Communication, signal systems and teamwork with doggers and riggers
One signaler
Only one person gives signals to the operator at a time - normally the dogger. Everyone must know who that is before the lift starts. Traps: multiple people signaling; assuming shouting is sufficient; and the operator acting on a signal from an unidentified person. The operator must stop if signals conflict or are unclear.
Signal systems
Use the standard hand signals, whistle signals or radio as agreed at the pre-lift briefing. Radio users must use clear, standard phrases, identify themselves, and confirm critical instructions. If radio fails, stop the lift until communication is restored or a safe alternative is agreed. Emergency stop signal - any person may give it.
Teamwork
The dogger directs the lift and controls the load with tag lines; riggers attach and inspect gear; the operator controls the crane. A pre-lift briefing covers the load, path, signals, roles, exclusion zone and emergency plan. Traps: assuming the dogger can be replaced by a bystander; and the operator "helping" by swinging before the dogger is ready.
Worked example
If the dogger's radio dies mid-lift, the operator stops and holds the load safely until communication is restored. Never continue on guesswork.
Blind lifts
For blind lifts, use a designated signaler with a clear view and agreed relay protocol.