/ Abbing on thin ropes

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Baz P 15 Mar 2020

I go abroad several times a year and usually take a 70m single rope. Just lately I have been doing lots of ridges, canyons and ferrata as well as sport. Carrying a 70m at my age is getting a bit tiring and overkill so I’ve been looking at the nice light 7.5mm ropes (obviously not for sport).
The problem I can see is going to be the speed of descent when abseiling, especially on free abs of which there are a lot in canyons. I can always use two crabs but was wondering if anyone had experience of abbing on 7.5mm or suggestions for a smaller abseil device. The rope is going to be double but I still anticipate it’s going to be like “sh#t off a shovel”. 

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GrahamD 15 Mar 2020
In reply to Baz P:

Stick another krab between your plate and your main belay krab.  Adds significantly more friction to the system. 

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Mr Messy 15 Mar 2020
In reply to Baz P:

I have never had a problem. I either use a DMM pivot or older BD guide plate

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Mr Messy 15 Mar 2020
In reply to Baz P:

Ho there will be quite a lot of rope stretch. 

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Baz P 15 Mar 2020
In reply to GrahamD:

Yes I always do this on free abs but even this freaks my partner out so I have to dead rope her.

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Baz P 15 Mar 2020
In reply to Mr Messy:

Yes, must remember not to let go of the rope at the bottom, been there.

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AlanLittle 15 Mar 2020
In reply to Baz P:

I find 8.1mm Ice Lines ok on a normal Reverso, but would probably be thinking  about something like a Micro Jul if I was going much thinner

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Baz P 15 Mar 2020
In reply to AlanLittle:

Thank you for the Micro Jul suggestion, don’t remember seeing that before. Looks perfect for double 7.5’s.

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Andrew Lodge 15 Mar 2020
In reply to Baz P:

Either a Pivot or a Reverso worked fine for us using 7.5's on a recent trip.

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alexm198 16 Mar 2020
In reply to Baz P:

I’ve used a MicroJul when climbing on Beal Gully 7.3s in the past. System worked well with plenty of friction. The MicroJul is a bit fiddly and not very nice to lead belay with, so I would consider taking a Reverso to belay with (if I was confident it would work — haven’t tried). 

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MischaHY 16 Mar 2020
In reply to Baz P:

Consider something like the Edelrid Canary. 8.6 single, 51g/m. 

I use this (or the Mammut Serenity 8.7) combined with a 60m tag line which means you can do full length abseils and haul a small pack etc with very few compromises. 

Something like the Canary is far more robust meaning it's less likely to get ragged in a dodgy fall/falling rock etc. Also zero problems belaying/abseiling and all the other benefits. 

Hope this helps. 

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ScraggyGoat 16 Mar 2020
In reply to Baz P:

If changing your device and adding a jean doesn't give the desired friction or increased confidence.  After threading and clipping the plate, take the rope round your back and then over your head, so that it is entirely round your waist, massive increase in friction.

If you have set off normally and realise you want more friction wrap around your thigh though this is less comfortable.

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Sean Kelly 16 Mar 2020
In reply to Baz P:

Gloves?

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Alkis 16 Mar 2020
In reply to Baz P:

Can't you just add a prussik on the deadrope?

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henwardian 16 Mar 2020
In reply to Baz P:

I did some multi-pitch abbs last year on thin ropes (not sure the diameter) and I was very much not a fan. It was tiring on the hands, even using a shunt for the backup (which normally works very pleasantly with 8.5mm ropes) and I wasn't even doing free-hanging abseils.

I'm sure a big part of my difficulty would be down to belay device, so my advice would be to abseil of some bridges at home with your chosen new setup _before_ you commit to going abroad with only that option because if it turns out to be too slick or otherwise difficult to use that would probably be quite frustrating.

I'll leave specific suggestions of device to others.

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David Coley 16 Mar 2020
krikoman 16 Mar 2020
In reply to Baz P:

I always abb with an extended belay, i.e. a sling larks footed through my belay loop and the crab and belay plate attached to that, it means I already have a sharp, and high friction, loop in the belay.

Like this, but this is more complicated than mine, though probably a bit safer. https://www.climbing.com/skills/rap-smart-rappelling-best-practices/

It also gives you space to fit a prussik on the dead side, without fouling up the belay device.

Never tired it on rope that small though.

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nniff 16 Mar 2020
In reply to Baz P:

Regularly abseil on skinny ropes in winter (7.3mm I think) with no issues with a Reverso.  The only caveat is that in winter I wear gloves, but never have any problems with excessive speed (usually the problem is trying to be silky-smooth abbing off something that is far from CE-certified) na dof course sometimes the ropes are icy.   Still, a glove might not be a bad idea, not so that you can go fast but so that you can grip harder if need be without cooking your hand

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Deadeye 16 Mar 2020
In reply to GrahamD:

> Stick another krab between your plate and your main belay krab.  Adds significantly more friction to the system. 


**Whoa**

There's a very important distinction between two very similar setups that have completely opposite effects.  Simply following the shorthand above on skinny ropes couold be very dangerous.

An extra krab, through the rope only, between the plate and the main krab, will **reduce** friction.  It's a well-used way of making thick/sticky ropes go through grabby plates.

An extra krab, through the rope *and the belay loop* (duplicating the belay krab), *and of the same size*, will increase friction. 

I'm sure you meant the latter, but you described the former.

The caveats in the latter are important - and those, plus the ease with which you can make a dangerous mistake, are the reasons I'd never advocate additional krab for increasing friction (the other way round - trying to reduce friction but failing - is failsafe).

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oldie 16 Mar 2020
In reply to Baz P:

In some posts people seem to like the BD ATC Alpine (don't think it has an "XP" in it), specifically for thinner ropes.

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Baz P 16 Mar 2020
In reply to Baz P:

To David Coley, thank you for the links, I have just purchased the Kindle version of that book and look forward to a good read.

Thanks to every one else for some ideas to look at.

Some of the ideas I have already tried. I use double screw gate crabs quite a lot and also gloves because a lot of the outings are on ferrata. As to wrapping the rope around the body, I have ruined lots of woolly jumpers a long time ago doing classic abseils so I probably wouldn’t with a Rab tee shirt. 
Most of my abs are absolutely fine but coupling a recent 50m ab with 45m being free with intended 7.5mm ropes had me thinking.

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Big Lee 17 Mar 2020
In reply to Baz P:

A standard BD ATC Guide has worked fine with my 7.5mm ropes for a few years now. I extend it as Krikoman describes and use a prussik off the front of my harness. This feels 100% safe and controlled on free-hanging abseils, with whatever gloves. I've used a Petzl Reverso 4 in the past but the metal wore too quickly, meaning it had a short life. I'd definitely consider the BD ATC Alpine if I was in need of a new plate tomorrow. Less metal can sometimes mean less heat dissipation though. My old DMM Buggett used to get red hot during abseils. The Microjul has a reputation of being pretty unpleasant to use, however the Giga jul might be worth considering if you can accept the weight. Much heavier than a regular ATC, but much lighter than a Grigri. 

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Timmd 17 Mar 2020
In reply to Deadeye:

> **Whoa**

> An extra krab, through the rope *and the belay loop* (duplicating the belay krab), *and of the same size*, will increase friction. 

> I'm sure you meant the latter, but you described the former.

> The caveats in the latter are important - and those, plus the ease with which you can make a dangerous mistake, are the reasons I'd never advocate additional krab for increasing friction (the other way round - trying to reduce friction but failing - is failsafe).

It's really good that you've pointed this out. To do with never doing certain things, I guess it depends on one's ability not to mess things up. It's something else to keep in mind for when it's needed, it could be useful.

Post edited at 10:59
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Baz P 21 Mar 2020
In reply to Big Lee:

Thank you for the options although I notice that the BD ATC Guide recommends ropes from 7.7 mm and I was considering 7.5 or 7.3mm.

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RR 22 Mar 2020
In reply to Baz P:

Has any one considered or experience with a Giga Jul, that’s the auto block thing of Edelrid up to 7.1 mm rope.

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steveshaking 22 Mar 2020
In reply to Baz P:

They may have meant the atc alpine guide which covers 6.9-9.0 . This would cover most people's outdoor climbing. But not all and definitely not the climbing wall.

As others have said the current Reverso and DMM pivot cover a wider range.

We ended up simul abing on steep ground ie just one strand on 7.5, on the latest Reverso, with a prussic loop. It all worked fine.

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