Turbine waterwheels. Gas, steam, and water turbines have a casing around the blades that contains and controls the working fluid. Credit for invention of the steam turbine is given both to Anglo-Irish engineer Sir Charles Parsons (1854–1931) for invention of the reaction turbine, and to Swedish engineer Gustaf de Laval (1845–1913) for invention of the impulse turbine. Modern steam turbines frequently employ both reaction and impulse in the same unit, typically varying the degree of reaction and impulse from the blade root to its periphery. The word "turbine" was coined in 1822 by the French mining engineer Claude Burdin from the
Rim-driven thruster Rim-driven thruster Rim-Driven Thruster is a novel type of propulsion unit which was presented at the Shipbuilding, Machinery & Marine Technology 2010 trade fair (SMM) by the companies "Voith" and "Van der Velden". The Rim-driven thruster is a marine propeller which does not need a hub for transmission of the driving torque. Conventional propellers need a shaft line which is driven by a turbine, a diesel engine or an electric motor. The more recent podded drives consist of a conventional propeller which is arranged together with a conventional electric motor into an azimuthable gondola under water. The blades of the