Thu Jun 04 2020

06 04

Modular design for largest crane worldwide


Door Bart Driessen

Belgian crane builder Sarens christened ‘Big Carl’, or SGC-250 (‘Sarens Giant Crane 250’), in November 2018. Both domestic and international relations came to see ‘Big Carl’ in the port of Ghent, which is logical as it is the largest ring crane worldwide.


// Factory Facts //

  •  Hybrid cables
  •  Collaboration cabling automation
  •  Complete network safety and hydraulics

Read the Dutch version here

This crane’s superlatives are reflected in different ways. The height alone, by which the crane is visible from a great distance, greatly stands out. The ‘Big Carl’ consists of a mainboom, varying in lengths of 96, 118, 130 to 160 metres. In addition, the mainboom can also be extended with a jib with sizes of up to 100 metres. The crane can hereby reach a height of 250 metre. In comparison: the Zalmhaventoren in Rotterdam reaches 215 metres and the Eifel tower reaches up to 324 metres. The crane also beats all records in hoisting capacity. The crane’s maximum load carrying capacity is 250,000 tonne metre. If the mainboom is hoisted to a height of 160 metres and at a horizontal distance of 40 metres from the ring’s centre to the hoisting position, then the crane can lift a 5000 tonne load. If the crane is topped down with its load, the hoisting capacity also decreases. But even then, the ‘Big Carl’ still delivers an impressive hoisting capacity. At a horizontal distance of 100 metres between crane and load, the hoisting capacity is 2000 tonnes, or the weight of 567 elephants. At 165 metres, this is still 775 tonnes: equalling the weight of three Airbuses A380. The use of the 160 metre mainboom can of course also take place without the 100 metre long jib. Where large loads and distances are concerned, the combination of mainboom and jib is evident. Fitting hooks can be hung from both booms.

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A new star is born; ‘Big Carl’ from Sarens is ready to conquer the world


Why so big?

The decision to make the ‘Big Carl’ so extensive and mobile has to do with the construction of Hinkley Point C, a new nuclear plant that is currently being built in Somerset, England. This project’s contractor is a joint effort of Bouygues Travaux Publics (France) and Laing O’Rourke Construction (UK). These two companies have accepted this project for roughly 22.7 billion euros. Sarens will carry out the major hoisting activities, as it meets all requirements concerning this plant’s construction. With ‘Big Carl’, Sarens provides sufficient capacity for moving very large parts, such as the five main parts of the ‘steel containment liner’ and the dome. Moreover, the crane is so mobile that it can swiftly move itself across a large area. This is useful, as the work area is 6 kilometres long and consists of two reactors, plus various installations. As ‘Big Carl’ can handle all this, the contractor has already rented the crane for a 4 year period. The expectation is that Hinkley Point C will after four years be able to do without the Belgian mega-crane.

Mobility for mega-cranes

A challenge for all mega-cranes is mobility. Because along with increasing the capacity, the crane’s mass also increases, resulting in a decline in the crane’s mobility. Mega-cranes with a size close to that of ‘Big Carl’ can therefore usually just rotate. The largest part of the crane construction then turns on a ring-shaped rail. However, a long straight-line rail is used in the case of ‘Big Carl’, as well as three separated rings. Sarens opting for the combination of long straight-line rail and three rings has to do with the location where ‘Big Carl’ will soon begin its work: the premises of Hinkley Point C. This will feature a 600 metre long rail, specifically built for the ‘Big Carl’. Three locations with ring-shaped lifting areas will also be added onto this rail, on which the crane can turn. This occurs at a diameter of 48.5 metres. As many as 128 hydraulically driven wheels of steel ensure the rotary movement. If the crane needs to be moved to another lifting area, then 96 other wheels spring into action, which are also hydraulically driven, ensuring that the crane moves straight. It is however important that the crane is raised from the hoisting area, which in turn takes place by means of 24 hydraulic lifting cylinders.

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The largest crane worldwide is Belgian

Modular construction

Another significant part of the construction is ‘Big Carl’s’ modular construction. The Sarens engineers have ensured that each part of the crane has been built in such a way, that it can be easily dismantled. When the hoisting task has been executed and the crane is dismantled, all parts are stored in containers, mainly standard sea containers. There are also 52 specifically constructed ballast containers, of which some transports machine parts. All of these ballast containers are however locally filled with sand or pebbles, and stacked onto the back of the crane, so the crane is guaranteed to have a counterweight of 5,200 tonnes.

Collaboration for cables and networks

‘Big Carl’s’ modular construction however reaches beyond the steel parts. ‘Big Carl’ is in fact a large mechatronic system, in which alongside mechanics and electrics, electronics, hydraulics, and ample operating software and network technology are also active. This means powerpacks with aggregates, hydraulic motors and pumps, PLCs and HMIs for controlling different boom parts, wheels, and winches. Components that are both directly and indirectly connected. All of the controls’ engineering was carried out in 4 months by Peter de Ras and Michael Brockhans from ZSystems, in collaboration with Maarten Koort from FELTEN Wire & Cable Solutions. Both parties have previously worked together on Sarens projects: ‘Big Benny’ or SGC-120, and ‘Big Benny XL’ or SGC-140. Michael Brockhans from ZSystems explains, “Because we already have previous experiences in constructing ‘Big Benny’, we were also assigned this project. We take care of the entire operation of the crane, including all networks, cabling and connections. With Maarten’s knowledge of cabling, we make a good team for the ‘Big Carl’ project. Due to the modular concept, we often work with plug type connectors. Controls, cabinets, sensors, motors, and pumps are separated in different sub systems, but are integrated in one large network. As all machine parts must be separated when moving, we must ensure the correct plug type connectors. The parts of the networks can therefore very swiftly be disconnected and connected. Maarten Koort and his colleagues have ensured this, resulting in the fact that our systems on ‘Big Carl’ are truly modular.”foto 4 2foto 4 IMG 429


Customer-specific solutions for ZSystems. LEONI hybrid network cable is assembled with modular inserts. Big Carl with big data runs on circular miniature connectors.

LEONI hybrid cables instead of tubes

The close collaboration between Maarten Koort from FELTEN Wire & Cable Solutions and Michael Brockhans from ZSystems makes up a special part of the project. Michael Brockhans was looking for a good and reliable cabling. Alongside PROFINET, the cabling also had to be able to provide Ethernet and parts CanBus communication. With two separate networks, PROFINET took up most of the network. Maarten Koort comments on the collaboration, “The ‘Big Carl’ is a highly prestigious project for us, too. We have supplied 700 metres of customer-specific cable for this. This is a hybrid cable, which means it is composed of different elements. All elements - two times PROFINET, one Ethernet Cat6a, CANbus, and two spare leads - were joined and extruded with one single FRNC outer jacket. The cable hereby meets all standardisation requirements, including IEC 60332-3-24, LS IEC 61034 (UK), increased oil-resistance IEC 60811-404 and offshore conditions according to 60092-360 SHF2 (ozone and UV resistance). The design and production of this hybrid cable was handled by LEONI Special Cables from Friesoythe. The Systems 2.0 department at FELTEN WCS engineered the entire assembly. The design’s main aspect was selecting the metal IP68 industrial housing, due to the increased EMC and resistance to water and corrosion. A modular construction was selected for the inserts, consisting of four circular MIXO connectors. We were hereby able to separately connect the different data elements from the hybrid cable. It is actually hard to imagine, but the world’s largest crane communicates via small gilded 1.6 mm leads! We have furthermore made 25 hybrid cable sets and junction boxes for the connections from the electrical cabinets to the lifting cylinders. These cable connections, totalling about 550 metres, do however include cable hoses. The cable set is subdivided into 8 standard LEONI cables and is mainly used for the data transport of 4-20 mA pressure sensors, SSI encoders, feedback logics, proportional valves, valve switches and a spare cable. All field cables have been complied by us into so-called kitting packs, which include 540 standard M12 sensor cables that we have purchased via our partner Weidmuller. Finally, we provided 35 CEE cables for 16 and 32 amp for the junction boxes supply voltage for the PowerPacks and winches.” says Maarten Koort.

L45467 J616 W6 EN 1

Cable hybrid PN ET by FELTEN Wire & Cable Solutions

In ‘Big Carl’s’ cabinets, the presence of Bosch-Rexroth controllers quickly stands out. Bosch-Rexroth was also present in ‘Big Benny’, albeit about seven years ago. What is the current situation with automation and networks? Peter de Ras from ZSystems explains: “A lot has changed. Just think of, for instance, power over ethernet (PoE): running power through the same cable as the controller data. This is huge progress for engineering. Video is another technology that is now much easier to integrate. For the Sarens project, we positioned 24 cameras all over the crane. All images are now simultaneously and effortlessly visible in real time via Ethernet. This was previously impossible. The capacity of Ethernet just did not suffice. Nowadays, the data of  24 cameras will still take up a lot of bandwidth. But I nevertheless still have at least half available for my control data-stream. Even some bandwidth for GPS-data reserved. It will up the requirements even further, but I expect we’ll  need it in  future, especially for the use of handheld PCs.”

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Electrical cabinets are equipped with SYSTEMS 2.0 internal cable sets.

Protocols for ‘Big Carl’s’ Machine Control

Michael Brockhans comments: “We have used PROFINET as protocol for machine controls in our projects since 2012. One of the benefits of PROFINET is the easy separation between motion control and slower data traffic. We use the VPB40.4, an industrial Box-PC from Bosch-Rexroth with integrated PLC and Motion functionality for the main controller of all processes within the Sarens crane. This PC is equipped with two PROFINET/PROFIBUS master cards that have been included on the same interface card. The PLC/motion controller can communicate with PROFINET and enables both the real time motion drive and slower data transfers. This control can therefore easily synchronously drive four winches. Another great advantage of PROFINET is that we can now follow everything both on location or decentralised. All information on the cranes process, including safety information, is now visible all over the crane. As we wanted PLe, the highest safety classification, we have included Bosch-Rexroth’s Safe Logic Compact safety components in our controller. The crane hereby meets the highest safety standards.”

Construction and Inspection

Kris Colman and Tom Derveaux, both engineers at Sarens, add, “The engineering by Sarens took about a year. The preliminary design was executed by engineers and consists of selecting both parts and specialists. Choosing the best companies for the outsourcing of specific activities in particular required ample focus. Our engineers furthermore came up with the necessary drawings. Interim quality inspections regularly take place. Metal parts are also regularly inspected on whether all steps comply with the provisions as described in EN10-90-2. Whilst the production of metal parts is usually subcontracted, the ultimate construction of the crane is carried out by Sarens. This takes place on a large quay in the port of Ghent. During construction, there are once again inspections on all parts to see if they are within their required tolerances. The dimensions of parts, including those of the large crane itself, are assessed to millimetre accuracy. Other tests on the quay include the so-called bandwith tests. These tests rigorously examine the maximum permissible load of all crane parts. This in practice means that we first load the crane to its maximum specified capacity. After this, we add another 25%. Obviously not a task that you could execute elsewhere, or ‘don’t try this at home’. When all inspections have been successfully performed, CE approval follows. And this is finally followed by the double check for certification by SGS.”

Network Parts

  • 19 PLC/Motion controllers (1 x Bosch-Rexroth VPB40.4 master controller and 18 x Bosch-Rexroth XM22 controller for local machine parts)
  • 6 PLC controllers (Bosch-Rexroth XM22 for powerpacks)
  • 25 Safety PLCs (an SLC from Bosch-Rexroth for every part of the machine)
  • 14 Bosch-Rexroth HNC100-3X-SEK hydraulic controllers for the hydraulic motors (secondary units)
  • 12 Bosch-Rexroth VT-HPC pump controllers for powerpacks
  • MLPI software from Bosch-Rexroth for HMI applications


First mage: SWL 3,200T hook (weighing 105T) with from left to right: Kris Colman from Sarens, Maarten Koort from FELTEN Wire & Cable Solutions, and Michael Brockhans from ZSystems

All images: Bart Driessen