Mechanical Depth Finder by Thomas Walker & Son, Ltd--SOLD


The instrument is designed simply to go straight down and find the depth of the bottom. It has an impeller which drives a threaded gear that turns a disk printed from  0-30 fathoms. There would be a sounding lead attached and thrown overboard. As the device makes its way to the bottom, the gear is counting. On the backside there is a flap which drops down and locks the rotor when the device has hit bottom and is raised back to the surface to record the depth. A small plaque reads Walker's "Harpoon" Depth Finder,  Thomas  Walker  &  Son  Ltd,  58  Oxford  St,  Birmingham with serial number 1341-M.  There is also a special manufacturer's stamp of an anchor and the letters T and W.  Circa 1920.  New old stock. 

Case 11 x 5 x 5 inch. The device is 9 1/2 inch.