Belay/rappel device for very skinny ropes?

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Child of the Abyss

climber
Seattle, WA
Topic Author's Original Post - Dec 4, 2017 - 03:09pm PT
I'm looking for a rappel device that provides adequate friction for rappelling on extremely slippery, skinny ropes (5mm). I have experimented with the Edelrid Microjul, the DMM Bugette, a mini figure-8 by Mammut, and a mini figure-8 by SMC. All of them provide just barely enough friction to work, but it is marginal.

I think there are some ultra-small tube-style devices that have been specialty-made. I think that Maxim used to sell one to firefighters to be paired with their 5.5mm tech cord, or something like that.

Anyone know of one? Bonus if it's actually available to consumers!

Thanks!
kunlun_shan

Mountain climber
SF, CA
Dec 4, 2017 - 03:34pm PT
Have you tried the DMM Pivot? I have not used it with 5mm, but it seems to grip 7mm cord quite well. Combined with a large radius biner - DMM recommends the Rhino, which I use. Also very nice for lowering.
johntp

Trad climber
socal
Dec 4, 2017 - 03:45pm PT
Six biner rappel rig. Just add biners till you get the friction you need.
couchmaster

climber
Dec 4, 2017 - 03:50pm PT

I use the Bugette and love it (for ropes to 7.8mm). Are you using 1 or 2 carabiners? You might try 2 (if they are the same size) if you are using one as it will increase your friction. The bigger the diameter the better.

If that still doesn't do it, try going old school and use a single link from a chain. You may have to experiment to get the right size. Just make sure it's strong enough or back it up with some kind of a friction hitch or shunt type of device. You may or may not know this, but chain comes in differing grades. I think (going from memory you can look it up) that grade 70 is the stronger stuff.

But look that up first.
skywalker1

Trad climber
co
Dec 4, 2017 - 04:15pm PT
As above increase the number of biners with some form of stitch plate. The chain link idea is a good one if as the poster said...

S...
Ksolem

Trad climber
Monrovia, California
Dec 4, 2017 - 04:19pm PT
Why?
xCon

Social climber
909
Dec 4, 2017 - 04:25pm PT
somebody made a tactical line of descenders and ascenders for 5.5mm Kevlar a few years back

cant recall who though
Robert L

climber
Dec 4, 2017 - 04:27pm PT
Is this for rapping on a single strand of 5mm?

I know that military SF is trained to use the Dulfersitz if they have to rap on para cord in desperate situations.

Steve House should be able to get you in touch with the dudes who gear test for the USN Seals. If anyone is going to have seen what ya looking for, it's going to be one of their test detachments.
Steve Grossman

Trad climber
Seattle, WA
Dec 4, 2017 - 04:42pm PT
I don't have direct experience with its use but the Petzl Pirana is supposed to be good with small diameter rope and has enough mass that the heat is dissipated well to avoid a melt through which would be my big concern on such a small diameter rope.
What are you trying to accomplish such that you have to use 5mm? Not much margin of anything there.
Steve Grossman

Trad climber
Seattle, WA
Dec 4, 2017 - 04:46pm PT
The Pirana came up in conversation with Bill Hatcher on a recent climbing trip when discussing the skinny cord quandry.
nah000

climber
now/here
Dec 4, 2017 - 05:05pm PT
haven't used the following myself... but it sounds from this review like the sterling ats likely offers more friction than the pirana that grossman mentions above [and thanks for that suggestion as that was how i ended up finding the ats, as i'd never heard of the pirana nor the ats before today]...

the review mentions the writer is 200 pounds and it had enough friction for a single strand 6mm rap...

anyway, is an interesting question. i've used 5.5mm cord a few times for rapping and just used a reversino... but there are situations where a dedicated small diameter belay/rap device could come in handy.

let us know if you figure something out.
mikeyschaefer

climber
Sport-o-land
Dec 4, 2017 - 05:55pm PT
I've used a standard extended atc device and then a munter on the belay loop to rap 5.5 tech cord and that skinny black tech cord that i have. Remember that working reasonably well. Or two bugettes in a row would be really smooth.
Child of the Abyss

climber
Seattle, WA
Topic Author's Reply - Dec 4, 2017 - 06:42pm PT
Thanks for the replies so far.

I'm not really interested in a long carabiner-brake solution, because it is slow to rig if doing many rappels (and uses up a lot of carabiners).

The ATS might provide enough friction, maybe the Pirahna as well, although they both seem a bit heavy, which slightly negates the advantage of such a thin rappel rope. More importantly, I've never managed to make long rappels with figure-8 type devices without the rope getting at least somewhat twisted. Perhaps this is simply user error, and there is an easy trick to never twist the ropes, but I haven't been able to figure it out.

With a tube-style device, on the other hand, I can always rig it quickly and I never twist the ropes. I find the Bugette works pretty well down to 2 strands of 6mm (with 2 carabiners in that case), but even then it isn't as much friction as I would like. I've never tried using 3 fat carabiners, but I suppose it's worth a try.

I think the ideal would be something like a Bugette, but even smaller in dimensions, and ideally with V-slots for added friction. I've started brainstorming options for some sort of small piece of metal to use as a makeshift tube or sticht (spelling?) plate. The right size old-style hexentric might do the trick.



Brian in SLC

Social climber
Salt Lake City, UT
Dec 4, 2017 - 06:46pm PT
I've used a Petzl Pirana a fair bit. Shines as a rappel device for wet, 10mm single strand rope.

I think it might be too "wide open" for a really small cord. That said, it does have a number of options to add friction.

This seem to work well on a smaller single strand:

http://www.bluugnome.com/cyn_how-to/gear/sqwurel/sqwurel.aspx

A munter in combo with an ATC type device (Reverso, etc) might work.

I've used an ATC with a 6mm Kevlar cord...helps to pitch it out on a sling then do a Z type rig for additional bends and friction.

Anyhoo...bad idea jeans! Ha ha.
rgold

Trad climber
Poughkeepsie, NY
Dec 4, 2017 - 07:43pm PT
A Rock Exotica Mini 8 might work...

Rock Exotica Mini 8 High Friction Mode
Rock Exotica Mini 8 High Friction Mode
Credit: rgold
NutAgain!

Trad climber
South Pasadena, CA
Dec 4, 2017 - 07:49pm PT
Any stories about dulfersitz on paracord? That sounds like heinous body scarring, and specialized clothing required to avoid slicing yourself in half. Must be pretty desperate to go for it.
Clint Cummins

Trad climber
SF Bay area, CA
Dec 4, 2017 - 07:59pm PT
Like Mikey and others said, if you are not getting quite enough friction from one device, use 2 devices in series.
I know, this makes it slower to go on and off each rappel.
But it gives you options that work for more than one particular rope type or condition (wet/dry, etc.).
Child of the Abyss

climber
Seattle, WA
Topic Author's Reply - Dec 4, 2017 - 09:11pm PT
I think Mikey's double-Bugette in series idea sounds good. I'll try that, unless someone does find a mini, super-high-friction tube/plate.
OlympicMtnBoy

climber
Seattle
Dec 4, 2017 - 09:47pm PT
How about one of these:
G. Storrick Photo
G. Storrick Photo
Credit: OlympicMtnBoy
G. Storrick Photo
G. Storrick Photo
Credit: OlympicMtnBoy

Too bad it's only rated for keys.

If you haven't explored it, Gary Storrick's site is a treasure trove of ascending and descending gear and may provide some leads or design inspiration.
It does list the Bugette and Jul as the narrowest slots from his collection.
http://storrick.cnc.net/VerticalDevicesPage/BelayDevices.shtml
Gnome Ofthe Diabase

climber
Out Of Bed
Dec 4, 2017 - 10:49pm PT
Seeing that the web site is already linked

I've played around with the Russian Petal(?)

http://storrick.cnc.net/VerticalDevicesPage/Rappel/RappelImages/MiscImages/DSC1253_7963.JPG


& regularly use Kong, Robot(s)

http://storrick.cnc.net/VerticalDevicesPage/Rappel/RappelImages/MiscImages/DSC1024_7814.JPG



Threading  various diameters - thinnest: 5 -7 mm &#40;upper left, unde...
Threading various diameters - thinnest: 5 -7 mm (upper left, underlined)
Credit: Gnome Ofthe Diabase










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