The Impossible just happened: Omni Tiract opens and disconnects

[topcat]

Hi TC,

This is what I think happened: the lack of other SRT kit (only using cowstails) allowed the Omni to rotate,  placing the barrel sleeve within the loop of the harness.  Then my jiggling about (think constricted pitch head though I had loads of room) did the rest.

So ? would you infer that this wouldn't (couldn't?) happen if you were using a type of harness with metal D-rings rather than material ones?

This would make sense.
Another factor might be the size of the material loop.  My main harness is a Verona and the loops are much bulkier than the Avanti: much harder to clip when putting on, so harder to inadvertently unclip?  Not that I'm going to test that theory.

 

[ZombieCake]

Thinking aloud - tell me if I'm talking rubbish. Is it possible to over-engineer something to be so safe it becomes less safe because of the human ritual you have to go through?  Tightening something up with fingers or a spanner is easy under stressful conditions.  If you have to go through multiple steps it's perhaps easier to miss something or be under a false impression it's set right, 'cos it feels good and was expensive?  Not having a go at anyone or anything it's just that when when things get cold, wet, stressful, and motor skills start to go to pieces and there's more likelihood of things going pear-shaped.

 

[thomasr]

IN a multi task operation like dressing up in srt.  There is the danger of skipping through ie fitting the  D ring partially tightening up [or not tightening at all]  then going on to another stage.  With the OMNI / TRIAC at least the fail safe is a closed gate

 

[topcat]

IN a multi task operation like dressing up in srt.  There is the danger of skipping through ie fitting the  D ring partially tightening up [or not tightening at all]  then going on to another stage.  With the OMNI / TRIAC at least the fail safe is a closed gate

This is what I thought too, and why it was on my loaner kit for novices.
Now I'm going to use a mailon and a spanner for this but continue with screw Omni on my kit.

 

[andrewmcleod]

It's another reason I like the metal loops on my Fractio... The 'comfort belt' is a bit of a waste of time since it just loosens of but there are very few (2?) harnesses now with metal loops.

 

[Fulk]

Hi TC, do you make a habit of hanging your ass out over rocky streams while dangling from trees? 

 

[CavingPig]

So ? would you infer that this wouldn't (couldn't?) happen if you were using a type of harness with metal D-rings rather than material ones?

I use a Singing Rock Digger harness with metal attachment points. Last year I found myself halfway down a 120m pitch with a heavy tackle bag clipped on one side of my harness. This pulled things in such a way that the barrel of my CC Moka (equivalent to the Omni Triact) was pressed against the metal harness point and had completed action 1 and part of action 2 of the three-step opening process, leaving me with almost just a snaplink as my main attachment point    I poked it with my finger and the rest of action 2 (twist) was easily completed.

Did it up as best I could, proceeded to the next rebelay extremely carefully to calm down, then transferred the tackle bag to the other side of my harness so the weight of it pulled the barrel away from the metal attachment point. Maybe I just need to carry less tackle!

 

[alastairgott]

Last year I found myself halfway down a 120m pitch...
Maybe I just need to carry less tackle!

I bet you needed all the tackle you were carrying, if it was Austria, it sounds like all the gear is needed on the front line.

further up the topic yuvals posted a picture of (his or her) harness and I've got mine set up similarly, except I've got individual 5/6mm cord going from either side to a fig8. When I've got a bag, I'll clip it into both fig8 cords and I guess if my harness opens then this will keep it together?
It was mainly to keep the weight distributed either side of the package. And seems to work quite well in that respect.

 

[CavingPig]

Last year I found myself halfway down a 120m pitch...
Maybe I just need to carry less tackle!

I bet you needed all the tackle you were carrying, if it was Austria, it sounds like all the gear is needed on the front line.

further up the topic yuvals posted a picture of (his or her) harness and I've got mine set up similarly, except I've got individual 5/6mm cord going from either side to a fig8. When I've got a bag, I'll clip it into both fig8 cords and I guess if my harness opens then this will keep it together?
It was mainly to keep the weight distributed either side of the package. And seems to work quite well in that respect.

Yes, it was in Austria and we did need all of it... I seem to do quite a good job of often being assigned "the small bag, because you're a girl" - look inside and it contains a huge pile of metalwork and a drill and weighs about twice as much as the rope bags!  :

I quite like that extra cord idea, I will give that a go next time I'm somewhere tall and vertical. Thanks! (and to yuvals too for the picture)

 

[alastairgott]

There's some photo's of the setup in the "caving technical guide" from the French lot (FFS).

I could say something about size of bags, but it's probably best left unsaid.

I'd say metalwork and drill is probably more useful than rope what would they do without you.

 

[paul]

IN a multi task operation like dressing up in srt.  There is the danger of skipping through ie fitting the  D ring partially tightening up [or not tightening at all]  then going on to another stage.  With the OMNI / TRIAC at least the fail safe is a closed gate

This is what I thought too, and why it was on my loaner kit for novices.
Now I'm going to use a mailon and a spanner for this but continue with screw Omni on my kit.

Use a 7mm GO Maillon for connecting your safety link to the bottom of your main Maillon and you don't need a spanner as the 7mm Maillon fits perfectly.

 

[SamT]

Something I've always done...

as per Nigels vid here (5.35) https://www.youtube.com/watch?v=4SGsaYf2qB0

 

[topcat]

Hi TC, do you make a habit of hanging your ass out over rocky streams while dangling from trees?

Only recently, but occurring more often as I try to preserve the trees lining my burn.  I was 'limbing' the tree to put back the day that it inevitably falls over into the burn.  Thankfully the incident happened on my test run, without the chainsaw.  It could have been really desperate to have the harness fail with a live chainsaw in my hand.  I guess I'm just lucky

 

[IanWalker]

Use a 7mm GO Maillon for connecting your safety link to the bottom of your main Maillon and you don't need a spanner as the 7mm Maillon fits perfectly.

you don't mention type of harness so i'm presuming conventional petzl superavanti/fractio type cavers harness. my understanding is that attaching load bearing links (eg hand jammer safety cord) to BOTTOM of central maillon is not in accordance with the manufacturers instructions for either the maillon OR harness. i think its important that people considering this method are aware of this.

maillons are not intended to be loaded on the gate side. loading on the underside also puts the jammer attachment point below the harness attachment points, increasing the risk of being tipped upside-down in a fall/loading (which is already known to be a risk with the low attachment of cavers sit harnesses). would be interested in forum users' real-world experiences of loading and falling onto this setup - does it match or differ from these expectations?

lastly it seems unnecessary to me to clip the underside given that the safety cord with MR - or without - could just as easily be attached to the upper side of the central maillon as intended. i would be interested to hear your reasoning on this point.

 

[Fulk]

Only recently, but occurring more often as I try to preserve the trees lining my burn.

Thank you for that explanation.

And I agree with you, marysboy, that the best place to fit one's foot-loop-safety is on top of the D-ring.

 

[paul]

Use a 7mm GO Maillon for connecting your safety link to the bottom of your main Maillon and you don't need a spanner as the 7mm Maillon fits perfectly.

you don't mention type of harness so i'm presuming conventional petzl superavanti/fractio type cavers harness. my understanding is that attaching load bearing links (eg hand jammer safety cord) to BOTTOM of central maillon is not in accordance with the manufacturers instructions for either the maillon OR harness. i think its important that people considering this method are aware of this.

maillons are not intended to be loaded on the gate side. loading on the underside also puts the jammer attachment point below the harness attachment points, increasing the risk of being tipped upside-down in a fall/loading (which is already known to be a risk with the low attachment of cavers sit harnesses). would be interested in forum users' real-world experiences of loading and falling onto this setup - does it match or differ from these expectations?

lastly it seems unnecessary to me to clip the underside given that the safety cord with MR - or without - could just as easily be attached to the upper side of the central maillon as intended. i would be interested to hear your reasoning on this point.

Yes, I have been using Petzl Fractio type harnesses for many years (starting with Caving Supplies, then two Petzl Crolls (yes, it was called that), several Singing River Diggers and then several Petzl Fractios).

The reason I was given to connect the safety-link to the bottom of the man Maillon was two-fold: first was that it left the top section less cluttered already having cowstails, chest jammer and descender attachment karabiner and second, so that a 7mm GO Maillon could also be used to tighten the main Maillon (as covered by Nige in the video clip above).

If I have ever weighted the safety-link, the central Maillon has tended to twist so that the bottom rises in front and the top lowers behind and with the length of the 7mm Maillon means the height WRT the footloop is hardly changed.

 

[Damo]

I have used an Omni Triact for several years and found that they need to be kept clean and grit free to ensure safe use or they do tend to stick. I have come across at least one while doing PPE checks that when flicked shut it completely failed to snap into the locked position for this reason. This is just a way of checking the function of the hardware and I am not implying that it is acceptable practice to just snap it on and go. I am just pointing out that an Omni can stick.

Damo

 

[Chocolate fireguard]

Use a 7mm GO Maillon for connecting your safety link to the bottom of your main Maillon and you don't need a spanner as the 7mm Maillon fits perfectly.

you don't mention type of harness so i'm presuming conventional petzl superavanti/fractio type cavers harness. my understanding is that attaching load bearing links (eg hand jammer safety cord) to BOTTOM of central maillon is not in accordance with the manufacturers instructions for either the maillon OR harness. i think its important that people considering this method are aware of this.

maillons are not intended to be loaded on the gate side. loading on the underside also puts the jammer attachment point below the harness attachment points, increasing the risk of being tipped upside-down in a fall/loading (which is already known to be a risk with the low attachment of cavers sit harnesses). would be interested in forum users' real-world experiences of loading and falling onto this setup - does it match or differ from these expectations?

lastly it seems unnecessary to me to clip the underside given that the safety cord with MR - or without - could just as easily be attached to the upper side of the central maillon as intended. i would be interested to hear your reasoning on this point.

Yes, I have been using Petzl Fractio type harnesses for many years (starting with Caving Supplies, then two Petzl Crolls (yes, it was called that), several Singing River Diggers and then several Petzl Fractios).

The reason I was given to connect the safety-link to the bottom of the man Maillon was two-fold: first was that it left the top section less cluttered already having cowstails, chest jammer and descender attachment karabiner and second, so that a 7mm GO Maillon could also be used to tighten the main Maillon (as covered by Nige in the video clip above).

If I have ever weighted the safety-link, the central Maillon has tended to twist so that the bottom rises in front and the top lowers behind and with the length of the 7mm Maillon means the height WRT the footloop is hardly changed.

I'm not sure how relevant that last point is to the tipping upside down problem.

When suspended solely from the safety link what matters is whether an imaginary line continued downwards along the line of that link passes through the body above or below the person's centre of gravity.
If below it the person will tip upside down unless they do something to stop that happening.
The 7mm maillon will not change the direction of that line.
The twisting action described will, if anything, make matters worse because the bottom of the central maillon will move away from the body, so the undesirable turning moment is increased.

Even if the link is on the top bar of the central maillon the tipping problem is there, with the low attachment point of an efficient SRT harness, and of course the chest harness is there to stop you falling out of the harness when inverted.

When working near shaft tops most people wear a harness and cows tails so they can clip in, but some don't seem to use a chest harness.

So far as the points in the OP are concerned, I think Mark Wright's posts said it all.

 

[Chocolate fireguard]

Rereading my previous post I see that in the 4th line ?upside down? should be replaced by ?backwards?. :-[