underschlächtige

Underschlächtige refers to a type of waterwheel where the water strikes the wheel from below. The water flows into a channel or trough that guides it to the bottom of the wheel's buckets or paddles. As the water fills the buckets, its weight causes the wheel to rotate. This design is distinct from overshot or breastshot wheels, where water impacts the wheel at different heights.

The undershot waterwheel is one of the simplest and oldest forms of waterwheel technology. It is particularly effective in locations with a low head of water, meaning a small difference in elevation between the water source and the discharge point. The flow rate of the water is more critical than the height of the fall for the efficiency of an undershot wheel. While it may not achieve the same power output as an overshot wheel for a given volume of water, its ability to operate with minimal head makes it suitable for many river and stream applications.

Historically, undershot wheels were used for a variety of purposes, including powering mills for grinding grain, operating bellows for blacksmith forges, and driving early industrial machinery. Their construction is generally less complex than other waterwheel types, contributing to their widespread adoption. Modern applications are rare, but the principles of undershot operation can still be seen in some small-scale hydroelectric power generation systems.