Makes Me Nervous

My company makes and delivers tanks that our knuckle boom cranes mounted on our trucks cannot handle, mostly because of simple geometry and reach. Kinda tough to lift and set a 35' tall tank when our booms only extend just shy of 40'. Plus, installation of some tanks require them to be lifted far over other tanks in an existing tank battery. So, our customers have to hire crane services to unload and install their new purchases. Now, I'm gonna say right out front that the vast majority of these folks know what they are doing. Then there are others:

RAW Crane Falls Crashes Drops Swimming Pool On House Roof Shorev - Free videos are just a click away

Most cranes I've seen have quite a few "gauges" that help the operator in the cab. One is a weight/strain gauge that approximates the weight the crane is handling. The other is a pointer that shows how far from vertical the stick is at that point, so the operator knows exactly how far over he's dropping that stick and increasing his radius. Most of these guys are very anal about finding out how much our tanks weigh before they ever hook up, because you've just seen why. Even if the stick is pointing ten degrees from vertical, the small radius increases the force on the crane. As the crane moves and lowers the boom to move the load further away, the "weight" increases with the increased practical radius, which is one side of a right triangle. Simple geometry rules the day - it ain't rocket science.

The crane company, Truck Crane Service, told the homeowner, who did not want to be interviewed, that a computer error is to blame for the mishap. They said there was a lot of margin between the pools weight, and what the crane could handle.

Yeah, no kidding there was a difference. That crane, as far as I can tell, didn't even have any place for counterweights, much less even using any. They didn't bring enough crane, period, and "computer error," as far as I'm concerned, means "operator inputting data error" more than anything.

No one was hurt in the accident. The homeowner says the crane company is doing everything to make things right, including covering the costs of the damages.

They would be doing their damndest to convince their insurance company to cough up. Which probably explains the computer error story.

The dead lifting capability of a crane isn't the only factor in determining how much extra capacity is necessary. Wind speed plays a major part in operating safely as well. If the wind catches that load and it starts swinging, the peak torque figures can easily spike well above the safe capacity in a hurry. I've talked to a few (very few, actually) operators who have had a crane go over, and it usually happened in windy conditions, or the ground they were parked on was unstable and their outriggers sank. There aren't any gauges for those extreme conditions and safety depends solely on the operator. I've had so sit and wait for the wind to go down plenty of times just to get unloaded. All part of the job, as far as I'm concerned.

It is truly a pleasure to work with professionals, and I always thank the "crane guys" after a job. They've got a lot of responsibilities, and they are performing skilled labor.

H/T Darin