoblock backup. And it is also a good way to get more control from a device that isn't quite grabby enough, because the extended device allows for the brake strand to be held more nearly vertical and so more friction is obtained. However, if the problem is already too much friction, then extending the rappel is only going to make that more pronounced, although one of items 1--3 will still alleviate it.

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