First establish why two cranes are needed
Before selecting two machines, consider whether one can carry out the work safely. A shared lift adds interactions, communications and opportunities for error that must be addressed through specialist planning.
Assessment of Cranes and lifting equipment requires the load’s mass, centre of gravity, lifting points and accessories to be known. Uncertain information cannot be resolved by trying the lift. Reliable details of access, ground conditions, obstructions and landing positions are also needed before a safe arrangement can be selected.
The load is not always divided equally
Each crane carries a share determined by the geometry of the arrangement. That share can change as the item is raised, rotated or set down. One crane could become overloaded even though total mass appears lower than their combined capacities.
Assessment must cover the working radius and configuration of each crane during different stages, together with forces caused by imperfect synchronisation. Applicable technical criteria determine capacity margins or derating; there is no universal percentage that can safely be chosen from memory.
One direction and a shared understanding
The lift director must be identified, with operators and signalling personnel working to the same plan. The briefing should review roles, communications, stop conditions and the response to lost visibility or communication failure.
Indication and control equipment must be in verified working condition. It is not enough for each operator to be experienced independently: they need to understand the coordination required for this load and these machines. Any proposed change needs to be communicated and assessed before continuing.
Plan for interruption as well
The plan covers pickup, travel and final positioning, with people excluded and other activities controlled. Weather, ground stability and nearby installations may require the operation to be suspended rather than completed as originally scheduled.
The team must know how to recognise departure from the plan and who directs a controlled stop. Engineering support is needed where complexity exceeds the competence available. This overview explains preventive decisions; it does not provide instructions for executing a tandem lift or replace local requirements.
