In recent years, container terminals are accommodating larger container vessels, which has led to growing pressures on ports to load and unload containers more productively. This is where tandem lifting comes into the field of play. Tandem means ‘side by side’ as opposed to ‘end by end’ – in this case, tandem lifting is a crane hoisting two container spreaders at the same time. Tandem lifting has opened a new avenue to improving port productivity and efficiency.
Tandem for mega vessel ports & terminals
Many ports and terminal operators think tandem lifting requires an investment of a dual hoist crane as well as a headblock but this simply isn’t true. Tandem headblock’s can be used on single hoist cranes, which weigh much less and cost significantly less than a dual hoist crane.
In addition, the height between the sheeve and the bottom of RAM’s 2940 STS spreaders means terminals can accommodate large mega vessels without risk of having equipment that is too low. The height of the SingFlex headblock and container spreaders attached is 3 metres, which means crane operators can reach new heights whilst operating in tandem.
More lifts per crane cycle
As the operator now has two spreaders attached to the crane, the operator has the power to lift more containers per cycle. If we consider the RAM SingFlex, in tandem mode the crane operator can handle 2 x 20ft, 40ft, 45ft ISO containers or 4 x 20ft containers, boosting container handling productivity.
Added operational flexibility
Though the SingFlex does not constrain the crane operator from using two spreaders, they have the option to choose. They can switch from single to tandem (& vice versa) using the purpose-built docking station within 90 seconds. Moreover, the docking station does not need any manual intervention from stevedores avoiding any element of danger.
When in tandem mode, crane operators can be challenged with trucks parked further away from each other (their intended location), a container may be lower than its tandem container or other reasons. These challenges can be frustrating and take away the shine from your tandem lifting. This is why it is important to have a tandem headblock that is flexible. The SingFlex headblock can adjust the gap between containers, longitudinal offset, skew and height adjustment, allowing your container handling to flow.
Less energy demand
Other terminals are using tandem lifting as means to make their operations more sustainable. For instance, in single spreader mode the crane operator can move 50 containers in 50 moves, whereas in tandem mode, the crane can move 100 boxes in 50 moves. Less moves means less energy needed. This adds a further benefit of operational costs being lower due to less energy consumed.