Cranes come in all shapes and sizes, but for the really big lifters, they also arrive in lots of small bits that are then built on site and can perform some truly enormous lifts. As they can be broken down into small and easily transportable components, often containerised, they can provide large lifting capabilities on very remote sites.
The “ringer” term comes from the fact that the slew ring of the crane is not mounted into the body of the crane as you would normally expect. Rather it is built on the ground with load spreading mats placed underneath and the slewing motion provided by a skidding system.
The movement of counterweight to a site is also a large component of mobilising a crane for any given lift. The very large ringer cranes get around this by often making use of local material, backfilled into the transport containers as ballast weights.