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The Voith Schneider propeller was originally a design for a hydro-electric turbine. [2] Its Austrian inventor, Ernst Schneider, had a chance meeting on a train with a manager at Voith's subsidiary St. Pölten works; this led to the turbine being investigated by Voith's engineers, who discovered that although it was no more efficient than other water turbines, Schneider's design worked well as ...
Bollard pull is a conventional measure of the pulling (or towing) power of a watercraft.It is defined as the force (usually in tonnes-force or kilonewtons (kN)) exerted by a vessel under full power, on a shore-mounted bollard through a tow-line, commonly measured in a practical test (but sometimes simulated) under test conditions that include calm water, no tide, level trim, and sufficient ...
English inventor Francis Ronalds described what he called a propelling rudder in 1859 that combined the propulsion and steering mechanisms of a boat in a single apparatus. . The propeller was placed in a frame having an outer profile similar to a rudder and attached to a vertical shaft that allowed the device to rotate in plane while spin was transmitted to the propell
In marine propulsion, a variable-pitch propeller is a type of propeller with blades that can be rotated around their long axis to change the blade pitch. Reversible propellers—those where the pitch can be set to negative values—can also create reverse thrust for braking or going backwards without the need to change the direction of shaft revolution.
The propeller shaft extends a sufficient length forward from the boat to ensure that the flow around the propeller is not disturbed by the boat. The test is conducted by towing the open water boat at a steady speed while running the propeller at a constant revolution rate.
[clarification needed] The choice between using thrusters or traditional propellers to propel marine vessels is a compromise between versatility and efficiency. Propellers are designed to work in-line with a propulsion plant and produce one-directional thrust while thrusters are more customizable and have a more versatile application.
A ducted propeller, also known as a Kort nozzle, is a marine propeller fitted with a non-rotating nozzle. It is used to improve the efficiency of the propeller and is especially used on heavily loaded propellers or propellers with limited diameter. It was developed first by Luigi Stipa (1931) and later by Ludwig Kort (1934). The Kort nozzle is ...
The device is different from the Voith-Schneider marine propulsion system (also mechanically linked), which can also quickly change the direction of thrust, as the Z-drive uses a shrouded conventional screw that pivots or rotates the propeller, unlike the variable-geometry blades of the Voith-Schneider.