Playing with Forces

TheTreeSpyder · Jul 25, 2011

To understand rigging and climbing on rope, i think it is best to understand the forces in rope. Also, the same science will hold true within the microcosm of a knot, commanding it's properties.

To live on rope, dependent on it for support, rigging , pulling, knotting, tie down etc. all day, everyday; one needs to understand and obey it rules to command it!

Use it in chains of systems, can give successive multiples of either maximizing force or distance as you like.

With the strategy in this pic, a climber can help pretension rigging lines more, climb his rope easier. Can also be more self sufficient on pretensioning and rigging down more alone, before needing full crew in kill zone. Better line tension can help reduce drop impact on rope, steer better sideways, offer more overhead clearance to obstacles etc.; all for taking the 'slop' out of a system/ tightening it up.

http://www.mytreelessons.com/ks/forcePlay.swf

SingleJack · Jul 25, 2011

Great diagram, Kenny! ... took a little work to figure it out but WHAT A WONDERFUL TIP ... gonna put that to good use >> THANKS!

TheTreeSpyder · Jul 28, 2011

Pulling the loop in this orange rope typically empowers a 3:1 compression jig etc. for us. Note with same here, the workman only exerts 100# and gets 850# return. This is because he also is sitting in swing on end of line, and capturing the equal and opposite of his effort, instead of this equal and opposite force potential pulling on outside anchor, it pulls inside the 3:1.

This pic is also different in that this is a remote pull on load (w/o touching leg directly to readout scale); like a groundman might be pulling on. Climber can be in previous pic, w/access to leg of line directly to scale/ no redirect pulley (or great distance) in between to change things. Climber and ground man can work to tighten, to ADD (not multiply) their outputs together to pretension line, do quick lift etc.

Also, if set up right, both climber and ground man (or just 1), can use leg force (rather than arm force) as effort input; and the effort is what is getting greatest multiplier in this strategy. Here bodyweight would get 3x multiplier and effort 4x, but do same in a 5:1, bodyweight gets the 'nominal' 5:1, but effort gets 3 more pulls for 8:1!

MyTreeLessons.Com/ks/forcePlay_b.swf

SingleJack · Jul 28, 2011

Hey Kenny,

Do you have any real work photo's of these principles in action? ... would love to see 'em!!!

treemaninmo · Jul 29, 2011

Thank you Treespyder , you validated a theory i had about when a y'ed crothced lead hangs up when we are above and line is tension we can pull up easier than 2 guys on the ground even if running thru a block.
thank you brother
climb safe n God Bless

TheTreeSpyder · Jul 30, 2011

Sorry i don't have pics/ vid.

Any pics i have during use, probably focused on line routing, cutting, the load etc., not this pretensioning .

The 2nd pic shows worker just sitting there, exerting 100# of effort into 3:1, to get 850# potential return. This would be rather elusive to camera, without scales/ in working practice.

In fact, this is so simple, you can accidentally fall into this pattern from time to time; maybe not realize why things got easier, worked better, or even against you etc. but, the mechanics are most correct IMLHO; so it just works. And, can't really truly assess all situations; if don't see this pattern readily.

If you just throw efforts to these targets, can look about same. On ground; workers reach up grab rope, only worker B leans on line with all but 5# of body weight (to stay stabilized, not swing leave some weight on feet) they both look same. Then, while upper pull hand seems focus, worker B also, almost imperceptibly pulls on system with free hand from recommended point(like some kind of trick judo move), and he can add effort to bodyweight as input( then also the equal and opposite of his effort), worker A can only pull up to body weight, without hanging weight and pulling on something to add effort to input.

If both workers use bodyweight + effort strategy by hanging and pulling, and worker A pulls on anchor outside of system(rock), worker B has advantage as his pull pulls inside the system again towards target, not exerted on rock as "non-returning / endpoint of the force flow". Max is if endpoints of system are on input/output, not exiting system with no return of same potential or leveraging more!

Several factors here for climber position vs. groundman positioning pre-tighten/lift. Due to greater length of line, groundman also incurs more effort 'fighting' rope stretch of greater length of line. Also, in first pic, climber pulls up right above meter/target (load), so that pull doesn't incur any friction from redirect, nor virtually any rope stretch(pull goes right to meter/ limb lift), and gets and equal/opposite return back into system also. But, i would always try to use that force to flex limb first (by reaching farther out on it than hitchpoint), gaining leverage lift as we tighten. A cheat on this, and to get leg lift as input rather than arm curl; i have put shoulder under limb, leveraged further out than hitchpoint, and then lifted thru foot cam on control side of rig. Couple of spare stobs from not making previous finishing cuts, can help at this point. If groundman (not going to stobs) still trying to tighten then to tweak, climb up some feets, and apply same forces to rig line with hand; to load some into the elasticity of the line if possible. With less line right above scale/ target pre-tension load, can't pre-load any tension into elastic line length. So, lift limb, then stretch line if desired. If such massive limb can't 'impress' / lift, just go for stretch line position tot make as much 'play' out of system as possible, preload into rope elasticity!

TheTreeSpyder · Jul 30, 2011

Broke into 2 posts, this shows olde world example of same strategy:

i think in exercising understanding of even this part of the rope mechanics to the point of were they seem to turn on themselves, gives better understanding of the rest of rope properties. Or, just makes them seem easier to understand by compairison.

Instead of 'insetting' your weight + output + equal/opposite of output into system, you can have another system do same to a system, for the same types of multiplying effects. So, that the normal output of the system, plus it's usually anchored outside the system end, also pulls on the original system; like this olde, perhaps ancient strategy:

MyTreeLessons.Com/Marlinspike_%20Sailor_Rig.htm

i think this was very purposeful, perhaps no cameras to take pix when used most! Worker can take this rig, and pull on it like in 2nd pic of this thread, and have highly leveraged advantage then other worker attaching the ship's rig 3:1 to a high anchor/mast, not back to the system, then not pull on it as shown. To a landlubber might look like same setup, and work! But, 1 worker is applying multipliers of multipliers to much higher output potential.

Kinda a secret passage to more force, to also throw forward more confident-ally and purposefully, knowing that every drop counts and is getting most leveraged position, really helps input too i think!

Another advantage to these systems you have 2 hands on, is that you can hold stable with a force (effort + equal/ opposite), and then impact with another force (drop bodyweight) for more tension, then must capture it quick / to grab line behind frictions, keep inertia moving etc..