Tandem/Multi-Crane Lifting
- 11 hours ago
- 6 min read
Tandem and multi-crane lifts are specialist lifting operations that require a higher standard of planning, supervision, and communication than a single-crane lift.
A tandem lift usually involves two cranes lifting one load. A multi-crane lift involves two or more cranes lifting the same load.
In both cases, the load on each crane can change during the lift, and that change is affected not only by the crane operator but also by the movement of the other crane or cranes involved.
This guidance is general information only. Every tandem or multi-crane lift must be planned for the specific task, load, lifting method, cranes being used, and site environment. Manufacturer instructions, the lift plan, and company procedures must always take priority.
When a Multi-Crane Lift May Be Needed
The use of two or more cranes may be considered when a single crane cannot safely complete the task because of:
the weight of the load
the physical dimensions of the load
a difficult or shifting centre of gravity
the required movement or orientation of the load
site restrictions such as overhead obstructions or limited headroom
the need to reduce ground pressure or improve load stability
A multi-crane lift should not be chosen because it appears convenient. It should be chosen only when it is the safest practical lifting method for the task.
Start With the Task
The first question is not which crane to use. The first question is what task is actually being carried out.
Define the task clearly:
what is being lifted
where it is being picked up
where it is being placed
what sequence of movement is required
whether the load needs to be turned, rotated, upended, or travelled while suspended
what people, plant, structures, and services are in the area
The task drives the lift category, the level of planning, and the controls required. Poor planning is a major cause of lifting incidents.
Know the Load
Before any lift begins, the total mass of the load and its distribution must be known or properly calculated. If the information comes from drawings or manufacturer data, allowances should be made for tolerances, attachments, retained materials, and any change in weight during the lift.
This is particularly important where the load is irregular, long, flexible, top-heavy, offset, or has an unknown centre of gravity. Multi-crane lifts of irregular loads require careful planning by a competent person, with attention to:
distribution of load mass
load shape
flexibility or rigidity of the load
location of the centre of gravity
If the load will roll, rotate, or transfer weight during lifting or set-down, that behaviour must be understood before the lift begins. A lift that appears balanced at pickup may become heavily unbalanced during travel, turning, or placement.
Choose the Right Lifting Method
The lifting method must suit both the task and the load. The method should state:
lift points
rigging arrangement
sling angles
lifting accessories to be used
pick-up path
travel path
set-down method
any rotation or load transfer during the lift
exclusion zones and drop zones
contingency arrangements if the lift does not go as planned
For awkward loads or loads with a non-central centre of gravity, purpose-designed lifting beams, spreader bars, or engineered lifting arrangements may be required.
Multi-Crane Lift Capacity Allowance
In multi-crane lifting operations, it must be assumed that load sharing between cranes will not remain perfectly balanced during the lift.
To maintain safe operating margins, additional capacity must be allowed above the calculated load share.
Recommended minimum allowances are:
Number of cranes | Allowance applied to the calculated load share |
|---|---|
two cranes | 20 % |
three crane | 33 % |
four or more cranes | 50 % |
These values recognise that load distribution becomes increasingly uncertain as more cranes are involved.
Minimum crane capacity = calculated load share × (1 + allowance)
Example |
|---|
Two-crane lift Total load: 10 t Planned equal share:
Apply 20% allowance Minimum crane capacity required: 5 t × 1.20 = 6 t |
This means the lift must be checked through the full sequence, including:
pickup
initial hoist
travel
turning
rotation
set-down
A crane may carry a much higher share at one stage than another. If the lift cannot meet the required safety margin, the procedure should be reviewed and, where needed, checked and certified by an engineer.
Important Note for Hiabs For truck loader cranes, these allowances are often not sufficient on their own, because:
Therefore, tandem lifts with Hiabs should still be treated as exceptional lifts requiring careful planning and supervision. |
Synchronise Crane Motions
Crane motions must be synchronised so the intended load share is maintained throughout the lift. The risk is not only from static weight overload. It is also overloaded from dynamic load transfer.
If one crane lowers or moves faster than another, momentary loads can rise sharply. Guidance notes that load spiking can occur if one end of a long load contacts the ground before the other, increasing the load on the opposite crane. Both ends or corners should be lowered together as planned.
Hoist ropes should remain as near vertical as practicable. Rope deviation can indicate unintended horizontal force, side loading, or uncontrolled load transfer. In travelling lifts, one crane may need to lead while the following crane adjusts its speed to keep the hoist ropes vertical.
Communication and Control
A tandem or multi-crane lift must have a clear communication system in place before the lift begins. All involved personnel need to know:
who is in control of the lift
who is giving signals
what communication method will be used
what to do if communication is lost
who has authority to stop the lift
Radio communication is often necessary when there is no direct line of sight, the lift is complex, or multiple lift operations are taking place. Only one person should give radio directions. If radio contact is lost or deteriorates, crane operations must stop until communication is restored or a safe visual signal method is in place.
The lift plan and associated procedures must be communicated to all people involved and followed by the lift team.
Review the Site Environment
Even a sound lifting method can fail if the site is not suitable.
A site assessment should consider:
ground conditions and bearing capacity
underground services
excavations, voids, or unstable edges
overhead power lines
adjacent structures
traffic and pedestrian movement
weather and wind
available space for setup, travel, and set-down
exclusion zones and counterweight crush zones
The crane must be set up according to the manufacturer’s requirements and on ground that can support the crane and the suspended load. Site slope and wind conditions also matter.
What a Lift Plan Should Cover
For a tandem or multi-crane lift, the lift plan should be written specifically for the job. It should include, at a minimum:
the task and sequence of operations
the load weight, dimensions, and centre of gravity
the cranes selected and their capacities for the required configuration
the rigging arrangement and lifting accessories
the pick-up point, travel path, and set-down point
the site hazards and control measures
the communication method
the exclusion zones and drop zones
the key people involved and their roles
contingency arrangements and emergency response
a review immediately before starting, to confirm conditions have not changed
Do Not Confuse Multi-Crane With Multi-Winch
A single crane using both main and auxiliary hoists on one load is not the same as a multi-crane lift. It introduces different load-sharing issues. During rotation, both ropes may carry more than 50 per cent of the load, and one may need to support 100 per cent. Unless each hoist can support the full load, the main hoist should be used to support the full load.
This is why multi-winch lifting should be planned as a separate lifting method, not treated as a simple variation of tandem lifting.
What Matters Most
Multi-crane lifting is a complex operation. It should only proceed when the task is clearly defined, the load is understood, the lifting method is documented, the cranes are checked against the maximum possible load share, and the site environment has been properly assessed.
If any part of the plan is uncertain, stop and review it. In tandem and multi-crane lifting, small errors in coordination, load share, rigging, or ground conditions can escalate quickly.
Follow the lift plan. Follow the manufacturer’s instructions. Use competent people. Communicate clearly. Stop the lift if the conditions, load behaviour, or communication do not match the plan.
Hiabs
We have published specific guidance for Hiabs as these machines add a layer of complexity. If you're considering using two Hiabs based on the load's weight, we highly recommend you read this post.
For further information, refer to your company procedures and consult with engineers and other qualified professionals. McLeod is available and happy to help.
