10 Years of SingFlex

Tandem Container Lifting

RAM Spreaders are celebrating 10 Years of the SingFlex

We are celebrating 10 years of tandem lifting with the SingFlex headblock. Over the years, the headblock has helped significantly boost container handling and ensure reliable operations. 

It has grown to be the industry’s most popular choice as a spreader headblock, with 130 in operation at container terminals around the world. 

SingFlex in tandem mode

Where it all began

Since its introduction, containerisation has become the most practical and economical way to transport goods globally.

Until the late 1990s, the dawn of twin lift spreaders emerged as the most practical solution to handling more containers per lift cycle in single hoist STS cranes. Our RAM 2900 twin lift series became a flagship spreader representing over two-thirds of our total spreader sales.

By 2011, heavier dual hoist cranes helped improve container flow, with a twin lift spreader below each of the two hoists. With heavier crane and wheel loads, complex operator controls, a larger trolley and two headblocks, a more effective solution for tandem spreaders working side-by-side on single hoist cranes was needed.

The biggest development since twin lift spreaders

Our design team developed and produced a prototype tandem headblock that allowed a crane operator on a single hoist crane to lift multiple containers simultaneously and adjust the gap, skew, and longitudinal offset between the two containers. Soon after, the first commercially ready tandem headblock called “SingFlex”, represented by single hoist flexibility.

A Quick change is a good thing

The unrivalled technological advancement is a key factor that sets SingFlex aside from the rest of the competition. It can change between single and tandem spreaders without manual intervention in under 2 minutes. No other tandem system can perform such a task more efficiently, which is done automatically when the crane operator lands the spreader(s) in the specially designed RAM docking station on the crane beam or quayside. 

This rapid change-over procedure which can be seen here in a short video, not only increases safety at the quayside but allows the crane operator to plan his lift schedule. There is no longer a need to factor in lengthy delays for changing from single spreader to tandem during a lifting schedule. The crane operator can increase lifts per hour, boosting a terminal’s productivity.

DPW London Gateway

The first set of commercially available “SingFlex” units was commissioned at DP World London Gateway, who back in 2011, using top of the range equipment, with some of the largest cranes in the world, created the second of the only two deep-water ports available in the UK, with access to rail terminals and logistics parks capable of receiving ever-increasing mega vessels.

“We supported the terminal in adopting tandem operations and worked alongside London Gateway’s technical team to ensure tandem operations ran as smoothly as possible.Philip Lee, CEO of RAM Spreaders

Today DPW London Gateway handle over 3.6 million TEU’s with over £43 billion worth of goods travelling to and from countries beyond the EU. SingFlex allows LGW terminals greater flexibility and a choice in shipping lines and cargo owners by offering a choice of deep-water entry and exit points to and from the UK. 

DPW says shipping lines recognise vessel turnaround at their terminal is superior to its competitors. Using tandem operations with RAM SingFlex has contributed towards a successful decade at London Gateway, with more terminals realising the benefits of single hoist tandem.

SingFlex has become a popular tandem lift solution thanks to terminals such as DPW London Gateway. We can see that tandem lifting on single hoist cranes will become the new industry standard in handling containers at the quayside.

london gateway - container handling

Andrew Bowen, Head of Engineering at London Gateway, commented after the first commissioning project, “We are pleased that single hoist tandem has allowed DP World to work more productively and as such, attract more business.

With over 150 units in operation worldwide, it is a testament to the sheer hard work and commitment our technical team and our customers who have invested in tandem operations with SingFlex and made it the industry phenomenon that it is today.

Winning Features

Why our customers choose to invest in the SingFlex headblock on a single hoist crane than a dual hoist crane for tandem lifting.

more productivity with a tandem container handling system


Adjust the gap, longitudinal offset, skew & height of containers


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. The SingFlex headblock can adjust the gap between containers, longitudinal offset, skew and height adjustment, allowing your container handling to flow.

low height for container handling system.

Low Height

3 metres between sheeve pin & bottom of container spreader

Low Height

 The height between the sheeve and the bottom of RAM’s 2940 STS spreaders means terminals can accommodate large mega vessels without the 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. 

Move more containers with container handling system

Move More Containers

Handle 2 x 20ft | 40ft | 45ft* or 4 x 20ft ISO containers

Move More Containers

Working with twin container spreaders, crane operators can handle 2 x 20ft | 40ft | 45ft* or 4 x 20ft ISO containers in one cycle. This allows terminals to boost their productivity by moving more boxes per hour. 

quick changeover between single and twin spreaders with container handling system

Quick Transition

Go from single spreader to tandem in 90 seconds

Quick Transition

When the crane operator places the spreader in the purpose-built docking station, it takes just 90 seconds to go from single to twin spreaders (vice versa). This is done autonomously without any manual intervention.

Less Maintenance

As a single hoist crane with headblock attachment is smaller in size & fewer in components than a dual hoist crane, less maintenance is needed & costly downtime is avoided.

Less Capital

A single hoist crane with a headblock attachment is a smaller investment than a dual host crane, due to the reduced amount of steel, fewer components & no groundwork modifications. 


Avoid Restrictions

The overall height between the sheave centre of the SingFlex & the bottom of the  RAM6900 spreader is just 3 meters. This allows a crane operator to reach higher whilst still in tandem. 


Using the SingFlex headblock on a single hoist crane will use 15% less energy than a dual hoist crane in tandem mode.

SingFlex - with European regional manager

Through the 10 years, our aftersales support team have been there to help our customers get the most out of their equipment. They have trained port staff, done preventative maintenance, commissioned headblocks onsite and provided genuine spare parts. 

Message from CEO or Cameron Hay on the future of SingFlex and tandem lifting.