Power in VersaTackle

General Discussion
1

Continued from Looking for a Knot - Thread

Very Nice!

A VersaTackle to me is like the tightening of a Trucker’s Hitch or Z-Rig; only with another loop eye to reeve bitters thru, allowing trailing the bitters thru both loops a number of times. This gives much more power; by giving more distance to pull for same work/ distance of drawing ends of systems closer together. The more turns taken on the moving load end, the more power output.

i like calling this mechanical advantage; becasue it is an inline strategy; more preserving non-inline/ perpendicular input forces on the line for being called leveraging. To me leveraging being more related to tourque/turn; so implicates also pulling at an angle to put turn force, not inline pull on target load.

i think in the 1st picture of the VersaTackle on that fine site; if rope can travel around both black dots; whether both are moving load points, or even if one is just a slippery anchor; there is more power output per effort input than in the 2nd example. In the 2nd example; 1 end of the system line must be fixed/anchored/ cannot travel. But, the more distance altered/traveled for the same work, gives more power. The first pictured system; offers altering distance at both ends of the pulls; so more distance traveled, gives more power.

Either system could get more power by 2Handing; which is really same thing that system 1 is doing for more power; recycling the equal and opposite force to work on the load, rather than terminate that force at anchor to not pull on the load. Also, pull from each system could be increased, by pulling ininle on bitters/ tail to tighten system; while other hand ‘sweats’ more purchase from each leg of pull with angular/leverage pulls. And/ or leveraging by locking off whole system and bending it as a whole. The system tightend is stiffer; so resists bending more, thus more leverage output.

More on 2 Handing; increasing force with inline and perpendicular to line pulls

i think these same patterns of forces, under the same loads, in this same rope materials; have the same mechanics inside the secret world of knots; as these rigs. Friction providing grip, but also degrading forces; while bends and curves alter distances it takes to accomplish a task; thereby manipulating forces. Only a straight line that doesn’t rub friction on anything, not altering force. But, knots have the least straight lines; so just preserve the frictions, bends and curves that have force altering mechanics; to make them work so many jobs.

Or, something like that! :o

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Thank you KC,
This is an explanation I can understand.

Willeke

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A [url=http://www.geocities.com/roo_two/Versatackle.html]VersaTackle[/url] to me is like the tightening of a Trucker's Hitch or Z-Rig; only with another loop eye to reeve bitters thru, allowing trailing the bitters thru both loops a number of times. This gives much more power; by giving more distance to pull for same work/ distance of drawing ends of systems closer together. The more turns taken on the moving load end, the more power output.
and , from the site:
The Versatackle has a high mechanical advantage
This is hogwash! I suggest you two get some dead weights, or use some measuring device, and confirm for your disbelieving selves that the reputed MA of such rope-pulley systems is miniscule compared to the theoretcal MA. --to wit, cf: [url]www.canyoneering.net/forums/showthread.php?t=642[/url] where, in a similar system but using one sheave of [i]metal--a 'biner--[/i] the theoretical MA of 5-to-1 was measured as actually 1.6-to-1. --not EVEN 2-to-1!!

One can see this to some extent in watching the cordage of the loops through
such a structure: the ones away from the haul line will often be slack, hardly
contributing to the bearing of load (until the haul line is released, and then they
take on load and lock the system).

–dl*

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i knew that friction into these non-pulley MA systems / jigs would degrade the multipliers of effort; but not quite that much. Of curse here the eyes collapsing and legs of pull rubbing each other in eyes and travel outside of eyes, does add up. But, that is quite a loss quoted there; and i also kinda question the testing layout. i think the numbers are variable to materials, rig, style etc.; but those numbers are rather pessimistic.

i think if the end of the Dyno was pulled, there might be a different amount found, especially after some purchase taken, then the amount of hold would be helpful(from same friction that is degrading 5:1 output), and more likely to be able to be freed up to force more sudden impact into the system.

i figure efficiency of rope on rope as pretty variable by materials, being squished etc. Rope on krab as rougly 65%; on smooth sheave only slip as ~80%, and on bearing(under sheave) as ~90%. Due to the sliding between axle and raw sheave or bearings; the thickness of the sheave over the axle gives leverage to overpower friction. This feels like less friction, but is just leveraged, so friction and heat still exist. Krab shape can also play a part in efficiency i think; especially teardropped/ pointed with more than 1 line reeved thru.

The theoretical MA is calcualted as friction free; then this friction is another multiplier or co-efficinet more properly; but here is set against efforts. In this Yin-Yang “Tao of Physics” (Fritjof Capra), anything that can styand agaianst’ye; can in fact stand (help) for’ye. If the same load was lowering (expanding system rather tahn compressing) instead of lifting; all that friction would be helping, and on top of the 5:1 mechanics. Such as if the climber testing theory on Dyno in pic was letting self down, holding or just resetting for another pull; the friction is helping on top of the theoretical 5:1.

The trucker’s hitch without pulleys suffers same examination, except less legs of line rubbing and no potential for 2 lines reeved thru same eye rubbing together. This is one reason i introduced the topic of sweating/bowstringing the individual legs of line, as this perpendicualr strategy will use the friction to your good on compression strategy. This is a trade off i’ve found in tree work; as friction stands against inline tightening it can help in perpendicualr tightening; and keeping purchases.

Also, in bending the whole locked off system/ jig at finish; the multi loegs of line help another way to increase tension. 1 leg of line carrying 100#; has more elasticity, than 5 legs carrying 20#. For, elasticity is arrived at by it’s factor in a material and braid; and the amount of tension as a % of the line’s tensile. So, the same line with less load per leg will have less elasticity. So, more of pull will be towards target load and not stretching rope, and more resistance to bending, for higher leveraged return to perpendicualr force on line/bending. The flip side is less shock absorbtion; so it depends on what you need.

i feel the observations on 2Handing stands, as well as the pairallell theory that the first versatackle providing distance alteration on both ends potentially/ using the equal and opposite to target too; to provide more possible power to task. Force is the only thing that can overcome distance; so anytime distance is altered on the input in relationship to the output; force is altered. 2Handing and the first pictured rig allow the distance of input to be altered by 2 inputs rather than 1.

Awe, come on Doctor Dan; ya didn’t think i’d just give up cuz it’s you speaking did ya? :o

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and , from the site: This is hogwash!

Calm down, Dan. The mechanical advantage of the Versatackle is high, but I don’t give a number, since the friction of materials, number of passes, and manner of threading and use all impacts the results.

If I gave an erroneous number, you might have something to get excited about, but I didn’t, so you don’t.

cf: http://notableknotindex.webs.com/Versatackle.html

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i knew that friction into these non-pulley MA systems / jigs would degrade the multipliers of effort; but not quite that much.
Yep, 'tis a shocker.

Rope on krab as rougly 65%;

Yep.

Krab shape can also play a part in efficiency i think;

There seems to be a marked difference for anodized 'biners, but that puzzles
me!? And whichever rope is used varies things a bit. But I don’t see all these things
in the usual published hype, and there’s a lonnnnnnnng way to go to imagine
improvement to 1.6:1 MA !!

The trucker’s hitch without pulleys suffers same examination, except less

Yeah, doesn’t usually extend to the point of near-no return. And there is that benefit
of the friction working FOR you, to hold surged gains.

Awe, come on Doctor Dan; ya didn't think i'd just give up cuz it's you speaking did ya? :o
Heck, no; but I [i]did[/i] think that you'd run out and try out some eBay'd dynamommameter or weights so you could sputter with more than speculative splendor. ;D

E.g., sitting outside now are two sets of barbell weights–30# & 50#–: guess
what doesn’t move which, despite all that “power” gained by Versatickling the rope?
–0.5(7/16?)" nylon solid braid, 5/16" soft-laid PP (more friction in former, where
40# didn’t much move 50#–until given some momentum),
Versatackle tied between upper thick, lower thinner, 'biners, with 2 reavings
through the rope eyes. 50/40, 1.25:1. And what’s the Theor.MA, btw?

For how many more decades (centuries?!), in how many more books, et cetera,
will such MA cordage systems be promoted as powerful solutions to … ?!!

–dl*

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Calm down, Dan. The mechanical advantage of the Versatackle is [b]high[/b], but I don't give a number, since the friction of materials, number of passes, and manner of threading and use all impacts the results.

If I gave an erroneous number, you might have something to get excited about, but I didn’t, so you don’t.

Your high-ness, this is a laughable response. You say "high", as I've emphasized: perhaps you'd like to give us a rough range of what MAs may be so regarded? Charles Warner did some testing of many MA systems w/rope & krab sheaves; his report in km23:13ff found the best (incl. a thrice-reeved Versatackle with [i]separate[/i] eyes, to avoid lock-up on loading) to be about 2-to-1, even so, with MUCH rope! No one will think that 2:1 is high, but by my two cases that's an unreached MA. Maybe you can give us the materials in which you got your high(s)? (Meanwhile, we have Geoffrey [i][u]Ultimate[/u][/i]ly liberating "bogged-down motor vehicles" with it, which reminds us of that courageous young fellow about to try ripping off a vehicle's bumper with a simpler structure in [i][u]The Knot Book[/u][/i]--hardly!) Until then, the main thing the Versatackle should suspend is belief.

::slight_smile:

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Your high-ness, this is a laughable response. You say "high", as I've emphasized: perhaps you'd like to give us a rough range of what MAs may be so regarded?
You must have woken up on the wrong side of the bed this morning.

If a single-eye tensioning system has a typical or normal degree of mechanical advantage for a pulleyless rope system, a Versatackle has a high degree of mechanical advantage. It is beyond me why you are belaboring this.

In accordance with my first diagram, I was able to get a mechanical advantage of 2.6:1 for the Versatackle with two passes per eye, tied correctly with polypropylene. That is high for a pulleyless rope system that is self-locking, easy to untie, easy to remember, and can apply force over a large range of motion if needed.

I don’t write my web pages with Dan Lehman’s personal undeclared standards in mind when I choose my adjectives.

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Hi Roo and Dan, I am between a rock and a hard place as I respect both of your views. I get a bit too hot on the posts. I respect both points and right now the isp[ will not let me post or edit. FUBAR. ?o.

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I can read my post and i can reply but I can’t edit or change my p;ost. Wow. sorry for all the exp;lectivies. Can’t edit them out. I went back to my ISP and that sems… awe horse appe;sles sems top be the p;roblem.. you al know I can type but this has altered my text. Sory. I’l rebot rebo awe f. rebo, cant get a o to type a second time. Whjy do I even try?

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Hi, Iv’e rebooted and tried to come back to the forum and at this moment it seem to let me edit my own post. I’ll not risk it to go back to previous posts. What I wanted to say is that Dan and Roo each have a point of view and that without the exchange between them I would feel cheated. Often I can not see the “point” on some posts. It may be a lack of wit on my part. Often I see exactly what “A” is saying and can not seem to help “B” to see it from my point. So I value Dan and all other at this site (now the fact that my ISP has let me back to the site may skew my post). I am elated that my ISP alllows me to post A and B view points. So my good friend Dan can oppose my good friend Roo (both of which I only know from this site). So my friends… can we just try to get along.???

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Heck, no; but I did think that you’d run out and try out some eBay’d
dynamommameter or weights so you could sputter with more
than speculative splendor. ;D

–dl*
====

Well, ya might have to
Wait!

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It is beyond me why you are belaboring this.
Then you must choose to ignore what I've said--I posted repeatable testing, both of my own and by Charles Warner. And the point is point blank obvious: rope-pulley systems, SUCH AS the Verstatackle, are hyped beyond any reason. And I stated quite clearly & succinctly my case. I'll quote CW below.
In accordance with my first diagram, I was able to get a mechanical advantage of 2.6:1 for the Versatackle with two passes per eye, tied correctly with polypropylene.
And anyone can see that this is NOT an adequate report; it cannot be repeated, for there is no specification--even crude, as in my case--of materials & forces. What "" was this? (Mine was 5/16" soft-laid.) How was the MA measured? (Mine was done by using weights, determining only movement or not. CW's was done with a scale for loads <27#, and a few small cords, incl. kernmantle. And he also tested using krabs for sheaves, throughout his systems.)
That is high for a pulleyless rope system that is self-locking, easy to untie, easy to remember, and can apply force over a large range of motion if needed.
I'll grant the 2.6:1 would be nice and arguably "high". But I don't see it here. In Charles's case, he couldn't get a thrice-reeved V. to work w/o locking during tensioning, and so went to using separate eyes. As for range of motion, the V. is limited to something less that half the span between anchor & load point --the same as a doubling a simple 2-to-1 rig--; a Z rig will move a load the entire span.
Hi Roo and Dan, I am between a rock and a hard place as I respect both of your views.
This isn't about [i]points of view[/i]: rather, it's a simple, practical objective assertion regarding a knotted rope structure, germane to those who fancy themselves as practical knot tyers. And there are those connected to this site who should [i]want[/i] to do more than weigh presumed PoVs and put assertions to the test! [b]To promote the art, craft and science of knotting, its study and practice. To undertake research into all aspects of knotting. [/b] As Charles wrote, quite a long time ago but seemingly w/o much effect: [i]From time to time one sees in the knotting literature (including Knotting Matters) notes on rope tackles. I wonder if all the authors have ever desperately wanted to shift a heavy weight and only had a length of rope to help. Whenever I have had that experience, I have been most impressed by the enormous friction in all the systems I have used. The friction is due not only to one rope rubbing over the other, but also, and usually most importantly, the rapid transfer of the sharp 180deg bend along the length of the rope.[/i]

.:. Ad hominen references are (as often) gratuitous; reasoning is decorative:
get out some rope and put the issue to test, and SEE.

PABPres, maybe you’ve a stack of relatively evenly hewn firewood logs for load
(and plenty of play ropes)?

–dl*

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This isn't about [i]points of view[/i]:
Sure it is. It's how this all started. You have an idea of what "high" means with regard to mechanical advantage, and any other point of view is labeled "hogwash".
15

Well, the monsoon paused; so the 2 10year olds and i set this up.

We have a 3500# and 2500# Dynos; as previously referred to; some 1/2" arborist lines ~7,000 tensile, and a come-a-long. We use the comealong as input force, to have something really readable on the scales/ not splitting hairs of a few pounds on these tiny face readouts; and more fun/ more power to boggle lil’minds (self included); to cook more imaginations as to the possibilities etc. Working in input range of ~250# for readability and yet staying within confines of safe working practices/ SWL.

We used DBY/bowlines rather than butterflys; as i’ve often thought short bowlines to place less side pressure/ friction on running ropes, than long eye bowlines or butterflys. i used multiple eyes with single line reeved thru, rahter than multiple lines ran thru same eye. We even (ab)used some kind of Lehman concotion of single eyed DBY in bight for this.

We found the 1.6x as fairly realistic for a theoretical 5x setup. But, quickly ‘pinging’ or sweating line, then relaxing would allow both scales (input and output) to read lower values, then cranking come-a-long more would get us up over 2.5x input to output ratio. Even just vibrating lines allowed force to equalize between the legs of pull more, to allow less effort input, to a higher output. Such input/output reads is why i have 2 Dynos.

After tightening input comealong to ~200#; and getting a readout on output Dyno of ~500#+; could bend the line comealong pulls; to a perpendicular angle by hand, to get ~700#. While grabbing all legs of lines and bending them perpendicular to the tension force flow thru them, rendered ~850#.

After such manipulations, that allowed higher tension into the legs of pull closer to output than input end; the same friction that reduced the ability to tension those lines with come-a-long; now seemed to help hold same tension, for slightly higher readings on output.

Placing 1 pulley in the system; did better as theorized, being placed on the input end, rather than output; but seemed to reduce the power of the sweating strategy somewhat. It’s looking to rain again; but in a hurried fashion, on 1 test of several runs, that is whut we got.

Bending and ‘rattling’ lines on this type of friction setup; is a usual strategy and style for me. The more friction on bends, the more useable this strategy is i think. Also the final bending for force is a very powerful force.

A lot of times i take the linear tightening; even with some temporary sweats and line rattlings; to be not the real tightening; but stiffening the line. Then, bending the lines in final stage (for tie downs etc.) as final stage of tightening. This bending the more stiffer/tighter lines from the stage 1 linear tightening, gives higher leveraged return when bent.

MOst of the high, high leveraged power of line bending is in the first few degrees from perfectly straight. So, a tighter line that resists bending more, bends less, and is in a higher leveraged multiplier position; so gives higher leveraged return from the bending force.

i wrote the Bent Line Force Spreadsheet allows manipulation of the angles and pressure at bend (to read out pressure at termination/anchor) by the user.

In all fairness, returns of 1.6x - 2.5x from a theoretical 5x system might not be considered high. But, then this is just on the compression strategy of rig use; but if used for lowering, keeping tension or relaxing tension slowly; i think we would have the 5x + these friction factors that fight us in compressing jig.

Taken to knot lacings of similair bends, forces, friction on self etc. i think we have lots of power in roundturn; but not as much increase in utility going to double round turn, then to coil when trying to feed line tension in; but then lots of help given by the increased turns in holding the line tension they’ve purchased.

Spock Out;
:stuck_out_tongue:

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Sure it is. It's how this all started. You have an idea of what "high" means with regard to mechanical advantage, and any other point of view is labeled "hogwash".
Well, I actually thought that no one would consider 1.3:1 to be a high MA, for there's little [i]advantage[/i] less than this--what would middlin' & poor be left with, 1.2 & 1.1 :1, resp.? Rather, my "hogwash" wasn't to what "high" meant--which I figured most folks would agree to be at least >2:1, esp. where so much theoretcial MA was built--, but to the assertions that [b]rope-pulley systems, and i.p. the self-locking Versatackle[/b], achieve it. That locking friction is extra to overcome.

And, how did you get & measure that “2.6:1” MA you reported?

Rope over a 'biner has been measured as diminishing tension to about 0.6,
and such a factor converges towards 2.5:1 with repeated wraps, and THAT
is w/o added friction imposed by multi-reeved sheaves. The twice-reeved
Versatackle for raising has a theoretical MA of 8:1. Running rope over rope
w/rope all around (multi-reeved) is going to signficantly reduce the efficiency.
As noted, 1.6:1 was measured with only 1 rope (and the other 'biner) sheave
using a Z-rig. (Not sure of KC’s exact 5-to-1–the Z-rig, or … , but note that
he "used multiple eyes with single line reeved thru, rather than multiple lines
run thru same eye.)

–dl*

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Maybe I will be considered grumpy for writing this, but… does it matter all that much if the MA of Versatackle is x.y:1 or z.q:1, or something else, as long as Versatackle is easy to handle and can deliver the force I need? Actually?

I agree that theoretical points have their value, and I can get absorbed by details just as easily as anyone else, but sometimes even I wonder if it really matters.

If a different solution or construction has much better theoretical data, but Versatackle is what I have access to in order to get me out of a sticky situation that makes Versatackle the best there & then!

Just a reflection in the morning… :wink:

Lasse

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does it matter all that much if the MA of Versatackle is x.y:1 or z.q:1, or something else, as long as Versatackle is easy to handle and can deliver the force I [b]need[/b]? Actually?
The point of this discussion was to remark at how little actual MA one gets from many supposed good MA systems implemented in rope. At 1.3:1 a system delivering the force you need isn't doing much more than you'd do w/o it; and no one would consider this a great advantage.
I agree that theoretical points have their value,
What was at issue wasn't the [i]theoretical[/i] but [b]actual[/b] advantage, for which I urged folks to go test and see.

The Versatackle has the nice immediate locking, although it can be a bother to
release this. For more power in a similar arrangement at the cost of range of
movement, the Versatackle’s self-locking mechanics can be replaced with the
Dbl. Spanish Burton’s ones, which I’m eager to give a test.

–dl*

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At 1.3:1 a system delivering the force you need isn't doing much more than you'd do w/o it; and no one would consider this a great advantage. --dl* ====

Well… I can not say much except that I do agree on that point.
I was a little tired and did not read the finer details well enough.

On the other hand, if the power I can deliver “bare-handed” is 9/10 of what I need, a 30% increase makes a difference that is big enough - which was what I was getting at.

LC

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Though it seems like hairs are being unnecessasarily split; the examination is viable i think.

This is needed to determine how much return of power is given; per extra time, rope and efforts needed to produce such power. Also, where the point of diminishing marginal returns is met, for these investments of extra time, rope and effort etc. And, if adding more turns would help or not.

In my experiment, i was quoting approximate values; seeking patten more than actual numbers. Overcast skies, while 3 different people where reading 2 different dynos etc. Also, the dial faces on dynos are about 5" diameter, to read 3500# of increments on the output; as these are not the fancier digital dynos as in the original picture posted.

i still maintain that all the power reducing friction that stands against efforts in using rig for compression; stands for you in the inverse of when fighting expansion ie. when using for binding, sewing etc. to not come apart; or everything would just have 2 stitches and be done.

1.3x; should be sweatable; with less rope, time and effort in many cases; but not have the same power against expansion as versatackle (or locking function) if later loaded.