Blake's Hitch Tether/PAS
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Wondering if a Blake's Hitch tether is a viable option as a tether (and not wondering whether a tether/PAS is necessary - there are instances where I would like a tether and would prefer to keep it on the simple side/not buy specialty gear). Compared to a Purcell, it's less bulky and gives more range in the sense that you'd be able to get much closer to the anchor. I'm mostly unsure because I haven't really seen a whole lot of literature from the climbing community about the Blake's Hitch, but arborists seem to use it. |
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Is this something you'd tie using the climbing rope? You're already Fig8'ed into that; you'd just need a longer tail (and a longer rope for those stretcher pitches. |
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It's hard for me to see what's going on here, not being familiar with it. But, if arborists use it, then it's probably a safe system. |
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That's an interesting idea and clever use of that hitch, but why do you need something like this? Using a clove hitch with the rope accomplishes everything that this does, and does not eat up all that extra rope. |
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I was envisioning it with 7mm cord as a replacement for a Purcell or PAS. t.farrell wrote:(and not wondering whether a tether/PAS is necessary - there are instances where I would like a tether and would prefer to keep it on the simple side/not buy specialty gear) |
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For a stand-alone tether/PAS, this looks like a lighter and less complicated alternative to the Purcell. I assume you would make it from 6 or 7mm cord (not climbing rope) with a Figure 8 on a Bight on both ends. The Fig 8 at the harness end could be intentionally long to girth-hitch to your harness and the other end lockered to an anchor. I don't typically use tethers, but if I did, I would try this. |
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Nick Sweeney wrote:That's an interesting idea and clever use of that hitch, but why do you need something like this? Using a clove hitch with the rope accomplishes everything that this does, and does not eat up all that extra rope.I'm not the OP, but one answer I have to that is there are a couple TR routes that I regularly set up that have anchors set back a ways from an edge. If I put a short tether to the anchors, I can't get to the edge to work on the masterpoint or see the ground at the base of the climb. And because I'm walking to set the TR, I'm not tied into the rope, and at some point, I'm tossing the rope over the edge, and would much prefer to not toss myself over the edge. So an adjustable tether is what would be preferred. TBH, most of the time, I pretty much just set up a equalette or a quad and let it self-equalize, or set a fixed line and a prussik to work on a cordalette. So now I pose another question to the OP: Why a Blake's hitch? Why not a tried-and-true Prussik? I assume you already have one on your harness as your hero loop/rappel third-hand. As people have already mentioned, if you're already tied in, just set a clove hitch. But, if you aren't tied in, and need a tether, then I guess you're effectively setting a fixed line and working from that, in which case I suggest just throwing a prussik on and closing the system. Or, clove hitch if you're not moving around too much. |
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Actually, now that I think about this more, I have another question. |
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It might be useful for cleaning sport climbs when the chains are high and a sling is too short/long. |
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I'll throw out my intended use since I'm sure some are curious. Part of my job includes photography, and some of the requests involve precarious situations (leaning off of ledges, etc.). Since I'm already carrying heavy photo stuff around, I'd prefer to have a light, minimal bulk system to keep me safe. I'm not going to throw a climbing rope in my pack which takes up a lot of space/weighs a lot and also don't want to buy more gear. This is the solution I came up with for an adjustable, minimal gear/cost, low bulk tether. That is the specific scenario I was thinking of but as others have pointed out there are other situations. |
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I don't think there is anything inherently unsafe about this Blake's hitch tether. I don't really think it would be all that less bulky than a Purcell prusik, but I can totally understand the advantage it has in its adjustability. ntlhui wrote:How well would a Blake's Hitch catch if tied from 7 mm cord onto a 7 mm line?Unlike most friction hitches the Blake's hitch is typically used to create an adjustable point on its own line. It works great for tent guy-lines! I don't see a problem with it being able to grip on itself, so long as you tie it with enough loops. One thing to keep in mind though, most of the time we use 6 & 7mm cord, we use it as a loop instead of a single strand. Depending on the situation, and how you plan on using this, I wouldn't feel very comfortable using anything smaller than 8mm. If you have or know someone with some retired ~9mm climbing rope, I think that would be ideal. The last thing I would worry about, and this is completely dependent on your situation, is what kind of exposure/ledge/fall potential are you dealing with? If this is something just to take your weight while you lean out of a window or something similar I'd say go for it. If there is a chance something could go wrong and you are freely hanging on this without any other means to get back to your anchor I would invest in something else that would allow you to travel up and down the line as needed, like a grigri and an ascender. Good luck dude! |
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t.farrell wrote:I'll throw out my intended use since I'm sure some are curious. Part of my job includes photography, and some of the requests involve precarious situations (leaning off of ledges, etc.). Since I'm already carrying heavy photo stuff around, I'd prefer to have a light, minimal bulk system to keep me safe. I'm not going to throw a climbing rope in my pack which takes up a lot of space/weighs a lot and also don't want to buy more gear. This is the solution I came up with for an adjustable, minimal gear/cost, low bulk tether. That is the specific scenario I was thinking of but as others have pointed out there are other situations. As to why I wouldn't just use a prussik/sling, I need something adjustable. Unless ntlhui was referring to a prussik on a tether cord, which is something I thought of but I don't really want to cut up my cord for a small prussik. Regarding falls/strength of the hitch, I have seen photos of a larger diameter blakes hitch on a smaller diameter line holding body weight. What I don't know is if it can hold a fall.Hmm. I understand your trepidation about carrying more gear. I do wonder, though, how much vertical exposure are you dealing with, and how much does this vary? Also, how much would this need to meet with any technical safety standards for work at height? As CrazyLegs said, if you are dealing with actual vertical terrain, you might want to look at other options that give you some self-rescue options. One thing about this as opposed to a Purcell tether is, if you slip and grab at the Blake's hitch, you defeat the hitch, whereas if you grab the hitch on the Purcell, you don't defeat the hitch (if the adjustable loop is attached to your anchor). This might be a safety issue if you are dealing with significant vertical exposure. Also, how long are you making your tether? If it's any more than a meter or so, why not use a fixed static and a prusik loop? For one, you wouldn't have a huge loop hanging off your harness if you adjusted the tether short, and you also now have the freedom to use the rope for as big a tether as you want, with the ability to switch to an ascent or descent system as you feel. |
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Here is a commercially available tether for caving that is the same set up. This is made with static rope, but you could make your own with dynamic if it is something you were worried about. |
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ntlhui wrote: I'm not the OP, but one answer I have to that is there are a couple TR routes that I regularly set up that have anchors set back a ways from an edge. If I put a short tether to the anchors, I can't get to the edge to work on the masterpoint or see the ground at the base of the climb. And because I'm walking to set the TR, I'm not tied into the rope, and at some point, I'm tossing the rope over the edge, and would much prefer to not toss myself over the edge. So an adjustable tether is what would be preferred. TBH, most of the time, I pretty much just set up a equalette or a quad and let it self-equalize, or set a fixed line and a prussik to work on a cordalette. So now I pose another question to the OP: Why a Blake's hitch? Why not a tried-and-true Prussik? I assume you already have one on your harness as your hero loop/rappel third-hand. As people have already mentioned, if you're already tied in, just set a clove hitch. But, if you aren't tied in, and need a tether, then I guess you're effectively setting a fixed line and working from that, in which case I suggest just throwing a prussik on and closing the system. Or, clove hitch if you're not moving around too much.If I'm worried about that, I will usually take my cordalette, figure 8 on the bight on the end, and tie a munter hitch on a carabiner clipped to my belay loop. Self belay myself to the edge, mule off, do my work. When I'm ready to come back in, I can do that too. |
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I've used a pair of Blake's hitches for my PAS in the past. With this setup, it gives me a rather large range of adjustability for the tethers, and I can set each one to a different length. I've had no issues with the hitches slipping, and with the extra barrel knots on each end, it's a closed system around the two lockers (aka if it slipped, it would still be connected to the locker). |
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Reviving this thread to ask about something with Blake's Hitch/friction hitches in general. |
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Brandon.Phillips wrote:Here is a commercially available tether for caving that is the same set up. This is made with static rope, but you could make your own with dynamic if it is something you were worried about. onrope1.com/store/index.php…That device looks as if it has the same (in my opinion significant) drawback as the Purcell prusik, which is that you can only adjust from full length to half length. All friction-hitch based systems have another drawback that I think would be considerable for photography, and that is that you can't adjust them while they are weighted or even partially weighted. Once the knot has set, you have to fully unweight it (and possible fiddle around a bit to get it loosened) in order to move it. If you are really hanging from the tether, this means holding a kind of one-arm lock-off with one hand while you struggle to loosen and move the knot with the other hand. Meanwhile, your shot is long gone... Sorry to go commercial on the OP, but for your purposes, I think you want an adjustable daisy for actual positioning and maybe a second PAS type tether (which you could tie yourself) as a backup. The new Petzl Connect would work very well and is a dynamic connection, but is very expensive for what you get. While you are at it, I'd put more turns into that Blake's hitch. A standard prusik has four weighted turns. Many of the Purcell's used by rescue folks use a three-over-two prusik, which is five weighted turns. I don't think two or three weighted turns has enough safety margin. As for that loop through the Blake's hitch, I wouldn't do it. When loaded, something like that could loosen the knot. It would be safer, I think, to leave a much longer tail and tie than into a grab-handle loop. |
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Yeah I think I was just trying to figure out a way to make my own form of that Petzl Connect as paying $50 for something like that seems absurd. |
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t.farrell wrote:Yeah I think I was just trying to figure out a way to make my own form of that Petzl Connect as paying $50 for something like that seems absurd. Thanks for the input on the loop. I have played around with it. So far it's working okay. Weighting of the hitch isn't as big of an issue as you'd think, but yes still problematic...At some point I should probably give up on being cheaplook into the kong slyde. It offers a cheaper way to make the petzl connect if you already have a length of cord to use |
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Years ago I used the Blake's hitch for a number of years. The OP's picture is a good way to make a totally adjustable lanyard. The Purcell is too limited on how close you can get to the anchor. |
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eli poss wrote: look into the kong slyde. It offers a cheaper way to make the petzl connect if you already have a length of cord to useI´d just use a Garda hitch (Alpine Clutch) anyway:-) |