Going with a bobbin or stop?

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

Moderator: Tim White

Re: Going with a bobbin or stop?

Postby paul » Apr 18, 2011 6:28 am

NZcaver wrote:
chh wrote:Heavier people and Stops will have different experiences as I've said, though I think mostly because of the braking mechanism. Without one I think it's just a matter of varying friction with biners. I've carried some heavy packs with me, and have also done two person loads on my Simple. Though I rely heavily on my second braking carabiner here or even a third in the case of a 2 person load, I've not had a problem with standard 11mm caving ropes. However, I can totally appreciate not wanting to use the braking carabiners 100% of the time and opting for a different device (like the rack) that would mitigate this problem.

This is the first I've heard about using multiple braking carabiners to add friction to one descender. How does that work?

One time I had to increase friction when using a Anthron Stop on an 8mm rope, but I just tied a Munter on my braking carabiner.


The way I do it (I believe it's the same way indicated in "Alpine Caving Techniques" but I haven't got a copy to hand in order to check on this) is to clip the second carabiner to the rope above the descender. Then clip the controlling part of the rope, which is passing through the first braking carabiner in the usual position, into this second carabiner.
paul
NSS Hall Of Fame Poster
 
Posts: 513
Joined: Dec 9, 2005 7:46 am
Location: Peak District, UK
Name: Paul Lydon
  

Re: Going with a bobbin or stop?

Postby cavedoc » Apr 18, 2011 1:36 pm

paul wrote:to clip the second carabiner to the rope above the descender. Then clip the controlling part of the rope, which is passing through the first braking carabiner in the usual position, into this second carabiner.


So you need a carabiner that will go around the rope, and allow the tail to go up and through it, but not so big that it slides over the Simple itself? In the end it's a jury-rigged hyperbar for a Simple? Seems like if it's that complex then a different device is called for. Picture?
Roger Mortimer
User avatar
cavedoc
NSS Hall Of Fame Poster
 
Posts: 455
Joined: Sep 5, 2005 3:30 pm
Location: Fresno, CA
Name: Roger Mortimer
NSS #: 26529
Primary Grotto Affiliation: San Joaquin Valley Grotto
  

Re: Going with a bobbin or stop?

Postby paul » Apr 19, 2011 6:30 am

cavedoc wrote:
paul wrote:to clip the second carabiner to the rope above the descender. Then clip the controlling part of the rope, which is passing through the first braking carabiner in the usual position, into this second carabiner.


So you need a carabiner that will go around the rope, and allow the tail to go up and through it, but not so big that it slides over the Simple itself? In the end it's a jury-rigged hyperbar for a Simple? Seems like if it's that complex then a different device is called for. Picture?


Unlike a Rack, the rope from the anchor enters the Simple at the lower capstan or "pulley" and the rope and Simple are at an angle to each other, so the second carabiner is not going to accidentally slip over the body of the Simple, so any size carabiner can be used.

A different device is not called for as it isn't often you need the extra friction, and this is very straightforward: lock off the Simple, clip a second carabiner to the rope above the Simple (it will naturally slide down to the point where the rope from the anchor enters the lower capstan), unlock the Simple and then clip the tail of the rope through the second carabiner and continue your descent. If the second carabiner is ready to hand, you can just apply a soft lock (pass the tail rope over the body of the Simple between it and the rope from the anchor) and while still maintaing a grip on the tail end, clip the carabiner onto the rope from the anchor using your spare hand. Then lift the tail rope from its soft lock position and clip into the second carabiner.

It's not really "jury-rigged" either, you're already using a braking carabiner (or nowadays, maybe a Petzl Freino's braking spur - but this is the same principle) atttached to your central maiilon at the bottom of the Simple, which is normal procedure and following the manufacturer's instructions , this is just adding an additional braking carabiner and by clipping it to the rope in the way described, it works in opposition to the first carabiner and greatly increases the friction available.

I have only ever needed to to this once and that was with a thinnish but very muddy rope. Any other occasion I needed more friction I just managed with the braking carabiner as normal or wrapped the tail of the rope beneath my controlling hand a couple of turns around the full length of my leg.

Sorry - I have no pictures.
paul
NSS Hall Of Fame Poster
 
Posts: 513
Joined: Dec 9, 2005 7:46 am
Location: Peak District, UK
Name: Paul Lydon
  

Re: Going with a bobbin or stop?

Postby Mugger » Apr 19, 2011 1:29 pm

I ended up going into one of the local sports shops the other night.... After everything I read I was planning on going with the Simple. They didn't have any in stock, but they had a Stop on demo there at the shop and I was able to play with it a little and give it a little test drive (very little). I liked it enough I had to ask how much (no price tag on it), and was surprised to see it was on sale (new one, not the demo) for about $20-30 less than most places online. I've known this salesman for years, so we talked a little longer about caving (he used to be in the local grotto). At one point he asked, "is your mind set on going with that French Killing Machine?" I laughed and said yes.... He sighed, mumbled something about clearing out more display room for racks, and gave me another 10% off! LOL

Picked up a Freino yesterday at another shop here in town and had an offer to do some on rope training for the stop (and a loaner Simple) with some of the staff in a few weeks.... Hard to pass up free training on your new toys, so of course I said yes :grin:
chh wrote:I use a Simple and love it. My wife uses a Stop and she loves it. Each have their advantages and disadvantages, as with anything. Here is a quick list of my pros and cons for each. My personal opinions of course:
Stop pro:
-size
-thunked in the noggin (or the brake arm/shoulder which has happened to me though not with a Stop) your device will hold you.
-can also be used to tension and release a tyrolean even if there's someone on it (usually, if the tyro isn't super tight and/or the load huge, though you do have to be able to squeeze pretty hard.)
Stop con:
-takes 2 hands to operate all the time if you don't restrict the brake cam
-heavier people will have a harder time holding the cam open on longer rappells.
-limited depth range

Simple pro:
-slightly smaller than the Stop
-as variable, if not moreso, than any micro rack I've used.
-I think the replacement bobbins are cheaper on the Simple, but I'm not sure It's been a while since I looked.
-they come in RED
Simple con:
-limited depth range

Another pro for the Stop:
-they come in BLUE :woohoo:
User avatar
Mugger
Occasional Poster
 
Posts: 41
Joined: Sep 20, 2009 10:40 am
Location: California
Name: Hans
NSS #: 61554
Primary Grotto Affiliation: Shasta Area Grotto
  

Re: Going with a bobbin or stop?

Postby OpenTrackRacer » Apr 19, 2011 4:32 pm

Lots of good information in this thread. Our group choose the Stop for abandoned mine exploring over the Simple and other options. A primary consideration was not free falling down the rope in the event of an injury which knocked out or stunned the person rappelling. This would seem to be a much greater concern in mines versus caves but it's quite possible in both.

Three years on from that decision and we'll all still pretty happy with the Stops. We use them almost exclusively on dry PMI 11mm Pit Rope. We've rappelled with 300' of rope below us without a problem. They do get hot on long pitches but we've found that you can control that to some degree but not descending too rapidly. We've never had one get hot enough to damage the rope or make the Stop uncomfortable to handle while wearing gloves.

I'm the only one that uses a braking carabiner (Freino). I added one mainly to experiment and have more control near the bottom of the rope. Everyone else has done fine without one. As I get more experienced and comfortable on rappel I'm considering locking out the stop function and running it more like a Simple. Having an extra hand free would be very useful in some situations. I've also found that my hand does indeed get tired pressing the level for extended periods of time, especially near the top of the rope. Still, it takes only seconds to securely lock off the Stop so it's usually not a big deal. Not free-falling down the rope in the event of an injury is still a significant concern in our environment so I haven't made up my mind on that yet.

Speaking of, we've found that near the top of the rope the Stop does indeed stop. Closer to the bottom it becomes a "slow" but that doesn't seem to be a problem.

Here's a short video of one of our rappels on a Stop with no braking carabiner and 300' of rope below.



Mike
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: Going with a bobbin or stop?

Postby chh » Apr 20, 2011 7:24 pm

gdstorrick wrote:I see that you know the second rule of gunfighting: Always cheat, always win.


You know it! :laughing:

But really, I find one braking carabiner almost necessary. Not because I need it on normal 11mm but when it's really muddy I find that a Simple rigged "C" or "zero" plus a braking biner is sometimes the sweet spot with a pack at least at my weight. It feeds better through the chunks and stuff. Is this cheating or not, I don't really care, it's what works for me and it's pretty fast. I can usually install my Simple with 1 or 2 braking carabiners faster than anyone I've caved with who was using a 6 bar. Get it off faster as well. Not to mention it's shorter and easier (again, my opinion) to use at rebelays and such. I just recently rapped a 9mm(I think) with a pack and didn't even need the braking carabiner, though I had it installed which surprised me, but it was a rope type I hadn't used before. I'm about 165 plus whatever I'm wearing/carrying.

Anywho, I think the devices/ascending systems are pretty much irrelevant so long as your team can move through the cave at a good pace. Whatever works, well, works.
Your words of caution are no match for my disaster style!
User avatar
chh
NSS Hall Of Fame Poster
 
Posts: 522
Joined: Oct 4, 2005 3:21 pm
Location: asheville, nc
Name: caleb
NSS #: 55745
  

Re: Going with a bobbin or stop?

Postby gdstorrick » Apr 20, 2011 11:16 pm

Post deleted.
Last edited by gdstorrick on Jul 8, 2012 6:20 am, edited 1 time in total.
gdstorrick
NSS Hall Of Fame Poster
 
Posts: 272
Joined: Jan 3, 2009 11:06 am
Location: MI, USA
Name: Gary Storrick
NSS #: 12967
Primary Grotto Affiliation: Pittsburgh
  

Re: Going with a bobbin or stop?

Postby NZcaver » Apr 21, 2011 4:32 am

gdstorrick wrote:
chh wrote:
chh wrote:<SNIP>. I'm about 165 plus whatever I'm wearing/carrying. <SNIP>


Good for you, I seriously wish I could get halfway there. I'm almost 200, and even at 6'4", anyone that can do the BMI arithmetic can see that I am clearly overfat :sadbanana: .

I prefer to think of this condition as "under-tall." :big grin:
User avatar
NZcaver
Global Moderator
 
Posts: 6367
Joined: Sep 7, 2005 2:05 am
Location: Anchorage, Alaska
Name: Jansen
NSS #: 50665RL
  

Re: Going with a bobbin or stop?

Postby Mugger » Apr 21, 2011 9:59 am

NZcaver wrote:
gdstorrick wrote:
Good for you, I seriously wish I could get halfway there. I'm almost 200, and even at 6'4", anyone that can do the BMI arithmetic can see that I am clearly overfat :sadbanana: .

I prefer to think of this condition as "under-tall." :big grin:

:exactly:

gdstorrick wrote:
chh wrote:Anywho, I think the devices/ascending systems are pretty much irrelevant so long as your team can move through the cave at a good pace. Whatever works, well, works.


Agreed and Amen! :cave softly:

Gary
:bat2:

Don't forget moving safely too :grin:
User avatar
Mugger
Occasional Poster
 
Posts: 41
Joined: Sep 20, 2009 10:40 am
Location: California
Name: Hans
NSS #: 61554
Primary Grotto Affiliation: Shasta Area Grotto
  

Re: Going with a bobbin or stop?

Postby Cody JW » Apr 21, 2011 7:25 pm

gdstorrick wrote:
chh wrote:<SNIP> Is this cheating or not, I don't really care <SNIP>.


Nor do I, it is only cheating typing, not cheating caving :shhh:

chh wrote:<SNIP>. I'm about 165 plus whatever I'm wearing/carrying. <SNIP>


Good for you, I seriously wish I could get halfway there. I'm almost 200, and even at 6'4", anyone that can do the BMI arithmetic can see that I am clearly overfat :sadbanana: .

chh wrote:Anywho, I think the devices/ascending systems are pretty much irrelevant so long as your team can move through the cave at a good pace. Whatever works, well, works.


Agreed and Amen! :cave softly:

Gary
:bat2:
Gary, I wish I was 6foot 4 and 200 -I am 5 foot 9 220, in my book you are skinny.I still cave , swim laps, and ride bicycles and walk my dogs each night. Even love to frog with my thick chest. Where does that leave my BMI???
It only takes one person to surrender a dog to a kill shelter ,but it takes many to rescue it.
User avatar
Cody JW
NSS Hall Of Fame Poster
 
Posts: 905
Joined: Oct 24, 2007 10:16 am
Location: Indianapolis In. USA
Name: Jeff Cody
NSS #: 23961
  

Previous

Return to On Rope!

Who is online

Users browsing this forum: No registered users