Self-locking descender for rappelling

Discuss vertical caving, equipment, & techniques. Also visit the NSS Vertical Section.

Moderator: Tim White

Re: Self-locking descender for rappelling

Postby fuzzy-hair-man » Jul 6, 2008 7:52 pm

OpenTrackRacer wrote:I think the Stop is the way to go but I'm curious to hear Hank's (and anyone else's) thoughts on my testing.


I might weigh in again...

I think the Stop is probably the best option <edit> of those described</edit>. I think once you spend more time on rope using a shunt or prussik you might quickly get sick of them and end up leaving them off, the Stop equips you well for almost any cave (except perhaps really long pitches with no rebelays).

My thoughts as some have said before in this topic are: I'd be wary of using equipment such as a Stop or shunt / prussik as a substitute for training or good technique, I personally prefer to recognize vertical ropework as risky and make sure you approach it in a way that reduces the risks involved without adding more complications or relying on equipment to catch you. Good technique and a simple and effective system are the best forms of safety IMHO.

In a nutshell: Recognize vertical ropework as inherently hazardous try as much as you can to control those hazards but maintain a simplicity to your system, the more you add to your system the more there is to get wrong.

Be aware that the Stop does tend to let (not teach :tonguecheek: ) you form bad habits and you need to aware of this and be strongly critical of your technique and make sure the stop feature does not become something you depend on. Ideally IMO you would learn on a bobbin style descender first and then switch to the Stop but I can see how this would be expensive and perhaps annoying.
Last edited by fuzzy-hair-man on Jul 6, 2008 8:33 pm, edited 1 time in total.
User avatar
fuzzy-hair-man
NSS Hall Of Fame Poster
 
Posts: 955
Joined: Apr 6, 2006 2:09 am
Location: Canberra, Australia
Primary Grotto Affiliation: NUCC
  

Re: Self-locking descender for rappelling

Postby Chads93GT » Jul 6, 2008 8:14 pm

So is the Stop preferred over a rack, becuase if you let go of the device you stop. where if you let go of the rack (intentionally or unintentially) you take a plunge?
User avatar
Chads93GT
NSS Hall Of Fame Poster
 
Posts: 2293
Joined: Jun 24, 2008 1:27 pm
Location: Missouri
  

Re: Self-locking descender for rappelling

Postby Scott McCrea » Jul 6, 2008 8:40 pm

Chads93GT wrote:So is the Stop preferred over a rack, becuase if you let go of the device you stop. where if you let go of the rack (intentionally or unintentially) you take a plunge?

Depends on who you ask. Here's a poll you that might shed some light on what folks around here prefer. Look down thru the posts to see even more polls taken elsewhere. You'll find that, generally, about 2/3 of those responding use a rack most of the time.

A properly configured and used rack will stop or slow down when you let go.
Scott McCrea
SWAYGO
User avatar
Scott McCrea
Global Moderator
 
Posts: 3198
Joined: Sep 5, 2005 3:07 pm
Location: Asheville, NC USA
NSS #: 40839RL
Primary Grotto Affiliation: Flittermouse Grotto
  

Re: Self-locking descender for rappelling

Postby OpenTrackRacer » Jul 6, 2008 11:15 pm

Thanks for the comments Fuzzy.

I agree 100% that one can get sloppy with the Stop. It'll will be very important that we do not allow that to happen. Everyone in by group has been rappelling using a figure 8 or ATC so we don't have any bad habits with regard to the rope ingrained. From my testing, the GriGri would be even worse for bad habits because it's really free when released and it's very easy to use the lever has a speed control. That can breed bad habits in a hurry.

I believe that with regard to falling debris and rappelling impact hazards, mine exploring can more dangerous than caving. The descents tend to be shorter (although we have seen some shafts that were 100-200 feet straight down) and are often filled with obstacles.

Here's two images that show a typical ladderway that we would descend. We rappel down and then climb the ladders back up using a Croll as a safety.

Image

Image

There are lots of obstacles in these shafts including platforms. We also run into various kinds of shafts...

Image

Image

As you can imagine, there are innumerable hazards at hand. I think the Stop will give is the extra safety that we don't have with an ATC or figure 8 (or rack for that matter) without any real negatives. I just picked up a Shunt for a good price that I'll play with and I'll probably look for a cheap GriGri too. It never hurts to try different things but I'm going to spec the Stop for the group at large.

The feedback here has been very helpful. I'm also trying to hook up with the local grotto but all their e-mail addresses bounce so I'm not sure how to get in touch. I'm going to keep reading and I'm still very interested in any further comments.
Underground Explorers
California Abandoned Mine Exploration
http://www.undergroundexplorers.com
User avatar
OpenTrackRacer
Prolific Poster
 
Posts: 189
Joined: Jul 1, 2008 1:05 am
Location: San Diego, CA
Name: Mike Schriber
NSS #: 65042
Primary Grotto Affiliation: Southern California
  

Re: Self-locking descender for rappelling

Postby hank moon » Jul 7, 2008 10:58 am

OpenTrackRacer wrote:Hank, I have a few questions for you as a "Petzl person" if you don't mind...

For 11mm PMI Pit Rope (typically dusty but not muddy), would you recommend an ATC and Shunt or a Stop? Again, the application is not big long rappels but shorter vertical descents slow speeds. We're talking 50 to 300 feet max. For sloping descents (decline shafts) I'd use just the ATC.

If the Shunt is used, do you think that the Spelegyca cows tail (from my Frog system) is an suitable tether?

Thanks!


Hi Mike

My experience with ATC/Shunt combo and PMI Pit rope is limited to one or two short indoor test raps, so I couldn't recommend it based on personal experience. What I do know: I don't like stuffing Pit rope into ATCs and they don't last very long in dirty environments. I've used the STOP for caving for the last 20 years or so but most often on 3/8" rope. Depending on your weight, rope condition, etc. it may work well (or not) for your intended use (dusty mines on 11 mm Pit rope). The only clear recommendation I can make is to try before you buy (kindofa duh?). Shouldn't be too hard to find a caver in your area willing to let you try his/her STOP in exchange for a beer or two... When testing, don't forget to weight the rope on a couple trials to simulate long rope.

The I'D would probably also work as long as the dirt and mud doesn't get too thick. Prolonged usage in nasty conditions will probably mean a short lifetime and...the parts on the I'D will wear out and are not replaceable as they are on a STOP. The "panic brake" feature is nice, though - accidents have occurred with the STOP due to gripping (instead of letting go) the handle in a panic situation. The I'D is theoretically more forgiving in such situations.

Ek, you asked about stories of SHUNT saves? I've heard good things over the years, but don't have any "documented" saves to share. I'll ask around.

hank
User avatar
hank moon
NSS Hall Of Fame Poster
 
Posts: 610
Joined: Sep 7, 2005 9:52 am
Location: Salt Lake City
  

Re: Self-locking descender for rappelling

Postby hank moon » Jul 7, 2008 11:30 am

Scott McCrea wrote:A properly configured and used rack will stop or slow down when you let go.



I would say "...MAY stop or slow down..."

There are a lot of variables hidden in "properly configured and used," including rope type, length, etc.. A rack on a soft, clean and flexible rope will often NOT slow down or stop when released. Rope diameter also a factor, etc....

Same goes for the STOP - there is no guarantee it will stop or slow an out of control rappel (for example) - there are too many variables.

hank
User avatar
hank moon
NSS Hall Of Fame Poster
 
Posts: 610
Joined: Sep 7, 2005 9:52 am
Location: Salt Lake City
  

Re: Self-locking descender for rappelling

Postby DrPrusik » Jul 7, 2008 1:21 pm

fuzzy-hair-man wrote:I think once you spend more time on rope using a shunt or prussik you might quickly get sick of them


There is only the one thing for making DrPrusik sick...thats the bad name spelling!

There is no prussik - there is only Prusik. Prusik should be capitalized for it is the very good name of a person (Dr. Karl Prusik). It has a little 'k' at the end and a big 'P' at the beginning. It has no 'c' and only one 's'

It is the Prusik to spell right, to use nicely, and to say with grace. Hello?
User avatar
DrPrusik
New Poster
 
Posts: 2
Joined: Mar 5, 2008 4:58 pm
Location: Prusikville
Name: Sonny Liverwurst Prusik
  

Re: Self-locking descender for rappelling

Postby NZcaver » Jul 7, 2008 2:58 pm

Scott McCrea wrote:A properly configured and used rack will stop or slow down when you let go.

Or, more likely, cause you to plummet just like most other non-autostop descenders. Have you tried letting go completely while descending on a rack? (Why would you?) And (like Hank was saying) a nice clean flexible 10mm rope is likely to perform differently, as a micro or other U rack might versus a J rack.

DrPrusik wrote:There is only the one thing for making DrPrusik sick...thats the bad name spelling!

Relax, Dr Prussssssssssssssssssssik. By now you must be used to having one of the most misspelled names in climbing, all the way from Austria to Utah. :big grin:
User avatar
NZcaver
Global Moderator
 
Posts: 6316
Joined: Sep 7, 2005 2:05 am
Location: Anchorage, Alaska
Name: Jansen
NSS #: 50665RL
Primary Grotto Affiliation: CCG
  

Re: Self-locking descender for rappelling

Postby Scott McCrea » Jul 7, 2008 3:31 pm

NZcaver wrote:
Scott McCrea wrote:A properly configured and used rack will stop or slow down when you let go.

Or, more likely, cause you to plummet just like most other non-autostop descenders. Have you tried letting go completely while descending on a rack? (Why would you?) And (like Hank was saying) a nice clean flexible 10mm rope is likely to perform differently, as a micro or other U rack might versus a J rack.

Yep, I tried it. It works on any variable friction device. Racks are configurable on the fly so it can be adapted to preform differently.
Scott McCrea
SWAYGO
User avatar
Scott McCrea
Global Moderator
 
Posts: 3198
Joined: Sep 5, 2005 3:07 pm
Location: Asheville, NC USA
NSS #: 40839RL
Primary Grotto Affiliation: Flittermouse Grotto
  

Re: Self-locking descender for rappelling

Postby hank moon » Jul 7, 2008 4:42 pm

Scott McCrea wrote:Yep, I tried it. It works on any variable friction device. Racks are configurable on the fly so it can be adapted to preform differently.


Then maybe consider amending your sentence to read something like

"a rack can be configured on the fly so that if the user lets go of the rope, the user will slow or stop...(under the following conditions)"

or you could just say "the rack can be tied off..." :big grin:

hank
User avatar
hank moon
NSS Hall Of Fame Poster
 
Posts: 610
Joined: Sep 7, 2005 9:52 am
Location: Salt Lake City
  

Re: Self-locking descender for rappelling

Postby ek » Jul 7, 2008 8:39 pm

hank moon wrote:Ek, you asked about stories of SHUNT saves? I've heard good things over the years, but don't have any "documented" saves to share. I'll ask around.

Actually I was asking about saves with a friction hitch or shunt placed under the descender but held by the non-brake hand. However, I am also interested in documentation of shunt saves when the shunt is employed above the descender and gripped with a small piece of cord, as you described.
Eliah Kagan
NSS 57892
Syracuse University Outing Club

Fund vital White Nose Syndrome research--donate to the NSS and select the WNS Rapid Response Fund.
Facebook users can also donate here.
User avatar
ek
NSS Hall Of Fame Poster
 
Posts: 1040
Joined: Apr 3, 2007 2:45 am
Location: Syracuse, NY
Name: Eliah Kagan
NSS #: 57892
Primary Grotto Affiliation: Syracuse University Outing Club
  

Re: Self-locking descender for rappelling

Postby OpenTrackRacer » Jul 8, 2008 12:25 am

The Stop seemed to work pretty well with my rope, even with 200 feet worth hanging down. I don't think we're going to even consider racks. They don't really offer any benefit for our type of rappels.

I just picked up a lightly used Shunt for a smoking price so I'll mess around with that too.

I can't wait for it to cool down so we can get back out there!
Underground Explorers
California Abandoned Mine Exploration
http://www.undergroundexplorers.com
User avatar
OpenTrackRacer
Prolific Poster
 
Posts: 189
Joined: Jul 1, 2008 1:05 am
Location: San Diego, CA
Name: Mike Schriber
NSS #: 65042
Primary Grotto Affiliation: Southern California
  

Re: Self-locking descender for rappelling

Postby ek » Jul 8, 2008 12:33 am

Why does it have to cool down?
Eliah Kagan
NSS 57892
Syracuse University Outing Club

Fund vital White Nose Syndrome research--donate to the NSS and select the WNS Rapid Response Fund.
Facebook users can also donate here.
User avatar
ek
NSS Hall Of Fame Poster
 
Posts: 1040
Joined: Apr 3, 2007 2:45 am
Location: Syracuse, NY
Name: Eliah Kagan
NSS #: 57892
Primary Grotto Affiliation: Syracuse University Outing Club
  

Re: Self-locking descender for rappelling

Postby OpenTrackRacer » Jul 8, 2008 1:17 am

Well, it's pretty cool in the mines but it was 106 degrees on the surface today. That's just too darn hot for camping, even in a trailer with generator and AC. There is little to no shade and the sun puts too much energy in and even the AC can't keep up.

ek wrote:Why does it have to cool down?
Underground Explorers
California Abandoned Mine Exploration
http://www.undergroundexplorers.com
User avatar
OpenTrackRacer
Prolific Poster
 
Posts: 189
Joined: Jul 1, 2008 1:05 am
Location: San Diego, CA
Name: Mike Schriber
NSS #: 65042
Primary Grotto Affiliation: Southern California
  

Re: Self-locking descender for rappelling

Postby ek » Jul 8, 2008 1:53 am

Perhaps you could camp in the mines...
Eliah Kagan
NSS 57892
Syracuse University Outing Club

Fund vital White Nose Syndrome research--donate to the NSS and select the WNS Rapid Response Fund.
Facebook users can also donate here.
User avatar
ek
NSS Hall Of Fame Poster
 
Posts: 1040
Joined: Apr 3, 2007 2:45 am
Location: Syracuse, NY
Name: Eliah Kagan
NSS #: 57892
Primary Grotto Affiliation: Syracuse University Outing Club
  

PreviousNext

Return to On Rope!

Who is online

Users browsing this forum: Google [Bot]