Construction Riggers and Doggers
Sling cranes and winches, assemble and install rigging gear, and direct the movement of loads while ensuring that they do not exceed lifting capacities.
A steel beam and a broken radio
You are a dogger working with a mobile crane on a city building site, slinging loads and giving the operator signals from the ground. It is 10am and the first steel beam of the day has to go up to the third floor. The crane operator is on the other side of the building and cannot see the whole load, so you are the operator's eyes, and the day is full of small decisions about who sees what.
Choose what you would do. Then see what happens. There are often good reasons for each choice.
The shackle I need for this beam has a bent pin. It still goes in. We've only got one other one in the shed, and that is a size down. The crane's waiting. Can we just use the bent one for this lift?
Use the bent one for this lift, then mark it and take it out of service afterwards
Under load, the pin does not sit properly and the shackle begins to open. The lift is stopped just in time, but the beam has already shifted. Gear that is damaged is not safe for even one lift.
Use the smaller shackle, since it is undamaged and the beam does not look all that heavy
The smaller shackle is sound, but it is below what the beam needs. Nobody checked the beam's weight, and the foreman has to stop the lift when the crane's load reading comes up high.
Take the bent shackle out of service, check the beam's weight and find one rated for it
You find the right size in the next shed. The beam is lifted safely and the bent shackle is tagged out. A rigger's most important tool is the willingness to ask what a piece of gear can carry.
The radio's cutting out. I can only hear every third word. I can't see you from here, and I've got a load hanging above the worksite. I'm holding it still. What would you like me to do?
Use the agreed emergency stop signal, wait for the load to be held, then arrange a person to relay signals
Wei holds the load, and a second spotter takes up a position where Wei can see him. A broken radio is a reason to stop, not to guess. The beam is placed safely.
Shout the instructions and wave your arms, and keep the lift moving as fast as possible
Wei cannot hear you, misreads a wave and swings the load the wrong way. It stops short of the scaffold, but the whole crew is shaken. You were guessing at a distance.
Walk across to the operator's side so you can talk face to face, leaving the load in the air
You talk to Wei in person, but the load hangs there for five minutes and no one is guiding it. The crew below keeps working, unsure what to expect.
The beam needs a little nudge to line up with the bolts. Just stand under the end and guide it in by hand. It's only a few centimetres, and it will save us lowering it again. You've done it before, haven't you?
Stand to the side, use the tag line and signal the operator to adjust the beam in small moves
The tag line works, but you are still close to the end of the beam, and a small swing could still reach you. It is safer than under it, but not as safe as it could be.
Stand under the end and guide it in by hand, since it is only a short distance and you've done it before
The beam swings suddenly as a gust catches it. You jump clear, but only just. No one should be under a suspended load, however short the distance.
Tell Garry you won't go under, and use a tag line from a safe spot to guide the beam in
Garry grumbles for a moment, then watches as the beam settles into place. The bolts line up in two small adjustments. No one was under anything.
How it went
The beam is in place, the bent shackle is out of service, and the radio has been replaced. Riggers and doggers spend a lot of time asking what something can carry and where people should stand. Would you like a job where careful checks and clear signals matter so much?
This is a simplified, fictional situation to help you explore. It is not professional instruction or a test of your ability.
Case study: The sling with the missing tag
A fictional case set in a steel-framed commercial building going up in a fictional port city, with a rigging crew working beside a mobile crane.
The situation
Carlos was a rigger on a steel frame job at Bayview Wharf. A lift of a heavy beam was due before lunch, and the crane was set up. Carlos picked a lifting sling from the rack and found that its tag, which shows what the sling can safely carry, had worn away. The sling looked sound. The other slings in the store were smaller or already in use, and the foreman was standing by with the crane operator, saying the sling was fine because it had been used on the last lift.
What they did
Carlos hung the sling back on the rack and told the foreman he could not use a sling he could not identify. He explained that without the tag no one knew what it was rated for, and that the beam's weight would have to be matched to a known sling. He found another sling with a clear tag in the next yard, borrowed it and inspected it, then checked the beam's weight against its rating before the lift went ahead.
How it turned out
The lift took an extra forty minutes. The foreman was impatient but did not argue, and later had the old sling cut up and removed. The yard started a routine of checking every sling's tag at the start of each week, and Carlos was asked to show new riggers what he looked for.
What would you do?
- Why might a sling that looks fine still not be safe to use?
- How would you handle a foreman who is pushing you to carry on?
- What small habits help a rigger notice problems before they become accidents?