14" Rack Ascent to Rappel Changeover Question

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

Moderator: Tim White

Re: 14" Rack Ascent to Rappel Changeover Question

Postby Anonymous_Coward » Sep 8, 2014 6:46 pm

To the OP,

There is nothing wrong with the convert-to-texas changeover that you are doing. This is exactly how I do changeovers with a 14" rack. I was never able to get the under-the-croll method to work well with a long rack. With my system, the tolerances are just too thin. Too much potential for tether-weighting. So, I would argue that your method could be quite a bit faster, since there is less potential to screw it up.

Just practice your method over and over and it will become faster and more efficient. I did my NCRC level 2 entrance skills using the method you describe. I was able to put my system on, climb 10 meters, change over, and rappel to five feet above the ground, change over to ascent, and downclimb to the ground in less than eight minutes. The actual changeover probably took about 1 minute. I find these texas changeovers faster than any method where I have to rig a 14" rack upside-down.
Andy Armstrong
American Carbide Council
User avatar
Anonymous_Coward
NSS Hall Of Fame Poster
 
Posts: 892
Joined: Feb 3, 2006 1:40 pm
Location: Inside the Beehive
NSS #: 45993RL FE
Primary Grotto Affiliation: Paha Sapa Grotto
  

Re: 14" Rack Ascent to Rappel Changeover Question

Postby GroundquestMSA » Sep 8, 2014 7:48 pm

I have used an attachment carabiner, or a direct attachment, both have worked ok. Having tried it both ways, I still don't understand the supposed advantages of various rack orientations. Indeed, the fact that there are flat eyes, turned eyes, offset eyes, and cavers who use all of these both with and without a link suggests that it's another of those personal preference things.

NZcaver wrote:What type of rack do you use? I use this same technique and it works well with a micro rack or other short descender, but I find it virtually impossible with a long J-rack. And I know I'm not the only one. I suppose if you're really tall it might work more efficiently.


I've just been practicing with a six-bar j-frame. No problems. I'm not tall, but I suppose I may have longish limbs... I'm honestly not sure. What is the cause of your difficulty? Weighting the tether instead of the rack? I have my footloop adjusted so that there is very little space between ascenders when standing. My safety tether is long enough that I have an inch or two of slack when the ascender is fully raised. This combinations works for me.
User avatar
GroundquestMSA
NSS Hall Of Fame Poster
 
Posts: 1343
Joined: May 5, 2011 1:32 pm
  

Re: 14" Rack Ascent to Rappel Changeover Question

Postby Chads93GT » Sep 8, 2014 7:56 pm

ITs not a personal preference thing, its about being able to do changeovers when 40-90 pounds of rope weight, or more, on long drops. ONe orientation you can do it fairly easy. The other is impossible becausethat orietation makes you have to lift the rope where as the other you can use your leg to swing the rope side to side to disengage bars, or add bars. If the rack frame runs parallel with your chest, you wont be able to do a changeover with significant rope weight.
User avatar
Chads93GT
NSS Hall Of Fame Poster
 
Posts: 2293
Joined: Jun 24, 2008 1:27 pm
Location: Missouri
  

Re: 14" Rack Ascent to Rappel Changeover Question

Postby Chads93GT » Sep 8, 2014 8:39 pm

I almost forgot. Parallel orientation = you can never truely go down to 5 bars. Only a perpendicular rack can be used with 4, 5 or 6 bars. Safely anyway. Have a perpendicular orientation makes your rack function much much more efficiently. For what its worth.
User avatar
Chads93GT
NSS Hall Of Fame Poster
 
Posts: 2293
Joined: Jun 24, 2008 1:27 pm
Location: Missouri
  

Re: 14" Rack Ascent to Rappel Changeover Question

Postby DawgsgoCaving » Sep 8, 2014 9:25 pm

Chads93GT wrote:ITs not a personal preference thing, its about being able to do changeovers when 40-90 pounds of rope weight, or more, on long drops. ONe orientation you can do it fairly easy. The other is impossible becausethat orietation makes you have to lift the rope where as the other you can use your leg to swing the rope side to side to disengage bars, or add bars. If the rack frame runs parallel with your chest, you wont be able to do a changeover with significant rope weight.


A lightbulb just went off in my head lol
DawgsgoCaving
Prolific Poster
 
Posts: 165
Joined: Jan 8, 2014 6:59 pm
Name: Josh Schultz
NSS #: 65630RE
Primary Grotto Affiliation: CTG SCCi 3501
  

Re: 14" Rack Ascent to Rappel Changeover Question

Postby DawgsgoCaving » Sep 8, 2014 9:26 pm

Thanks for the advice everyone
DawgsgoCaving
Prolific Poster
 
Posts: 165
Joined: Jan 8, 2014 6:59 pm
Name: Josh Schultz
NSS #: 65630RE
Primary Grotto Affiliation: CTG SCCi 3501
  

Re: 14" Rack Ascent to Rappel Changeover Question

Postby GroundquestMSA » Sep 8, 2014 10:00 pm

Josh, I'm glad you're getting some answers. I hope you won't mind if I ask for a bit of clarification from Chad...
Chads93GT wrote:ITs not a personal preference thing, its about being able to do changeovers when 40-90 pounds of rope weight, or more, on long drops. ONe orientation you can do it fairly easy. The other is impossible becausethat orietation makes you have to lift the rope where as the other you can use your leg to swing the rope side to side to disengage bars, or add bars. If the rack frame runs parallel with your chest, you wont be able to do a changeover with significant rope weight.

I understand the advantages when adding/removing bars with a bunch of weight below (you can use your legs), but I can't imagine what relation rack orientation has to ease of changeover.
Chads93GT wrote:I almost forgot. Parallel orientation = you can never truely go down to 5 bars. Only a perpendicular rack can be used with 4, 5 or 6 bars. Safely anyway. Have a perpendicular orientation makes your rack function much much? more efficiently. For what its worth.

What have I been doing all the while? Why is it unsafe? From what source does this abundance of efficiency spring? I've read a bunch of discussions about this issue, and as yet, I don't understand most of them. I'm not a vertical caver, just a caver that occasionally rappels and climbs, but I would love to be able to decide which bin to file this argument in. The Academic, Hair-splitting, Sermonic Nonsense bin is pretty full... I'd like to put some stuff in the Functional, Sober, Practical Advice bin.
Feel free, Chad or anyone, to PM with enlightenment if you don't want to clutter this topic further.
Thanks!
User avatar
GroundquestMSA
NSS Hall Of Fame Poster
 
Posts: 1343
Joined: May 5, 2011 1:32 pm
  

Re: 14" Rack Ascent to Rappel Changeover Question

Postby DawgsgoCaving » Sep 8, 2014 10:17 pm

I don't mind, Groundquest. Moderator(s) may, but not me. I value all of this information and appreciate any related responses and discussion.
DawgsgoCaving
Prolific Poster
 
Posts: 165
Joined: Jan 8, 2014 6:59 pm
Name: Josh Schultz
NSS #: 65630RE
Primary Grotto Affiliation: CTG SCCi 3501
  

Re: 14" Rack Ascent to Rappel Changeover Question

Postby Chads93GT » Sep 8, 2014 10:39 pm

Traditionally speaking, when a rack is oriented perpendicularly to your body, to be on 4 bars, the rope is over the right hip. 5 bars, left hip, 6 bars, right hip.

When oriented parallel, 4 and 6 bars the rope is coming out facing you, for 5 bars its facing away from you.

When perpendicular you can simply use your feet to swing the rope from side to side, adding or lessening friction. When the rope has to swing front to back, its not so easy.

Besides..............the rack was designed to be oriented perpendicular. That being said, I know lots of people who orient parallel.

why does it make it easier to do changeovers with rope weight? Because when its perpendicular you kick the rope side to side to thread the rack. If its parallel you have to LIFT the rope up. On long drops, its virtually impossible to lift that much weight.

besides, perpendicular also keeps the rope from ever rubbing on the frame and cutting it in half.

Take it for what its worth. Your abundance of efficiency comes from experience, not a book.
User avatar
Chads93GT
NSS Hall Of Fame Poster
 
Posts: 2293
Joined: Jun 24, 2008 1:27 pm
Location: Missouri
  

Re: 14" Rack Ascent to Rappel Changeover Question

Postby GroundquestMSA » Sep 8, 2014 11:00 pm

I see. I have, no matter the orientation, always left the tail between my legs (as may soon be the figurative necessity if I keep exposing my ignorance in this thread).
I have noticed no difference between pushing and pulling to add/subtract friction when compared to lateral swinging, and the rope stays off the frame. I should, and will, practice more with weight on the rope. While one needn't lift the entire rope weight to thread the rack, I'm interested to experiment with the possibilities. I have heard, in cases where extremely heavy rope makes threading difficult, that clipping the rack to a qas and levering it onto the rope before attaching to the harness is an option. If you're doing a changeover beneath the croll, this could also help to reduce slop.
User avatar
GroundquestMSA
NSS Hall Of Fame Poster
 
Posts: 1343
Joined: May 5, 2011 1:32 pm
  

Re: 14" Rack Ascent to Rappel Changeover Question

Postby Chads93GT » Sep 8, 2014 11:12 pm

Yes, detaching the rack and threading it on separately, tethered to your cowstail, is what is necessary on HEAVY ropes. The longer the frame, the more leverage you have, making it easier to get it on, then clip in.

as for the rope going between your legs, you can do that, or throw it over your hip, or have it beween your legs and hook it with your foot and push it straight out, or bring it back in, to add and reduce friction. Granted, you have to have considerable weight for that to even matter. 100-200' drops you wont ever need to do that. using your legs allows you to add and drop bars while on the fly as well, removing the need to come to a dead stop, add or drop a bar, then go back to rappelling. :)
User avatar
Chads93GT
NSS Hall Of Fame Poster
 
Posts: 2293
Joined: Jun 24, 2008 1:27 pm
Location: Missouri
  

Re: 14" Rack Ascent to Rappel Changeover Question

Postby Scott McCrea » Sep 9, 2014 10:04 am

Here is the article I wrote about controlling friction with a rack that explains why perpendicular orientation is important.
http://www.swaygogear.com/variable-friction/
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: 14" Rack Ascent to Rappel Changeover Question

Postby GroundquestMSA » Sep 9, 2014 6:08 pm

Just did some more playing. The changeover below the croll was no problem with a direct connection to the D. With a carabiner added, there was zero room for slop, though I was successful both times I tried to changeover. Since a carabiner is frowned upon for connecting the rack anyway, a small mallion would allow a little more wiggle room. Then I weighed a 41-pound rock, and strapped it to the tail. If you have 41 pounds of rope under you, it's probably wise to add another connector, and clip the rack to the cowstail to thread it. Unless you're strong. I was determined to changeover instead of downclimbing ten feet though, and I did, but it wasn't easy. Especially because a bee stung my neck during the heat of my struggles. It occurred to me that if you carry a third ascender, It could be clipped, upside down, to the D. Then you could haul up some slack with both hands and rig your rack in comfort.

41 pounds of rope, assuming it's clean, which it usually isn't, equals 761 feet of PMI Pit. Struggling 761' from the ground is probably going to be genuinely unpleasant. I'm sure that anyone who is doing major pits should be practicing and planning for the rope weight in advance.

This was a twofold session, the other thing was to see if rack orientation had any effect on the ease of the changeover. It did not. At all. With the rack connected to the harness, a frog system, and attempting a changeover beneath the croll, the rope must be lifted no matter the rack orientation. This isn't really a practical discovery, since very few people are frogging with immense rope weight below.

This relates to most rack orientation arguments, then, in only a negligible degree. Most of the arguments normally heard are those Scott presents on his site. They are short on "whys." Technically, mechanically, they may make sense. In practice, though, they assume something about rack use that I am not ready to accept; namely, that it is necessary for us to squeeze every ounce of theoretical efficiency and variable nuance out of the rack. One can add and remove bars while moving, control entrance angle, and control bar spacing, with either orientation. Entrance angle control is certainly enhanced with perpendicular orientation, but how important is this? As far as safety, the only really meaningful measure of SRT technique, is concerned, probably not very.
User avatar
GroundquestMSA
NSS Hall Of Fame Poster
 
Posts: 1343
Joined: May 5, 2011 1:32 pm
  

Re: 14" Rack Ascent to Rappel Changeover Question

Postby Scott McCrea » Sep 9, 2014 7:52 pm

Try that upside-down ascender thingy. It's a fun challenge. Just make sure you have a ladder near by.

Excellent realism with the bee sting. It happens. There's an accident report of some cave divers that were rappelling into a cenote when they got stung dozens/hundreds of times. Terrifying.

The nuances of variable friction are magnified on longer drops. But, they can be used anywhere. Usually, when you least expect it.
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: 14" Rack Ascent to Rappel Changeover Question

Postby Chads93GT » Sep 9, 2014 9:41 pm

soak that same rope with water. 800' i mean, and I wonder how much weight that would add. Bridge day in the rain..................wouldnt want to haul up that rope, then again, 2 years ago i hauled a 10 pound sack of rocks tied to the end of our rope, all the way back up to the bridge at the end of the day. That sucked.
User avatar
Chads93GT
NSS Hall Of Fame Poster
 
Posts: 2293
Joined: Jun 24, 2008 1:27 pm
Location: Missouri
  

PreviousNext

Return to On Rope!

Who is online

Users browsing this forum: Yahoo [Bot]

cron