Grabs are used for unloading dry bulk cargo vessels such as iron ore or coal. The request for higher payloads, shorter cycletimes and longer lifetime results in a permanent desire of a more efficient grab.

Development of grabs and other types of bulk handling equipment is still a complicated process: predicting the performance of a new design is hard, as continuous models are not very suitable due to the particulate nature of the dry bulk material. The current design process of bulk handling equipment such as grabs is based on years of experience and consists of designing a prototype, building it in the factory and evaluating it at a test site. This is an expensive process involving high risks and long R&D times. Virtual prototyping is proven to be successful in predicting the performance of bulk handling equipment such as grabs and an efficient method to improve grab designs.

A validated model using the Discrete Element Method (DEM) and Multibody Dynamics (MBD) has been developed at TU Delft and is ready to be used for predicting the performance of a virtual prototype grab. This combined model computes the behavior of the individual particles as well as the behavior of the grab. With this tool, the performance of virtual prototypes can be compared, indicating whether a design change is an improvement or not. As many variables can influence the performance of a grab, finding an optimal performance is a challenging task.


Currently there are multiple MSc thesis and Research assignments available within this project. Ranging from DEM supported optimization of grab designs to development of completely new grab concepts.

The research will be carried out together with the TU Delft, 3ME, section Multi Machine Engineering. During this project the supervisory team exists of Dingena Schott (section Multi Machine Engineering) as well as the Engineering team at Nemag B.V..

The office location of the student is open for discussion (Delft and/or Zierikzee). A monthly allowance and travel expenses will be offered.



Interested in one of these projects? Students can apply for this position by sending an email to or



For more information contact us or apply for this position.

Apply now

Persoonlijke informatie


Want to know more about working at Nemag? Please contact our colleague.

ir. Michel Corbeau
General manager

+31 111 418 934

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Compare the grab glossary

Crane capacityIs the Safe Working Load of your crane in tons in grab duty, i.e. the total sum of grab dead weight and payload.

PayloadIs the nett load of cargo in the grab. Because it’s linked with the grab weight it will be filled in automatically.

Grab weightIs the Dead weight of your existing grab. Not sure? Check your grab manual, CE declaration, or on the ID plate on your grab.

Grab rope withdrawal lengthIs the length of the closing rope which needs to be pulled out in order to close the grab (not to confuse with the total reeved in grab rope length).

Not sure about the numbers?Check the grab manual. Don’t hesitate to contact us.

Riny Stoutjesdijk
Sales manager

+31 (0)653109307