Evaluation and Analysis of Vertical Cycloidal Propulsors

Research Project, 2024 – 2026

A variety of propulsion systems for ships have been developed to improve performance and thereby reduce energy consumption. However, it is difficult for shipowners and other stakeholders to ensure that these concepts work in real-world conditions and to evaluate them objectively.

Vertical cycloidal propulsors have been on the market for a long time, but their main advantage has been maneuverability rather than energy efficiency. ABB is now developing a new propulsion system inspired by humpback whale fins, with a potentially very high open-water efficiency. The ABB Dynafin propulsor is a unit consisting of several vertical fins that rotate around a vertical axis. As the axis rotates, the angle of attack of each fin is adjusted by a separate servo motor in order to achieve maximum lift. Since the lift components from all fins act in the same direction, they function as thrust to drive the vessel forward. An advanced control system enables the thrust to be directed as desired, eliminating the need for a rudder. Because the fins are individually controlled by servo motors, the system can potentially optimize the maximum thrust generated by each fin during each cycle, increasing efficiency compared with similar concepts.

The purpose of the project is to develop a method for independent evaluation of vertical cycloidal propulsors. ABB’s Dynafin innovation is used as a case study to evaluate the method. Being able to assess the potential of these propulsors is necessary for the maritime sector to accelerate the transition toward sustainable shipping. The use of these propulsors could potentially be advantageous for electric vessels, as high propulsion efficiency significantly reduces total energy consumption. This technology is also considered potentially useful for wind-assisted vessels, since the thrust direction of both the propeller and the sail can be optimized simultaneously.

Through this collaborative project, Chalmers University of Technology together with RISE, ABB and STENA Teknik develop evaluation methods for high-efficiency cycloidal propellers. The study also includes the scalability of the technology, the dependence of efficiency on the Reynolds number, the design of measurement techniques for testing, and an estimate of the required power scaling for servo motors.