According to the SC&RA, at issue is whether candidates can work with numbers. The US ASME B30.5 crane standard requires that crane operators have demonstrated an ability to ‘read, write, comprehend and use arithmetic and a load/capacity chart.” Do they know their times tables, and how to multiply, this argument goes, if they only punch the numbers into a computer?
Crane operators certainly need to know their way around the numbers. Here are some important ones: maximum load-moment, maximum overturning moment, outreach, load, ground-bearing pressure. I hope that operators understand the acceptable margin of safety of each of those numbers, and how different configurations of the crane changes those numbers. Riggers, too, may need to do some complex geometry to build up sling angles to rig an awkward load.
And both operators and riggers should know how to compute the basics in an emergency. If a mobile crane were hit by lightning, for example, an operator might need to calculate whether the crane would go out of safe capacity to lower a load to the ground by booming down, for example.
I think that calculators should not be seen as some kind of a crutch supporting those with weak math skills. Today we depend on computers in every aspect of our lives – the time to avoid them is past. Even basic cranes run on a computer. There are fly-by-wire joysticks in the cabin, computerised load charts in the load-moment indicator, networks of IT management systems in the diesel engine. In short: if the crane runs on a computer, why shouldn’t the operator?
* For more opinion, check out a new page in the magazine this month, just inside the back cover. This new readers’ page is written about, and often by, you the readers. Here, we re-launch In Our Fleet, a regular article about a company’s favourite crane, what they are buying and using, and why. Look out for letters and other comment, every month, on the new back page.
