Vertical Rigging....Can you see what I see?

[ProgressiveRescue]

I fully admit I am a bit anal when it comes to rigging operations and how they're done.I came across this pic and I wanted to throw it out there to see if anyone else has the same or a similar thought process on rigging for a vertical operation. This question and pic pertain to a confined space entry. I'm not going to say what I think is wrong with this pic...that would be a spoiler, I'm going to wait until there are a few posts.
I'm not saying this pic is necessarily wrong...I love the redundancy in the actual anchor system it's the rigging that I'm having problems with. I'm throwing this out to you because I know there are some great rope guys in this forum and I'd love your two cents.
Mike Donahue
[IMG]

Uploaded with ImageShack.us[/IMG]

[jdcalamia]

Looks like the MA and belay lines are sharing the anchor. As well as the double sheave pulley on the left appears to have two separate belay lines through it. I know in a lot of places this is common practice especially in a confined space evolution due to the limitations on space, etc...Realistically at the least a separate anchor strap/rope and rigging plate for the belays. Also no sharing of the pulleys (single pulleys for each belay). If there was room enough for one anchor rope in this situation, then then should be room enough for a separate anchor rope/strap for the belays. Assuming they are bombed off we can use this bomb proof anchor for our MA and Belay. The bomb proof anchor won't be subject to failure, however everything past the anchor in the system is subject to failure. I do like the redundancy in the rope attached to the rigging plate. assuming the side we can't see is secured in the same or similar manner. If one side fails the other side will pick up the load, at least long enough to safely restore the system. Same principle as a two-point load sharing anchor with webbing crossed and a biner clipped through the "X" of the webbing.

[ADSNWFLD]

I would like to learn more about this set up. Off the cuff, I think I would use butterflys over the in line 8's. Any other pictures?

[servantleader]

Primary safety issue: main line and belay share the same anchor.

Assuming that the primary anchor (whatever that red rope is attached to) is bombproof, I'd prefer two separate slings on that anchor: one for the main line and one for the belay. Maybe a "football knot" setup would work nicely...

[jdcalamia]

Servant can you elaborate a little more on the "football" knot, I'm not familiar with this.

[servantleader]

Servant can you elaborate a little more on the "football" knot, I'm not familiar with this.

- Take a section of cord or rope (8, 9, 11, 12.5 mm) of sufficient length
- fold it into four equal length sections
- put all four sections around a BOMBPROOF anchor
- tie off into a closed loop with an appropriate bend

You'll have four independent loops of rope around the anchor. Use two loops for the main line and two for the belay. I think it's called the football knot because the bulky knot that results from the bend looks like a football.

It looks like two I-beams are possibly being used for the anchor. The entire football knot setup could be wrapped around both I-beams. Maybe.

A photo is attached (I hope).

I also noticed that the tensionless tie-off lacks padding between the rope and the I-beam. Can't tell how smooth the the edges of I-beam are...

[ProgressiveRescue]

Looks like the MA and belay lines are sharing the anchor. As well as the double sheave pulley on the left appears to have two separate belay lines through it. I know in a lot of places this is common practice especially in a confined space evolution due to the limitations on space, etc...Realistically at the least a separate anchor strap/rope and rigging plate for the belays. Also no sharing of the pulleys (single pulleys for each belay). If there was room enough for one anchor rope in this situation, then then should be room enough for a separate anchor rope/strap for the belays. Assuming they are bombed off we can use this bomb proof anchor for our MA and Belay. The bomb proof anchor won't be subject to failure, however everything past the anchor in the system is subject to failure. I do like the redundancy in the rope attached to the rigging plate. assuming the side we can't see is secured in the same or similar manner. If one side fails the other side will pick up the load, at least long enough to safely restore the system. Same principle as a two-point load sharing anchor with webbing crossed and a biner clipped through the "X" of the webbing.

John,
I couldn't ask for a better response. Granted this rigging configuration may not me technically wrong, It shows that there was "no what if"or redundancy thought about prior and during the construction of this system.
Having belays attached to the same anchor point sharing a double pulley really defeats the purpose and ignores the concept of independent lines and safety systems. I'm a big fan of every rope having its own home rather than sharing a connection point. Rope and webbing really don't take up much space so even in a tight spot we can achieve separate independent connections.
ADSNWFLD also had a great point. Butterfly knots would be a better choice here. Should one connection point to the plate fail the directional eight on the opposite side wouldn't be loaded in the best possible position. The knot would actually load and pull back from itself. Butterflies would surely fix that problem.
I think this is a case of putting all your eggs in one basket. If there is anyone new to the world of rope rescue reading this and has any questions about whats going on in this thread please post a question. I guarantee you'll get a great answer.
Thanks,
Mike

[servantleader]

Also, if one side fails the other side will certainly take the load, but the whole anchor will take a huge swing and end up hanging from one I-beam way off to the side of the original fall line.

[EricUlner]

-I'd choose from the very large family of bowline knots. Personal preference. They're certainly easier to untie.
-Did you intend for the jumper between to be under tension? It is...
-The single overhand knot tied secondarily to the 8 (upper left) doesn't do much of anything other than eat up a bit of the unnecessarily long tail. Single overhands don't stay tight. Doubles do. Further, with figure 8 family knots on a bight (overhand, 8, 9, 10, etc.), the secondary knot doesn't do much. They serve their purpose on the follow-through tied.
-Single rope in a double sheave pulley creates inner plate rub. It works, but it's not clean.
-Same rope is torquing the same pulley is torquing the 'biner is torquing on plate hole.
-Belay rope(s) through pulley? Friction is your friend in a belay rope.
-Belay system isn't parallel above the belay 'biner. If this rig is for training, it wouldn't pass for my team.

[GTRider245]

Kind of on topic, but when would you prefer the inline 8 over a butterfly? I agree with the suggestion of using a butterfly, but I have found through limited expirience that the butterfly ends up being the choice between the two, not only for greater versatility, but it seems easier to tie for new people to learn.

[jdcalamia]

GT, when you can guarantee the direction of the load will not change an inline 8 will suffice. Basically, if the load is pulling the same way the loop is facing like in a straight up and down orientation without sway or deviation, or pulling a litter in a low slope evac. Anytime the load has a potential to change direction either on purpose or otherwise use a butterfly. It's a multi-directional knot that will maintain it's strength no matter what direction the attached load changes in. As far as ease of tying, practice makes it a non-issue. Either knot requires just about the same amount of rope, and the differences in tying are minute. Stay safe.

[FiremanLyman]

fully admit I am a bit anal when it comes to rigging operations and how they're done.I came across this pic and I wanted to throw it out there to see if anyone else has the same or a similar thought process on rigging for a vertical operation. This question and pic pertain to a confined space entry.

Good topic, great discussion. It is refreshing to see a confined space set up that is not using a tripod, back to the patient packaging discussion we must be proficient at adapting to what the scenario presents.

Looks like the MA and belay lines are sharing the anchor. As well as the double sheave pulley on the left appears to have two separate belay lines through it. I know in a lot of places this is common practice especially in a confined space evolution due to the limitations on space, etc...Realistically at the least a separate anchor strap/rope and rigging plate for the belays. Also no sharing of the pulleys (single pulleys for each belay).

Needs to have a separate attachment. Running a second mirrored set up for the belay line would not be difficult (given you have the equipment, something that might have been a scenario constraint, we don't know. This could explain why they also ran both belays in a double pulley?)

-Did you intend for the jumper between to be under tension? It is...

Yeah, looking at it closer it might have multi-directional loaded the directional 8s.

-Belay rope(s) through pulley? Friction is your friend in a belay rope.

Think this is a change of direction, with a dcd/friction device located somewhere else. Putting it through say a carabiner would put a nasty bend in the rope if it loaded.

[EricUlner]

Skip the pulleys in the belay redirect and use double 'biners. Reduces the total load against both the redirect anchor and the belay below per friction gain. Increased wear against the rope is a non-issue for me.

[rescuedylan]

Seems as thou there is alot going on in a very small spot by just using the one rigging plate. I might have tried to have placed a second anchor in behind the one in the pic to have cleaned it up a little. If I was going to have used the in line eights ( I would have gone with the butterfly) I would have gone with using the in line nine. Concidering that it is being used as the anchor knot there is going to be full weight on that point, and when placing this on angles this is increased (not saying the angle here is bad but does add to force on the knot). Dont want to say anything about if there is a LRH in the system seeing how we dont know whats going on in the pic where we cant see. We can see that the anchor is a beam with skechy corners on it, try using your edge protection in that area. Again cant see all that is going on and dont know what the situation was here so im not judging.

[ProgressiveRescue]

Skip the pulleys in the belay redirect and use double 'biners. Reduces the total load against both the redirect anchor and the belay below per friction gain. Increased wear against the rope is a non-issue for me.

Can you explain your answer better? If you replace the pulleys with beaners and are forced to piggyback onto the belay for emergency egress purposes you're going to pick up a lot of unwanted friction. Also...maybe I'm misunderstanding what you're saying but how is replacing the pulleys with beaners going to reduce the load?
Thanks,
Mike Donahue

[EricUlner]

Can you explain your answer better? If you replace the pulleys with beaners and are forced to piggyback onto the belay for emergency egress purposes you're going to pick up a lot of unwanted friction. Also...maybe I'm misunderstanding what you're saying but how is replacing the pulleys with beaners going to reduce the load?
Thanks,
Mike Donahue

The side of the belay rope going from the redirect pulley to the belay has greater strain energy in it because of the pulley's efficiency. Say at 90% efficiency for the pulley, the redirect anchor will be taking 1.9 units on tension- 1 unit on the load side and 0.9 unit on the belay side. Therefore, the anchor holding that pulley is feeling more load than with less efficient pulley. An inefficient pulley- i.e. carabiners- won't allow as much strain energy to be in the strand of rope going down to the belay. With carabiners being in the 50ish % range of efficiency, the redirect anchor will instead feel around 1.5 units of tension, and the belay around 0.4 less units of tension. All of those units of tension I mention would of course be in some form of dynamic impact, should the belay actually engage.

As for your concern about having to gang onto the belay rope- I don't have the big picture regarding this particular set-up because you hadn't provided that. My comments were aimed at the zoomed-in image you provided only. If I could see the rest of the scene, I have a feeling that I'd probably not set up like that anyway with the 2X1 anchorage. Probably would use an offset, like a dynamic deflection coming in from somewhere else in order to make it easier for the rescuer to get into position on the system.

[ProgressiveRescue]

The side of the belay rope going from the redirect pulley to the belay has greater strain energy in it because of the pulley's efficiency. Say at 90% efficiency for the pulley, the redirect anchor will be taking 1.9 units on tension- 1 unit on the load side and 0.9 unit on the belay side. Therefore, the anchor holding that pulley is feeling more load than with less efficient pulley. An inefficient pulley- i.e. carabiners- won't allow as much strain energy to be in the strand of rope going down to the belay. With carabiners being in the 50ish % range of efficiency, the redirect anchor will instead feel around 1.5 units of tension, and the belay around 0.4 less units of tension. All of those units of tension I mention would of course be in some form of dynamic impact, should the belay actually engage.

As for your concern about having to gang onto the belay rope- I don't have the big picture regarding this particular set-up because you hadn't provided that. My comments were aimed at the zoomed-in image you provided only. If I could see the rest of the scene, I have a feeling that I'd probably not set up like that anyway with the 2X1 anchorage. Probably would use an offset, like a dynamic deflection coming in from somewhere else in order to make it easier for the rescuer to get into position on the system.

Eric,
I can't say I agree with your thoughts simply based on the fact that in a Technical Rescue operation (this one being confined space) I want the most bang for my buck regarding my MAS and any rope that has the possibility of being introduced to one (belay line) Using carabiners as directional pulleys just creates to much friction for me in a system. I'm not overly concerned about impact forces on a belay catch simply because the belay devices we use today (540, I'D, ) have such a minuet slippage of rope the adverse effects on the rescuer or victim would be minimal if any.
I'm not saying your thought process is wrong I just choose not to use pulleys in an application where their inefficiency will effect the efficiency of my hauling operation. I do believe there's a time and place for everything and if a rigging operation calls for a carabiner redirect for some reason....of course I'd use it.
Thanks
Mike Donahue

[rescuedylan]

Mike, do you by any chance know what kind of confind space this was? Or maybe have more pics/information from this? It is a little difficult to critique some of this without more of the picture. Im not a big fan of the angles of the anchor, but again not sure how much space they had to work with from anchor to hole/ walkway/ drop off. Are we assuming that they are working off a walkway or are they going into a pipe? Both are confind spaces in the enviorment they appear to be at, but still hard to know.

[EricUlner]

Eric,
I can't say I agree with your thoughts simply based on the fact that in a Technical Rescue operation (this one being confined space) I want the most bang for my buck regarding my MAS and any rope that has the possibility of being introduced to one (belay line) Using carabiners as directional pulleys just creates to much friction for me in a system. I'm not overly concerned about impact forces on a belay catch simply because the belay devices we use today (540, I'D, ) have such a minuet slippage of rope the adverse effects on the rescuer or victim would be minimal if any.
I'm not saying your thought process is wrong I just choose not to use pulleys in an application where their inefficiency will effect the efficiency of my hauling operation. I do believe there's a time and place for everything and if a rigging operation calls for a carabiner redirect for some reason....of course I'd use it.
Thanks
Mike Donahue

No offense meant here Mike, but it seems to me that your take on this is that you've only one type of "wrench in your toolbox" to fix the problem if the belay were to be engaged- that being start hauling on the belay line as is. There are far to many variables per operation to have an internet conversation of well what would you do then if... Suffice it to say that carabiner friction can be dealt with rapidly if need be.
Reduced forces in the belay system can and will reduce fall distance. The rope slippage at the belay device is definitely not the only contributing factor to fall distance. Many other points in the system that give. Unnecessarily increasing forces at the redirect and beyond may make the difference in your rescuer's ankles or more.

[ProgressiveRescue]

No offense meant here Mike, but it seems to me that your take on this is that you've only one type of "wrench in your toolbox" to fix the problem if the belay were to be engaged- that being start hauling on the belay line as is. There are far to many variables per operation to have an internet conversation of well what would you do then if... Suffice it to say that carabiner friction can be dealt with rapidly if need be.
Reduced forces in the belay system can and will reduce fall distance. The rope slippage at the belay device is definitely not the only contributing factor to fall distance. Many other points in the system that give. Unnecessarily increasing forces at the redirect and beyond may make the difference in your rescuer's ankles or more.

Eric,
Your right this is a conversation that really has to many variables to have online. I definitely think some points of view have been lost along the way. All in all I'd say this topic did however create some great conversation.
Sta Safe,
Mike