Repairing a Crane with a Chicken, and Voodoo Logic (or, why two is sometimes better than three)

Repairing a Crane with a Chicken, and Voodoo Logic (or, why two is sometimes better than three)

That’s how they do it in Benin (fixing cranes that is).  Back in 2002 a new roadway bridge was under construction in Cotonou, Benin’s largest city. This also meant drilling shafts there for the very first time, and I was there to install the bi-directional test.   I’ve been to a couple hundred installs before in over 40 countries, but never seen anything like the story I’m about to tell you.

Benin, on the coast of West Africa, has a tragic history. It used to be the main departure point to transport enslaved people to the New World.  It is also the source of the voodoo beliefs that were spread to the Americas and the Caribbean.  To this day, some locals in Benin still practice voodoo, a.k.a. “juju”.

My Own Voodoo

I’d only seen and heard about voodoo in Hollywood movies and comic books. But here I was, about to experience something new.

I was making progress on instrumenting the test shaft rebar cage, and accidentally practicing a bit of voodoo myself.  The plans called for three strain gages per level, spaced 120° around the cage, in the hopes that if one failed, there would still be two working gages left.  Strain gages are usually positioned diametrically opposed, so that any eccentric loading or bending in the shaft is negated by taking their average.  If one gage in a triplet fails, the other two, not being opposed, cannot by definition measure the average axial load at that level anyway.  Since each gage has an equal statistical probability of failure, putting three gages on a single level actually increases the net probability of getting bad data. Two is more reliable than three – voodoo logic!  Better to stick with two, or if the data is critical, four (two sets of opposed pairs, which are independent of one another).

The project itself wasn’t making much progress, because the crawler crane (the only crawler crane in the country) broke down.  The mechanic did his best, but could not fix the problem.  Smuggled parts from neighboring Nigeria did not do the trick.  The schedule was shot.

The Ceremony

I suggested to the Italian project manager that we needed a bit of juju.  Instead of laughing at my joke, he got a gleam in his eye. “I will try anything!!”

Turned out one of the local laborer’s father was a big-shot juju priest.  His son knew how to brew the right potion, so to speak.  With a fistful of cash from the Italian, he pedaled to the market.  A big grin on his face, he came back with a live black-and-white speckled chicken.

He drew some circles in the dirt, scattered some leaves and sprinkled water around.  The chicken had its last meal. Out came the knife. Off with the head.

The priest’s son observed which direction the headless chicken ran off (yes, they really do that!), smeared chicken blood all over the engine block of the crane, and proclaimed success.  Best part was, that evening the workers had a bit of roast chicken for dinner.

The Aftermath

Two days later, the crane was still dead.  The project consultant (a very serious older German gentleman) and I were discussing the failure of the juju ritual to repair the crane.  In true German engineering fashion, he diagnosed the problem in a direct, no-nonsense style:

“Well it’s like this:  If a foreigner comes to Benin and ignores the juju, the juju gods understand this and leave him alone.  However, once the foreigner starts dabbling into juju, he better do it right.  The gods can see into his wallet.  For a crane that size, a chicken won’t do.  You need to kill a cow!”

Voodoo logic…

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