Comments about technological history, system fractures, and human resilience from James R. Chiles, the author of Inviting Disaster: Lessons from the Edge of Technology (HarperBusiness 2001; paperback 2002) and The God Machine: From Boomerangs to Black Hawks, the Story of the Helicopter (Random House, 2007, paperback 2008)

Saturday, September 14, 2013

Parbuckling on the Costa Concordia: Historical Origins

You've probably seen the term parbuckling in connection with the Concordia work, as on The Parbuckling Project website. The website is partly correct in its description of early parbuckling as a way to roll heavy casks uphill.

That was one meaning in 1800, but “parbuckling” goes back earlier, and concerns artillery instead. Parbuckling was a way to haul heavy cannon from the base of a hill to the top, say when building a new fortification. Relocating heavy wheeled cannons across rough landscape proved such a problem during the Seven Years War in Canada that the Royal Artillery added rough-ground rigging to its curriculum for new cannoneers, and set up obstacle courses to train them.

As an example, a common parbuckling job for artillerymen was to remove the gun tube from its carriage (which can be done without a major effort by tilting the carriage forward until the muzzle is on the ground), then rolling the tube uphill, using ropes, blocks, and wooden runners. The carriage was brought up separately, on its wheels.
While it may seem that the gun crew could have saved some trouble and used whatever wheeled carriage the gun came with, when it came to the bigger guns, those carriages were only usable on a level, hard surface. Otherwise the carriages were top-heavy and the wheels dug in. If dragged across rough and steep ground, the carriage and mounted gun would likely mire or tip over on a slope, rolling over and freeing the tube's trunnions from their mounts, at which point the cliche “loose cannon” takes on real meaning.

So it was best to pull the gun tube from the carriage at the start of the operation and roll it along the ground, using parbuckle ropes, then remount it at the destination. For very heavy tubes, the gun crews laid wooden rails along the ground to ease the job.

Parbuckling is one of many ingenious rigging methods worked out by combat engineers through the centuries. Many are still in use, such as the gin pole I saw used by tower workers when I visited a tower-building job for Smithsonian.

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