Screw gate Carabiner for rigging Question(s) and rigging concepts!

ATH said:
Nothing is 100% the same all the time.

Years ago I got to visit the MSR office/factory in the Seattle area (don't remember exact location...just remember it was on that trip in '97) with a friend who ran a mountaineering shop. They made carabiners at that time. The guy explained that their average breaking strength was actually quite a bit higher than the rating. However, the stamped rating (as best I recall) was 1 standard deviation below average. Noteworthy that they had more outliers breaking ABOVE the average than BELOW the average...which significantly increased the gap of the standard deviation meaning the equipment was much stronger than the rating but they still rated the equipment 1 standard deviation below average.

I don't know if all companies test and rate equipment that way or not, but I found it very interesting...and reassuring.
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Exactly what I was guessing they would do..
 
Legal CYA of conservative rating.
Quality companies will bluff low, plenty of usable powerband within rating range, even if not new.
Others, not so much.
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Same with just a little over weight cereal box or milk volume;
best if .gov inspection catches you just a toe over the line, rather than under.
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Taken to court on device failure in or above headroom of lesser quoted rating could be git'outta'jail free card; or otherwise off the hook in litigation.
 
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ATH said:
Nothing is 100% the same all the time.

Years ago I got to visit the MSR office/factory in the Seattle area (don't remember exact location...just remember it was on that trip in '97) with a friend who ran a mountaineering shop. They made carabiners at that time. The guy explained that their average breaking strength was actually quite a bit higher than the rating.
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I really like all my MSR gear their stoves are awesome...
 
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*useless info* said:
Legal CYA of conservative rating.
Quality companies will bluff low, plenty of usable powerband within rating range, even if not new.
Others, not so much.
.
Same with just a little over weight cereal box or milk volume;
best if .gov inspection catches you just a toe over the line, rather than under.
.
Taken to court on device failure in or above headroom of lesser quoted rating could be git'outta'jail free card; or otherwise off the hook in litigation.
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I use mostly stationary line on high strong anchor poin t and use redirects from there off belly with biners or adding rings for heavy repetition..biners are midline attach and can redirect weight and vectors anywhere quickly flow important.. turn speedline into 3 to 1 quick need sturdy biner , cheap isc screw style steel biner 25kn sheave non rational , accepts pinto pulley in snap . Speedline ok big weight add another sling and biner opposing gates, double whip large low lead over house ease of transition ground profresh easy pickens. More concerned with choked strap rating 1 inch nylon sewn sling 36 inch size no larger girthed down on biner breaking g before biner itself. Thinking even with large long white oak limb still ok in kns ., even if the biner isnt screwed shut, it doesn't auto lock . I dont rush I due diligence. Not so much me but new learner in my care Mostly 30kn ct speedline snaps . Orientation on added pinto not as well as 5 dollar isc screw gate.. best tree spyder talk I got ina flurry
 
In arena rigging we tighten the shackle all the way then back it off 1/8 turn so it doesn't lock up after loading.

For trees I feel the biner is the biggest variable with moving loads. A half hitch can take most of the shock before the biner sees the load but on big stuff I prefer to tie a quality knot I can trust.

"Screw it down so you don't screw it up"
 
Treetopflyer said:
I use mostly stationary line on high strong anchor poin t and use redirects from there off belly with biners or adding rings for heavy repetition..biners are midline attach and can redirect weight and vectors anywhere quickly flow important.. turn speedline into 3 to 1 quick need sturdy biner , cheap isc screw style steel biner 25kn sheave non rational , accepts pinto pulley in snap . Speedline ok big weight add another sling and biner opposing gates, double whip large low lead over house ease of transition ground profresh easy pickens. More concerned with choked strap rating 1 inch nylon sewn sling 36 inch size no larger girthed down on biner breaking g before biner itself. Thinking even with large long white oak limb still ok in kns ., even if the biner isnt screwed shut, it doesn't auto lock . I dont rush I due diligence. Not so much me but new learner in my care Mostly 30kn ct speedline snaps . Orientation on added pinto not as well as 5 dollar isc screw gate.. best tree spyder talk I got ina flurry
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Treetop.. had a hard time following that post.. are we still talking about unscrewed biners, strength of tubular nylon when choked or both?

I just thought I'd point out, Richard Mumford did some decent testing on 1in tubular slings, choked, straight, etc.. the results were pretty impressive. If you can find the YouTube video you'll see what I'm talking about.

As far as the biner... Just close it!!!
 
Joeybagodonuts said:
Treetop.. had a hard time following that post.. are we still talking about unscrewed biners, strength of tubular nylon when choked or both?

I just thought I'd point out, Richard Mumford did some decent testing on 1in tubular slings, choked, straight, etc.. the results were pretty impressive. If you can find the YouTube video you'll see what I'm talking about.

As far as the biner... Just close it!!!
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Thanks for the yoyolink I will check thatout..
We're talk bout all the above, rigging concepts , human nature, annd whatever you want..without getting too far out too early...I love rigging with 1 inch slings on biner and enjoy versatile options working with them. I keep as little friction as needed and increase as needed, and vs. Versa. In tree friction and quick redirects,making strongangles in the tree allow me to work the tree with less hang ups more often. I can quickly change to any style rigging from speed line to heavy lift on same tree with ease and a long line.. When I describe this work, it's in what I hope could be recognized as a formidable tree be removed with defect or pitiful location to extract.. wide , heavy tight, broken , you name it. Same ol story we all know. if any screwed biner or an over weighted nylon sling fails . I failed.. failed to plan and calculate. It's pretty well known arbs don't mostly care for screw biner s like we like our quick links for climbing anchor and redirect. I just happened to pick up some cheap sweet steel screw boys from isc and have mostly closed them , of course in high tension situations. I'd be Ly in if I said I did shut everytime.. I really just was curious about the strength of them open or closed as there isn't much literature out there I could find on the little detail of open or closed ,,notably I like steel better for rigging than aluminimum for bend before break , far as I know .. again not happening on my watch if it did , fail...better info out there like break testing is what we need. Choked nylon tube runners I'm hoping is the weak link in my system although I doubt I'm near that , notably what nice is how you can quickly double them up and double up rating , then the knot in end of the line is weakest I hope maybe before the tube sling and that's good when you need it. Cant wait to check that Break test vid from Richard Now. In parting a little more ttf pycho babble, over ..
 
Raven said:
For trees I feel the biner is the biggest variable with moving loads. A half hitch can take most of the shock before the biner sees the load but on big stuff I prefer to tie a quality knot I can trust.
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i think this is most correct.
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Once again, my personal classical reference imagery theory to frictions on supports, anchors and inside of knots: jrre.org/att_frict.pdf
Technical Paper: The Mechanics of Friction in Rope Rescue presented to International Technical Rescue Symposium 1999 by Stephen W. Attaway:GA.Tech Masters Structural Engineering + Computational Mechanics (modeling stresses, displacements) Ph.D.
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Reveals, force reduction of turns between load and hold points TOTALLY depends on:
A>rope tension
B>friction co-efficient of mating surfaces
C>rotational degrees of contact
Counter-Intuitively: DISTINCTLY NOT DISTANCE OF ARC CONTACT
>>same force reduction numbers reveal on 2"diameter as 12" by degrees of contact NOT distance of contact
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Finding in preceding Half Hitch a full 360 wrap on load, with 2x 90 degree turns of rope on rope in and out of Half Hitch.
trails to another full 180 wrap before carabiner pulls sideways and draws together to terminate, this reduced line of force after Half Hitch. Seems, carabiner/krab taking less than 1/20th of hits and loads in this buffered position. Another preceding Half Hitch giving even more reduction EXPONENTIALLY.

att_frict-table-of-force-reductions-in-rope-turn-arcs.png

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Ratings for un-crossed, sequential turns. Of curse Crossed Turns of lesser rope tension on greater rope tension increase these frictions as 'pastes' rope tighter to host mount for firmer frictions (Clove family etc.); just as grabbing hot metal tighter burns more, as any tighter connection transfers more frictions,heat, electricity etc. While properly positioned and held crossing of greater tension over lesser can totally Nip load force in classic Hitch form.
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Carabiner, especially steel, makes nice throwing weight around load and catch etc. for lacing. Tho, take care not to chip tooth or dent your coconut!
In actual usage, i do also many times go more properly with ending soft link of DBY rather than hard metal link, for are seating on round arc, and rope conforms, metal resists, therefore can be leveraged against self/krab.
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Half Hitch also converts from right angle only stop force utility to add lengthwise pull direction stop force ability, and gives double bearing too!
 
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Treetopflyer said:
Impressive! Love it!

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Oh great! You found it! I knew there was alot of "break videos" when i referenced it, i was hoping you'd be able to find it...

Ironically enough, a few days before that video was referenced & you mentioned girth hitching, i actually reached out to Rich regarding strength loss with girth hitches in general. More specifically, girth hitching biners, rings, rapid rigs, etc with the most common cordages we use...(double braids, 16 strand, 12strand etc). I suggested if he hadn't already, that he think about doing a small recording on it as i constantly see people girth hitching stuff into configurations where your minimum MBS of 5000lbs for climbing would end being way way lower. Or for rigging, girth a ring on a 1/2in line with a 6in eye, is that ropes capacity really cut in half now? I say half as that's just one of the many percentages I've read regarding girth hitching.. then add a knot from a bowline or a splice into that scenario & that's 2 reductions, then add some dynamic forces in there.... You can see where I'm going.. regardless it would be an interesting video to watch.

Anyhow,
He sounded interested in the proposed idea. However I'm pretty sure he's got alot on his plate right now. However, when the timing is right, I bet if we donated materials, he'd make it happen.

In the end, he did mention that he has seen webbing fair pretty good in these situations.

U know what? I bet Mr Spidey ^^^^^ has charts on this..
 
i don't remember a specific chart on this, many knot tests etc. at Pro Assoc. of Climbing Instructors (PACI ) if Mark Gommers alias agent.Smith made a .pdf seen, the password = thankyou , quite simply..
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But hear goes..
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Webbing/flat rope on a tight bight of krab etc.
For me has an advantage, in it lays flat; does not stand tall on the deformation/curve.
As a deformed axis, round rope height on this arc is telling you how hard line is leveraged to using fewer fibers, as compressed inner fibers can't pull.... And if outer arc fibers are pulling(tensioned) and inner arc fibers seated to krab are compressed; i maintain in the gradient slide from tension to compressed there MUST be region of neuter/neither/twilight between full light/dark of tension and compression. Of this stack, ONLY the fewer tensioned fibers are pulling load. Flexible supports (rope, web, chain, cable etc.) are tension only supports. By extension if tight bight on pulley, these outer tensioneds become the cranking leveraged arm distance giving leverage over pivot of slip bushing or bearing, rather than track of outer sheave I'd think.
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Flat rope/webbing by contrast doesn't sit tall, does not have any real 'dimension' on this deformed axis of tight bight curve around the krab.

i also think,
that a girth/choke type sling grab secures by cutting across the structural column of the loaded Standing Part to 'weaken' knot by throwing off the geometry efficiency, specifically changing the angle of the column from pure inline. This reduction in efficiency is mostly falling cosine. i read cosine as the remaining support column percentage of a rope tension. So that pure inline cosine 1.0 means all of line tension is to support column. By this measure, a knot of 70% strength/efficiency shows approximate deformity of 45degrees (who's cosine is .707).
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i think venerable ABoK offers some answer across the (p)ages.
At one point he does offer a Round Turn on a small mount to spread out wear.
Lesson#1720 offers this tidbit "... If a spar is small a round turn is preferable to a single turn. It makes a stronger knot and dissipates the wear."
But then more generally in lesson#1669 offers :
"...If the rope is weak and the hoist is heavy, a round tum on the standing part adds
materially to the strength of the knot"
i pretend all loads are heavy compared to rope, as to weigh and measure all knots against this precept.
Knot sage knudeKnoggin offers tho, can't do both; can't have cake and eat it too..
If use strategy #1720, don't get even more strength by adding in strategy#1669 to the build.
(i think Round Turn on host spreads out wear, and leaves less force in Working End to deform Standing Part that is column of support against loadings proper. In extreme example 5 turns on host and Bowline around Standing Part support column is said t be 'Tensionless Hitch' as no appreciable side tension across Standing Part support column , per att_frict.pdf benchmark chart shows Working End /Bitter End would be 1/250th of Standing Part that Working End is trying to bend.. But think that Round Turn around Standing Part support column might be best in trade of no Round Turn on host mount).
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arc-of-the-rope-secrets-4-efficiency-strength-losses_2.png

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For me, i have named this as because #1669 needs force to grip Standing Part. This force is reduced if preceded by Round Turn around the host support or load.
>>i think gripping the rope more, serves to pull away more for a less flat teepee
as the securing leg is now pulling more like a stronger splice along Standing Part rope column, rather than simply cutting across the support column like simple girth/choke.
Sometimes can VISIBLY witness, Girth cutting more across Standing for flatter teepee, seating tighter towards/into krab. While Round Turn of more extended Chinese finger trap lacing style securing pulls away from krab, to more pointed teepee, less deformed from pure inline, pulling ALONG Standing Part column more like a splice as opposed to girth cutting ACROSS said support column at 'Samson Angle' across temple columns of support.
If can pull more along column properly, look for more strength. If second leg not only pulls along column rather than across, and can be made to conspire to carry part of the load, i think can look for even more strength to this model! (friction hitch grab distanced out on Standing Part giving closest perhaps to model of dual support leg eye splice, lower loading per leg giving less impact of loss from deformity, that itself is minimized, Purcell Prussik anyone?!).
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In wider flat rope, that we will say for here is the opposite profile/geometry of round rope
>>just as the opposite geometry of flat performs better on the krab arc
>>and this opposite geometry of flat takes weakest round rope structure of Overhand Knot and makes it a star in joining flat webbing as 'Water Knot'
>>AND as a Whatknot can misalign in round but again can be a star in flat rope (doesn't reposition as easily)
We can see alas, more deformity to weaken (i believe) in Round Turn on Standing Part in flat rope/webbing. Might make neat full Windsor tie triangle knot that is pretty, but still violation of pristine manufactured column(s) structure.
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EXCEPT, perhaps the slender dyneema slings offered, for stacked 2 high (like laying across krab) is closer to round profile/geometry as is now about ~ as thick as wide. And major dyneema is the slender slick strands surrounded by polyester for grip handing. i'd think any dyneema would be a bit buffered from deformity in that build. An extended series can make spacer to more visibly flag if a leg passes inside of gate(where can look like on krab rite and then shear off under load)
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sling_krab_theory2.png



Not sure age of pic(my blue towel era around Y2K), but this 'boot' strategy worked fine fer me. Visualize imbuing some dynamic absorption if rest of build is tight stable braid on likewise unforgiving support.
Will warn tho, perhaps not one of my better accepted notions...
>>and if sling is allowed to be free ranging more evens out wear
i say 'builds' cuz that is what i think we are doing, carving a structure from easier to work rope (pliable at room temp until 'forged' to less pliable by loading) rather than from wood or metal. But still creating structure against loadings.
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Note: in trade, as we talk about more column strength from tension going to support column cosine, via softening angle, demands lower tensions applied on cross-axis to grab host as a reduction in tension for same load AND lower sine multiplier to calc side force grip by. Perhaps a consideration as grip against slide might be only anti slide on otherwise unguarded angle or movement.
 
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I never thought about a long sling forming a basket on biner and birthing a basket choke until this thread and a light ting bolt hit me! Very curious of this configuration says grasshoppa
 
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