Toroidal propellers, also known as rim-driven thrusters, have been designed to offer several benefits over traditional propellers, but their efficiency is not always higher.
The efficiency of a propeller is typically measured by its ability to convert power input into thrust. The design of toroidal propellers allows them to produce less turbulence and disturbance in the water, which can result in reduced drag and improved efficiency. In addition, the lack of a hub or central shaft in the design of a toroidal propeller can further reduce drag and improve efficiency.
However, the efficiency of a toroidal propeller can also be influenced by several factors, such as the size and shape of the propeller, the speed of the vessel, and the power output of the propulsion system. In some cases, traditional propellers may be more efficient than toroidal propellers, especially at higher speeds or for vessels requiring higher power outputs.
Therefore, whether toroidal propellers are more efficient than traditional propellers depends on the specific application and requirements. In general, toroidal propellers can offer improved efficiency in certain situations, but their effectiveness should be evaluated on a case-by-case basis.