Slew
Also called Slewing
The rotation of a crane’s upper structure and boom around its vertical axis, allowing the load to be moved to a different position without moving the crane’s base. Slewing changes where the load sits relative to the base, which can alter the loads on individual outriggers even where the load and radius stay constant.
In practice
For ground bearing this is the term that catches people out. The total load does not change as the crane slews, but its distribution between four feet does — and the foot that governs the matting is whichever one is worst-loaded through the full arc the lift uses, not the one worst-loaded at the pick.
Where this comes from: Standard crane terminology; the effect of slew on individual outrigger reactions is taken from the machine’s data.
Where it matters on site
Size the matting for the governing slew position across the whole planned arc, including the set-down, and mat every foot that reaches that condition rather than only the one under the pick. Where a lift is planned over a narrow arc, restricting slew is a real control — but it is one that has to be written into the lift plan and enforced, not assumed.