Well Balanced Physics

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Backup Loops are Aid (and that is OK)

Posted on 21 Sep, 2021
Tagged highline, inventions

Backup loops are aid. Aid loops. Everyone who uses them is an aid-liner, and there is nothing wrong with that! But, let's be honest with ourselves that it is aid, and think about the implications of that. The real question should be: are we using the right kind of aid?

Aid loops are brilliant and insidious because they are such an efficient use of existing material. Before aid loops became a thing, everyone was, of course, already using a backup line, but it mostly just sat there and made the line harder to walk without noticeably saving your life at all on most days. As people slowly discovered that loose lines with draping loops in the backup are actually easier to walk, it was the most natural thing in the world to start rigging that way, adding stability with a tool already at hand. Never mind that doing so compromises the original purpose of the backup; everyone wants to send.

The point is, would slackliners have accepted aid loops if the material for them wasn't already there, in the form of a backup? I think not, at least not at first. If backups didn't exist and somebody was like, "I'm going to bring an entire second rig's worth of material, just to make this line easier to walk", would anyone have treated that as a legit send style? My guess is no, but since the backup was already there, it didn't seem like such a contrived thing. Just a small rigging adjustment, and all of a sudden everyone is sending 300m, 1000m, 2000m. Did people get that much better at slacklining in 2014? I don't think so.

slackline records
Highline length records over time.
Note the discontinuity in 2013-2014 when aid loops started becoming ubiquitous.

Look, I'll be honest: I hate aid loops. They are annoying to walk on when they get wrapped around the line, which they always do, and they look terrible. Worst of all, and this should really be the only reason needed, they make the line less safe.

But let me also be real: I'm addicted to aid loops just like everybody else. I've tried to go back to tight backups, to make the lines safer and to show up the kids with some old school style, but the reality is that walking big lines with a tight backup is just stressful. The crowds are right: highlines are more fun with some aid. As much as I might like to do it, convincing people to stop using highline aid would be an uphill battle. I can't even convince myself to go back to the way things were.

Instead, I've been thinking about what other kinds of slackline aid we could come up with. The acceptance of aid for highlines came in through the back door via backups, but now that it is here, we don't have to be so limited. The difference between a 300m line being a world record or a commonplace send is the crowd sourced engineering breakthrough of aid loops made from the already existing backup. The aid loop era started only a handful of years ago. More recently, segmented lines showed up, another engineering advance that helps to recover some of the safety margin that gets lost when lines get huge and backups get co-opted to be aid loops. My question is, what comes next? We don't have to stop now with current rigging practices, and I wonder if more openly acknowledging that the accepted style is a type of aid can help stir up more ideas.

I have lots of ideas. Probably most of them are terrible, but I like to try some of them out just in case. I'll share one here that I tested recently, and I'll post more if people seem interested.

For the last few years I've been more inspired by big waterlines than big highlines. I've been thinking about how the aid mentality that is so successful in highlining could be brought to waterlines. Can we make waterlines more fun and sendable with a little clever rigging? One could always resort to a full backup line with aid loops, but that no longer feels efficient with a waterline where the backup isn't necessary. Also, are aid loops actually the best way to damp vibrations? Maybe we can do better.

The basic concept I've been exploring is like extra long wind dampers that hang down from the line. I'll call them vibration dampers, because they aren't about wind in this case. The problem with attaching strips of webbing (or anything flexible) longer than about a foot is that it quickly gets wrapped around the line, and often ties itself in knots. What if we add some stiffness to the vibration dampers, so they can't wrap around the line? I needed something cheap and plentiful that was about an inch wide, several meters long, and not totally flexible. I decided that slats from mechanical window blinds would be worth a try. I rallied a crew of unsuspecting local slackers, and we got to work rigging a 200m waterline and taping together 8 window blind vibration damping contraptions.

Just normal parking lot stuff.

To be scientific, we first rigged the line without the dampers, and took a walk on it to get a reference point. The line was a little more walkable than I anticipated, but did get difficult for me in the final quarter when most of the line was behind me where I couldn't keep an eye on it. Once vibrations start, it can be hard to calm them down on a big, undamped line.

Next, we partially detensioned, and went out on a paddle board to attach the dampers at semi-regular intervals across the line. We re-tensioned, I hopped back on, and it was... not that different, at least at first. In the final quarter where I struggled before, it did get a bit better. Vibrations behind me were just a hair quicker going away.

Vibration dampers on a 200 meter waterline.
Getting the dampers damp.

I jumped off the line into the water near the far side, and when the line rebounded, the dampers flopped everywhere and got stuck draped and folded over the line. The window blinds were nowhere near stiff enough.

Overall, the particular idea we tried that day didn't work very well, but was promising enough that I want to try again with what we learned. The vibration dampers need to be stiffer, and they may need to be longer, weigh more, or be more numerous to get a bigger damping effect. Finally, the idea I'm most excited about is to use the water as a source of drag, maybe by attaching buckets or parachutes that hang down into the water.

What do you all think? Is anyone else working or thinking along these lines? Does anyone want to try to argue that adding some assistance to a waterline is cheating, but aid loops on a highline are totally fine for some reason?