Two Points of Contact Rule

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

Moderator: Tim White

Two Points of Contact Rule

Postby ron_miller » Nov 4, 2013 1:03 pm

Various reference sources mandate that with respect to ascenders and other rope grabs, two gripping points of contact contacted at or above the user's waist must be maintained at all times during changeovers, and while crossing obstacles such as knots and rebelays. Yet the same reference sources are generally in agreement that it is perfectly acceptable to descend with a single sliding point of contact that will fail (by "fail", I mean that the user will experience an uncontrolled descent) if the user releases her grip.

First, I am interested in learning when and how the "rule" of maintaining two gripping points of contact during changeovers and obstacle negotiation originated.

Second, I am interested in hearing from other rope users their opinions as to whether this rule is really necessary as an "absolute" rule during such maneuvers.

Have there been instances in which someone was suspended from a single ascender, and that ascender suddenly failed? I get the icy/muddy rope issue - I'm talking about once an ascender has already gripped and is holding body weight. Also I realize that this is the infamous "dead bodies at the bottom of the pit" question.

If the rule is necessary, why is it OK to have a single, sliding, hands-on required, point of contact during descent? I understand that advocates of rappelling backup devices/techniques such as the French wrap may argue that it is not OK; I would greatly appreciate it if posters not hijack this particular discussion by resuscitating this oft-argued issue!
ron_miller
NSS Hall Of Fame Poster
 
Posts: 235
Joined: Jan 5, 2007 6:24 pm
  

Re: Two Points of Contact Rule

Postby Scott McCrea » Nov 4, 2013 2:07 pm

I suspect the two-points rule came about when Prusik knots were the preferred ascender. And, it has since carried over to the mechanical ascenders.

Heck no, it's not necessary. Using only one point during transitions speeds things up and simplifies gear management, which makes it safer.

Sometimes, you might want two points of contact, but you always need one.
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: Two Points of Contact Rule

Postby cavedoc » Nov 4, 2013 2:09 pm

I don't think it's an absolute. For changeovers and knot passes I still think it's a good idea but there are exceptions. I disagree that two points are necessary when crossing rebelays; a cow's tail to a rebelay is sufficient. If crossing an anchor on a tension line, two carabiners are on the rope/cable but when you cross, you undo one to clip on the other side. Temporarily you have one. A single well oriented handled ascender that will stay well oriented should be enough. During changeovers and pick offs things can get wiggy enough that I will stick with two though.
Roger Mortimer
User avatar
cavedoc
NSS Hall Of Fame Poster
 
Posts: 448
Joined: Sep 5, 2005 3:30 pm
Location: Fresno, CA
Name: Roger Mortimer
NSS #: 26529
Primary Grotto Affiliation: San Joaquin Valley Grotto
  

Re: Two Points of Contact Rule

Postby Extremeophile » Nov 4, 2013 3:00 pm

Unfortunately there is a growing pile of bodies from relying on a single point of contact.

http://forums.caves.org/viewtopic.php?f=2&t=15375

It may save a few micro seconds to skip clipping the anchor while crossing a rebelay on ascent, or to not test your descender before unclipping from an anchor on descent, but there are a number of ways to make mistakes during these maneuvers and without a second point of contact the penalty for a mistake may be fatal. The argument about a static, and properly loaded ascender not having a high probability of failure has been made before, but in climbing or descending rope those ascenders almost never remain static. The load direction often changes and they are frequently weighted and unweighted, even if they aren't being slid up or down the rope. Nothing is absolute, but I think maintaining two points of contact is certainly a best practice. Sure, maybe when someone is stranded on rope, non-responsive, the cave entrance is flooding shut, and your cowstail was severed by rockfall, then relying on a single point may be called for.
User avatar
Extremeophile
NSS Hall Of Fame Poster
 
Posts: 761
Joined: Dec 7, 2009 7:37 pm
Location: Littleton, CO
Name: Derek Bristol
NSS #: 34941
Primary Grotto Affiliation: Colorado Grotto
  

Re: Two Points of Contact Rule

Postby Scott McCrea » Nov 4, 2013 4:21 pm

Clarification: when I refer to using one point, I mean briefly. I have seen people freak out and get stuck because they are afraid of going to one point during a transition (traverse, passing knot or lip, etc). When frogging or Texas'ing over a difficult lip, sometimes it is much safer to momentarily, while sitting on the Croll, go to one point while removing your upper ascender and re-attaching it above the lip than it is to struggle and thrash while trying to muscle over.

You want two. You need one.
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: Two Points of Contact Rule

Postby Chads93GT » Nov 4, 2013 4:47 pm

When doing change overs I always hang from my QAS/Cows tail but I dont ever have a 3 cowstail system. I have a frog croll in my ropewalker so i thumb slack through this and rig my rack between my croll and hand ascender at the end of my cowstail. Is this considered 1 point or 2 points while I am getting ready to start threading my rack? Having a 2nd "QAS" for changeovers to me is extra unnecessary equipment, extra weight, extra bulk.
User avatar
Chads93GT
NSS Hall Of Fame Poster
 
Posts: 2293
Joined: Jun 24, 2008 1:27 pm
Location: Missouri
  

Re: Two Points of Contact Rule

Postby Extremeophile » Nov 4, 2013 6:05 pm

Chads93GT wrote:I have a frog croll in my ropewalker so i thumb slack through this and rig my rack between my croll and hand ascender at the end of my cowstail. Is this considered 1 point or 2 points while I am getting ready to start threading my rack?

Sounds like 2 points to me.

I've stated in past threads that I also consider a small ledge you stand on as a point of contact. I am generally using a "textbook" Frog system with the long cowstail attached to the foot ascender, but no third ascender or QAS. So while ascending I've got the foot ascender, chest ascender, and short cowstail as points of attachment. Any one of these can be removed while the other two are still attached. On descent I have both cowstails and the descender for crossing rebelays, knots, or changeovers. About the only scenario I can think of that presents a dilemma is crossing a knot during a Tyrolean with no ledge to stand on. It's not practical to use the chest ascender or descender as a point of contact, and something has to be removed. I suppose you can attach your footloop to the anchor and stand in it as a point of contact, but I'm not sure I've encountered this exact scenario. I am not motivated to carry an extra ascender for these rare instances, but I would be especially cautious when doing the move, and if I found myself in caves that required doing this as common practice then maybe I would be motivated to bring an extra tether.

It seems that Ron's original question is why insist on two points when ascending, when one point of contact is commonly accepted for descending. There are a few differences - when a descender is properly installed (and tested), it is difficult to impossible to get it to detach from the rope. Descenders also are generally built with a higher maximum load rating, so they have a higher safety factor than a single ascender, and falling on a descender is much less likely to cause the rope to sever.

I'm not sure about the statistics, but it wouldn't surprise me if descending was more dangerous than ascending. Professionals and organized events like OTE seem to use dual ropes and devices like the ID and ASAP, which adds some redundancy to descending, and certainly has saved some lives. In recreational or expedition caving these techniques may be inconvenient at best, and completely impractical or even unsafe at worst. Maybe a descender will some day be built that is inexpensive, robust, immune to mud, with a foolproof brake, a backup arrest system, and allow easy changeovers and crossing of rebelays and knots. Until that time I'll keep using my Simple and hope to cheat death a little longer.
User avatar
Extremeophile
NSS Hall Of Fame Poster
 
Posts: 761
Joined: Dec 7, 2009 7:37 pm
Location: Littleton, CO
Name: Derek Bristol
NSS #: 34941
Primary Grotto Affiliation: Colorado Grotto
  

Re: Two Points of Contact Rule

Postby NZcaver » Nov 4, 2013 7:26 pm

Hi Ron. Long time no hear.

ron_miller wrote:First, I am interested in learning when and how the "rule" of maintaining two gripping points of contact during changeovers and obstacle negotiation originated.

Not sure when it originated (likely before my time), but I certainly remember it being reinforced during my early NCRC training.

Second, I am interested in hearing from other rope users their opinions as to whether this rule is really necessary as an "absolute" rule during such maneuvers.

My personal opinion is that it's not necessarily an absolute but certainly preferred in many situations. However I also think it's a good rule to insist upon when teaching/advising novice vertical cavers, or in a structured training environment such as NCRC. As cavers gain more experience with their equipment and techniques, it might be appropriate for certain rules to become less absolute.

Several years ago Andy sparked a similar discussion about the pros and cons of hanging from one point of contact. You might want to check it out.
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: Two Points of Contact Rule

Postby GroundquestMSA » Nov 4, 2013 8:01 pm

ron_miller wrote:Second, I am interested in hearing from other rope users their opinions as to whether this rule is really necessary as an "absolute" rule during such maneuvers.


And here's another entertaining old thread that deals with the problem of rules vs. education. The fact that you can climb a rope without maintaining two points of contact and without dying proves that it isn't an "absolute" rule. It's our job as individuals to ask questions, use our brains, and learn (hopefully gently) from our experience. Thus educated, we can decide when a rule is a good one or an outdated one or a narrow one or a very good one. In my own case, I view the two-points-rule as a very good one, not because I'm afraid of my equipment failing me... I'm afraid of my brain failing me.
User avatar
GroundquestMSA
NSS Hall Of Fame Poster
 
Posts: 1343
Joined: May 5, 2011 1:32 pm
  

Re: Two Points of Contact Rule

Postby Bob Thrun » Nov 6, 2013 11:53 am

ron_miller wrote:Various reference sources mandate that with respect to ascenders and other rope grabs, two gripping points of contact contacted at or above the user's waist must be maintained at all times during changeovers, and while crossing obstacles such as knots and rebelays.

How about three points of contact? See "Attach Three for Safety" by Bruce Smith, Nylon Highway No. 5, p. 16, January 1976
Bob Thrun
NSS Hall Of Fame Poster
 
Posts: 322
Joined: Jul 18, 2006 12:50 pm
  

Re: Two Points of Contact Rule

Postby CaverCSE » Nov 6, 2013 7:57 pm

My viewpoint: I've never heard of a modern ascender failing but, I do believe that redundancy should be the favored option when practical enough to justify.
User avatar
CaverCSE
Occasional Poster
 
Posts: 35
Joined: Dec 5, 2012 11:32 am
Location: Middle Tennessee
NSS #: 49706
Primary Grotto Affiliation: Upper Cumberland Grotto and Spencer Mountain Grotto
  

Re: Two Points of Contact Rule

Postby Scott McCrea » Nov 6, 2013 9:55 pm

Ha. Nice find, Bob. Here's the link to the list of NH in PDF. http://www.caves.org/section/vertical/nylhi.html
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: Two Points of Contact Rule

Postby snoboy » Nov 7, 2013 1:18 am

CaverCSE wrote:My viewpoint: I've never heard of a modern ascender failing but, I do believe that redundancy should be the favored option when practical enough to justify.


Let me change that for you. I have had a modern ascender pop off the rope when it was loaded a little crooked. I had two ascenders on, and a backup knot below, as is standard practice when aid climbing above ground, so there was no drama. :banana_yay:
snoboy
Prolific Poster
 
Posts: 176
Joined: Apr 6, 2009 10:05 pm
Primary Grotto Affiliation: BC Speleological Federation
  

Re: Two Points of Contact Rule

Postby caver.adam » Nov 7, 2013 3:53 pm

I had two points that struck me.

It is worth re-itterating that you must always have one. Once you've seen someone struggle in a rope-walker because they slipped and are falling over backwards without an upper anchor you realize that getting in the habit of unclipping can be a very bad habit.

Second, I prefer whenever possible to rig my drops so that you don't have to thrash or unclip an ascender to get over a lip. Many times it is possible to push back with your hand or knee if the lip is rigged well and to pull the rope back away from the rock ledge. (I know that sometimes this isn't possible...but I've had a lot of people tell me its not possible because they don't know how to try). We need to work on teaching people how to avoid tunnel vision while on a rope or a handline. Bad habits can be catostrophic.
User avatar
caver.adam
NSS Hall Of Fame Poster
 
Posts: 345
Joined: Feb 8, 2012 12:26 pm
Primary Grotto Affiliation: Louisville Grotto
  

Re: Two Points of Contact Rule

Postby PeterFJohnson » Nov 7, 2013 6:40 pm

ron_miller wrote:Have there been instances in which someone was suspended from a single ascender, and that ascender suddenly failed? I get the icy/muddy rope issue - I'm talking about once an ascender has already gripped and is holding body weight. Also I realize that this is the infamous "dead bodies at the bottom of the pit" question.


I asked the same question awhile back. See here. There were a couple of examples given of ascenders slipping after being weighted. My takeaway was essentially what Extremeophile said above. That while ascenders should theoretically hold after being weighted, in reality it isn't a theoretical situation and it is far to easy to change the situation - by shifting your weight, touching the ascender etc. etc. - and causing the ascender to slip.

When I went through my training on the industrial/professional side they viewed ascenders as 1/2 a point of contact and descenders and other devices as a full point of contact. I liked that academic distinction because it kept the total points of contact the same and reinforced that ascenders do slip/fail sometimes.
User avatar
PeterFJohnson
Prolific Poster
 
Posts: 109
Joined: Nov 12, 2010 6:29 pm
Primary Grotto Affiliation: Colorado Grotto + GVKS
  

Next

Return to On Rope!

Who is online

Users browsing this forum: No registered users