Have heard, but can't understand, idea of using a figure-8 to tighten a speedline...

[*useless info*]

Sweating/Swigging line is bastardization of support science from rope.
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In all cases, un-malleable stone, malleable metal, wood stiff fiber and flexible rope fiber etc.
>>Use as support, thru cosine as % of length and force
>>the amount of total carried 'expressed' against load (same math for length of force)
>>This is it's columnar , INLINE support column usage
i think of cosine as co(lumn)sine
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To other yin/yang extreme of the powerband
we have wrenching to break, not support to capitalize on sine /side force (instead of capitalizing on cosine as in supporting)
This is not inline , but rather lateral/cross axis loading
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Tighten linearly down line length to iron bar tight, grabbing purchases as can.
>>are going to use 3:1 tightened line as a lever
>>so tighten as hard as can in setup linear pull so will be less rubbery lever/for highest leveraged return when apply side force across not down line length.
Then you pull across the line, release as 'tailer' pulls another purchase thru the 'friction buffer' from loaded to control side.
Rope now tighter, to resist bending more, so more leverage if do
>>go again to grab another purchase.
'tailers' were also used in bollards with 10:1 levers powered by perhaps dozens of hungry ,scared men lost at sea; still need person to sneak purchase thru friction straits from loaded to control side of the works in same fashion.

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The tension part of this sweat/swig is as simple as child's swing plz.
On peak of swing, support legs to swing most loaded/load least inline
>>and over-riding motion is at neutral point
Child can pull back hard across the loaded line to raise tension
>>side force of tension wants to serve to inline (compression side force opposite pushes out of line)
so child swings back under support etc. harder after raising tension pulling across line
Sweat/Swig is like that; only capturing the sequential purchases
>>for higher return each time (if load not moving)
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Climber access allows this to be done to raw/load side before frictions.
>>Also ground can sweat from that position if prussik midway with pull arm to ground
>>or use to turn horizontal on hinge sideways with this pressure from side
Trick is to load target rope HARD before bending it.
The best machine or team as a machine ain't chit w/o proper timing!
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Of course slanted rope to side can give side force as well
>>each click of the clock/hashmark give 10% more side force until about halfway 45degree midpoint.
>>noon/TDC=no side force, 12:01=10%side force, 12:02=20%side force, 12:03=30%... (my rule of thumb calc sine from Babylonian clock pattern i try to show)
Sweat before or during movement to accentuate above geometries.
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(my)Rule of thumb for cosine per hash/minute/second
is noon/TDC =1 cosine, 12:01=1-.01, 12:02=1-.01-.02, etc.
Each tick/hash/minute/second is 6degrees of total 360 in their base 60 math...
mostly use rules of thumb between 12 and 1o'clock where most accurate to ~1%.
i was always math pattern crazy and made these up along the way i guess, as can't find any source to verify, not even engineer son.
Note how we lose 1% efficiency in first 'click', BUT jump 10% side force
>>stuff blows out more from the 10%load increase in different direction than the 1% efficiency loss in same direction.
Best to watch both of magicians hands,
>>at least the trickier one..>>that would be the side force!!!

 

[eyehearttrees]

Maff's, geometries & (algebra? trig? beyond my full comprehension)

I think you're significantly over-estimating the math-competency of 9-outta-10 of us, I know that for myself if I'm not actively studying sine/cosine stuff then I'll lose it immediately it just doesn't stay intuitive like it is for you.. at any rate thanks for the post am always happy to see you've replied in a thread I always need to read them several times to digest what I'm able to & always learn something

Re lateral/cross/axial loading OR in-line pulling of a rope, that yin&yang you phrase/contextualized your post in, that's been on my mind lately and I'd love your thoughts. SOOooooo..... When I'm using my Safebloc with bull-rope going through >1 hole, or using a 4-ringed rigging-system, hell - if I'm just using 1 ring as a sole-anchor - that awesome effect of "built-in brakes" is achieved by *both* forms of rope-loading, axial/lateral/sideways and pulling/in-line loading...the actual #'s for this would be far beyond what I could grasp, but the setups I rig are able to put some massssive "built-in-brakes" if I choose to in fact I can easily add more-than a given log can even descend and this is where I'd LOVE to understand more (even if I can never put #'s to it!)
For instance, I can "add brakes" by setting, say, 4 separate ringed-anchors + 1 Safebloc and this suddenly lets me control - with 1 hand even - surprising amounts of log-weight.... Hell, it's happened plenty of times that I'll feed-rope to the log because I'd set too-much friction-brakes in the system!
I've been wondering about ^ this type of friction-braking and expect you're one of the few who just 'sees' the forces&#'s behind this w/o trying I wonder:
- When a Safebloc is in-use, providing "brakes" by means of surface-friction, wouldn't the rope's-elasticity become a bigger factor? Specifically, I mean in terms of greatest reduction in peak-force if snubbing a log, the peak-force of a given log is lower when the rope is more-elastic (of course, as the rope is absorbing shock/force), and the peak-force for a given log is lower when the rope is fed through friction-hardware than a frictionless block, but what about when considering these together, ie would it be fair to say that a more-elastic rope would be better able to "take advantage of" such friction-based systems? Not only would I expect more-elastic ropes to have a more-than-linear advantage when run-through friction devices, but would also expect a higher ABS for the rope (relative to spec-ABS) when pushed to fail in such cases.
- Is the more-than linear relationship between wraps & force from the Capstan Equation result from it being a coiled-rope, or is it merely surface area? For instance, doubling from 2 wraps to 4 wraps is more than a 2X boost in power on the control-side of the bollard...is a similar increase seen when going from a (2) ring-slings system to a (4) ringed-slings system? Alternatively, let's say we had a 10-hole Safebloc (10 vertical holes, very tall/skinny piece of hardware!), and fed the rope through all 10 holes... Would that force be comparable to 5 wraps on a bollard with a diameter matching the Safebloc's hole's distances? IE is the phenomena from the Capstan Equation seen in-general with friction, or only on drums/bollards/spools?

Thanks for any insight you may be able to provide! Am having fun making systems with "bigger brakes" but need to be conservative because I've had enough "accidental snubs" where I thought I'd be 1-handing a log but instead my system just snubs it and it bucks me (it's not just fear of losing my balance it's the fear of compromising one of my anchor-points, if a snub isn't acceptable in the situation then I back-off the friction a ton so I don't risk breaking an anchoring-point)


(PS- Re the Capstan Equation... when picturing rope squeezing-out of the capstan/bollard and "into the system", that rope is hockling/curling on the bollard- is that action of any significance? Like, if you had a realllly long bollard (but same diameter), and took same amount of wraps, I can't imagine there's much difference if they're on a 10', or 3', long bollard - bollard-friction is "stronger than" friction from a comparable-surface-area composed of discrete surfaces...wish I could visualize *why* it's the case though!)

 

[evo]

Wow... some solid mentor ship is in order

 

[*useless info*]

Rope elasticity can buffer spikes (like electrical capacitor) , and lay down flatter to more contact in some cases. But, also stiffness against the arc-ing i think , that then leverages thru more against rope , for more effect by trapped tighter seating of higher friction(?).

The geometry given by the Ancients, command most all things.
>>especially to the intensities we taunt them, and control by simplest of tools.
Babylonians gave us 360 circle and clock from their base_60 math.
For me they are related and i only focus on about 10 repeating degrees, from clock face, on second/minute hashes reference as guide AND mnemonic of values too. (mostly simply use from 12 to 1 o'clock range as in previous post) Presently cant find old drawing(will have to re-make), but also can't believe i'm the only one to see the pattern, and even wonder if it is purposefully put there as guide, some 4 millenniums ago in Ancient Babylon..
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SafeBloc to me is a list of 'linear arcs' as like a fixed rappelling rack; that also invokes the yes/capstan effect of compounding arcs of friction. The capstan formula is thus based on compounding interest formula of arc frictions. Expansion/compounding based on Euler's number. That is simply approximation of logarithm of 1. Adding logarithms to multiply the related numbers is how a slide rule works, that we used to put man on moon w/o missing in orbit, and bring'em back whole. The compounding uses log of 1 to exponentially expand the base factor of money or friction etc. in this way. Euler's and PI are 2 of the most powerful numbers devised by man to follow faithfully the Natural Laws; and then so define them back to us.
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Not sure if hockling on a list of 'radial arcs' would increase friction, perhaps could even make case where the rock hardened torqued rope rides slicker?? i have tried reverse/not continuous turns on original T-bone style Porty(was first kid laughed at on my block/town with one) that helped against hockling.
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Counter-intuitive point of capstan math is that it is the degrees of contact, not distance. So larger brake gives softer arc to rope for higher capacity/efficiency; and more heat spread out/less concentrated and dissipation on metal as heatsink; but to this theory, nets the same braking force per degrees of turn(s) invoked..
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jrre.org/att_frict.pdf
i think takes us beyond capstan math and defines forces in all of work load knotting. That the tension travels only in simplest, single dimension of a straight line {co(lum)sine, anything else to sides is it's non of sine, not contained in the simplest, single, inline dimension of focus, thereby non-linear factor} ; so by definition we only have straight extensions and 180arcs back to same line/axis(but in opposite direction). The arcs are the magic, the straight lines just extensions of the magic from point to point. 'Linear Arcs' as list thru SafeBloc, rappelling rack,Stevedore Stopper, Surgeon's Knot, splicing etc. kinda hybrid as show in name of 'Linear Arcs'; friction reduction is straight line overall allotting both factors as one(extension and friction)..
my spreadsheet on standard flat friction CoFs expanded to radial frictions per att_frict paper

 

[Jonny]

For instance, I can "add brakes" by setting, say, 4 separate ringed-anchors + 1 Safebloc and this suddenly lets me control - with 1 hand even - surprising amounts of log-weight.... Hell, it's happened plenty of times that I'll feed-rope to the log because I'd set too-much friction-brakes in the system!

Best case scenario this is just undesirable. Worst case is gonna be death, injury, and property damage.

Shock loads are less if pieces can run and be slowed to a stop. Your equipment will thank you and your climber won’t get so easily struck or violently flung about like a rag doll.

A good experienced ground person with a solid understanding of how their lowering device works can make those big old scary negative rigging forces almost gentle even with the most static of ropes.

I’ve quit my job once because my boss who was working the ground insisted on 3 wraps on the porty when one or one and a half wraps were needed. He didn’t understand that he was putting me at higher risk and he wouldn’t listen. I left a face cut in the top of a spruce, came down, grabbed my stuff and went home to call around for a new boss. Too much friction and losing the ability to let a piece run at the right time sucks.

I’m not here to give you a hard time man. I’m concerned though and it’d be tragic if you suffered a life changing injury because of a bad decision or a lack of knowledge. I admire your drive to learn this stuff, and you’ll learn so much more practical knowledge if you would take on an entry level groundie job with a busy and reputable tree service in your area. Winging this work is lethal. Experienced professionals don’t always make it back home after a job. You need an experienced pro to watch your back and give guidance and put a stop to mistakes before they’re made.

 

[*useless info*]

There is story around these parts of a Dr Peter Donzelli asking for 2 wraps on Porty and got 3, cost him his life (y2k) as rope seized against load and column of lightening struck tree failed below him/with him in it. The jump in friction can go from like 10xBallast (hand hold) @ 4 half circle arcs, to 50xBallast @ 6 half circle arcs per chart of nylon on aluminum; even greater jump if nylon on steel CoF(CoEfficient of Friction).
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This is a compounding event of ever increasing JUMPS, not serially adding just so much more surface contact serves back that amount of force. Degrees of contact, not distance. Size of brake only matters in softer/more efficient rope arc on device, and spreading out same friction to less concentration (and larger heat sink for that if metal).
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i think half circle arc is key measurement, as linear force input into device has component that still runs in straight line, and rope/all flexibles only resist inline. So either have that line or 180 arc back to that line/axis (but in opposite direction on that line/axis) as the basic components to all working knot usage.

 

[*useless info*]

If take common 8' 2x4 w/2"sq.block each end we neatly have 8x12" + 2x2" =100" column
>>as a FINITE usable length that can be 'expressed' vertically or horizontally w/hybrids of each in between ranges.
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If from center of clock, 2x4 w/blocks column rises to TDC/12 noon,
>>all of the potential length is 'expressed' vertically, none sideways
>>thus cosine is 1 (efficiency of vertical rise 100%) and sine is 0 for side drift
BUT if this pure vertical column drifts to the side 6degrees (12:01 on clock)
>>cosine drops 1% to .99 efficient, thus column reach upward loses an inch vertically
>>while at same time sine JUMPS to 10% drift/side force
As board now 'only' rises to 99", it also JUMPS to 10" drift at top, thus the major change is the drift/side force horizontal
>>@ 12:02 minute hand angle board now reaches 98"(cos.98) but drifts another 10" to side (sine.20)
FORCE uses the same maths, just to different potential force in equation, and is just as real JUMP sideways
>>just as the length in equation is a potential, with percentages expressed to cosine column and not
>>the amount of force borne by device is the finite force potential, percentages of which are expressed vertically and horizontally all the same by same calculation, just to the different potential of force in the equation
In motion to these positions (tree felling etc.) , we thus can incur very harsh sudden impacting side force that in first few 'minutes' on clock as a very counter-intuituve point as eye sees height more or less same not decrease.
>>or only a hair, and with out study i think totally don't imagine that potent jump to side, that also happens in forces!
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The ruling 360 degree circle and the clock were both made by the Babylonians 4000 yrs ago to be handed down.
>>they used a base_60 math, as shown on clock, so each hash/tick/minute/second is 360/60=6 degrees
For hand-grenade close rule of thumb i simply use clock marks as angles and then numbers as cos/sin mnemonic.
>>hand grenade close as in errs in the hundreths to model all around 360 circle from 10pts. in first 45 degrees!
This is how i EASILY calc angle and percentages, using common clock:

sample usage of thumbrule:​

@Noon/ 0degrees cos:100%, sine:0%, tang:0% (TDC)

@1min/ 6degrees cos:99%, sine:10%, tang:11%

@2min/12degrees cos:98%, sine:20%, tang:22%

@3min/18degrees cos:95%, sine:30%, tang:33%

@4min/24degrees cos:91%, sine:40%, tang:44%

@5min/30degrees cos:86%, sine:50%, tang:55%

@6min/36degrees cos:81%, sine:59%, tang:66%(tang 2%err)

@7min/42degrees cos:74%, sine:67%, tang:77% (tang ERR do not use!)

@7.5mins/45degs cos:70.7% sin:70.7% tang:100% (mid point)

In simplest, Natural gravity force direction:
i use cosine to show % of 'displaced' space & force from the available potential length/force used VERTICAL
likewise sine to show % of 'displaced' space & force from the available potential length/force used HORIZONTAL
While tangent (not focus of this model but a freebie)
>>@ 12 degrees/2 mins on clock and holding 100", will 'express' ~22# to the side
>>@ 18 degrees/3 mins on clock and holding 100", will 'express' ~33# to the side etc.
SO rigging sideways on hinge almost cut thru, limb bearing down 400# on rope
>>gets 44# instead of Zer0 pulling sideways if can get rope angle to 1 minute/not vertical
>>if can connive 1 more minute/click that sideforce doubles to 88#, about what 1 man pulling tree might give..
The clock hand angles and minute marks lend very well to this, cant believe i'm the only ever to see this
>>but cant find elsewheres when look. Wonder if purposeful guide coded in 4000yrs ago..
It is MOST accurate in first 5mins, that mostly use, then can flip that 12-1 to find the 2-3 numbers
>>leaving center 1-2o'clock mid range as most err , in most unused zone of primary 90
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This 'primary 45 degrees' can be flipped to define the rest of the 'primary 90 degrees' .
>>then the primary 90 can be flipped around to all 4 corners of the squared circle model
>>thus PI is simply 4 - 21.5% loss ea. corner . 4-(4x 21.5%)=~3.141592
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In my force imagery models, i project the need of the unique, simple, single dimension of the cosine first against the linear force
>>as necessarily conjured against opposing force, then sine force as a trailing responder
This is in keeping with also the unseen waveforms all around of air, water, electricity, light etc. who's sine waves are ALWAYS preceded by their corresponding cosine waves.
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The numbers given by the Ancients are all around us, but especially magnified in force and leverage of that force in this thing that we do with virtually the heaviest, longest, most rigid leverage-able force in a life form known. Especially as we work with the simplest of tools rope & friction pivot to command the beasts. A front row seat of magnified view of how all much else works, as perhaps greatest persisting gift of this work, persisting far beyond the paycheck.
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They eventually cast PI as 3 1/8, 3.125 , so as to be .01659 short
>>so s/light 1-2% err found a bit here and there/mitigate, seems likely reality.
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Each generation's cast luxuries to children, risk taking them further from the unspoken lessons of the rawest of forces.
These peoples had no such buffering, and engaged forces most rawly, with fewer distractions and simplest of tools to do battle with.
What they decoded in the sight of such rawness, rules the world, and beyond the stars; let alone a simple tree in said context.
i truly hope this simple clock model gives a look into this key/pivotal world;
as it has allowed me to read the code and l-earn from much around me!
Further definement takes protractor and calculator/slide rule, tables etc.
>>But at a glance of the clock, can answer many questions on the fly!

 

[eyehearttrees]

[ @*useless info* -- thank you VERY much, that'll eat my spare-time this wkend I am sure hehe will be able to appropriately reply once I've been able to re-read & digest all of that You don't happen to post on BonsaiNut do you? If not, there is a 'mental doppleganger' of you only in-context of bonsai, but I've found a good deal of bonsai//arborists overlap, though TBH not remotely the % I would've expected...]

Wow... some solid mentor ship is in order

For right now the closest I've got is online discussion-- was there anything in-particular you could at least point-out so I can look-into it myself? Even if it's just that you think I have a generally-risky-approach or something like that, I'd be eager to hear any elaboration man, am thick-skinned enough & respect you-in-particular on these boards so would really appreciate any elaboration! FWIW the only people I've worked w/ so far in real life (this includes guys who've been doing it for 20yrs), I am watching them and mentally making laundry-lists of errors, so am not in any way holding my breath that I'll find a good mentor before I've gotten another 6mo, 18mo etc into this profession.

(Re the 'Wow', that's really got me worried..I do have trouble conveying things online sometimes so perhaps I gave an impression I do riskier things than I do, TBH I consider myself "on the conservative side" (by choice) and if that's not the case then thinking I am when I'm not is extra dangerous so wanna cover my bases sooner than later, appreciate it man!!! And btw I hope things are going smoothly-as-possible on the home-front, life can realllllly be F'ing unfair :/ )