Maybe Relax a Little

There's this phenomenon online in the technical production world called the "Scary Rigging Photo."  This is the theatre version of the kind of photos that home inspectors post from time to time under "Home Inspection Nightmares"  The idea being that while in the course of working in a theatre that you stumble upon some rigging that really ought not be the way it happens to be.  The photo finds its way online and then dozens if not hundreds of people that purport to know what they are talking about proceed to dissect every possible thing that might be wrong with what we're looking at.

Here's one from today:

This was posted in a Theatre Educators group I follow on Facebook.  The poster was using the photo as an opportunity to recommend rigging inspections for high schools.  Those inspections are a good idea - with or without these pictures, and FWIW not necessarily limited to high schools: any school, church, community center; anyplace there's rigging without riggers ought to have inspections.

(OK, actually, anyplace with rigging, riggers not withstanding.)

Here's the thing though, while that picture might look scary it might not really be all that dangerous.  There's an ANSI approved detail for this connection.  Making that chain connection is something that has had lots of discussion over the years.  The critical bit that often gets missed is that the chain is supposed to create a dual load path below the thimble.  Often the chain goes around the pipe and then fastens back to itself rather than to the thimble.  They don't get that right here, but they might not get it as wrong as they could get it.  This is sort of a dual load path, sorta, kinda.  One end of the chain is hard connected in the thimble and then the other sort of chokes the cable around the thimble.

Don't get me wrong, this is 1000% the wrong way to make this termination.  Neither the thimble people or the shackle people (or the chain people or the batten people) would advise you to terminate this connection in this manner.  It is definitely wrong and it is definitely not a clean installation.

I am curious though about how much it would hold before it would fail.

The initial failure would likely be crushing the thimble.  It looks like if that happened there might be enough space in the shackle bell for it to drop down onto the first chain link.  I guess it also might be possible that all the chain would pull through the shackle until is was simply choked around the pipe.  Maybe not though.  It is difficult to see if the chain could pass through the shackle.

In either of those cases though I'm not sure there would be a catastrophic failure.  Partly it depends on the position of this pick on the batten.  If it is in the middle someplace at some point in the failure the pick would essentially go slack as the beam would carry the load to the adjacent picks.

A worse case would be that rather than the thimble being crushed that the shackle bell would crack.  That might mean that this particular pick would break catastrophically.  But again, depending on where it is along the pipe the batten might be ok.

There is, I guess, the possibility of some kind of shock loading failure that could zipper down all the picks - especially if they all look like this one.  That would be scary.

Really though, in normal use, this connection would probably just sit there looking scary until someone undid it and brought it up to spec.

As part of work we do this Tumblr where we collect pictures of things we're doing in the shop while they're in process.  The site is called In Process.  Pretty much I don't curate what the students put up there, but one of the rules we do have is that I don't want them to post rigging photos.  My reasoning isn't that we're doing anything wrong or that would be unfortunate for the world to see.  It is more about not wanting to go a dozen rounds online with commenters insisting that instead of an outside Bowline we really should have used an inside Bowline.

Maybe we could all just be a little less enthusiastic.

Last week I joked with a rigger friend that I couldn't post the photo below as folks would want to make sure I knew that Sabian's lanyard was improperly terminated.

Perhaps.  But it isn't a failure mode.  Sometimes it is.  Often it isn't.