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

eyehearttrees

Active Member
So I'm unable to find the exact advert but surely you guys(&gals)'ve heard of this, a speedline kit containing a metal Figure-8 piece for "tensioning the speedline".... Could someone explain the concept/configuration to me? Cannot tell how on earth a Figure-8 is useful here (or any more useful than an o-ring or 'biner woulda been!), I mean I'm picturing putting the end of the speedline around the Porty and, w/ that working-tail, run it through a micropulley I've tethered to the tree (or to a prussik that's biting the rope before it's reached the Porty) and pull it to proper tension w/ that mech.advantage (just like you'd do for a standard pre-tensioning of a Porty, sure it's typically a micropulley as hardware but I've gotta imagine an o-ring, 'biner or Figure-8 would be fine / wouldn't induce enough friction to disable you from pre-tensioning as-if you'd had a micropulley there! Obviously w/ a figure 8 you wouldn't wrap it the way you do for belaying but would just use it as "a double o-ring" piece of hardware, maybe the intent of using it for anchoring a speedline is that you can use it *both* for pre-tensioning *and* subsequent locking-off of the line?)

Thanks a lot for any insight, has always bugged me and am finally determined to figure out how a fig.8 is being used for line-tensioning!
 

Jonny

Well-Known Member
Haven’t done it myself, but I’m pretty sure it’s just used in place of a porty. Sweat the slack out and it’s easy to maintain tension one handed or lock it off.
If you already have a porty, you’re better off using that. Easy to add and remove wraps and half wraps.
 

Jehinten

Well-Known Member
It's not used so much for tensioning the line as it is for holding that tension once it's been loaded with a limb. If you own one, I find a rig-n-wrench works great for a light weight speedline. Friction less for tightening and added friction for holding, plus it runs in a straight line so the rope does not develop hockles like an 8 or porta wrap. In order to slack the rope to remove the slings, just collapse the wrench and pull some slack through.
 

eyehearttrees

Active Member
I just love this site :)

Haven’t done it myself, but I’m pretty sure it’s just used in place of a porty. Sweat the slack out and it’s easy to maintain tension one handed or lock it off.
If you already have a porty, you’re better off using that. Easy to add and remove wraps and half wraps.
I'm a bit unclear on the 1st-half of your passage could you specify precisely how a fig.8 would be used 'in place of a porty' ie how would the rope be configured here, can't picture it...

I have a home-made porty lol, it's an absurdly heavy / overly redundant DIY (nope, not gonna post it, will be welding "my version" of a beasty plate-type bollard-fixture w/ winch-adapter but prolly not this season!), at any rate how is a Porty helping to tension a line? Progress-capturing of tension, sure, but the tensioning itself? Can't picture it.... You've got a stronger grip/pull on the line before it hits your friction-bollard not after. In writing my reply (v.3 at this point I think? am srsly tho..) here I have found something really off-putting which is that my conception of pre-tensioning lines seems to be irregular/unusual, I'd always thought this was the norm and can't even think of any practical alternatives to replace it with *but* I couldn't even find a photo of this online, I had to take a Macro photo from an advert in Wesspur(luvvvvv Wesspur!!!) for Stein's pulley-version but I just have a small o-ring on an Ice Tail loop that serves the same purpose of grabbing the rope pre-bollard (prussik-hitch) and holding hardware to feed the post-bollard tail into for tensioning:
19700104_141302.jpg


I think I may be mis-understanding a basic concept here- Is it wrong to be aiming to lock-off, like literally locking-off not just having a guy holding 2 wraps on the bollard&told to keep it still, but just tension then tie-off? In most things I see w/ speedlines (youtube, adverts etc), I see people actively managing slack in the line during log-descent....I see that (actively pulling-slack during log-descent) as a practice that's useful in some vertical speedline drops and, for heavy-duty speedlining I imagine it's probably requisite simply as a safety/insurance on acute line-failure IE better to drag a groundie and have a chance the slack isn't enough to be a catastrophe than to risk an overloaded line just rupture/failing! But for a normal speedline I see it as almost an inherently light-duty technique, almost a "speedline what you can get away w/ speedlining, drift-rig or vertical speedline whatever you cannot" when doing 'targeted drops' that can't be direct-drops.

(hopefully I can understand what you're getting at Re rope-placement for the 8 in your 1st two sentences, I took a picture for my reply to Jehinten which I'm writing right now / will post in-tandem w/ this so in the following post there's pics w/ a fig.8 + "easily-describable landmarks" like leaving a lil 'biner on it, and w/ rope passed-through, hopefully helps w/ verbalizing rope-movements!)
 

eyehearttrees

Active Member
It's not used so much for tensioning the line as it is for holding that tension once it's been loaded with a limb. If you own one, I find a rig-n-wrench works great for a light weight speedline. Friction less for tightening and added friction for holding, plus it runs in a straight line so the rope does not develop hockles like an 8 or porta wrap. In order to slack the rope to remove the slings, just collapse the wrench and pull some slack through.

At the risk of sounding a broken-record here, could you elaborate/clarify precisely HOW one locks it off on the fig 8? Is it just tying it around the 8 a bunch of times? Seems about identical in-use to simply tying it around the trunk? Am just not getting the wraps/configuration sorry to be a dunce here lol am just not picturing anything beyond crude "pull-arounds" but that wouldn't be any better than simply using the tree for tie-off & a usual pre-tension pulley..


Also Re tensioning you'd said that it's "not so much" tension given by the 8 here, is that to mean that if you yourself were setting up a system using this configuration, that you would add ADDITIONAL HARDWARE to allow a stronger tensioning? Or that it doesn't ttension so well, but it's sufficient & is all that you'd use (in that scenario, I know it's not a scenario you'd choose I just mean ****IF***** someone had you show proper way to conduct what you're describing)

Re hockling: is it always suffered due solely to a tight-bend? I thought it needed curvature, so IE you can hockle bull rope easily by using a thin bollard Porty, or hockle climb lines quickly using a figure-8 in normal descent-mode (though I've seen little in-practice to be fair), but I'd been under the impression that STRAIGHT PATHS don't hockle, for instance this configuration:

19700104_140342.jpg

Ok ok 5/8 just looks awkward so let's keep it to light-duty-speedline levels:

19700104_140745.jpg

BUT, ****IF**** the fig-8 is really just a lock-off, it can basically be anywhere (but imagine still best to use in-place of what I'd call "normal" pre-tensioning? I put a picture - had to take that pic from Wesspur's catalog couldn't find depiction of this technique online, I'd thought this was standard pre-tensioning whether it's pre-bollard or in setting a fixed-anchoring of that tail but since I had to find a pic from a catalog to illustrate what I'd thought 'optimal' for pre-tensioning a static speedline would be the way I do the 'micropulley pre-tension' which is simply using an o-ring instead of the micropulleys (because I only use the 1/2 'dyne when I need its length I typically use & very strongly prefer my 5/8 polydyne it just functions in a ring-based rigging setup better than 1/2", surprised 1/2" seems to be the favored 'default' especially when some of these 5/8's have the strengths other ropes need 3/4 for, ie stuff like polydyne/nystron/atlas are wicked strong @5/8, anyway this is the 'yank around the o-ring' (instead of around micropulley) I meant:

[the fig-8 would be the Portawrap in this picture, I've fed the post-Porty tail through an O-Ring hitched to pre-Porty line so I get a 3:1 pull on my Porty instead of usual 1:1, here:
19700104_140438.jpg
[^again Fig-8 represents a Portawrap here, that's how I'd pre-tension rope on my bollard, I imagine it'd be fine using a fig-8 as a speedline basal-anchor that *also* served as an "anchor plate" for getting the 3:1 once using a hitch in the pre-tensioning so this is essentially how I'm picturing using the fig-8 as a basal-anchor for light-duty speedlining, tension using your 3:1 over/through the o-ring then lock off on the 8 itself. I guess I can see this being a solid way of setting (pre-tensioning + anchoring) a light-duty speedline like something you're using those $5 nylon loop slings on to send 25-->75lbs pieces down, would want to wrap my basal tie-off on the tree itself though as the bend-radius' are so much friendlier, though on larger trunks it's much easier with 2 people for this since one's pulling tension on the hitched o-ring/keeping it taut while other wraps tail around tree & ties rope to itself]
~~~~~

Anyway I think some of my basic understandings are off here...any clarification/elaboration is appreciated!!

(to be clear, I am most-definitely NOT rigging heavy/dangerously, bought my kit to 'grow into' and am currently at a point where I can't go-further[heavier] til I find a new insured outlet as I've gone through 2 local, shitty/unethical/scummy, tree companies already as 'contract climber' and now thinking it's either go all-in and license/insure myself, or go get on a medium-scale company's roster ASAP as summer is coming in quick here in FL!! But I would not be unethical I have said No plenty of times even to things I knew I could do)
 
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Brocky

Well-Known Member
The fig 8 is used in an auto bloc manner to hold the load, rotating the small hole down releases.
Sweating the line, as mentioned earlier, is an effective, low tech way of tensioning.
4AEEC2C4-6837-4FA5-93A7-208C70FF929D.jpeg
 

Jehinten

Well-Known Member
You'll want your figure 8 installed midline, not running through in a straight line as you've shown, as it will be much harder to slack for taking slings off. You'll likely not be locking the basal side of your speedline because as you mentioned you want to be able to control the slack and pieces as they come down and land them where you want. If the rope is locked off your hardware on your slings would slam into your hardware holding the rope.

Read up on sweating a line, the friction helps do this and is a stronger pull than pulling in line with the rope by hand. You can see the amount of slack built into the rope below her hands in this video.

Hockles can be caused many ways and possible to prevent in many ways as well. When I notice them the most is repetitive use with a rope that is much too long. Having a bunch rope laying on the ground or in a bag not being used allows the twist to build up.
 

Jehinten

Well-Known Member
As with most things, different scenarios need different solutions. The more vertical your speedline the less tension you'll need. If your moving material 20 feet horizontal from 80 feet up it won't need much tension or friction. If your attempting to move material 80 feet horizontally from 20 feet up you'll need a lot of both tension and friction.
 

Jonny

Well-Known Member
I’ll see if I can find something illustrating how to hard lock or tie off a F8 without ears. Here’s it on an F8 with ears, or a rescue 8.
Brocky’s pic is exactly how to soft lock with or without ears. It’s reliable but I’d be very worried about letting go of it and walking away and expecting the tension to stay put.
DB09431F-26EF-4062-B234-62D51CBF5875.png
 

Jehinten

Well-Known Member
@eyehearttrees another video reference. August Hunike has several videos on speedline, in this one he does an in tree explanation at 4:20 and Damien does an on the ground examination at 11:00 which covers how much friction they use and when to drop the limbs down.
 

*useless info*

Well-Known Member
Pulling with 3x1 jig* would be taking a purchase* of line
>>releasing some back would be paying out* to belay* etc.(in ol'sailor terms*)
This would be linear tightening down long axis/rope length.
.
Could use Fig.8 to pull rope into; like do Porty, to capture the purchase* and to 'hold fast'*, to then take another turn to preTighten more.
>>with fig.8 locked in place as Porty would be
Or could float like Brocky's Deaf_8, pulling the fig.8 itself
Can kinda try twisting as ya go line coming out of fig8, to alleviate but fig8 likes to spiral towards hockle rope as noted, unlike Porty.
.
Sweating/Swigging* line is bastardization of support science from rope.
>>Support of rope capitalizes on cosine,linear support, trying to minimize sine
>>Sweat/Swig does opposite, goes to wrenching rope across it's length/non-inline, to capitalize on sine instead of cosine
(always look for support from cosine 'wave' vs. wrenching/leveraging always capitalizes on 'sinewave' instead as opposite mechanix from supporting, Samson served across support columns)
>>the same science that will work against the rope in actual loading of speed line, now helps tighten same rope
>>now working for you(payback!)
.
old refs:
mytreelessons.com/sweatingToss-Adkins.JPG
Youtube camp swigging lesson
May sound crazy or complicated, but is easy as a child's swing, Bending the rope when most loaded (when most not inline, height of swinging) and at neutral point (also height of swing before return) gives raise in forces to rope when can impact it (motion is squared in this, to over rule your additive of efforts, so child waits for neutral point of swing to pull in right direction to leverage/sweat/swig line across , just not capture purchase) .
.
So can tighten line LINEARLY with pulls/jig etc. and call it a day
or just use that as a setup to REALLY tighten
>>when rope is iron bar tight as can from linear input effort, bend across the linear line
>>the tighter the rope, the less rubbery/more powerful the leverage reaction.
>>in tie downs can use zrig,then bend that leg, or 2 Z's and bend one against the other
This purchase can also be captured, in series of tightenings
>>each time line is tighter (if load not moving), so resists bending more
>>the greater resistance to bend, gives the greater leveraged return
The tighter straightness the line, the faster the load can 'skitch' down the line/rail
>>shaking line during travel can slow load down, but also raises pull line forces
.
In normal rigging, climber is many times in unique position to bend load side of line to sweat/swig, when ground control can only get to control side of rope, and any efforts must go thru the 'friction buffer' of the support.
Furthermore, if climber can stand on control side of rope in cam or prussik and then pull up on load side is in unique position to use bodyweight + effort + equal and opposite of effort to tighten line linearly, before then on load side sweat/swig across now tighter rope etc. Anything to tweak a bit more tension, usually easier to relieve on the fly, than increase. Climber is only one to be able to reach raw load end of rope w/o friction buffer degrading input. UNLESS install prussik (clear of either end that would limit bend) on load leg to give ground control some remote sweat/swig ability in precut. But also once a lot of weight on line/less on hinge a high tension turn response, and then steering on ground for best reception to clearest zone.
.
Sling and krab sets are marvelous flexible utility of functions. Can have a load rigged half cut that doesn't want to pull into speed line, and rig other limb off that limb to make it's impact cut fold load into line when cut/impact 2nd limb. Also rig off more friendly limb closer to speed line, cut first limb to be carried by 2nd better placed not to impact line etc. The combinations and opportunities become even more endless and powerful.
.
Some ideas on Speedline from original Tree Forum, ooooooooooops i mean we called it a BBS 'way back' then, when i first thought gee i found my people (some as now disputed that tho)!
From across the wages, sages and ages of time, thanx again to Dave Spenser!
.
Note how if can pull and capture purchase quick enough, can have bend on load and use it to pull the load around to proper position, then, snatch line thru frictions and then release hinge to let load ride the tightened rail/rope down. 1995 GAME CHANGER.
.
Sine gives most volatile changes, just off of TDC alignment.
>>Sine from center of clock to TDC/noon is Zer0
If move 1 hash mark/minute/second (6degrees)on clock towards 1
>>sine jumps to 10% of length sideways, leveraging force just the same
>>another minute on clock jumps another 10%
'My' (think i made it up) rule of thumb is true about to halfway point of 45degrees or 7.5mins half way to 90 degrees at 3o'clock
Using same clock mnemonic , the cosine starts out at 1 at TDC/noon
>>at 1 minute hashmark tho where sine jumped to 10%, cosine only recedes 1% from 1 to .99
>>at 2 minute hashmark tho where sine jumped to 20%(total) cosine only recedes to toal of 1-1% -2% =1-3%, or .97, i use as 97%
>>at 3 minute hashmark sine:30%, cosine drops to 1-1%-2%-3%=.94 etc.
>>fair until mid point, but then scales reverse; so can see full picture that way
These are slightly off thumb guide maid up from Babylonians base 60,12hr clock and 360 degrees they gave us type observation(but perhaps how they designed these things as center of understandings); but has served me VERY well in where to place how much 'respect' and to what levels. In sweat/swig usage, these forces are divided against 2 points, but only against 1 point if pulling a weight sideways that is hanging from 1 end of rope/not mid between supports as speedline. But all the math is the same, as it repeats in all things; as the Ancients tried to had us.
 
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eyehearttrees

Active Member
The fig 8 is used in an auto bloc manner to hold the load, rotating the small hole down releases.
Sweating the line, as mentioned earlier, is an effective, low tech way of tensioning.
[photo removed for space]
"auto bloc manner" will have to google that but think I've got it now, will admit it sounds odd "rotate small hole down releases pressure" IE where is the groundie focusing here, is it 1 hand on the rope and one on the 8?

And gonna need to google Sweating as well (unless you guys wanna give me the true, arborist-colloquial usage/meaning!) because I'd always thought that was synonymous w/ "make taut", "tension", "pre-tension" ie any movement to remove slack from the line?

Thanks for taking the pic, you've got great post-quality thanks again for the reply :)

You'll likely not be locking the basal side of your speedline because as you mentioned you want to be able to control the slack and pieces as they come down and land them where you want. If the rope is locked off your hardware on your slings would slam into your hardware holding the rope.
I see it as 2 different methods (and invite correction/further understanding!!) when zipping something, "normal/regular" wherein someone's on the other end of the line but also a "diagonal-vertical speedline" type of thing where you've setup a low-anchored tie-off on the end of the line, have nobody on the rope's tail end, and've setup to where the pieces are smashing down into a pile on the lawn (basically set the final anchor at ground-level, if you've got a long enough run, and you'll be building up a pile in-front-of you basally-anchored tree)
 

eyehearttrees

Active Member
Hockles can be caused many ways and possible to prevent in many ways as well. When I notice them the most is repetitive use with a rope that is much too long. Having a bunch rope laying on the ground or in a bag not being used allows the twist to build up.
Is "figure-8 rope-coiling" seen as good form? I try to be careful about finding&eliminating twist before storing my ropes!

BTW thanks a lot for the vid on Sweating lines am gonna watch now had always thought it just meant "tensioning the line" :p


EDIT: Missed something:
As with most things, different scenarios need different solutions. The more vertical your speedline the less tension you'll need. If your moving material 20 feet horizontal from 80 feet up it won't need much tension or friction. If your attempting to move material 80 feet horizontally from 20 feet up you'll need a lot of both tension and friction.
For sure! And the forces (lateral vector forces) created vary greatly, it's interesting to ponder how they change as a perfectly-vertical speedline goes to some 80' wide, 20' tall system as you describe (wowzers the amount of forces, mid-line on an 80' system, would be insane am guessing that even w/ 3/4" Stable Braid, pre-tensioned w/ 2 guys on a 3:1 over a bollard, would still limit you to quite small loads!)
 
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eyehearttrees

Active Member
~~~video on Sweating a line~~~~~~
Thanks again that's great, if bodyweight/pull-down is insufficient I'm immediately looking for a "tensioning hitch" so I can setup a 3:1 to pre-tension....Sweating (please correct me if I'm off base here!!) is basically somewhere in-between the two and used in all the same ways, right?
Looks awesome, in-practice I'll often pre-tension by just pulling the line when, if time was no object, I'd rather have pre-tensioned w/ the hitch at 3:1 (as I brought up in last pic of post #5, which I'm still hoping to verify is the common/proper/most-efficient way of pre-tensioning a system when by-hand, or even sweating the line, have failed to get it as taut as desired...it's actually the only way I know, short of bollard-mounted-winches, to really pre-tension a system, eager to verify if it's truly the optimal way as I don't get why I couldn't find a single picture on Google demonstrating it outside of Stein's advert for their "purpose-built" micropulley!)
 

eyehearttrees

Active Member
1st, I know I've not replied to at least 1 of you posts and apologize, also can only reply in-part to this as googling from your reply here will probably be most of my next hour or two of online-time lol and am guessing your post-history is chock-full of worthwhile stuff, so thanks am glad you've chimed-in here :)

Pulling with 3x1 jig* would be taking a purchase* of line
>>releasing some back would be paying out* to belay* etc.(in ol'sailor terms*)
This would be linear tightening down long axis/rope length.
.
Could use Fig.8 to pull rope into; like do Porty, to capture the purchase* and to 'hold fast'*, to then take another turn to preTighten more.
>>with fig.8 locked in place as Porty would be
Or could float like Brocky's Deaf_8, pulling the fig.8 itself
Can kinda try twisting as ya go line coming out of fig8, to alleviate but fig8 likes to spiral towards hockle rope as noted, unlike Porty.
.
Sweating/Swigging* line is bastardization of support science from rope.
>>Support of rope capitalizes on cosine,linear support, trying to minimize sine
>>Sweat/Swig does opposite, goes to wrenching rope across it's length/non-inline, to capitalize on sine instead of cosine
(always look for support from cosine 'wave' vs. wrenching/leveraging always capitalizes on 'sinewave' instead as opposite mechanix from supporting, Samson served across support columns)
>>the same science that will work against the rope in actual loading of speed line, now helps tighten same rope
>>now working for you(payback!)
.
old refs:
mytreelessons.com/sweatingToss-Adkins.JPG
Youtube camp swigging lesson
May sound crazy or complicated, but is easy as a child's swing, Bending the rope when most loaded (when most not inline, height of swinging) and at neutral point (also height of swing before return) gives raise in forces to rope when can impact it (motion is squared in this, to over rule your additive of efforts, so child waits for neutral point of swing to pull in right direction to leverage/sweat/swig line across , just not capture purchase) .
.
So can tighten line LINEARLY with pulls/jig etc. and call it a day
or just use that as a setup to REALLY tighten
>>when rope is iron bar tight as can from linear input effort, bend across the linear line
>>the tighter the rope, the less rubbery/more powerful the leverage reaction.
>>in tie downs can use zrig,then bend that leg, or 2 Z's and bend one against the other
This purchase can also be captured, in series of tightenings
>>each time line is tighter (if load not moving), so resists bending more
>>the greater resistance to bend, gives the greater leveraged return
The tighter straightness the line, the faster the load can 'skitch' down the line/rail
>>shaking line during travel can slow load down, but also raises pull line forces
.
In normal rigging, climber is many times in unique position to bend load side of line to sweat/swig, when ground control can only get to control side of rope, and any efforts must go thru the 'friction buffer' of the support.
Furthermore, if climber can stand on control side of rope in cam or prussik and then pull up on load side is in unique position to use bodyweight + effort + equal and opposite of effort to tighten line linearly, before then on load side sweat/swig across now tighter rope etc. Anything to tweak a bit more tension, usually easier to relieve on the fly, than increase. Climber is only one to be able to reach raw load end of rope w/o friction buffer degrading input. UNLESS install prussik (clear of either end that would limit bend) on load leg to give ground control some remote sweat/swig ability in precut. But also once a lot of weight on line/less on hinge a high tension turn response, and then steering on ground for best reception to clearest zone.
.
Sling and krab sets are marvelous flexible utility of functions. Can have a load rigged half cut that doesn't want to pull into speed line, and rig other limb off that limb to make it's impact cut fold load into line when cut/impact 2nd limb. Also rig off more friendly limb closer to speed line, cut first limb to be carried by 2nd better placed not to impact line etc. The combinations and opportunities become even more endless and powerful.
.
Some ideas on Speedline from original Tree Forum, ooooooooooops i mean we called it a BBS 'way back' then, when i first thought gee i found my people (some as now disputed that tho)!




[video removed for space/readability]


From across the wages, sages and ages of time, thanx again to Dave Spenser!
.
Note how if can pull and capture purchase quick enough, can have bend on load and use it to pull the load around to proper position, then, snatch line thru frictions and then release hinge to let load ride the tightened rail/rope down. 1995 GAME CHANGER.
.
Sine gives most volatile changes, just off of TDC alignment.
>>Sine from center of clock to TDC/noon is Zer0
If move 1 hash mark/minute/second (6degrees)on clock towards 1
>>sine jumps to 10% of length sideways, leveraging force just the same
>>another minute on clock jumps another 10%
'My' (think i made it up) rule of thumb is true about to halfway point of 45degrees or 7.5mins half way to 90 degrees at 3o'clock
Using same clock mnemonic , the cosine starts out at 1 at TDC/noon
>>at 1 minute hashmark tho where sine jumped to 10%, cosine only recedes 1% from 1 to .99
>>at 2 minute hashmark tho where sine jumped to 20%(total) cosine only recedes to toal of 1-1% -2% =1-3%, or .97, i use as 97%
>>at 3 minute hashmark sine:30%, cosine drops to 1-1%-2%-3%=.94 etc.
>>fair until mid point, but then scales reverse; so can see full picture that way
These are slightly off thumb guide maid up from Babylonians base 60,12hr clock and 360 degrees they gave us type observation(but perhaps how they designed these things as center of understandings); but has served me VERY well in where to place how much 'respect' and to what levels. In sweat/swig usage, these forces are divided against 2 points, but only against 1 point if pulling a weight sideways that is hanging from 1 end of rope/not mid between supports as speedline. But all the math is the same, as it repeats in all things; as the Ancients tried to had us.
Heh, 'purchase' (instead of 'progress'-capture), I like/gonna try remembering to use that :D

Well put on using the 8 and thanks for the "2 ways" I much prefer locking-off sooner and if I get your point on 'twisting as you come out of the 8' you mean using it almost as "pre-lock-off", kinda like how if you had a person falling over a cliff w/ rope attached, you'd wanna be getting that rope around a pole/tree to leverage-against? It's crossed my mind but I dismissed it as something that's probably ineffective, since the sling cordage itself has so much give!

Wish I could understand Sweating/Swigging paragraph (at-minimum you are speaking as-if everyone's got a college-level understanding of calculus[or whichever form of maff that is :p ], I imagine I'm not alone in having learned right-before-tests / forgotten everything / couldn't explain sine waves to save my life!) But you've brought them up >1X now, both in a vertical and, here, horizontal context (where you seem to say they're of more import than on vertical blocking), would love to understand I actually wiki'd sine or cosine after reading it in your last mentioning and was out of my depth so quickly I bailed :p

Re "tightening from both ends" and climber being in unique position over ground crew (at least if there's not superior mech.advantage on the ground), isn't that really "just theory" though? I mean, sure, we want slack removed from the system, but it almost sounds like your ideal is to pretension to like 5%ABS...surely there's too-tight! I don't have the experience you do (and you sound like precisely the type of operation I'm actively seeking to spend my summer with right now, would be sending my resume if you were Tampa LOL), but no matter which way I picture it in my head, "optimal" wouldn't be "super tensioned", merely "taut", because elongation of the line part of the system's log-catching-attributes, sure if you're using Nystron(2.4%) you'd tension it harder than Stable Braid(1.1%) so long as all other things were equal, and you'd have two comparable peak-forces when identical logs were dropped into the system (further, if you pre-tensioned the nystron enough, wouldn't you have negated its edge over Stable Braid when it comes to dynamic strength?)

So much more to digest and learn about will surely have another Q on that, thanks again for posting it :)

(BTW, if it was you who'd linked a paper on forces/kinetics and had asked if I'd read it, I haven't & can't find the post w/ the link, would be grateful for a re-link if that was you am suspecting it was :D )
 

Jehinten

Well-Known Member
I see it as 2 different methods (and invite correction/further understanding!!) when zipping something, "normal/regular" wherein someone's on the other end of the line but also a "diagonal-vertical speedline" type of thing where you've setup a low-anchored tie-off on the end of the line, have nobody on the rope's tail end, and've setup to where the pieces are smashing down into a pile on the lawn (basically set the final anchor at ground-level, if you've got a long enough run, and you'll be building up a pile in-front-of you basally-anchored tree)
There's at least 50 ways to skin a cat, ask @JeffGu If you'd like the complete list. ;) it all depends on the scenario. if working solo I've done a speedline with the rig-n-wrench up high and adding tension as I cut with the ground end anchored. If working with someone I prefer to anchor the high end and tension at the ground. Its possible to set up a speedline with "about the right amount of tension" and clip into it and cut. The problem is that as more limbs load it it gets tighter and harder to clip into the next piece.


Is "figure-8 rope-coiling" seen as good form? I try to be careful about finding&eliminating twist before storing my ropes!

BTW thanks a lot for the vid on Sweating lines am gonna watch now had always thought it just meant "tensioning the line" :p
I'm not sure about coiling, I flake my ropes into storage totes or bags. My preferred method before flaking was daisy chain.

And no problem on the video. I first found that video on a thread here on treebuzz.


Thanks again that's great, if bodyweight/pull-down is insufficient I'm immediately looking for a "tensioning hitch" so I can setup a 3:1 to pre-tension....Sweating (please correct me if I'm off base here!!) is basically somewhere in-between the two and used in all the same ways, right?
Looks awesome, in-practice I'll often pre-tension by just pulling the line when, if time was no object, I'd rather have pre-tensioned w/ the hitch at 3:1 (as I brought up in last pic of post #5, which I'm still hoping to verify is the common/proper/most-efficient way of pre-tensioning a system when by-hand, or even sweating the line, have failed to get it as taut as desired...it's actually the only way I know, short of bollard-mounted-winches, to really pre-tension a system, eager to verify if it's truly the optimal way as I don't get why I couldn't find a single picture on Google demonstrating it outside of Stein's advert for their "purpose-built" micropulley!)

For most cuts I find it sufficient to do a quick sweat of the line then if it needs to be tighter a slow cut will transfer weight into the rope until it is holding the full weight of the piece which is all the tighter it needs to be. If it requires more tensioning than that, then you are lifting the piece and I typically use the mini skid for that.
 

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