Basic Highline System with Pulleys, Rope and Pulley Systems for High Angle Technical Rescue
We have the tensioning system. This part of the track line. The track line is a rope that our carriage is going to be going on. It’s the highway for the same one across the canyon here. This basic track line consists of a three to one tensioning system. One of the key factors of a Highline is we don’t want to over tension this thing. The less amount of tension we can have on the Highline, probably the happier all of our anchors are and the less likely we are to fail something.
There’s a lot of ways to figure out the tensioning, but this is real simple. I look at the distance across. So, say I have 100 feet going across this canyon. I’m going to multiply my load times that distance. So, if it’s 100 feet across and I have a 400 pound two-person load, that’d be 40,000. I’m going to divide that number by the needed deflection. Basically, that span going across whatever that sag is in the middle, that is my deflection. Rule of thumb, I would like one rope, one 11 millimeter rope here. I would like that to sag 10% of that distance.
So, I’m going to divide that 40,000 number by four times that needed deflection, which is 40. 40 into 40,000 is about a thousand pounds. That right there tells me I have roughly a thousand pound hit based on a 400 pound load, 10% deflection. I have about a thousand-pound hit on this anchor.
After I get my tensioning the way I like it, you’ll notice there’s only this single Prusik that’s holding the entire load. A lot of people like using Tandem Prusiks here, and maybe that’s advisable if this is the terminal end.
What I would like to do after we get the tensioning completed and where we like it, we’ll come right off the back into this pulley, take a bite, and we’ll tie it off to the anchor. I’m going to go through this eyelid of the load cell, and I’m going to dog it off with a couple of [inaudible 00:02:47] pitches.
I have somewhat of a clutch here. If we had a shock load, we’d have some slippage here and it would ease onto this knot.
Let’s talk a little bit about the control line. The control line does a couple of things for us. It controls the movement back and forth of the load across our span here. And it controls the movement of that carriage system. There’s a lot of devices that we can use for a friction control, or when we have to convert to a haul system to come back this way, a number of things could be done. It’s probably somewhat new and a little unconventional using a Petzl ID for a Highline. Traditionally, it seems like we’ve used brake racks a lot. And then we would have brake racks bypassed with Tandem Prusiks. So, it’s doubling as a main line, but it’s also our belay line as well.
So, it’s kind of a working belay. We call it the control line. As opposed to using Prusik’s shock absorbers, we have a stitched shock absorber. This is a manufacturer’s shock absorber made by Yates and it deploys it at two kilonewtons or around four… I’m sorry, 500 pounds.
And as the backup, we have this doubled up Prusik loop. Okay? So, this will deploy and it will ease the load onto the Prusik loop. If indeed we had a catastrophic failure of the main line or of the track line and we loaded the control line. Okay? So, this is a way for us to control the shock absorption of this system if we did have a catastrophic event.
What we’re looking at right now is a floating A-frame. You can see it’s an A-frame, but you notice there’s no back-tying to it. There’s no other real structural support like you might expect on an A-frame. But what is back-tying this? Well, it is the track line itself. This track line is under tension, quite a bit of tension. More than enough to support this A-frame. So, what’s holding this in place is opposing Prusiks. So, this Prusik is pulling in this direction. This Prusik is pulling in the opposite direction. With both of them connected to the head pulling opposite directions, you can see that this is…, in essence, it’s back-tied into place, and it will not move. Very secure. I can really rack on this thing and I’m not getting a lot of movement. What it does, it affords us a landing zone for our deployment and retrieval of a rescue package, if you will.
If we look at this angle, note this right here, this angle on top of this pulley right here. This angle is so minor there’s really not that much on this. There’s not a lot of stress on this floating A-frame right now for when the load comes back up over this lip, we have to have an elevated point, and this is what the A-frame provides us. Could we use something else like a tripod or a sideways A-frame? Absolutely, we could. This is a convenient use of your track line. It’s kind of doubling as my tensioning system for this A-frame.
I never really connect these Prusiks to the pulley itself because it tends to want to move a little bit more. The opposing Prusiks have to go directly to the head, separate from the pulley itself. You may ask, what this is? Well, it’s an AZTEK, a set of fours. We’re using this as a way of controlling the height of our control line. So, I can lower this down or if I want to clear the edge, or what have you, once my load is deployed or my rescue packages is deployed over the edge, we can bring it back up into place.
We could also put a pulley here if we wanted to. There’s such a minor hit on this, it’s just going to the carabiner right now.
Right now, we’re just looking at some of the concepts right here. Track line, control line and here we have our shock absorption. We are bypassing these knots so to speak. These knots, we don’t want to have the hit. We don’t want the knots to be part of the equation of the degradation of this rope. And the way we address that is by putting these shock absorbers in. We’ve traditionally rigged quite a bit with Prusiks- Prusik bypasses. And again, we’re using the 8-Shorty. We can use these as singles. We can put them in tandem for larger loads, larger ratings.
It’s almost like it’s a poor man’s load cell. If we’re starting to pop the stitches on this, we’re probably overloading the system in the first place. In the event that we had a failure of the track line, remember the control line is what’s going to save the load from cratering. These would deploy, the stitches would pop, and we would, in a controlled manner, load these knots. They wouldn’t have a shock load to the knots. Hence, we would save the load.
We have a Directional 8 with a jumper going to a butterfly. Note that the butterfly is on the spine of the carabiner. We want that. If it did have to load, we don’t want it to be hooked up on the gate and we want it to be able to freely slide on the carabiner. This is a mirror image on this side over here. Directional 8 going to that side and a butterfly right here.
There’s probably other knots that would be appropriate for these applications. This is what we chose to use right here. This Directional 8’s pulling this direction, this Directional 8’s tied to pull in that direction, interfaced with the stitched shock absorbers.
There’s a lot of ways we can connect our victim-rescue-adjunct to this pulley system up here. What we chose to do to highlight right here is a litter basket, and we have our rescue Randy in the litter basket. Connected to it though, interfaced with it is a set of fours. Here’s an AZTEK again that allows some movement up and down of this litter basket. Most likely there’s an attendant in this package right here, but it works pretty handy for short reeves. So, I’m able to reeve up and down. It might be the type of deal where we come up over an edge when we’re coming back to home base, so to speak, and we have to lower the victim down to the deck. This comes in very handy for something like that. So, it’s good for short reeves. It’s not for the bigger ones that we’ll be addressing later.
For a backup, we just use the other end of the AZTEK. We use the travel-restrict end. We have the shock absorber going to our mannequin here. We can also provide a second point of contact going to the Kootenay Carriage, but also encompassing the control line. Notice that this is all going through these two carabiners. So, there’s some redundancy rigged into this system right here.
What we’re looking at now is a floating gin pole. If you remember, on the other side, we talked about the floating A-frame. So, this is the third leg of the tripod. And you can see it’s the TerrAdaptor that we’re using right now. And so that’s the common practice with us. We may use half of it for an A-frame on one side and the other half is a gin pole on the other side. In the floating A-frame that we saw on the other side, we refer to this as a floating high directional as well.
We have the back-ties or the guying system side to side in the form of the AZTEKs. Front and back, you can see once again, we’re using these opposing Prusiks. We have an opposing Prusik to the front and an opposing Prusik to the back. All this is lined up. The Prusiks go to separate connection points, as opposed to going directly to the pulley. If it went to the pulley, you would see some side to side movement on this gin pole. Right now, very solid high directional. And as we talked about before, with the A-frame, this allows us a landing zone.
We’re looking at our final stage of this basic Highline. In quick review, we had the control side over there, which went through a floating A-frame, went through a floating gin pole. We talked about the carriage system. Right now, we’re looking at the opposite side of this system.
One of the key factors is taking all the knots out of the track line. When we talk about a Highline, we’re talking about a system that is under substantial tension, much more than you would find with a normal rope rescue system. So, it’s critical that we take all excessive bending out of the fibers of this rope, which means we want to eliminate the knots. A good way to do this on the terminal end is using a tensionless hitch. High strength tie off…, a form of a high string tie off. Sometimes it’s referred to as what the no-knot. Notice that when the knot, and this is a Boleyn with the Yosemite backup, notice that this is just tight enough to where it’s really secured back onto this rope, but there’s nothing on that knot that’s not part of the system.
We have a no-knot system here. It’s going around. It’s been used up. The friction is being used up and controlling this tension with the wraps around this tree. The larger the anchor, the less number of wraps we have. There’s a misconception that when you tie a tensionless hitch that you have to have a minimum of six wraps. People have had that drummed into their head that you have to have six wraps every time. That’s not the case. You just need enough wraps to take the knot out of the system.
One thing I like to see is controlling this slack on this last loop right here. A lot of people will do the six wraps. That’s fine. They’re doing six wraps on this thing, but then they will have the sloppy loop that comes back up. Maybe they’re connecting it with a carabiner. It’s probably a waste of a carabiner.
They have this slack that’s taking place here. What does that slack want to go? Eventually, over the course of the operation, I have seen that slack start moving around. Maybe people are adjusting the line. Maybe you have multiple evolutions of this Highline system. You’ll see that slack start to work its way back around. Even if there is six turns on it, you’ll see that slack start working this way round. So, what we’re doing here is a couple of things. We’re gaining more rope because we’re not wasting it around a bunch of wraps on this thing. We only have just the number of wraps needed to take the knot out of the system. And the last leg, we’re controlling the slack going back to the host rope by keeping it really kind of nice and tight without really loading it. It’s not loaded. We’re managing this slack has likely to work its way back around the anchor.
This is a job well done in my opinion. The control line is literally a mirror image of what we have on the other side. We have the ID with the shock absorber interface with the back anchor. You see a Wrap 3, Pull 2. You have a basket hitch with the system, Prusik. In other words, a basket…, a Prusik that’s been doubled up. Very strong. It meets our static safety system factor quite well within this Highline system. The ID is quick to release. We’ve done a lot of testing on this and we feel very comfortable that this is a good belay device, especially in the application it’s being used and in conjunction with the shock absorber. It can quickly be transformed to a haul system. I’m not as concerned… I know this is not as efficient as we would like it to be, as we would have a pulley system. The ID is not a pulley so there’s some inefficiency here.
But we have a horizontal Highline as such, we’re pulling horizontally. We’re not pulling up a cliff. If I was going totally vertical with this thing, I would probably do something else and probably eliminate the use of the ID in my hall system because I want more efficiency. But for this application here, it’s pretty easy to turn this into a three to one. Now we’re pulling this direction. If we want to release, go back the other way. Now we’re back into the lowering mode on this side.
Peace on your Days