On Ropes

Abunch of people attached to hooks. Cutegirls dangling upside down bytheir knees. Handsome photographersabounding. It looks cool, but is it a big deal?

Well, creating a suspension setting takes hard work; it’s a project.Accidents can happen even with the most experienced crews.

Two seasoned professionals wound up falling recently. Allen Falkner brokea six-gauge hook in Oslo, Norway (video here).

I asked him why, in his opinion, the hook broke.

That's a very good question and I'mstill not 100% positive. We have tested sea demon hooks and they seemto fail around 250 lbs per hook. With 2 hooks in my back, they shouldhave held my weight. The only thing I can think is that on the finalswing, the loading must have shifted and all the pressure was put onthe one hook. That and/or the hook itself was not as strong as theothers we have tested. From now on I'm just going to have tohang from Oliver's new locking hook design.

Meanwhile, half a world away in southern California, Ron Garza (iam:Sicklove) was suspendingJay (iam:NJWhiteTrash)and decided to hang from him. They thought they had purchased 550 rope,but they had instead gotten a rope with a 350 pound limit. They two ofthem together weighed 359 pounds. As Ron put weight on Jay, the ropesnapped. They did both survive, but Ron’s back bore the brunt of theweight of both of them in the fall.. Ron and Cere (iam:Cere) from Rites of Passage both sentme the following on rope strength:

There are plentyof alternatives. None are quite as cheap, but it's more in how you useit than what it actually costs per foot. I thought I had beat thishorse a few months ago, but here you go again: "550" is abreaking strength it's not a work load limit. YOU MUST UNDERSTAND THEDIFFERENCE. When you hang from a parachute you have as many as 20 or 30lines close to evenly distributing the weight of the person. Using oneline that's got knots in it and taking turns around solid metal objectsand then hanging a person from it is just flat irresponsible. (yeah, Iuse the stuff, but not in anything resembling critical applications. IfI can't touch the ground, I'm not hanging from that stuff.) Every pieceof equipment rated to lift people has a breaking strength at least 5times the WILL and in most cases it's 10 times.

Now a lesson inphysics. when you swing several things happen. You create forces muchhigher than your actual weight. When you consider shock loading, youmay be introducing forces to the lines that are as much as five timesyour actual weight. So you have a line that should be rated at aconservative 55lbs and is being introduced to forces on the level ofhalf a ton and you guys wonder why it snaps? Like I said before, theonly single strand applications I have for the stuff are as improvisedshoelaces and for wrapping around knife handles.

There are awhole host of cords that would be much safer to hang people from.Collectively known as "tech" ropes and sold under the brand names ofspectra, technora, dyneema, and kevlar they almost all have breakingstrengths 4 times higher than 550 in the same 1/8 inch size and some asmuch as 8 times stronger. Depending on the construction some havealmost no stretch and others are more dynamic than 550 which stretches20% before it lets go. (Compared to dacron/polyester and I thinktechnora which stretch less than two percent before they let go.) Nothe best alternatives aren't cheap, but neither are hospital bills.

- Oliver Gilson (iam:Antagonist)

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