How NOT 2 Rig
Anchors
Redundancy is the name of the game in every part of rope swinging. Your anchors will see around 8kN in most jumps, 16kN if you are being naughty. So they also need to be strong. Those are the two really important ones.
If you are using bolts, and especially if you are using trad gear, it needs to be equalized enough. If you can avoid any extension if a single anchor point fails, that's just bonus points.
The short answer to all this is a 3-point BFK, assuming you have 3 anchor points with a minimum of 8mm rope. This photo equalizes enough, is redundant in
cluding the loops you attach things too, and is about 40kn strong.
A 2 point bfk needs to have much more than an 8mm rope because your tiny ass knot that makes isn't going to be stronger than your span. You can see in
this episode how something that looks similar to a BFK could kill you in a rope swing. If you have two really good bolts, and that's it, consider doing a sliding X with 3x 22kN slings. They are 40kn EACH in that configuration and you get redundancy if you use a wad of them.
Apocalyptic backups are when everything else fails, something else will catch. Rig like you have no backups, but it's not a bad idea to have a ultimate oh shit thing that could catch. This could be a single strand going to a tree 50 feet back or a bolt off to the side. It will likely not be strong enough or get cut in the process and you'll still die, but it's nice to have. Remember, only one anchor needs to break for you to die so do them both like your life depends on it.
Here's a food pyramid but for strength: you want your bolts stronger than your anchor rope which is stronger than your span, which is stronger than your jump ropes which is stronger than your harness which is stronger than your back. You want to be the weakest link in your rig.
Span
Don't let this rub on the edge. Good, I'm glad we got that out of the way. Please don't watch the first video I ever made because it's embarrassing but it's such an important topic that it's the cornerstone of all the rigging videos on the channel.
Don't let this rub on the edge. Good, I'm glad we got that out of the way. Please don't watch the first video I ever made because it's embarrassing but it's such an important topic that it's the cornerstone of all the rigging videos on the channel.
Webbing: If you use highline webbing, it's often times 30kn strong, it can be gripped with a linegrip and tensioned into a weblock retaining most of its strength. You can travel across it with a lineslide and put sewn loops terminating at the fulcrum. The downside is that if you are trying to stabilize a free-floating fulcrum, prusiks don't do as well on flat webbing that is tight
Too much of a good thing is bad: This episode has 7 lines going across to exaggerate a point but what was learned is the webbings rub on each other in a way that isn't good for them and unless you have a large enough sliding pulley, you can't travel across it... it's too thick! When you have a rope backing up 2 webbings for tri-dundancy and the rope gets wrapped around all the webbing, it actually risks cutting it.
Ropes: A 10.0 semistatic rope is about 18kn in a figure 8. If you tie figure 8s to terminate things, good luck untying them. Traveling across a rope span is less ideal but a Kootenay works. Ropes have sheathes so they do handle wear better than webbing. If you just tension it with a grigri and an ascender, and leave it in the grigri, it's not getting very much strength. They slip around 6kN and if you put a knot behind it, it can twerk it weird and explode the device. Not likely to happen but that is the ultimate failure of that scenario.
