scheepspropellers

A scheepspropeller, or ship propeller, is a propulsion device mounted on the stern of a vessel to generate thrust by moving water backward. It converts rotational power from an engine or motor into forward (or reverse) motion. The propeller is driven by a shaft connected to reduction gears or a direct-drive system, which lowers the engine speed and increases torque to suit hydrodynamic requirements. Typical large vessels use three or four blades, though two- or five-blade configurations are also found. Blades are usually made of bronze or steel, chosen for strength, durability, and resistance to cavitation.

History and development: The screw propeller emerged in the early 19th century through the work of inventors such as Francis Pettit Smith, Josef Ressel, and John Ericsson. The screw, used instead of paddle wheels, offered greater efficiency and allowed ships to achieve higher speeds with smaller engines. By the mid- to late 19th century, screw propulsion became standard on most ocean-going vessels and transformed maritime transport.

Design and operation: Propeller performance depends on diameter, blade shape, and pitch. Fixed-pitch propellers have a constant blade angle, while controllable-pitch propellers allow blade pitch to be adjusted in operation, improving efficiency across speed and load changes and enabling effective reverse thrust. Proper selection of propeller size and pitch is connected to engine power, hull form, and operating profile.

Modern developments: Many ships employ alternative propulsion concepts such as azimuth thrusters or podded propulsion, where electric motors drive propellers in pods that can rotate to change thrust direction. Water jets are used on some high-speed craft and specialized vessels. Regular maintenance, including inspection for cavitation, corrosion, and blade damage, is essential to preserve efficiency and reliability.