According to Stefan, the SSB research was also an enabler for scale increase. The big projects in Singapore and Hong Kong would never have been possible without the work of SSB. It goes even further back. All the ports in the Middle East where rock dredging was taking place would also not have been possible without the fundamental research on rock cutting and cutter suction dredgers. In the beginning, dredging companies were very secretive about sharing their research and developments in vessel design and production innovations. This too has changed. Companies realised that closing themselves off from the rest of the world was not wise. If you want to stay a frontrunner in competition, you have to develop your knowledge and technological standards. The moment you stop developing, your competitors will take over.
Early research days
In the mid-70s, Kees was involved in all kinds of research projects. Volker worked with the municipality of Rotterdam carrying out research around the city. Many areas had been reclaimed with contaminated dredged material from the port of Rotterdam and were in fact polluted. Together with the port of Rotterdam, Volker did a joint study with the United States Corps of Engineers (USACE) to find a solution to the problem. First, they had to establish how dangerous the chemicals attached to the silt particles were. Did they enter into foods that were grown in urban gardens in the reclaimed areas? And how thick would you need to cover the polluted soil to eliminate those dangers. Through that project, Kees came to know many colleagues in the US and the Corps. The fact that he is still a member of ASCE-COPRI indicates the importance of that time in his career. Looking at the dredging process today in the port of Rotterdam, it no longer has to do with contaminated sediments. Due to all kind of measures, the water quality has improved tremendously and all the sediment that settles in our estuaries is no longer polluted, which is a great victory.
As already mentioned, research on specific equipment was necessary. There was no specialised equipment at that time, it had to be invented and developed especially concerning the reduction of turbidity. An example is the development of a diffuser to reduce the turbidity when discharging material in a deep pit. For the same purpose, many companies changed the design of the overflow of the trailing suction hopper dredgers so that the turbidity remained close to the bottom. The attention was not restricted to the disposal of material, it was also attempted to reduce the spill of material at the actual digging location like the cutter of a CSD, the bucket of a BLD and the draghead of a TSHD. The research of the dredging industry together with supply chain partners and research institutes has resulted in several very effective measures such as the green valve system for trailing suction hoppers, which reduces turbidity caused by overflow during the dredging process. The knowledge collected by environmental monitoring was evident in decisions on dredging around coral reefs. And the development of predictive models and simulation tools contributed to knowledge-based decisions.
A more formal approach to training
30 years ago, dredging was considered perhaps more an art than a science. Later came the realisation that a more formal approach to training than practical experience was desirable. When Kees was appointed professor at Delft University of Technology, the only education in the field of dredging was in the faculty of mechanical engineering and core of that course was the construction of dredging equipment. It was not aimed at working with dredgers. Whilst some of the professors tried to introduce the subject, there was hardly a civil engineering student who studied dredging.
Kees was not happy with what the students were taught. When he took over the lectures of Eco Bijker on maintenance of coastlines, Kees saw his chance and started lecturing on the role of dredging. He taught students the theoretical background, how the production process works, as well as how you cost estimate a project and all the factors involved.
“I taught students how a trailing suction hopper dredger works and what impacts the dredging process. I explained how to calculate the cost of a project taking into account the production cycle time, mobilisation, installation and dismantling costs, etc. And most important, factoring in the risk as there are many uncertainties that come into play. What is the risk for the contractor and for the employer? And last but not least, calculating the profit margin. All of which gives you the price to the client.” In a later stage, Kees got support from the industry through the Dutch Association of Dredging Contractors that made a dedicated part-time teaching role possible.
“We give exactly that same class today,” says Stefan. “It’s the starting point that provides students with the basic scenario, whereby you can only optimise based on the requirement to maximise production rates. And then we build out with additional requirements, including environmental requirements. If one of the requirements is to take care of a coral reef, located two kilometres from the site, then you have a simple model to estimate how the suspended sediment concentration decreases with increasing distance from the dredging activities. Then additional requirements come into play such as limited emissions allowed, which becomes increasingly important. There are, of course also functional requirements. If you have both good and poor quality sediment, but you need good quality sediment at the location where you’re going to construct a port for instance, this also needs to be considered.” It’s interesting to hear how both professors taught the same class. Today, students receive lectures on both dredging equipment, taught by the Mechanical Engineering department headed up by Cees van Rhee, as well as the more civil engineering elements that Stefan teaches together with Mark van Koningsveld, as part of the Hydraulic Engineering track at the faculty of Civil Engineering and Geosciences.
Teaching the commercial aspects of the industry
According to Kees, it is a responsibility of the university that students are taught the commercial aspects of the dredging industry. He explains, “You’re not simply preparing students for scientific work. You’re preparing engineers for a life in the real world. Whether it’s working for the government, a company, as a contractor or a consultant, students have to realise it’s part of their education. You have to realise that everything costs money otherwise you cannot be a proper engineer.”
In broadening the conversation, Stefan explains, “This is one element where we want to educate students. At the end of the day, you want to apply your technical knowledge and expertise in a real- world context. And the commercial consideration is one element of that context. You want to employ an engineer who knows how to apply their knowledge to the benefit of something bigger. The environmental aspect is another element. As an engineer, you also need to be able to communicate to an ecologist for instance and to be aware of the impact of dredging activities to the outside world. You don’t need to become an ecologist, but you need to be able to interface with people in this and other specialties.”
Transition from theoretical to practical knowledge
Students today are extremely enthusiastic when they have the opportunity to deploy their technological expertise to the benefit of real-world projects; designing and building interventions to the benefit of society, protecting against flooding for example, and creating opportunities for nature. That’s a big driver nowadays according to Stefan. “Off course, there are still those who really go for the big equipment and big projects but the majority of students have a much more altruistic attitude.”
From that perspective, the dredging industry has really transformed, starting from the strong core that it has. At the end of the day, dredging companies have successfully built all kinds of complex projects at challenging locations across the world. “When dredgers come in,” continues Stefan, “it generally means that there is nothing there. Only a beach and an ocean and there you go. That’s still the case, but at the same time, the industry wants to work in a responsible way. That’s where high-end dredging companies nowadays are making a difference. And that’s something students in particular want to be associated with.” Students get the whole story by being shown the entire picture of what the dredging industry looks like and entails. “These links between the industry and all universities, not only Delft University of Technology, are so very important,” says Stefan. According to Kees, it goes deep into the philosophy about the role of a university. “You want to employ an engineer who has had an academic education, but you still expect that they also have the practical experience and know how to carry out the job at hand.”