A brass and metal “Cherub” rotor, designed for use with a Walker’s ship’s taffrail log to measure a vessel’s speed and distance travelled through water. The rotor consists of a torpedo-shaped brass body with three fins, attached to a braided rope with metal fittings. A manufacturer’s tag bearing the product name and illustration of its use remains affixed.
The “Cherub” model was a compact and efficient version of the taffrail log system, patented in 1878 by Thomas Ferdinand Walker (1837–1921). It was widely used during the early to mid-20th century for both merchant and naval applications, particularly prior to the adoption of electronic speed-measuring instruments.