In the German Bight of the North Sea a huge number of offshore wind power plants are planned, under construction (Bard Offshore 1) and in use (Alpha Ventus). Each of these wind generators will have an electrical power of more than 5 MW, which means that especially the foundations of the respective gigantic towers have to be laid out with outmost care and accuracy.

The founding structures are normally mono-piles or tri-piles/tri-pods and jackets, and they are rammed into the sea bed, because the soil of the North Sea is too weak for simple gravity foundations. On the other hand there are at least two important points of uncertainty for this founding procedure: Rocks in the seabed and the acoustic impact on marine mammals.

Thus, the German company Herrenknecht AG has initiated a feasibility study to find out the ecologic and economic advantages of its Vertical Shaft Machine (VSM), which is drilling the basement holes of the piles. This feasibility study has been funded by the German Government.

The VSM can cut 40 m long founding cylinders at a sea depth of 80 m in the soil with a diameter up to 10 m. It turned out that the founding parameters against bending are equal to those of the ramming method in the normal founding depth. But what is most important from the ecological point of view is that the acoustic impact is less than 117 dB, compared to 162 – 173 dB as produced by pile driving methods.