Interview: Dr. Dirk Jürgens explains the contribution of Voith's test tank during the development of the eVSP

The eVSP is far more than just a further development of Voith's legendary propulsion concept. Its design makes it significantly different from its predecessors. The many advantages of the innovation are based on years of research, often taking place in Voith's test tank. The test tank enables realistic measurements of the propulsion system including the hull. These measurements are indispensable, even in times of powerful computers, says Dr. Dirk Jürgens .

What part did Voith's test tank play in the development of the eVSP?

The test tank is an important tool for us in the development of new propulsion concepts as well as in their improvement. The tank has a large water surface as well as a special wavemaker. We can generate speeds of up to 4.5 meters per second. This allows us to make realistic measurements with ship models. One challenge with the eVSP was that the permanently excited electric motor (PM motor) has high efficiency across the entire power range. It also has a very high torque and fast response. This distinguishes the eVSP from its predecessors. In the test tank, for example, we can check in a practical way how these advantages can be optimally used for economical propulsion, e.g., very efficient dynamic positioning (DP) of ships.

Why do these tests involve testing the propulsion system with the hull?

The ship’s design plays a major role in the efficiency of the propulsion system. Therefore, a propulsion system must always be seen as part of an overall solution. In order to allow the customer to make optimum use of the advantages of the eVSP, we have to know the motion behavior of a ship in interaction with the propulsion system. In this way, we can work together with ship designers, yards and ship owners to develop an optimal unit of ship and drive.

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Aren't simulations more efficient than test tank trials?

Computational fluid dynamics (CFD) has immensely expanded our testing capabilities. The series of measurements allow us to work with almost every possible variable and to obtain results promptly. This certainly expands our possibilities. However, despite the continuously increasing performance of the IT infrastructure, it has been shown repeatedly that in-tank tests are closer to the real physics of special hydrodynamic effects and especially the interaction of the PM motor and the VSP’s thrust and torque. Furthermore, in the development of the eVSP, it has proven to be purposeful to combine both worlds. We are very fortunate to have such a powerful tank.

Some questions are answered but many others probably not: Please feel free to contact Dr. Dirk Jürgens , Vice President Research & Development, Voith Turbo Marine.