Barrel/'Fisherman's' vs. EyeSplice

[TheTreeSpyder]

Barrel/\'Fisherman\'s\' vs. EyeSplice

i think that our friction hitches help absorb the dynamic portions of loading forces to save us a number of ways. i think the coils place more line before dead end for absorbing some shockloads in the hitching, that one would not have dead ended at an eyesplice at the same point. Also, the way that the coils can compress down onto the host at higher loading would give some 'snubber' effect? Then the Maaslovian Mini- test on the slight slide; any 'give' from any element can be as to a leak, that let the highest force iimediately depressurize somewhat; whether it be the compressing of the line, the more line to stretch before termination (more coils before 'lock' the better), give from sliding on host line a bit etc. All function to release some high momentary forces of dynamic loading so that the whole system is saved from these intense peak loads. If we can be within the SWL, and have 'leaks' to dissipate momentary peak loads, the system is safer logically.


The Barrel Hitch has a high strength close t eyesplice, and i think more capable of dealing with dynamic loading than an eyesplice. Barrel has the turns (i like 3), the line compression (to itself), and the line slip (as it tightens tighter to carabiner sliding thru tighter gripping coils). A single bowline would rank lower, a double/roundturn choke on bowline better than a single i think.

So, besides cost, self apply in field, taper, simplicicty, working with knots/learning myself etc.; i think i have another reason to prefer a Barrel to an eye splice for terminations especially for cords/prussiks. As well as the dang DBY over single bowline, more capable to deal with the dynamic portions of loading(?).

Lots of knot tests are done under static, stretch to break etc. type loading; not dynamic. With high SWL adherance, the intense momentary dynamic multipliers to almost unpredictable levels could be better dissipated i think.

Like Cobra Cable has the dynamic range buffer of the chosen line; and the dynamic range buffer of the snubber as 2 seperate factors; i think the hitch and termination can give options to the dynamic loading factors as any parts of the system linkage trail can.

Or something like that.

 

[frans]

Re: Barrel/\'Fisherman\'s\' vs. EyeSplice

SWL or 'safe working load' means the total safe load on the rope is (i think) 10% of the rated capacity. 1000 lb rope, 100 lbs. safe working load.
At the SWL(s) listed on our current climb lines we are using huge safety margins with our SWLs.
If anything is to be learned from this it is that our climb lines are tottally safe to hang from.
Even with the addition of knots, bends, and hitches we are still well within the SWLs.
What else does this mean? To me it means if I SHOULD break a line it would be with forces that exceed the capacity of my body to withstand without some sort of fundamental injury to my body.
Where should my attention be focused then? On rope/knot strength? On whether or not a rope will hold me?
No.
To me what is of greatest importance is the question, "is my rope dynamic"? will it give when my body is hanging(dropping) into it.
for awhile it seemed everbody was obsessing over the strength of ropes, the greater the strength, the 'better' the rope.
I think changed with the 'fly' rope and it's reduced strength.
To remain focused on the issue of knot strength (or the tiny force absorbing factor), splice strength etc, in my opinion is ignoring the reality of what REALLY WILL HAPPEN to your body in the event of you falling into your rope from a height.
Frans

 

[TheTreeSpyder]

Re: Barrel/\'Fisherman\'s\' vs. EyeSplice

i think it has been shown that impacting forces can go off the scale; and a good technician might prepare for their suden incurrance; why not?

 

[frans]

Re: Barrel/\'Fisherman\'s\' vs. EyeSplice

The question of knots vrs. splices:
I have spoken to climbers who prefer knoting their climbing hitch but I prefer splicing, the same with my climbing line. The amount of 'give' in a knot (such as the barrel/fishermans eye splice is tiny, what maybe a 1/8" inch? so to get any real shock absorbing from this you would have to take 20 or 30 wraps. Majoring in minutia this train of thought.
What I predict will happen in this industry is a different construction of our ropes.
so far we have rope manufactures building 'static' and
'dynamic' ropes. Those are the choices so far. However dynamic ropes have no real rating for how far they give, and static ropes do give a little before stopping.
So the designations are blurred and each type of rope has no real measurement or rating for when a dynamic rope will stretch, and what exact weights will cause it to elongate to certain lengths, OR how far a static rope will give before becoming 'static'.
I belive in the future we will see a different construction of our climbing lines.
Imagine a dynamic climbing line that will remain static under passive loads but will stretch under a dynamic load. So you would be able to footlock/body thrust as with a static rope, but in the event of a fall the rope 'unlock' and become a super streatchy rope. The dynamic effect would have to be one way/one time so you did'nt bounce like a bungee cord. In envision after a dynamic loading event you would have to maybe store the rope until it slowly retracted and locked back to it's 'static' setting again. And then again the work cycles would maybe be limited.
The materials in rope manufacture have not changed much over the years, we have stronger and stronger ropes now (I have a 7/16" rated at 14,000 lbs) and their have been some changes in construction but no real breakthrough in basic rope construction materials.
frans

 

[TheTreeSpyder]

Re: Barrel/\'Fisherman\'s\' vs. EyeSplice

We are pretty much on the same page, on rope needs. i think give in any chain in the link can release some 'steam' from pent up loading forces in the system. In the cobra support example, the snubber gives one range of dynamic absorbtion, as the chosen line gives another range to build into the system. Choosing too stiff/strong a line will alter the maximum of correctly matching line to loading to have 1 range of dynamic absorbtion from line(that is 'weak' enough to react with dampening rather tahn static jolt; and another range from snubber, yet another from the dynamics of the wood itself etc.; all buffering different ranges of loading. One sytem being maximum, the rest being less than; add in feasibility to modify and go(?).

The line is one way; and i beleive the construction can be tuned as you say to be static to a common loading and enter dynamic range only on higher loading; like adjsuting it's powerband of function.

The knot discussion was to why choose this knot over that in all things, but mostly; another thing in the balance of barrel vs. splice camps of thought; just another item in the balance. It would be interesting if barrel was ~10% weaker on static pull but much stronger on dynamic etc. Tilting towards barrel some at that angle of thought. Kind of an extension of pretightening a line to expected needs, so as to react statically to that load, then the stretch comes in later at the incursion of more loading; jsut perhaps a better strategy to cover things not commonly calculable perhaps.

i think to a certain extent, the slide + compression + coil stretch in frcition hitches can be an operative for 1 range of dynamics, the line have static and dynamic property ranges, the support, maybe a stitchpack etc. Any time the loading force hit one of the dynamic ranges of one of the instruments in the chain of support, 'steam' escapes, and whole system is less loaded. so, maybe in certain assemblys we are closer than we think to maximizing the dynamic/static powerband ranges to our use!

Partially i get the dynamic knot analysis from those seemingly always ahead of us; mountain/ rescue. One of the quoted reasons i've seen for Fig.8 loop over Bowline is dynamic loading; the Dog and Tails i beleive is for the dynamic loadings of getting yourself out alive, and another scared person too etc.! Their lines are segregated to dynamic and static etc. too. The real loading, hardest to calculate are the dynamic loads; having several 'steam' pressure releases in the system to allow some pressure relief in higher ranges doesn't seem harmfull!

i think, that due to the fact that the input force must be matched,that any of these heat producing slips etc. allow that force to show up as heat energy and not mechanical energy on line tension. i think that is how the compression, slip, stretch etc. works; returning the heat to the atmosphere; asi t originally came from the sun.

The dynamic absorbtion of systems could be dependant on the different ranges of absorbtion by different assembled componenets in the linking; each acting as a "fuse' to release system 'steam' at that loading level; and being able to recover system element for anther run if necessary.