sternpaddelwiel

Sternpaddelwiel, literally stern paddle wheel, is a propulsion device used on watercraft in which a large wheel with paddle blades is mounted at the stern. The wheel is driven by an engine and rotates to drive water backward, producing forward thrust. The design allows a relatively shallow hull draft and is especially compatible with river work and calm seas. Paddle blades can be fixed or hinged to adjust immersion.

Historically, stern wheels proved common on inland waterway steamers in the 19th century. They offered robust operation, simple drive trains, and good maneuverability at low speeds. In North America, sternwheelers operated on major rivers; in Europe, similar vessels appeared on some rivers and coastal routes before propellers dominated. The transition to screw propellers from the late 19th century reduced their use, though some vessels remained in service into the early 20th century and are preserved as heritage ships.

Operating considerations include wheel diameter, blade geometry, and clearance from the hull and waterline. Efficiency depends on matching engine power to wheel size and hull conditions. Disadvantages include limited top speed, greater wake, debris vulnerability, and maintenance of the large wheel and bearings, as well as a larger hull clearance than with a single propeller.

Today, sternpaddelwiel systems survive mainly in museums or on heritage steamers used for tourism and education. They are studied as part of the history of marine propulsion alongside paddle wheels, screw propellers, and other steam-era technologies.