<b>Wind Drives</b> For many years, innovative concepts for wind drives have been brought into play again and again, but mostly as additional technology for otherwise conventionally powered ships. This happens against the background: - rising fuel prices - possible fuel shortages - Reduction of ship-side emissions / the greenhouse effect All technologies developed so far, such as. e.g. Flettner rotors or large kites (sky sails), however, it is inherent that additional investments are necessary for their realization and it is by no means certain that these additional expenses can be amortized over the course of the ship's operating life through saved fuel costs. In particular, because despite all the technology available today and a high degree of automation, additional effort may be required with regard to the operation and maintenance of these drive systems. However, these disadvantages could possibly be compensated for in the long term by sharply rising energy prices. In any case, wind propulsion, be it as a replacement or supplement to turbine or motor-supported propulsion systems, can only be used in a meaningful way for certain types of ships at low speeds and on certain routes, namely where steady winds blow over long distances and the cruising speed ultimately plays a subordinate role.