Cranes mounted on barges, pontoons and vessels are commonly used for marine construction, bridge works, dredging, offshore projects and heavy lifting. Unlike a crane operating on land, the crane’s supporting platform can move beneath it. Wind, waves, tides, vessel movement and changing ballast conditions can all affect stability during the lift. What’s the Big Risk? - Vessel list and trim can change as the crane slews. - The load can begin swinging due to vessel movement. - Tides and currents can change conditions during the operation. - Wind can affect both the crane and suspended load. - Incorrect ballast or load positioning can affect stability. - The crane’s allowable capacity may differ from equivalent land-based operation. Key Lessons Learned A marine crane lift must consider both crane stability and vessel stability. A lift that appears acceptable from the crane’s load chart may still be unsafe if the supporting vessel cannot withstand the resulting forces and moments. The crane, vessel and load must therefore be considered as one lifting system. Safety Recommendations - Confirm crane and vessel suitability. - Establish allowable list/trim limits. - Check weather, tide, current and wave conditions. - Confirm ballast and vessel stability requirements. - Establish operational weather limits. - Maintain effective communication between the lifting team and vessel crew. - Stop operations if conditions exceed the agreed limits. - Incident Source Safety-learning case based on common hazards associated with crane operations from barges, pontoons and vessels. Regulatory Mapping ● LOLER Reg. 4 – Strength and stability of lifting equipment. ● LOLER Reg. 8 – Proper planning, supervision and safe execution of lifting operations. ● PUWER – Suitability and safe use of work equipment. ● BS 7121 principles – Crane selection, stability, environmental conditions and safe lifting operations. Key Point On land, the crane moves the load. At sea, the crane moves the load while the platform underneath the crane can also move.

During port lifting operations, a crane was lifting a shipping container using a container spreader. While suspended, the container suffered major structural failure and split apart, creating a serious risk of falling cargo and debris. Importantly, the lifting system appeared to remain connected, the load itself failed. What Went Wrong - Container structural integrity was lost during lifting. - Possible previous damage, corrosion or weakened structural members. - Incorrect or uneven cargo distribution should also be considered. - Personnel could have been exposed to a major falling-object hazard. - The exact cause cannot be confirmed from the photograph alone. Key Lessons Learned Inspecting the crane and lifting accessories is not enough. The condition of the load itself must also be considered. For containers, obvious damage to corner fittings, posts, rails or structural sections should never be ignored. If unusual distortion, movement or cracking is observed during take-off: STOP THE LIFT. Safety Recommendations - Inspect the container before lifting. - Check for corrosion, deformation and structural damage. - Verify container gross weight. - Maintain a suitable exclusion/drop zone. - Use a controlled initial lift to identify abnormal behaviour. - Quarantine questionable or damaged containers for competent assessment. Incident Source Safety-learning case based on the supplied photograph. The exact location, date and official cause have not been verified. Guidance Mapping ● IMO/ILO/UNECE CTU Code – Container condition and safe cargo transport principles. ● LOLER Reg. 8 – Proper planning, supervision and safe execution of lifting operations where LOLER applies. ● PUWER – Suitable and safely operated work equipment where applicable. Key Point The crane can be safe. The spreader can be safe. But what about the load? Never assume that because something can be picked up, it is structurally capable of being lifted safely. Wolf Lifting Dynamics | www.wolflifting.uk | Case Study 134

A spider crane was selected for lifting operations on a restricted construction site where access was limited and a conventional mobile crane would have been difficult to position. Spider cranes can be extremely useful. Their compact dimensions, folding outriggers and relatively high lifting capacity for their size allow them to work inside buildings, courtyards, between structures and other confined locations. But their compact appearance can create a dangerous misconception: Small crane = small risk. It doesn’t. Once the boom extends and the radius increases, stability, ground conditions, outrigger configuration and load weight become critical. Why Spider Cranes Are Useful Spider cranes can provide major advantages: - Excellent access to confined areas. - Small working footprint. - Flexible outrigger configurations on suitable models. - Useful for glass installation and steelwork. - Suitable for indoor lifting where conditions permit. - Can reduce the need for much larger cranes. - Precise positioning of loads. - Some models can operate using electric power for appropriate indoor environments. Used correctly, they can solve lifting problems that would otherwise require much larger equipment. What’s the Big Problem? Stability. The crane may be compact, but the forces generated through its outriggers can be substantial. Problems can develop when: Outriggers are not deployed in the required configuration. Ground bearing capacity is unknown. An outrigger is positioned over a void, service, suspended slab or weak ground. Suitable mats/spreader arrangements are not provided. The operator works outside the permitted duty/configuration. Load weight is assumed rather than confirmed. Radius increases unexpectedly. Safety systems are overridden. The Outriggers Matter A spider crane’s stability depends heavily on its support arrangement. Before lifting, the team needs to understand what is underneath each outrigger. On a suspended slab, for example, saying:

On a busy construction site, slingers and other site personnel were observed using the area behind and underneath a crane as a temporary place to stand, wait or shelter. To them, it appeared to be out of the way. In reality, they had positioned themselves inside one of the most dangerous areas around operating plant. A crane can slew, travel, reposition or move unexpectedly as operations change. The operator may have significant blind spots and may have no idea that someone has walked behind, underneath or alongside the machine. One unexpected movement could leave that person with nowhere to escape. What Went Wrong Personnel entered the crane’s operating area unnecessarily. Workers positioned themselves within operator blind spots. The crane was treated as somewhere to shelter or wait. Personnel relied on the operator knowing where they were. Potential slew, counterweight and tracking/reversing zones were not respected. Safe pedestrian areas were not being used. Key Lessons Learned If you cannot see the operator, never assume the operator can see you. The danger is not limited to the suspended load. Depending on the crane type, hazards can include: - Slewing counterweights. - Tracks and wheels. - Reversing movements. - Outriggers and stabilisers. - Crushing points between the crane and structures. - Suspended loads and lifting accessories. - Unexpected crane repositioning. A crawler or mobile crane may also start travelling after sitting stationary for a period. Stationary does not mean safe. The Slinger Has an Extra Responsibility A Slinger/Signaller should understand plant movement and exclusion zones. They should therefore be setting the example — not hiding behind the crane between lifts. If the slinger needs to take a break, wait for another lift or shelter from weather, a designated safe area should be used. The crane’s footprint is not a welfare area. Safety Recommendations Establish clear crane and plant exclusion zones. Identify counterweight and slew-radius hazards.

A competent Slinger/Signaller does much more than simply attach lifting accessories to a load. During a lifting operation, the slinger may be responsible for selecting and attaching the correct lifting accessories, checking the load is secure, controlling the load, maintaining the exclusion zone and directing the crane operator using recognised signals or radio communication. When the operator cannot see the load or landing area, clear communication becomes even more important. Consider a tower crane carrying a heavy load to a blind landing position. The operator is relying entirely on the slinger’s radio instructions. Instead of clear commands, the radio becomes filled with conversation: “Yeah mate, keep coming… little bit… little bit… no, the other way… watch it… hold on… STOP!” By the time STOP is given, the crane may already have moved in the wrong direction. The load could strike the structure, trap an installer, enter another crane’s envelope or swing towards personnel. Radio communication during a lift is safety-critical communication, not casual conversation. What Went Wrong Unclear terminology was used. Instructions were too long. Unnecessary conversation occupied the radio channel. Direction was not clearly identified. The operator had to interpret what the slinger meant. No positive confirmation was used. Critical information became mixed with irrelevant conversation. Key Lessons Learned A Slinger/Signaller needs competence in four connected areas: •Sling the load correctly. •Check the load, lifting points, accessories, WLL, configuration and security before lifting. •Direct the crane correctly/Communicate correctly. •Position yourself where the load can be safely managed. Instructions should be short, clear and understood by the operator. If communication becomes unclear: STOP THE CRANE. Never guess what somebody meant. Example of Good Radio Communication A simple exchange could be: Slinger: “TC1, this is Slinger 1. Radio check.” Operator: “TC1 receiving you loud and clear.”