Terneuzen lock: DCN Diving deploys divers where needed, remote equipment where possible

Safety comes first in the construction of the New Terneuzen Lock. Both above and under water. This is why DCN Diving is making a well-considered choice between deploying divers and remote equipment for the underwater work. 

The New Terneuzen Lock is characterized by the versatility of the work, much of which takes place underwater. "We are not a standard diving company and the work for the New Lock Terneuzen was so diverse that virtually our entire range of services was covered," explains Maikel Fierloos, project engineer DCN Diving. "In doing so, we literally and figuratively went into the depths. From pouring underwater concrete and applying cathodic protection and developing a new machine, to inspecting quays. From the beginning, we were involved. The first call-out was the pouring of underwater concrete floors and the preparatory work for this. We are also experts in this. In total, we poured around 40,000 m3 of concrete, a substantial amount. During the course of the project, we were called in in several areas, including the burning away of sheet pile walls, inspections of new quay walls, cleaning the underwater contact surfaces, checking that the bottom protection fits properly, sinking and (de)assembling bottom grids and removing equipment from a ship's propeller." 

Human or machine?

Depending on the work, but also on the client's wishes, DCN Diving makes a choice between deploying divers and remote equipment. "There is an increasing demand from clients to perform underwater work diverless, due to safety perception and technological developments," says Mick van den Bergh, manager inshore at DCN Diving. "With our experience and knowledge of both inshore and offshore, we know that working with divers can be done safely. We also demonstrated this in this project. However, it is important to work according to strict regulations. Nevertheless, we too choose to use remote equipment for certain work. For example, for the work for Sassevaart we developed a special sawing machine to cut the reinforced concrete under water. As a diving company, we have the great advantage of knowing exactly what is and is not possible under water. And we have the engineering in-house which makes it interesting for our client. So we can, when necessary, develop customized equipment for a specific part of the job. So that also means that we can perform work safely underwater at all times, with or without the use of divers."

Testing, testing and more testing

In the final phase of the project, the Bergen op Zoom family business is closely involved in the cathodic protection of the lock components, maintenance and installation of the lock gates. "For example, a lot of tests have to be carried out to demonstrate that the locks are working as conceived," explains contractor Ties den Oever. "To give an example of a test: the lock gates are fitted with under rollers at a depth of 18 meters, which in turn are fitted with quite a lot of measuring equipment. Suppose they have to exchange these at the lock in the event of a calamity, we have to be sure that we can carry out the maintenance work within the set stoppage hours, so that shipping traffic is affected as little as possible." 

Compliment worthy

What all three of them personally find special about the project is that they get to experience up close the entire development of the New Lock Terneuzen. "It is fantastic to be involved in this. The scale is impressive as are the many parties involved. Looking also at the importance of safety, we are certainly proud of the fact that in the past seven years we have worked with so many man hours without any accidents. It is certainly a compliment to Sassevaart that the coordination of the entire project is going well in practice."