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In defense of the (sort of) Jumar system.

PostPosted: Dec 17, 2013 6:51 pm
by GroundquestMSA
I used this method after I bought my first ascenders. I had two handled ascenders and knew nothing about climbing systems, so I put a footloop on each one and started climbing. I didn't know this was a bad idea until the good folks of Cavechat let me know that this was dangerous and "the least efficient method" of climbing. Now I'm starting to question some of the judgements of the Jumar system, especially after reading the Ascent chapter of Vertical.

On Rope calls the Jumar method unsafe since letting go of the ascenders will leave the climber hanging upside down, and that there is no easy way to rest while climbing. Why the obvious solution (adding safety slings) is not mentioned, I don't know. Ascent also tells us that the Jumar system has no "resting position" which may mean that there is no resting position as part of the natural climbing cycle. Further, Ascent says that the Jumar system has poor safety (why?) and "copes poorly with all maneuvers." This last bit is certainly rubbish. It may not be the best on bad lips, but I can downclimb, pass rebelays, and changeover far faster and easier with Jumar than with Frog. This may be because I Jumar without a chest harness. On Rope and Ascent call for the footloops to pass through a carabiner at the chest. I never considered trying this since I had no trouble staying upright.

One complaint is true. It is tiring. Compared to frogging. Originally, when I didn't know that frogging existed, I thought Jumaring was easy. I've used it with no significant fatigue on pits of 15' to 90'. Obviously, for long climbs and weak arms, another system is better. I think more people should consider Jumaring as an option. If you have short drops, what beats it? Forget the chest harness, all you need are two ascenders, two footloops and two tethers. In one cave with a couple of extremely short pits I even skipped the tethers and seat harness. The only systems with less materials are what? Prusik loops? It goes on and off rope very quickly, climbs pretty fast, and the cycles (for me) are longer than frog cycles.


Re: In defense of the (sort of) Jumar system.

PostPosted: Dec 17, 2013 9:59 pm
by Scott McCrea
I guess a Texas would have less material, since it only uses one footloop.

Not using lanyards between the harness and ascenders is foolish.

The Jumar system is great on slopes. As you found, downclimbing and changeovers are a breeze. But, very inefficient on free-hangs.

Every system has something that it is better than anything else. Get one of each and wear them all, all the time.

Re: In defense of the (sort of) Jumar system.

PostPosted: Dec 17, 2013 11:13 pm
by caverdan
Scott McCrea wrote: Get one of each and wear them all, all the time.

Jumar's Frog Walk'in Texas Hass?? :shrug:

Re: In defense of the (sort of) Jumar system.

PostPosted: Dec 18, 2013 12:09 am
by GroundquestMSA
Scott McCrea wrote:Not using lanyards between the harness and ascenders is foolish.

Sure is. I did it originally out of pure ignorance. I've only done so since in a situation where I didn't have most of my stuff. The cave had two pits of probably 15'. We felt we could probably climb them, but I had my ascenders so we slid down a bit of borrowed rope and climbed out with the lanyardless Jumars.

Scott McCrea wrote:But, very inefficient on free-hangs.

This is an often mentioned disadvantage that I don't really understand. I assume that the argument is that climbing the same distance with a Jumar system takes more energy than with, a Frog, for example. When I'm only climbing 40', though, and can do so faster and with less gear, why does it matter if I use a bit more muscle? Efficiency isn't important unless you need that saved energy for something else.

Re: In defense of the (sort of) Jumar system.

PostPosted: Dec 18, 2013 5:36 am
by Scott McCrea
Sometimes the most efficient way is not the best way.

Re: In defense of the (sort of) Jumar system.

PostPosted: Oct 31, 2014 12:00 am
by GroundquestMSA
While goofing about this afternoon, I made a few slight modifications that improved both the performance and comfort of Jumaring. I hadn't given enough consideration to the length of the slings, and I haven't yet found any reference that deals with building the most effective Jumar system. I found that increasing the length of the top ascender helped for two reasons, both of which directly improve the most often stated disadvantages of the Jumar system.

1. A longer upper footloop makes it easier to stay upright. Arm strain is cited as a big negative, and the higher I get that arm, the less strain the bicep takes. I understand that this is the opposite of what is claimed by others, including highly experienced big wall climbers. I don't know what to say to that, perhaps there's something freakish about my body structure.
2. A big complaint is that one ascender (that the climber is required to manually advance, unlike the Frog) is only capturing progress and playing catch up on each cycle. This is true of another widely known system, the Texas, but it's not entirely true of Jumaring. Raising the upper ascender to nearly full arm extension with the largest reasonable step allows one to rig the lower ascender with significant separation between the two. The feet can then pass each other while climbing, meaning that each step of the "lower" foot adds to the progress of the climb.

It's somewhat difficult to verbalize these observations, especially in a credible way. I'll perhaps make a video demonstrating what I'm talking about. I still believe there is an unfair prejudice against the Jumar system, and that it has a place in vertical caving. Maybe their wholesale rejection of Jumaring is a statement on the average arm strength of cavers :big grin: Of course, there are plenty of climbing methods that are widely accepted, so maybe more options aren't really needed...

Re: In defense of the (sort of) Jumar system.

PostPosted: Nov 2, 2014 9:13 pm
by GroundquestMSA
After more tinkering and research, I have gone about as far with this idea as I think is possible. It really isn't the old original Jumar system, more of a Jumar/Mitchellwithoutaroller/M-system (remember this?). It allows for maximum stroke length and a stepping motion without a roller. When I tested my slings a couple of days ago, everything was fine until I did a changeover. In order to accommodate the long footloops (necessary for long steps) I needed long tethers. That meant that a resting position left me far from my ascenders. So far that I couldn't rest with my feet in the footloops since they were at about face level, and I had to climb back up to get at my ascenders. That wouldn't do. So I fixed it with two different methods, both of which work.

Here is the basic setup:
-Set the top footloop so that maximum arm extension and maximum step height are reached more or less simultaneously.
-Set the bottom ascender as low as possible while still allowing for good control and balance. For me this meant putting it just above the waist while in a standing position.
-Add a safety sling for the lower ascender.
-For the upper ascender, either add the "floating bridge" found in the M-system demo, or another safety sling with a butterfly knot that can be clipped to the upper, taking the slack out of the sling before you sit. See below.
Either of these will serve to keep you close to the ascenders when you sit, and each has its own disadvantages. The floating bridge puts one at theoretical risk of shockloading the upper ascender if the lower fails. How severe this could be, I'm unsure. The butterfly solution introduces another step in resting and changeovers, but it is not a difficult one. The problem could also be solved by the introduction of a separate cowstail, but with all of the long slings already involved, I wanted to avoid being too wrapped in cordage (but then I could call it the Moby Dick System, hmm...).

In the end, the point is to put as much distance between the ascenders as is possible. This is really the same premise as the M-system, but without the problematic remote ascender. The result is a system that can be very fast, is extremely simple and relatively light, deals well with on-rope tasks, and can be somewhat taxing on the arms. How strenuous the system is will depend, I suspect, on your body type. I climbed through 80' of rope with a pulley in the tree without stopping, and without significant strain on the arms.

I will make a video to demonstrate what I'm talking about here, but I need to buy some proper sling materials first. I've been doing this with hardware store rope until I get all of my lengths right. On that note, I'm going to look back through the archives and decide what material would be best for tethers and footloops. So far I've used the "whatever is on hand" philosophy, within reason. Suggestions are welcomed, but I know that there has been a lot of argument on the topic in the past, and it's an argument that for some reason I can't get interested in, so let's not do that again.

Re: In defense of the (sort of) Jumar system.

PostPosted: Dec 4, 2014 2:35 pm
by rjack
I don't log in here much but I do have a decent amount of experience jumaring big walls in the past...

If you shorten the upper tether so that its the same length as your outstretched arm you then move up the upper jumar and can sit down without going "down" at all. That makes the upper jumar movement more efficient.

The lower tether is typically set so you can move the lower jumar up to the height where stepping up in the footloop is problematic. E.g. to the length where the height of the jumar on a vertical wall is such that your foot in the footloop makes your thigh parallel to the ground. You don't typically rest on the lower tether, at least I tried not to since it felt like I was sitting backwards when I did.

In my system I kept the tether lengths constant (some people use daisy chains though). I varied the effective length of the tethers by using a different step in the aiders. I am 5'8" and used 1x 4 step and 1x 5 step aider. I can imagine these might snag on stuff in a cave, it wasn't an issue in Yosemite.

I would skip the sliding cord. Back when I was jumaring with actual jumars shock loading them was considered an absolute no no. I think the forged rather than cast aluminum ones are slightly more shock tolerant but I haven't actually checked the specs. Everything I jumared was on dynamic rope, we only hauled on a static line. The golden rule was to be tied into the rope periodically since jumars can certainly pop off on a traverse quite easily. I have only used a frog with croll in a cave and that's a lot harder to pop off (at least I thought it was) so I'm not sure if I would be willing to traverse in a cave with jumars and only a static rope to tie into. I imagine I'd be really slow from all the knots I was tying.

Re: In defense of the (sort of) Jumar system.

PostPosted: Dec 4, 2014 3:03 pm
by GroundquestMSA
I'm still adjusting to get the best speed/effort combination.

Can Jumars really jump off easily? I can't see how, especially with a static rope. I've climbed with actual Jumars several times and probably a dozen times with Ultrascenders. If there's a safety issue, I'd like to know about it.

Re: In defense of the (sort of) Jumar system.

PostPosted: Dec 15, 2014 12:46 pm
by Tim White
GroundquestMSA wrote:Can Jumars really jump off easily? I can't see how...

rjack said "jumars can certainly pop off on a traverse quite easily." That is a know FACT that all ascenders can rotate off when used on a horizontal traverse line.


Do a little more research outside of caving publications. Check out some of the great books and links for big wall climbing. Climbers have bee jumaring or jugging for decades. rjack gave some good advice and insight.

Re: In defense of the (sort of) Jumar system.

PostPosted: Dec 15, 2014 3:00 pm
by GroundquestMSA
Tim White wrote:rjack said "jumars can certainly pop off on a traverse quite easily."

So he did, and I missed the point.
Tim White wrote:Do a little more research outside of caving publications. Check out some of the great books and links for big wall climbing.

Have been doing this... except for the books. It is very interesting to compare, and try to apply, the rules of different disciplines.