Prusiks

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

Moderator: Tim White

Re: Prusiks

Postby Carl Amundson » Oct 4, 2014 12:20 pm

J, have you considered using a ascending knot; either a Klemheist or a Hedden; instead of the Pursik?
They hold just as well and break loose easier.
User avatar
Carl Amundson
NSS Hall Of Fame Poster
 
Posts: 681
Joined: Nov 8, 2006 11:27 am
Location: Berryville, Virginia
Name: Carl Amundson
NSS #: 50213
Primary Grotto Affiliation: Front Royal and Tri-State Grottos
  

Re: Prusiks

Postby GroundquestMSA » Oct 4, 2014 12:23 pm

I played with a Klemheist several years ago, but didn't really try climbing with it. Maybe because I don't weigh very much I haven't had many problems breaking the prusik. I would like to try the other knots again though, I forget how to tie them.
User avatar
GroundquestMSA
NSS Hall Of Fame Poster
 
Posts: 1343
Joined: May 5, 2011 1:32 pm
  

Re: Prusiks

Postby Carl Amundson » Oct 4, 2014 4:27 pm

Here is a fun knot system to try: The Knotted Frog"
I've used this one a couple of times - http://caves.org/section/vertical/nh/44/kfrog.html

But I gotta say, I really love my mechanical ascenders!!
User avatar
Carl Amundson
NSS Hall Of Fame Poster
 
Posts: 681
Joined: Nov 8, 2006 11:27 am
Location: Berryville, Virginia
Name: Carl Amundson
NSS #: 50213
Primary Grotto Affiliation: Front Royal and Tri-State Grottos
  

Re: Prusiks

Postby Marlatt » Oct 4, 2014 5:02 pm

Jonah -

Despite some suggestions to the contrary here, a very simple, minimalist system is often the most practical and efficient solution for a small remote drop in an otherwise horizontal cave. I don't know what scenario you are considering, but I can immediately think of a number of caves where even a very basic frog (w/ harness, biners, and ascenders) would be overkill - the one that comes to mind first is a small, overhanging ~30ft drop approximately 2 hours in (much of it crawling). For my money, a simple Texas system with a webbing diaper harness and 5mm continuous loop prussiks (or helicals, or heddens, etc.) is going to be quite satisfactory.

One reason I like continuous loops is the ease of a secure foot loop. Here's a graphic that I drew a long, long time ago describing a foot loop method originally taught to me by Doug Wilson. It has the advantage of being light, easy to throw over a boot, reasonably comfortable - and will stay on your foot even if you end up hanging by your foot loop.

Image

One (amongst several) thing to consider when going light is to think about coping with unexpected problems. You don't absolutely need a bunch of biners, ascenders, or pulleys to affect a self rescue, but a few extra slings or a bit of extra rope might make all the difference. Also, if you're going to use a diaper sling for a harness, notice that it is completely non-redundant - if the sling breaks or comes untied, you'll be hanging off your ankle. A possibly better option is a tied-webbing harness (for instance, http://www.canyoneeringusa.com/techtips ... g-harness/), or add an independent swami belt to your diaper sling.

Cave safely (and softly),
Stuart
Psalms 95.4 / Proverbs 25.2
User avatar
Marlatt
Prolific Poster
 
Posts: 110
Joined: Sep 5, 2005 9:38 am
Location: Colorado
  

Re: Prusiks

Postby NZcaver » Oct 5, 2014 4:59 pm

trogman wrote:It's called tech cord, and it is only 5 mm dia., but has a 5000 lb breaking strength. I use it for my handled ascender tether, and it works great. I'm sure it would work fine for prusiks also, although I haven't tried it yet.

Another option for minimalist is using a Tibloc ascender. They work OK, but you have to make sure it is set on the rope with each step, otherwise it can slip and shred your rope.

Be careful using tech cord or similar material for climbing hitches as it is more dense/rigid than common nylon accessory cord. It tends to be less supple when gripping around larger diameter rope, and more difficult to "break" the hitch each time. In my experience, any theoretical strength advantage of this cord is more than negated by poor handling properties when used for Prusiking. But it's been a long time since I climbed on Prusiks, so feel free not to take my word for it.

Tiblocs are much more efficient, but also much more expensive and a little bulkier than simple hitches.
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: Prusiks

Postby GroundquestMSA » Oct 5, 2014 5:29 pm

NZcaver wrote:Tiblocs are much more efficient, but also much more expensive and a little bulkier than simple hitches.


Have you used a Tibloc enough to gauge its effect on rope after several uses? Rope is a major expense for me and I don't want to tear it up if I can help it.
User avatar
GroundquestMSA
NSS Hall Of Fame Poster
 
Posts: 1343
Joined: May 5, 2011 1:32 pm
  

Re: Prusiks - Efficiency and Safety

Postby GroundquestMSA » Oct 5, 2014 7:44 pm

Efficiency and Safety

Some of the same principles can be applied to both topics. Efficiency and safety are both important and can be intimately related under certain circumstances. I don't intend to write "against" either, only to talk about some examples of detrimental fixation on increasing both, without regard for circumstantial factors or common sense.

Efficiency, as Chad has noted above, is not the same as speed, though the two are often connected. Efficiency is the ability to get maximum output from minimum input. It should be immediately obvious that more efficiency is not always desirable. At its extremes, it starts to look like greed, selfishness, and laziness. When efficiency is treated as a priority, other things of value are in danger of being sacrificed. What has been sacrificed by a global commerce whose only goal, only value, is profit, which is just another word for monetary efficiency? Blind pursuit of efficiency in the management of a household sacrifices self-sufficiency. Blind pursuit of an efficient descent into Ellison's would sacrifice the structural integrity of the body, and probably hurt...

But this is all philosophical, and this thread is really about climbing, so I'll start by re-telling the story of my start in vertical caving. I climbed my first few pits with prusiks, and then bought a couple of handled ascenders and used the Jumar system, or "jugging" for several more. This was all without any instruction or input from anyone. I learned about prusiks from a knot book and found ascenders on Ebay. Worried about a possible lack of safety, I asked for advice on this forum, and was immediately informed that jugging was wildly inefficient. When I first tried a frog system, I expected a dramatically easier/faster/better experience. All I got was a slower experience. I now understand the disadvantages of jugging for long distances, but this was my first exposure to the fallacious doctrine of The Holy Efficiency. There is no question that jugging, or a Texas prusik, isn't efficient. The questions are; Does it matter? When is efficiency important?

I fully believe that a basic truth exists that can be applied to lots of things, including climbing: If it isn't hard, it doesn't need to be easier. When I was jugging 20-90' pits, I was operating out of my surplus. My arms were not fatigued, so there was no need for them to be less fatigued. If I undertake a climb with a method that will force me to operate on the margins of my strength and stamina, then I need a more efficient method. Scott and others are right in saying that efficiency becomes more important when problems arise, that efficiency is a matter of safety. I feel that the only real argument for greater efficiency must be directly tied to greater safety, and not just theoretical safety. The principle above can also be applied to safety: If it isn't unsafe, it doesn't need to be safer. It is not irresponsible to assess the likelihood of complications instead of assuming that they will happen, and must be taken for granted. There are endless possible complications. Our responsibility is to ask ourselves which of these is most likely, and how we will deal with them if they occur. To fail in this preparation is foolish, no matter how we choose to climb.

So what are some possible complications that would make the efficiency of a Texas prusik a real problem? A badly injured caver, or one with one arm completely disabled could find such an ascent impossible. However, it is likely that such an injured caver would be unable to make an unaided climb anyway. So the real question is; how likely am I to be injured to such an extent that a prusik ascent will be impossible, but a frog will still be manageable? Perhaps a group of wet, exhausted, cavers after a long trip could become hypothermic waiting on slow prusikers. On these sorts of trips, a faster and easier system would likely be preferable. Maybe the cave in question is intensely strenuous, and every possible drop of energy should be conserved to successfully navigate the cave, or accomplish the goals of the trip. What though of this cave: An already rigged 19' drop located 400' from the entrance. There are a few leads to dig on 40' from the bottom of the drop, and about 100' to survey. The cave is dry, but there are tight squeezes and the passage is pristine and heavily decorated. Using the basic system I outlined at the beginning of this topic, we can put everything I need; vertical gear for two people, survey gear, a trowel, extra batteries, some painkiller, a little water, and some granola in our pockets plus one of those cute little GGG survey pouches. I have judged any possible safety disadvantages to be unrealistic, and value a soda straw or a bit of beautiful rimstone more than saving a little tiny bit of time or energy. "Well, under those circumstances," you might say, "prusiking will be fine." I have no doubt though, that if I had provided the details of this one of my projects at the beginning of the thread, someone would still have suggested a more efficient way. Why?

Some feel that they have the responsibility to provide disclaimers to anyone who may read about potentially unsafe methods. Some are most interested in caving as an excuse to collect and employ increasingly "better" gear and technique. Some are indoctrinated without ever giving serious thought to the reasoning, or lack of reasoning, behind popular arguments. Some are really concerned about the safety and success of other cavers, and see what they actually know to be an area that could be significantly improved. Whatever the case, why not think about these things before pushing a better way to someone who may not need or want it. And let me say that I am not upset if you suggest a better way. I have been helped very, very much by your suggestions and will continue to be.

The Earth is being more efficiently destroyed than ever, and this destruction is directly tied to our pursuit of efficiency in all things. Anyone who says that things are better now than ever is incredibly nearsighted. Things are certainly easier, for many of us, but at what expense? It is sad that there are few of us who would voluntarily give up conveniences for the good of the Earth. Only by a return to relatively inefficient lives that we have left behind and now disdain can we accomplish a beautiful symbiosis with the Earth that is the stated goal of the "green economists". It is a symbolic statement, but when possible and practical, I increasingly return to old-fashioned methods and old-fashioned thinking that reflects the value of work, resources, skills, and knowledge that are now treated as a lot of rubbish by the majority.
User avatar
GroundquestMSA
NSS Hall Of Fame Poster
 
Posts: 1343
Joined: May 5, 2011 1:32 pm
  

Re: Prusiks

Postby Scott McCrea » Oct 5, 2014 9:25 pm

Nice, well thought out post, Jonah. I agree with most of what you said. But, I can add a couple things, I think.

Speed is a finite thing in a cave. One can only move so fast and still be safe. Trying to do things faster is rarely the best option. If I could suggest one thing for every caver to be more efficient with it would be transitions. Think about how long you wait for cavers to cross a lip (transitioning from rope to ground). How long you wait for someone to get geared up before a trip. Changeovers. Putting vertical gear on in a cave. Rebelays. We spend the most time waiting at transitions. It doesn't matter if someone can climb 100' in 50 seconds if it takes them 8 minutes to cross the lip and get off rope. Is the time you save getting off and on rope with a two-ascender Texas or Frog more valuable than the tiny size of knots? Is the ease at which you can cross a lip using the handle on an ascender vs muscling a knot worth the weight savings? How about when you need a QAS? Knots are not Q.

All that being said, there are certainly times when knots are the most efficient option. As always—it depends. Your original situation may be a perfect example.

tl;dr—Practice transitions to increase efficiency.
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: Prusiks

Postby NZcaver » Oct 6, 2014 3:40 am

GroundquestMSA wrote:
NZcaver wrote:Tiblocs are much more efficient, but also much more expensive and a little bulkier than simple hitches.


Have you used a Tibloc enough to gauge its effect on rope after several uses? Rope is a major expense for me and I don't want to tear it up if I can help it.

Short answer - it's also been a while since I last used Tiblocs. They are not quite as plug-and-play as a regular ascender, but I managed to use them without tearing up any rope. I keep hearing people bemoan them, but a caver I know who actually likes Tiblocs and uses them often seems to have no trouble and no adverse wear and tear on caving rope. Check the Petzl website as there's a particular handling technique, which if ignored due to lack of knowledge or if a person is tired may result in some adverse sheath wear.

Know anybody who has some you can try?
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: Prusiks

Postby trogman » Oct 6, 2014 9:23 am

Marlatt wrote:One reason I like continuous loops is the ease of a secure foot loop. Here's a graphic that I drew a long, long time ago describing a foot loop method originally taught to me by Doug Wilson. It has the advantage of being light, easy to throw over a boot, reasonably comfortable - and will stay on your foot even if you end up hanging by your foot loop.

Image



Cave safely (and softly),
Stuart


Stuart- thanks for sharing your little graphic. I will need to try that method in the future.

Trogman :helmet:
User avatar
trogman
NSS Hall Of Fame Poster
 
Posts: 911
Joined: May 2, 2008 8:35 am
Location: North Alabama
Name: Stephen Brewer
Primary Grotto Affiliation: Gadsden Grotto
  

Re: Prusiks

Postby caver.adam » Oct 16, 2014 9:02 am

Carl Amundson wrote:Here is a fun knot system to try: The Knotted Frog"
I've used this one a couple of times - http://caves.org/section/vertical/nh/44/kfrog.html

But I gotta say, I really love my mechanical ascenders!!


I really enjoyed this page! I used two Bachmann Knots instead of Prussics, but was able to climb with 3 biners, 30 feet of 6mm cord, and 20+ feet of webbing. Need to get this calibrated for my height before our trip to do the climb up 1.9 miles of crawling into a cave.
User avatar
caver.adam
NSS Hall Of Fame Poster
 
Posts: 345
Joined: Feb 8, 2012 12:26 pm
Primary Grotto Affiliation: Louisville Grotto
  

Re: Prusiks

Postby GroundquestMSA » Oct 30, 2014 10:00 am

caver.adam wrote: I used two Bachmann Knots instead of Prussics, but was able to climb with 3 biners, 30 feet of 6mm cord, and 20+ feet of webbing.


That seems like a lot of material. I just measured my little kit and got these totals: 15' cord, 9' webbing, 1 AL and 1 steel carabiner (for descent). This more than allows for the material in the knots. So if ever I was stranded without climbing gear, and there was an outdoor shop handy, I could buy and build a way to get up and down for under $40.

Update:
I went to the Cincinnati Museum Center this past weekend, and met some vertical cavers. The museum is housed in a defunct train station built in the late 1920s. The domed rotunda is said to be the largest semi-dome in the western hemisphere. Once a year, Greater Cincinnati Grotto & associated cavers are permitted to demonstrate vertical caving techniques by climbing in the 106'-high room. Two ropes are rigged at a point that is somewhat lower than the top of the dome, probably about 90'. I was pleasantly surprised that I was allowed to climb (after demonstrating a changeover) since I had never met anyone at the event. I had my little Texas rig with me, but I was afraid that I would take too long on rope, and so I frogged. I did learn a new knot that I'm surprised no one here has mentioned. One of the climbers was also an arborist, and climbed very quickly with a Texas and Blake's hitches. The Blake's hitch is tied in a single strand instead of a loop and performs very well. The arborist/caver used 6mm cord or so for his footloop line and a 9/16" braid on braid with an eye splice for his harness line. Despite being massive, this supple rope grabbed very easily. I've played with a Blake's since, and have found the performance, with cord, is equal to a prusik.

Gary Storrick notes that the tail of the Blake's needs a stopper. The climber who showed me the knot says otherwise, and climbed with only a short tail (2-3") and no stopper. Since he has climbed with it for years, I'll take his word. I have been unable to get the tail to pull through while playing with the knot myself, unless I completely neglect to dress it.

The Blake's hitch would be a way to further reduce the bulk of a tiny climbing system, and it seems like a good emergency knot for cavers to know, especially since it works with a single strand and a wide variety of rope diameters. It works great with my 10.5 dynamic on Pit rope and while it gets extremely tight with tiny strands (I used some cotton clothesline), it is easier to break than a prusik.

On a related note, I would love to know of a friction hitch that will work with 11mm Pit on 11mm Pit.
User avatar
GroundquestMSA
NSS Hall Of Fame Poster
 
Posts: 1343
Joined: May 5, 2011 1:32 pm
  

Re: Prusiks

Postby caver.adam » Oct 30, 2014 12:37 pm

On a related note, I would love to know of a friction hitch that will work with 11mm Pit on 11mm Pit.


I'm not aware of one. But if you find one please let me know. I'm trying to understand why we need to use smaller chord so that we can try a thought experiment. No luck so far.
User avatar
caver.adam
NSS Hall Of Fame Poster
 
Posts: 345
Joined: Feb 8, 2012 12:26 pm
Primary Grotto Affiliation: Louisville Grotto
  

Re: Prusiks -Extreme minimalism

Postby GroundquestMSA » Dec 19, 2014 8:04 pm

If I ever find myself at the bottom of a pit with no gear at all... now I know what to do. Realistically, the best thing would probably be to wait for rescue, and I don't know how I could get in this position to begin with, but it was a fun exercise.

We recently cut a damaged section out of my brother's static rope, and I've been playing with it to see if I could find a friction hitch that could be tied with 11mm. I couldn't, but I was able to ascend 15' with nothing more than a 3' scrap of rope. After milking the sheath off of the core, I separated the core strands into four bundles and tied them together in a loop. Using the empty sheath, I tied a Prusik around the ascent rope without forming a loop. Then I used the core loop as a diaper harness, which I secured with the free ends of the Prusik sheath, which were then tied together with a tape knot. Foot wrapping and advancing the Prusik was slow, but far less problematic than the discomfort from the small core strands of the "harness".

Using this in real life will almost definitely not happen, but exploring such things is useful for building confidence in your own problem solving skills, and for learning about the limits of even the components of your gear.
User avatar
GroundquestMSA
NSS Hall Of Fame Poster
 
Posts: 1343
Joined: May 5, 2011 1:32 pm
  

Re: Prusiks

Postby Scott McCrea » Dec 19, 2014 10:02 pm

:clap: :clap: Did you get any pics? This would make a nice Safety and Techniques Committee article.
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
  

PreviousNext

Return to On Rope!

Who is online

Users browsing this forum: No registered users

cron