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Thread: Negative Rigging

  1. #91
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    Murphy, have you ever read the rigging research done by the HSE in the UK? It's a few years old now but it has tons of useful information. Lots of real world/tree world testing. This is a page from it.
    Could you give a link to this ?
    I don't recall seeing this test with a log as an attachment point.

  2. #92
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    http://www.hse.gov.uk/research/rrhtm/rr668.htm

    It is a large download but like I said it has tons of good information.

  3. #93
    TreeHouser murphy4trees's Avatar
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    INteresting tid bit..
    the knot always fails at the marl or half hitch when it is used to back up a running bowline and contrary to popular opinion the marl or half hitch can actually make the rigging system weaker.... so using it for additional grip is in order, but not necessarily additional strength... circa pg 157..

    yes that is an awesome resource.. thanks for the link..
    Attached Thumbnails Attached Thumbnails knot strenth loss.jpg  

  4. #94
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    To me the Half(HH) Hitch/Marl strategies provide a 2nd grip yes;
    But most importantly, are for inline pulls along spar like our loads commonly hang.
    To place the entrance/Standing Part of HH/Marl pure inline to exit/ Bitter end of same HH/Marl;
    correcting the inline pull on spar(that should be across minimal axis/at right angle to spar)
    .
    Specifically to this part of 'my' theory:
    A> is correct angle of pull across minimal axis of host/spar
    B> is in-correct angle of pull along major axis of host/spar(MUCH better Bowline eye is over branch/taper swell)
    C>modifies the incorrect angle of pull on rope of B to pure inline for primary hit.
    .

    .
    i look at HH/Marl as precedent/primary of Running DBY (that is backing up primary HH/Marl)
    .
    Bowline deformity of Standing Part from pure inline is more radius of change, but softer bend than HH/Marl?
    Bowline also splits loading to eye/dual leg HH is single leg support from Standing Part to Bitter End
    >>HH/Marl i figure 50% relative tensile
    Lessons consistent with rest of pure inline theory
    >>harsher bend from pure inline seems to give more impact of change against HH/Marl even if not as far arc-ed!
    .
    HH/Marl will make weaker, but more secure, not just because of 2nd grab, but i think proper angle of pull also
    >>if would or metal architecture would look at as same! Why expect more from rope?
    .
    Many things work on double grab/bite fastenings; also duals as failsafe.
    >>nothing is 100% efficient, so simple dead stop not 100%, almost gets it, 2nd stop dead ass ends motion.
    .
    Ashley's book of knots, virtually all pulling knots are at right angle to spar, across minimal axis.
    Then totally separately have knots for along the long axis pulls in 1 small chapter, all with HH/Marl/VT type primaries for this alignment i believe.
    >>these forms include our friction hitch types, as themselves inline pulls on a host rope rather than spar
    >>i think we will find HH,Marl,VT/rat tails type precedents/primaries (or total package like VT)
    >>i don't think we will find friction hitch inline pulls on rope column to have any 1 stop part, nor wrong angle of pull in primary!
    Round Sling grab along spar column found here, but ANY type of noose, Running Bowline etc. (as primary/only) 'conspicuously absent'
    >>So trust Round Sling dual grab if no HH/Marl precedent, but actually used HH/Marl before round sling a lot going over ~2-300#
    >>especially if can't give that more inline resistance with branch/swell as stop on deepest side of eye from Standing Part. as closer to inline architecture of stop vs. Standing Part pull
    .
    i believe in watching numbers, don't really speed, nor race when have to change tire, but NASCAR has brought us far!
    >>reaching, rating etc. does expand, groom, care for systems
    But just watching all strength seems overly 'macho'/un-even/1 sided at some point; even blinding; when other considerations!
    .
    If you drag a lot of stuff, will find with just Bowline, Clove, Cow etc. all trustworthy right angle of pull strategies ;
    Tied to drag branch etc., load can flip around wildly side to side(in rite conditions) like dragging a wild cat trying to get it's collar off ;
    >>until tamed by slipping a HH (or Marl) over 'nose' end of spar ; and pulls straight and true w/o all the melodrama!!
    >>at correct angle of pull, pure inline!
    (i guess will fall into place w/theory nicely, as theory was, once again, actually formed around it!!)
    .
    OLD LINK :next screentest youtTubie target is to bring in more animations, going slow for water molecules, will try rope over weekend.
    Hope voice isn't too tinny, i think this is going to be big year of growth for voice tech in/out
    artificial voice has no background noises and is always consistent even if not on same day etc.
    .
    Polly Price Page Link - AWS
    1st yr.free, after that 1million characters $4 (think that is in 1 month, max 1000 requests of max 1000 chars)
    AWS Amazon Web Services is gonna kick butt, google/ms/apple etc. scrambling for a piece.

  5. #95
    TreeHouser Sponsor cory's Avatar
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    Quote Originally Posted by sawman View Post
    Got it double blowline= two rabbit holes
    I've seen it referred to as a jacked bowline, too, fwiw.
    Mastery is an illusion, grace a momentary gift, apprenticeship endless.

  6. #96
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    Thanks for the link.

  7. #97
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    Knot names vary, several references for Jacked Bowline.
    Double Bowline upgrades the "Nipping Loop"(IGKT) in Bowline construction from a single Turn base to Round Turn (RT on IGKT forum).
    If make same RT into CLOVE is 'Water Bowline', because is a sometimes a very needed upgrade in water, grips more tenaciously even in that context.
    Take Bitter /Working tail of normal or Double Bowline and 'reeve' it back up along the Standing Part (S_Part on IGKT forum) is a "Yosemite Tie Off" for more security and to 'clean up the eye' as now more resembles an open/clear eye splice to attach to etc.
    DBY is Double Bowline with Yosemite tie off, much more symmetrical look and feel, open eye, more secure; discussing how much stronger.
    .

    i favored the slip-knot inversion method of making Bowline(can't believe slideshow is 20yrs old!)
    >>Instead of the rabbit going up thru the hole, around the tree, the mountain comes to Mohamad!
    In olde times if stranded on a side of a cliff, holding on w/1 hand, they could lower a line with the slip knot in 5' or so up.
    With one hand person would try to get Working End around themselves under armpits (or seat if real good hanging on), back up thru the Slip Knot and fold back down outside it.
    If holds on right , even if falls at this point should invert slip-knot and make FIXED eye around self not shrinking eye on lungs etc.
    >>Lesson can pre-make half of Bowline for quicker tying 2nd half if needed, can even hang slip knot eye on hook, even own thumb;
    >>visualizing almost needing to capture some strong bull soon as contact, release confidently to rope ..
    .
    Olds-cool numbers
    >>(modern HPME stronger than steel ropes have special needs and rope bend references now all show higher in general ):
    Not too stiff like Stable Braid etc. / more like ArbroPlex/True Blue class,
    Would assume 50% strength loss on knots etc.
    This takes into consideration like Marl, HH (50% 'strength') and
    notably a 1/2" rope (x4 diameters)on a 2"pulley as 50% 'strength'
    >>approximate 4" pulley(x8 diameters) for 1/2" line about ~100% 'strength.
    So, HH/Marl matched to 2" arc in 1/2" line as matched components, chain only as strong as weakest link anyway.
    >>bigger branch than 2" more radius/ strength retention, but more frictions deforming line too/strength drop..
    Knot 'strengths' over 50% are more 'premium'; and rightly all that we look at using generally in our world.
    >>Overhand knot on primary loaded Standing Part at full load a no-no cuz is around 40-45% 'strength' knot deformity
    >>Sheet Bend around 50% line, so ok in their working class
    >>Bowline i think re-routes some of the load on Working End of primary bend from S_Part
    >>so anyway, test out higher than Sheet Bend of similar architecture going into primary loaded deformation, but not out of..
    (as i try to visualize what is going on inside knot microcosm)
    .
    Still trying to werk animations.
    Biggest strength increases in hitches i think:minimal deformity to most fully loaded S_Part, after that , if working end is to deform S_Part: RT around S_part w/minimal previous frictions (or grip mechanic doesn't werk) to more than just bend fully loaded S_Part but then hug it to manage deformity better/ give some strength back. When visualizing rope as power vessel like wire with force running thru it i look at RT on S_Part as upgrade like grommet rather than sharp bend going into tv/knot machinery as just deformity managed better/ more strength retention. Beyond that , offloading some force at or before any deformity, maintaining S_Part pure inline as much as possible , and can make float away from / not have to collapse to host mount, like an eye slice can or a friction hitch in right circumstance. NOT collapsing to host showing Definitively as separate leg of support to load, so less tension on part of primary loaded deformity, for less, strength loss. The 'secondary leg' on these also will pull more inline than across the fully loaded S_Part.
    >>i think that and some rope angle ranges are mostly all there is to it!
    >>ABOK does note RT on host is stronger on small hosts as evens out wear, but if do this don't get benefits of RT on S_Part that i think is better.
    .
    A single, simple Turn around a polished 24" capstan/pipe i'd guess can't hold 500# by self confindentally.
    But guess RT on 2" might only take around 50# hold, another turn on 2" host just a few pounds to hold 500#.
    >>even though, more surface area contact on the 24" i think, so look at this pinch , grip thru host, even if line as TOTALLY different mechanic than a simple, single Turn.
    "Nature, to be commanded, must be obeyed" -Sir Francis Bacon
    We now return you to the safety of normal thinking peoples.
    ~ Please excuse the interruption; thanx -the mgmt. ~

  8. #98
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    Kenny...The slip-knot inversion method of tying the bowline is what I first learned. Here is a video I did awhile to show that...I think this is the method you reference.

    I have not tied a "double bowline" using this method before...I'll have to try that. Thanks for the idea.

    Gary

  9. #99
    TreeHouser Sponsor theTreeSpyder's Avatar
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    YES, all the same, sorry; been distracted.
    .
    The 2 Turn builds like w/Round Turn for DBY or Clove for Water Bowline; can be harder to mange 'Nipping Loop' part of construction (w/2 rings).
    .
    Slip-Knot method makes multiple rings easier to manage; gives them structure to sit on.
    Slip-Knot method then pulls Bight of Working End thru Turn(s);
    rather than 'threading' the rabbit up hole around tree down hole;tree comes down hole for rabbit to jump over
    >>or another view slip-knot becomes like wire-slip for drawing thread thru needle.
    .
    Once again the intermediary stopping point of slip/noose stage can be very handy; and is even stiffer/stabler with multiple rings!
    .
    Been trying to think how to better explain HH/Marl as most proper on inline pull stance.
    (1 work around is limb as stop for running bowline on opposite side of Standing Part pull; giving more inline stop that is missing)
    >>You can work an adjustable wrench/pliers rotating backwards putting more pressure on minor facing/pawl; but it isn't mechanically correct!
    You want to lock into not out of the larger framework; similarly in a hand should rotate thumb wrapped, in direction thumb pointing.
    >>So, rotation locks host into larger framework of hand, and thumb is just baby pawl managing it in place
    >>hand rotation towards fingers stresses thumb, easier to lose host/handle/bar wrapped around.
    Similarly inline pull on host by Running Bowline alone is not a 'positive mechanic'; especially to smooth spar model, especially any shrinking taper etc.
    >>Running Bowline works many times; especially textured host, against taper, seated into deformities all help to bring to a more inline pull necessary; but not by direct, positive means(i think i mean..)
    "Nature, to be commanded, must be obeyed" -Sir Francis Bacon
    We now return you to the safety of normal thinking peoples.
    ~ Please excuse the interruption; thanx -the mgmt. ~

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