Rim-driven thruster

The concept was proposed by Kort around 1940, but only became commercially practical in the early 21st century due to advances in DC motor controller technology.

[1] As of 2017, commercial models of between 500 kW and 3 MW are available from manufacturers such as Rolls-Royce, Schottel, Brunvoll, Baliño, Voith, Van der Velden, etc.

Conventional hubcentric propellers typically use a shaft driven by a turbine, a diesel engine or an electric motor.

The largest advantages of the rim-driven thruster are lower noise emissions, potentially increased efficiency, and a compact design that enables relatively simple integration in many applications.

The potential efficiency improvements might also be tricky to achieve due to friction losses in the gap between the rotor and its surrounding stator.