Author Topic: Harness Tie In  (Read 10614 times)

roo

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Harness Tie In
« on: June 22, 2013, 10:52:14 PM »
I saw an interesting discussion here:
http://www.8a.nu/forum/ViewForumThread.aspx?ObjectId=32418&ObjectClass=CLS_ForumGeneral&CountryCode=GLOBAL

What particularly caught my eye was this:
Quote
First response from the DAV sicherheitsforschung / German Alpine assocation Safety commission:

Yes, you can tie in the belay-loop. The force is 15 kN in the EN 12275 for harnesses, not 25 or 30 kN. Same test for tie in situation leg/waist-loop. So both is possible and correct. All manufacturers advice the leg/waist-loop, only Edelrid advices both methods. But in practice it doesn't matter. The difference is, that the tie-in-knot is a bit lower using the leg/waist method, if hang dogging and bouldering. The wear is not a strong argument, because you see it by both methods. The wear comes from lowering down and abseiling when you move your legs. Then you have a abrasion between the leg-loop and the rope (leg-waist-method) or the leg-loop and the belay loop (belay-loop-method). Maybe the rope is a bit more rough, but it's not a big difference.

Would any of you out there be willing to tie a loop or hitch directly to the belay loop and forgo using the tie-in loops?

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SS369

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Re: Harness Tie In
« Reply #1 on: June 23, 2013, 02:43:25 AM »
I would be willing to if there was some reason, but I regularly tie in using the tie in loops. I generally try to follow the manufacturers recommendations, since they design and test their products.
That said, the brands I have owned and used over the years have not indicated that to tie in using the belay loop would necessarily be a good move.

I regularly, before heading out to do some climbing, inspect all my gear and if there happened to be signs for retirement then that is what happens, I retire it. Harnesses are cheap, comparatively speaking, to the failure of one.

I can't think of any reason to use the hitch you've linked to for this application.

SS
« Last Edit: July 05, 2013, 11:10:43 PM by SS369 »

roo

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Re: Harness Tie In
« Reply #2 on: June 23, 2013, 03:01:33 AM »
I can't think of any reason to use the hitch you've linked to for this application.
It uses little rope, is simple, quick to tie and has nice security.  Just an option.
« Last Edit: June 23, 2013, 03:02:29 AM by roo »
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Luca

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Re: Harness Tie In
« Reply #3 on: June 23, 2013, 03:13:38 AM »
Hi Roo and SS369,

I do not intend anything with regard of mountaineering, but this thing is not new to me :while, for other reasons,time ago,I gave a look at some Italian forums about mountaineering, I noticed that a number of users, conscious of the fact that in the instructions booklet  of their harness was not recommended to use the belay loop for the tie-in,they walk over this,and used it anyway for this purpose. By certain people this was regarded as a practice to be deplored, for others it was indifferent(others were favorable to use the belay loop in certain situations,and the regular tie-in loops in other situations, but I do not know of what I speak, I guess that after the weekend someone will be back from his mountain excursion and tell us something more significant than what I write ..!)

SS369

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Re: Harness Tie In
« Reply #4 on: June 23, 2013, 03:20:35 AM »
Thanks for the option suggestion, but I think I'll pass as I use a loop to attach with.
I hope that climbers do the smart thing and always have sufficient rope.
Many climbing knots are simple once they have been practiced enough (as it should be done).

Has the security of the gnat hitch ever been seriously tested, to the point of extreme strain/rope destruction?

"Nice security" based on hand testing is OK for non-critical applications.

Are you suggesting this hitch for potentially life endangering activities?

SS

roo

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Re: Harness Tie In
« Reply #5 on: June 23, 2013, 03:24:12 AM »
Are you suggesting this hitch for potentially life endangering activities?
Yes.  The Gnat Hitch has better security than the Buntline Hitch that is routinely used as carabiner hitch, for example, but resists jamming better.
« Last Edit: June 23, 2013, 03:25:45 AM by roo »
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SS369

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Re: Harness Tie In
« Reply #6 on: June 23, 2013, 03:34:54 AM »
Hi Roo and SS369,

I do not intend anything with regard of mountaineering, but this thing is not new to me :while, for other reasons,time ago,I gave a look at some Italian forums about mountaineering, I noticed that a number of users, conscious of the fact that in the instructions booklet  of their harness was not recommended to use the belay loop for the tie-in,they walk over this,and used it anyway for this purpose. By certain people this was regarded as a practice to be deplored, for others it was indifferent(others were favorable to use the belay loop in certain situations,and the regular tie-in loops in other situations, but I do not know of what I speak, I guess that after the weekend someone will be back from his mountain excursion and tell us something more significant than what I write ..!)

Hello Luca.

Climbing is a dangerous endeavor, no doubt about it. Sometimes egos and bravado influence what happens and what someone does. Sometimes with grave consequences.

I have no fear that the belay loop is a strong attachment point and can be used. It has to be strong because that is where you attach to belay and abseil from. Clipping a carabiner in that spot provided makes more sense than to make a sling to use the other tie points.

There is a little mental thing about using multiple tie in locations even though the belay loop uses them both. Psychology can be a good thing. ;-)))

Following the design criteria and recommendations of the maker is usually best policy.

SS

SS369

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Re: Harness Tie In
« Reply #7 on: June 23, 2013, 03:45:57 AM »
Are you suggesting this hitch for potentially life endangering activities?
Yes.  The Gnat Hitch has better security than the Buntline Hitch that is routinely used as carabiner hitch, for example, but resists jamming better.

You did not answer the other question. > Has the security of the gnat hitch ever been seriously tested, to the point of extreme strain/rope destruction?

For me, since I do little tree service work, don't use a hitch in the way your are suggesting. But when I have needed to secure a rope to a carabiner a double overhand noose has been my choice. There are other options of course.

SS

roo

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Re: Harness Tie In
« Reply #8 on: June 23, 2013, 04:25:10 AM »
You did not answer the other question. > Has the security of the gnat hitch ever been seriously tested, to the point of extreme strain/rope destruction?
I'm sorry I missed the thrust of your question.  Anyway, yes, I have subjected the Gnat Hitch to numerous (dozens?) of extreme strain tests.  It shows no indications of problems.
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alpineer

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Re: Harness Tie In
« Reply #9 on: June 23, 2013, 05:46:08 AM »
I think there are more (shape)variables tying in with a hitch, not that it can't work.
I really wouldn't have any qualms tying onto the belay loop, although I think traditionally the idea here is to minimize the number of components (i.e. the belay loop) in the system. 

SS369

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Re: Harness Tie In
« Reply #10 on: June 23, 2013, 12:25:34 PM »
You did not answer the other question. > Has the security of the gnat hitch ever been seriously tested, to the point of extreme strain/rope destruction?
I'm sorry I missed the thrust of your question.  Anyway, yes, I have subjected the Gnat Hitch to numerous (dozens?) of extreme strain tests.  It shows no indications of problems.

I am interested in any test pictures or data you would be willing to share please.
Thanks in advance.

SS

Dan_Lehman

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Re: Harness Tie In
« Reply #11 on: June 24, 2013, 04:12:20 AM »
An issue with hitching to a harness is that the SPart's
hard loading will move the rope around whatever it's
tied to --a concern of rope-on-harness wear.
Whereas with an eye, both legs are drawn away,
so the case there is one of compression and less
abrasion.  The belay loop, in the usual semi-wide
webbing, is if anything (IMO) less well suited to
bending rope to, to folding/crunching around it.
(The connection for the leg loops seems to be
a more rounded cross-section.  And one can run
a twin eye so to make the cordage broader.)

Frankly, I'd like to see a 'biner snell put to the test,
to get a hard, smooth metal interface.  But with this
come the concerns about how well locking the gate
is.  The snell should ensure proper orientation/loading.


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agent_smith

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Re: Harness Tie In
« Reply #12 on: July 03, 2013, 03:08:57 PM »
The notion of 'no single point of failure' springs to mind here.

Lower body harness designs broadly come in two flavors:
1. Independent segments consisting of waist loop + leg loop bridge (with separate interlocking belay loop) - this design is commonly used in lead climbing applications.
2. Single loop only.

In item 1 above, best practice is to tie the rope directly through the harness in a way that encapsulates/captures both segments.

In item 2, you don't have a choice - there is only one loop to attach to (Note: These types of harnesses are common in 'commercial groups' such as challenge ropes courses, climbing gyms, school groups, etc. They are a cheaper (no frills) alternative.

...

When giving professional advice to clients in relation to item 1 above, I only advocate tying the rope so that it encapsulates/captures both independent segments. I do not recommend tying the rope solely through the 'belay loop'. In this way, the tie-in provides no-single-point-of failure.

A popular harness in mountaineering is the Black Diamond 'Alpine Bod' - this harness design does not have a separate belay loop. The rope must be tied through both the waist and leg loop bridge segment.

Also, I do not recommend a knot structure that is a noose/strangle/hitch form. This would induce a cinching action at the moment of impact in a free-fall arrest. Instead, I only recommend tying a connective eye-knot structure such as:
a) ABoK #1047 (figure 8 loop); or
b) A secured/locked version of ABoK #1010.

Any knot structure that suddenly cinches tight at the moment of impact creates additional risk to the user. The sudden jerk induces cinching - which in turn creates friction/rubbing. A fixed connective eye knot will not cinch tight and both legs of the eye will distribute force (ie force will be distributed across the 'eye-leg of the SPart' and the 'eye-leg of the tail side').

I would disregard any advice to the contrary - and I stand by my advice outlined in this post. This includes any published advice even from some manufacturers - who in some cases do not have vast experience or expert level knowledge themselves. Some manufacturers have little actual field experience and some are over-populated with sales staff who are good at selling but not much else (ie spin doctors).

Mark
« Last Edit: July 03, 2013, 03:15:39 PM by agent_smith »

Dan_Lehman

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Re: Harness Tie In
« Reply #13 on: July 04, 2013, 06:02:13 PM »
A popular harness in mountaineering is the Black Diamond 'Alpine Bod';
this harness design does not have a separate belay loop.  The rope must be tied
through both the waist and leg loop bridge segment.
Nice to deal with some specifics.

Quote
Also, I do not recommend a knot structure that is a noose/strangle/hitch form.
This would induce a cinching action at the moment of impact in a free-fall arrest.
  ...
Any knot structure that suddenly cinches tight at the moment of impact creates additional risk to the user.
The sudden jerk induces cinching, which in turn creates friction/rubbing.
Btw, how would a set-clinched hitch affect one's movement
in such a harness?  --i.e., in having the leg-loop/-connector
drawn up snug to the waist loop?!  This isn't asked in terms
of safety so directly but of comfort, workability/usability?

I had thought of having a *compound* tie-in in which a hitch
is a base --as a last-man-standing safeguard-- and its *ends*
are joined in an eyeknot : should the latter knot somehow
come untied, there would at least be the base hitch to hold.
But I found one use of the clove hitch to not hold, but in
a form/setting (looseness) possibly present in spanning the
two tie-in points, to just spill !!  --oops, let's not use this!
But then I came to wonder the question/issue above,
about having one's tie-in force those two connecting parts
together, and how that might impede movement.

So, I shifted from the idea of hitch-into-eyeknot tactic
to eyeknot-into-eyeknot (getting structures much like
the mirrored bowline), which is fertile with solutions.


--dl*
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roo

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Re: Harness Tie In
« Reply #14 on: July 04, 2013, 10:05:40 PM »
The notion of 'no single point of failure' springs to mind here.
Since there are other "single points of failure", such as using only one rope (etc.), I think it maybe your sentiment might be more of a matter of "why use one when you can have two?".

Quote
This would induce a cinching action at the moment of impact in a free-fall arrest.
Cinching is part of just about any knot system.  The question becomes what part are you OK with having one part of rope/webbing stretch by other parts of rope/webbing during impact.

I'd probably be interested in trying both and seeing if the wear from bending/hitching directly to the belay loop would be more rapid than other knots in a rope-intertwined-with-rope scenario, as you'd see with a loop knot.  I suppose a hitch to carabiner to belay loop connection would avoid the issue if it turned out to produce a lot of wear.

It seems like there is a certain segment of users that distrusts the belay loop in general.  Whether that is justified or not, manufacturers might use beefier belay loops as a selling point for those people.

update: Cinching effects are not an issue:  http://igkt.net/sm/index.php?topic=6081.msg40871#msg40871

« Last Edit: February 02, 2018, 05:20:51 PM by roo »
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