Friction Savers! are they worth it

[murphy4trees]

I read Peter D.'s paper on friction displacement some years back... Ab=nd thought the same thing....
going down friction displced...
going up friction reduced....
and I still don't like the name "friction saver"....

 

[TheTreeSpyder]

The Hold must equal the Load; the system desires to support you; and will avail all efforts in it's range of powers to do so.

The hold is friction; we are the load, so that hasn't changed. So the total friction hasn't changed, or you'd fall; for the friction is supporting you. The system friction total is just a mirrored reflection of your own weight force; that is set back against you to support. These 2 forces are in exact balance always, or movement makes up the quantity of the imbalance; like a sailor wandering from port to port, only resting when he meets his total matching; everything must all ways and always balance or moves until it does searching for it's equal and opposite to satiate and rest. Everything having been promised an equal and opposite reaction; the force seeks it's own.

The friction at support is lost, so must be made up at the only other friction point to support load, the hitch. The system wants to support you, and makes up the needed friction quantity here; maintaining friction as the mirror reflection of your own force; without this matching, you fall/ move to new position till matching is met. When you pull line hitch is on (dynamic leg) , hand friction takes over for the hitch friction at that same position. Because we have moved the control of the total friction to be in reach, we then can override that position with hand hold to bear weight. This frees up hitch to slide. Unless like in tight crotch example, it is pinched/crossed maintaining force, after it has been unloaded of your bodyweight.

Hitch must be fairly unloaded to slide in any direction, as the turns act each like 2x1 leverage from each side of host lifeline by your bodyweight powered into pinching/choking lifeline. Lots of hold then in this French knot machine, or we wouldn't trust it. Climbing up SRT, unload/disengage hitch by lifting and holding bodyweight yourself, then slide friction hitch to another position and let it engage by laying weight back into it; fighting no overhead turning friction. Same in DdRT, only can fight the overhead friction if it is there in the 2/1 lift potential by line pattern. Descend in SRT, disturb top 2 rings, and the bottom 2 rings just bite tighter to make up the total friction, as the system still works with this desire to support you, so reflects bodyweight force back at ya in friction if it can. Even inertia wants you to stay put/not change speed/direction as you sit still, everything working to support. In DdRT we have added a leg of line, your weight shifts over to the static leg of line as system tries to support you as you disturb top 2 rings of hitch. This unloads hitch on the dynamic leg, and hitch can then slide fairly unloaded. Any failure, stretch, lowering, expanding of the dynamic leg in any 2 leg system; will automatically shift load weight over to the more static leg, instead of trying to pull hard on the moving point to support. The static leg is more reliable to Nature to support you than more friction grip on dynamic line. DdRT provides this on ascent, SRT doesn't; thus slide in the former on descent, not on the latter.


Orrrrrrrrr, something kinda like that!

edit: Ummm. i don't have ART, but think it should be able to be inverted onto branch by methods we commonly employ for such inversions; pulling both ends of climbing line thru ring with throwline as bight of lineline is in pulley; so that pulley ends up thru ring with line in it, device choked on support???

 

[Mr_Brushcutter]

I've only used one once, it was one with aluminim rings and 3 people went up 6' or so and back down and there was a fair amount of wear on it from just doing that. It was new as well, not a damaging amount of wear but i expect if you use it every day for a month it probaly wouldn't be too safe to use. If you can get your hands on a steel ringed one i would go for that.

 

[murphy4trees]

Spidy,
i most repectfully disagree.......
When going up its harder to pull yourself up when tied into a natural crotch...
So there must be greater friction at the hand grip... So there is more friction at the hand and more friction at the t.i.p.
Think of trying to lift a load... ie big branch with GRCS... through a pulley vs. over a natural crotch.... Is all the friction equal??? I think we may need a second grader with some good common sense to settle this dispute..

 

[underwor]

I use a false crotch/friction saver/whatever on all live trees. The first few times I tried it I was not impressed. Being used to having friction over the natural crotch hold part of my weight as I advanced my hands body thrusting, I quickly noticed that I had to hold tighter to the rope as I advance with the FS. Seemed to require a lot more strength at first. Then I realized how much easier the pull was on the thrust part of the operation and realized that I was gaining on that side of the equation, as far as effort. The plus was that the friction over the natural crotch, which I had to overcome at some point and which put considerable wear on the newer synthetic ropes, as opposed to manila which I had just abandoned, was almost eliminated. I have not tried one of the ones with a micro pulley on one side yet. I finally talked myself into buying one at ISA in Milwaukee a few years back and they were sold out. I never did go ahead and order it.

I have my students try both ways, natural crotch and FS, and they all seem to prefer the FS, particularly the heavier ones.

 

[Lumberjack]

I think we may need a second grader with some good common sense to settle this dispute..

Here I am.

 

[a_lopa]

there a waste of time period,learn to climb

 

[Lumberjack]

lopa, I am not the best climber by far, but I can climb.

Learn to try new things.

Explain how your blanket statement of its a waste of time is true, afterall I do like to learn.

 

[Tom Dunlap]

LJ,

I don't understand what you mean. What am I saying that doesn't make sense?

Do a simple experiment.

Put your climbing rope over a limb and tie it off, ready to climb
tie a five gallon bucket onto the biner where the climber ties in
Fill the bucket with water, not full, maybe half way. Just enough to hold it in place
You now have a fixed weight
Above the climbing hitch tie a friction hitch and hang another five gallon bucket.
Add water to the top bucket until you move the lower bucket.
The difference in water weight is the amount of friction that you have from the rope going over the limb.
Now, change things out and use the Rope Guide
Repeat the test

What do you find?

Same load on the system but it takes less input energy to overcome the friction on the branch. That amount of energy is what is DISPLACED into your hitch.

You could do the same experiment to find out how much energy it takes to slide the friction hitch. You'd need to have a slack tender below the hitch. Add a load to the line below the hitch.

 

[MasterBlaster]

Actually, I prefer the friction of a natural crotch. Go figure.

 

[Lumberjack]

Butch I like the frictionless ascent but I like the friction coming down too.

Tom, I will explain more in a sec, gotta find the rivet gun for a worker.

 

[Ekka]

Well, I reckon we're still correct.

The Art and Science of Practical Rigging video series has this example. They use a Dynometer to measure loads and weights.

It is clear that if you have the rope going over a pulley that there is almost no friction. On ascent it's purely 1:1

How often have you had a throw bag not come down because the rough bark has too much friction and there's not enough weight in the bag ... now if the throwline was running through a pulley up there instead of a branch it would come straight down.

And when you try to retrieve the throw bag you have to pull the weight of the bag plus the line plus the amount of friction, where if it was through the pulley it would be easier as there would be no friction plus the weight of the line on the side your holding would equal out the weight of the line on the throwbag side ... I did a diagram to help.

 

[Lumberjack]

Ekka Tom is right also, but he isnt seeing the frictionless (basically) ascent offered with a pulley, he is only seeing the added friction (which is correct) on the hitch when your working or coming down. When your ascending the easier the rope can cross the TIP the less friction in the total system for ascent. When it comes to decent the more friction at the TIP the less friction on the TIP.

Then if the tip is natural the hitch can see more or less of a load, but that is minor and too lengthy to explain at this point in time.

In ascent the friction isnt displaced, its removed (practically).

 

[Tom Dunlap]

LJ,

You're speaking a different language than me. You're talking about friction at the hitch, I'm talking about friction in the whole system. Micro and macro.

In the end neither of us is right or wrong.

 

[Ekka]

Jeez, I can feel that headache coming back.

This is simple, really simple.

TS, replace all those pulleys in those diagrams with rough bark and crotches and then how efficient would it be?

Why do we use pulleys and blocks etc, because they're low on friction.

So how can a rope over a branch be more efficient in ascent than a rope over a pulley. It cannot, simple!

 

[a_lopa]

lopa, I am not the best climber by far, but I can climb.

Learn to try new things.

Explain how your blanket statement of its a waste of time is true, afterall I do like to learn.

true its probably a bit harsh and a blanket statement,i just dont like adding anything other than the basics

a climber i know is in a wheelchair from having to much kit onboard, his own admission.thats good enough for me.

 

[Tom Dunlap]

a climber i know is in a wheelchair from having to much kit onboard, his own admission.thats good enough for me.

There is more to this story. Care to explain? What does having too much gear have to do with someone ending up in a wheelchair?

 

[MasterBlaster]

I agree, please expound on that!

I love that word!

 

[Lumberjack]

Explain your friends situation please loopa. Using advanced gear properly is never a safety risk IMO.

 

[a_lopa]

ok im not here to cross examine the incident or have an opinion on what gear ANYONE uses.if you happen to read this phil please let us know your story sad as it is.

ok he was using a 2 biner set up to attach himself (i dont know or care to know which one of these "modern types")swinging back to the trunk he didnt have one done up or he had caribiner roll out yes his fault but he still says if hed been climbing with one biner chances are it wouldnt have happened.he is now a climbing instructor and features in workcover adverts