Speed, Time & Distance Slide Rule

A Naval slide rule pattern 1448 and marked with a broad arrow. Used by navigating officers to find the time required to run a given distance or to find the speed made good from the time taken to run a known distance. An essential tool in the days before satellite navigation, complete with original operating instructions and card case. It appears to be in good working condition and a great souvenir of times gone by. It measures 12.5" (32 cm)