Identify unknown slide and grip hitches

[agent_smith]

To Dan and any other potential layperson reading this post:

The link to the video that Dan posted is an 'outlier' test.

I note the following:
1. The hitching cord was 9.0mm diameter (which is unusually large compared to what the vast majority of user groups would use)
    Most climbers (for example) use 6.0mm diameter accessory cord (+/- 1mm).
    Most professional VR teams use 8.0mm cord on 11mm diameter low stretch rope.
    The host rope used in the video appeared to be of a much larger diameter than 11mm (thereby decreasing the bend radius and aiding heat dispersal).

2. The tree climbers only used a 180lb drop mass (81.6kg) - which is significantly less than the normal 100kg drop mass specified in relation to low stretch ropes)
    An average tree worker, with all PPE and tools would weigh at least 100kg - or more (think helmet, hearing protection, full body harness, fuelled chainsaw, hand saw, various devices, etc). Rope access operators almost certainly weigh more than 100kg with all their PPE + tools.

3. The tree climbers did not have a rigid anchorage point above (it was attached to a tree climb - which flexes).

...

Dan, I think you searched for a video - and found one - in an attempt to contradict my warnings about using slide and grip hitches for human fall-arrest.

I stand by my caution and warning to NOT rely on a slide and grip hitch for any life critical fall-arrest applications.
Legally (and with regard to duty of care) - you would be wise to follow suit. Keep in mind that these posts on this forum are published to the world!

There are specific standards that are published to cover devices that are designed to arrest a free-fall on synthetic ropes eg; EN 353-2, ANSI Z359.15, etc.
NO SLIDE AND GRIP HITCH WOULD PASS THE DROP TESTS SPECIFIED IN THESE STANDARDS.

...

Scott may not like me saying this BUT;
I have to say that tree climbing arborists are one of the last remaining class of users who still heavily use and rely upon hand tied slide and grip hitches.
Virtually the entire rope access industry and vertical rescue (VR) operators have long since moved on and use properly certified and fit-for-purpose devices designed to arrest free-falls.
Virtually no one at a workplace relies on hand tied slide and grip hitches anymore... (except tree climbing arborists).
Sorry Scott!

[SS369]

Hi Mark.

I take no offense with what you've written. What industries do over time, well they evolve. I might use S&G hitches mostly when I rock climb. Sometimes as an arrest on a construction project when hand hoisting.

To date, I have not invested in any mechanical/professional S&G or fall arrest gear. Many times the fall arrest gear/extra safety gear is provided by the general contractor on industrial projects (By law).

So far, so good, I am still breathing. If the needs arise I will purchase what is needed.

I've search for your two and I have not found them .

S

[Dan_Lehman]

I personally drop tested a 3 wrap Prusik hitch (#1763) using a 100kg mass at factor 1, and it disintegrated (refer image below).
I extrapolate this result to any slide and grip hitch that is subjected to a fall factor exceeding 1 (with 100kg mass).

That's quite some leap --from a particular test to such
a broad assertion!

The link to the video that Dan posted is an 'outlier' test.

... which showed a hitch holding.
There are other similar tests, to wit ::
https://treetools.co.nz/__media_downloads/00-downloads/T/Treevolution/Report_hitches_PBavaresco.pdf
seems to have FF-1 & even FF-2 tests, w/success, in the materials used.

Dan, I think you searched for [information]

And now another (and another, though I think w/lower FFs (1/3)).

in an attempt to contradict my warnings

... to simply to see what evidence there was to support
whatever assertions.  To see what was failing (the hitch,
the hitching rope, the object) and why.

NO SLIDE AND GRIP HITCH WOULD PASS THE DROP TESTS SPECIFIED IN THESE STANDARDS.

Again, this is a broad assertion --of hitches & materials.

...

Scott may not like me saying this BUT;
I have to say that tree climbing arborists are one of the last remaining class of users who still heavily use and rely upon hand tied slide and grip hitches.
Virtually the entire rope access industry and vertical rescue (VR) operators have long since moved on and use properly certified and fit-for-purpose devices designed to arrest free-falls.
Virtually no one at a workplace relies on hand tied slide and grip hitches anymore... (except tree climbing arborists).

And arborists get on; is there a mechanism that could replace
the knots for their application?!

--dl*
====

[agent_smith]

To Dan:

It is sad to see such a reckless and irresponsible position that you are taking on this matter:
(ie using slide and grip hitches in life critical fall-arrest applications at a workplace).

You are broadcasting your assertions to the world - which is a potential breach of duty of care.

And; this thread is now being de-railed.

I am going to start another thread topic on this subject (under "Knotting concepts and explorations").

I wont discuss this particular matter any further in this thread... instead, preserving it for new knot claims.

[Dan_Lehman]

You are broadcasting your assertions

"Assertions" you say?!  Where are there any assertions?!
Can anyone find any assertions by me in this regard?!

In some older mountaineering literature,
one can find an assertion about using a slide-possible
Tarbuck Knot in fall-arrest situations.  I'm looking for
any testing to back up its promised benefits, so far
w/o luck.  The K.Tarbuck booklet emerged ca. 1960.
The knot disappeared when kermantle ropes became
common.

--dl*
====

[agent_smith]

Thanks Dan - fair enough.
I retract my remark re "Your assertions".
Probably should have typed something along the lines of...
>> "please add appropriate warnings that relying on slide and grip hitches for fall-arrest at a workplace is not recommended".
(this of course assumes that we are both defining the term "Fall-arrest" in the same way, and assuming a minimum 100kg drop mass).

Anyhow, back to the original intent of this topic thread:
I still don't know if my 2 originally presented slide and grip hitches are original...
Again, perhaps in the fullness of time I may gain more confidence with regard to making any claim of originality.

EDIT NOTE:
Since my original post, I have managed to acquire Bob Thrun's book "Prusiking".
I could not find my presented slide and grip hitches in that publication.
I did find a precursor to the so-called 'Schwabisch' hitch (via Thrun's 3 turn illustration).
Thrun did not illustrate the 5 turn (ie 5 'coils' around host rope)  version (aka Schwabisch hitch).
It might be possible to extrapolate/surmise that Thrun knew he could add 1 more 'wrap' thereby making it 5 'turns' (ie 5 coils encircling the host rope)...
...and I have no plausible reason to doubt that he might have done so.
But, from purely an evidence-based perspective, Thrun did not actually illustrate the 5 turn (Schwabisch) variation.