Dual-Crane (Tandem) Lift SWMS
SWMS variants reference your state’s WHS legislation. Instant download after payment.
A tandem lift is not two lifts happening at once — it is one lift in which each crane's load can change without anybody touching the controls. That is the central hazard and it is not intuitive. In a single-crane lift the load is what it is. In a tandem lift the share carried by each crane is determined by the geometry, and **the geometry moves**: if one crane hoists fractionally faster than the other, if one boom deflects more under load, if the ground settles under one machine, or if the load rotates as it lifts, load migrates from one crane to the other. **A crane can be overloaded without its own operator doing anything at all**, and the first indication may be the rated capacity indicator on the *other* machine.
Every tandem lift therefore requires an **engineered lift study prepared by a competent person before the cranes arrive**, calculating load share at every stage rather than only at the pick, and a deration of each crane's rated capacity — conventionally not less than **25%** — to absorb migration, dynamic effects and the uncertainty of share. And there is **one lift director** and one set of signals for both cranes. Two supervisors is not redundancy, it is ambiguity, and ambiguity in a tandem lift is what drops the load. A dual-crane tandem lift is a critical/engineered lift by definition and requires the engineered lift study that classification demands; this SWMS is the tandem-specific method that sits inside it. It covers the lift study, crane selection and set-up, rigging, the synchronised lift, travel or slew, placement and the disengagement sequence. Regulator: SafeWork NSW.
Hazards identified
14 hazards covered, sorted by priority.
A crane overloaded without its own operator touching a control — the geometry moves and the load follows
Load transfer and boom side loading when one crane moves faster than the other
Structural failure of a boom pulled out of its vertical plane
Electrocution — a tandem lift gives the director more to watch than one person can
The crane breaking through backfill, a slab, a trench or an unsupported edge with a load suspended
Radius and share changing on both machines at once
Gear rated for the nominal share failing under the migrated share
Two people directing, or none — ambiguity in a tandem lift is what drops the load
The entire load transferred to one crane when the other hook is released early
Booms, jibs or counterweights contacting during slew
Swing and side loading on two booms at once
Fall injury during attachment or release at elevation
Crush injury to a worker guiding a load by hand at the landing point
Musculoskeletal injury handling spreader beams and chain sets
Control measures
Hierarchy-of-controls order: elimination → substitution → isolation → engineering → administrative → PPE.
- 1Require an engineered lift study calculating the load share at EVERY stage of the lift, not only at the pick, and reject any lift where the share cannot be calculated.
- 2Derate each crane by not less than 25% of rated capacity to absorb migration and dynamic effects, with a functioning calibrated rated capacity indicator on each machine.
- 3Have both operators monitor their own indicator continuously and stop the lift immediately on any indicator movement not predicted by the study — a crane can be overloaded without its own operator touching a control.
- 4Plan motion so that only one crane moves at a time wherever the study allows, rather than relying on two operators matching speed.
- 5Match and verify hoist speeds during a trial lift just clear of the ground, and walk a dry run through before the load is attached.
- 6Name ONE lift director for the whole lift, identified and briefed to everybody, with no other person authorised to give a signal to either crane — two supervisors is ambiguity, not redundancy.
- 7Design the lift so both hooks stay directly over their attachment points throughout, with a spreader beam where the geometry would otherwise induce side load, and never drag or pull the load with either crane.
- 8Stop immediately if any fall goes out of plumb, and never correct by slewing under load.
- 9Assess ground bearing at BOTH crane positions against the maximum outrigger load including any migrated share — not the nominal share — and treat any settlement as a stop condition because it changes the geometry.
- 10Specify every rigging component against the MAXIMUM share it can see during any stage, with any spreader or lifting beam engineer-designed, certified and marked with its rating.
- 11Operate a dedicated common radio channel with tested range at both crane positions, a stop-on-loss-of-comms rule, and an emergency stop signal ANY person may give and every person must obey.
- 12Specify the disengagement sequence explicitly in the study, land and support the load fully before ANY hook is released, verify share is zero on the indicator, and release one at a time in the specified order.
- 13Ensure each operator holds the appropriate high risk work licence class and the dogging and rigging duties are held by licensed persons — the complexity of a tandem lift commonly requires advanced rigging competency.
- 14Consult workers per Section 47 of the WHS Act 2011 (NSW), record it, and review whenever the load, cranes, geometry, rigging or ground changes, after any incident, or at minimum every 12 months.
Applicable Codes of Practice
The benchmark for plant risk management and safe use of both cranes as a single system.
The benchmark for approach distances to overhead electric lines — a tandem lift gives the director more to watch than one person can.
The benchmark for construction-phase risk management, exclusion zones beneath both cranes and the full load path.
The benchmark for multiple-crane lifts: the engineered lift study, deration of rated capacity, a single lift director, and synchronised controlled motion.
Set-up, ground assessment, load chart application and operator duties for each machine.
Slings, shackles, spreader beams and lifting lugs, their rating, inspection and use, including the design of any spreader distributing load between cranes.
High-Risk Construction Work triggered
Two cranes operate as powered mobile plant in a shared work area, with intersecting swept envelopes and counterweight swing circles.
Two booms, the load and the rigging all operate within reach of overhead electric lines, and the swept path of the load between the cranes must be assessed as well as each boom.
Riggers attach and release at elevation, and any work on the load or the structure during the lift carries a fall risk exceeding 2 m.
Dual-crane tandem lifting is high risk construction work under Section 291 of the WHS Regulation 2025 (NSW), so a SWMS must be prepared before work commences (Section 299), kept readily accessible, reviewed as necessary (Section 302), and given to the principal contractor if one is appointed. Both cranes are registrable plant under Chapter 5, with duties to ensure they are inspected, maintained and used within their design limits — and in a tandem lift 'design limits' means the derated figure from the engineered lift study, not each machine's chart in isolation. AS 2550.1 requires an engineered lift study, deration of rated capacity, and a single lift director for multiple-crane lifts. Each operator must hold the appropriate high risk work licence class under Part 4.5. Energised electrical work is prohibited under Part 4.7 Division 4, sections 154 and 157 unless de-energisation is not reasonably practicable. An overturn, an electrical contact, a dropped load or a serious crush injury is a notifiable incident under Sections 35–38 and is prosecuted as a Category 1 or Category 2 offence, with the most serious breaches carrying imprisonment for individuals.
Who this is for
- →Crane hire and heavy lift contractors performing dual-crane lifts to move, upend, turn or lay down loads beyond a single machine's capacity.
- →Lift directors, who in a tandem lift are the single point of authority for both cranes and every signal given.
- →Competent persons preparing engineered lift studies, calculating load share at every stage and specifying the deration.
- →Riggers and doggers assembling rigging to a lift study, where every component must be rated for the maximum migrated share rather than the nominal split.
- →WHS managers and HSE advisors responsible for critical lift governance, ground assessment and exclusion zones on multi-crane operations.
What you receive
- ✓A complete, editable Safe Work Method Statement authored for New South Wales — the WHS Act 2011 (NSW), the WHS Regulation 2025 (NSW) and SafeWork NSW as regulator.
- ✓14 identified hazards with initial and residual risk ratings on a 5x5 matrix, each with controls ordered through the full hierarchy — eliminate, engineer, administrative, PPE.
- ✓The load share migration control set built on the fact that a crane can be overloaded without its own operator touching a control, and the first warning may be the OTHER machine's indicator.
- ✓The engineered lift study requirement: share calculated at every stage, not only at the pick, with deration of not less than 25% to absorb migration and dynamic effects.
- ✓The single lift director rule stated as a rule — two supervisors is ambiguity, not redundancy.
- ✓The disengagement sequence control set, which addresses the failure where one hook is released while the load is still supported and the whole load transfers to the other machine.
- ✓Rigging specified against the MAXIMUM share any component can see during any stage, rather than the nominal split.
- ✓The full high risk construction work breakdown — powered mobile plant, energised electrical and falls over 2 m — with the reason each applies, plus a PPE matrix, emergency procedures and a worker sign-on table.
- ✓Microsoft Word (.docx) format, unbranded, editable fields for PCBU, ABN, site, prepared by, reviewed by, approved by and review date.
Worked example
Two cranes are upending a 30-tonne steel truss. The study is done, the deration is applied, both operators are experienced. The lift starts clean. As the truss comes off horizontal and begins to rotate toward vertical, the geometry does exactly what geometry does — the share starts sliding toward the crane at the head end. Nothing on that operator's console has changed; he has not moved a lever. His RCI creeps up, and by the time it alarms he is at 92% of a figure that was supposed to have a 25% buffer in it, because the study calculated share at the pick and at the set-down but not at 40 degrees of rotation in between. The other operator, watching his own gauge fall, thinks it is going well. This SWMS closes that: the study calculates share at EVERY stage of the lift including the intermediate geometry, both operators watch their own indicator continuously and either can stop, and an alarm on one crane is treated as a whole-lift stop rather than that crane's problem — because in a tandem lift it never is.
Related legislation
- Work Health and Safety Act 2011 (NSW) — Section 19 primary duty of care; Section 47 consultation; Sections 35–38 notifiable incidents.
- Work Health and Safety Regulation 2025 (NSW) — Section 291 (high risk construction work) and Section 299 (preparation and content of a SWMS), with review under Section 302.
- Work Health and Safety Regulation 2025 (NSW) — Chapter 5 (plant): registration, inspection, maintenance and the duty to use plant within its design limits — which in a tandem lift means the derated figure from the lift study.
- Work Health and Safety Regulation 2025 (NSW) — Part 4.5 (high risk work licences) for both operators and the dogging/rigging duties; Part 4.7 (electrical) including the prohibition at Division 4, sections 154 and 157.
- AS 2550.1 (Safe use — General requirements, including multiple-crane lifts), AS 2550.5 (Mobile cranes), AS 1418.5 (Mobile cranes design) and AS 4991 (Lifting devices).
Frequently asked questions
Both cranes are well within their charts. Why derate 25%?
Because in a tandem lift each crane's load is not fixed — it is set by the geometry, and the geometry moves. If one crane hoists fractionally faster, one boom deflects more, the ground settles under one machine, or the load rotates as it lifts, load migrates from one crane to the other. A crane can be overloaded without its own operator touching a control. The deration — conventionally not less than 25% — is the buffer that absorbs that migration plus the dynamic effects the static chart never accounted for. Planning at the undated chart figure means the first geometry change takes you over.
Can each crane have its own supervisor?
No. There is ONE lift director for the whole lift, named and briefed to everybody, and no other person gives a signal to either crane. Two supervisors sounds like redundancy and is actually ambiguity: two people with authority means two sets of signals, two judgements about when to stop, and a moment where each assumes the other has it. In a tandem lift, where the two machines are mechanically coupled through the load, that moment is what drops it. What you can have — and should — is a dedicated safety observer per crane for overhead clearance, because clearance is more than one person can watch.
What do we do if one crane's RCI alarms?
Stop everything, on both cranes. An alarm on one machine in a tandem lift is a whole-lift event, not that crane's problem — it means the geometry has moved and the share has shifted, and the answer is never to correct it by moving the other machine, which changes the geometry again. Cease all motion, and land the load only under the lift director's instruction and only if it can be done without further migration. Then it goes back to the competent person, because the study did not predict what just happened.
Why does the disengagement sequence need to be in the study?
Because releasing a hook is a load transfer. If one crane comes off while the load is still partly supported, the entire load lands on the other machine instantly — and the other machine was derated for its share, not for all of it. The study specifies the sequence explicitly: the load fully landed and supported so it is stable without either crane, landing supports or dunnage placed before the load arrives, share verified as zero on the indicator, and hooks released one at a time in the specified order on the director's confirmation. Not on an operator's judgement that it looks landed.