Nautical Navy Shaft Revolution Indicator System

During WWII, the US Navy relied on it to monitor and regulate ships’ propeller shaft speeds. The system, with a tachometer generator, transmitter, and indicating unit, had the generator attached to the ship’s propeller shaft.

The generator produced an electrical signal corresponding to the shaft’s rotational speed. The transmitter amplified the signal, displaying it in RPM on the indicating unit. Its precision was crucial in modern naval operations.

Remarkably, some units still operate today, over 80 years later, a testament to their enduring durability and precision engineering. As a collector’s item, it holds practical and historical value, making it a fascinating addition to collections focused on military or technological artifacts.