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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 ...
A pump-jet, hydrojet, or water jet is a marine system that produces a jet of water for propulsion. The mechanical arrangement may be a ducted propeller (axial-flow pump), a centrifugal pump, or a mixed flow pump which is a combination of both centrifugal and axial designs. The design also incorporates an intake to provide water to the pump and ...
Marine engineering is the discipline concerned with the engineering design process of marine propulsion systems. V12 marine diesel engines . Human-powered paddles and oars, and later, sails were the first forms of marine propulsion. Rowed galleys, some equipped with sail, played an important early role in early human seafaring and warfares.
[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 propeller (often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working fluid such as water or air. [1] Propellers are used to pump fluid through a pipe or duct, or to create ...
ABB provided an azimuth thruster for ShinNihonkai Ferries in form of the CRP Azipod, [2] claiming efficiency gains from the propeller (about 10% increase [3]) and a simpler hull design. Volvo Penta have launched the IPS ( Inboard Performance System ), [ 4 ] an integrated diesel, transmission and pulling contra-rotating propellers for motor yachts.
It is carried out to determine the open water characteristics of a propeller. A geometrically similar model is produced with the model-prototype correlation. The model propeller is attached to a propeller dynamometer fitted in an open water boat. The dynamometer measures the thrust and torque of the propeller.
This bubble completely encompasses the propeller that is in operation. With the differing characteristics of the seawater outside of the bubble and the air inside, a zone develops that has the ability to reduce the resonance frequency. [1] Due to this reduction, cavitation is less likely to occur during the operation of a marine propeller. [1]