An antique - but likely unused - ship's log by Thomas Walker of Birmingham. A critical piece of equipment dating back to the days long before the invention of global positioning systems, it recorded the distance travelled by a vessel at sea. Navigators would use this information, along with compass headings and measurements of elapsed time, to plot a ship's course.

This particular example of Walker's 'Excelsior IV' most likely dates to the 1940s and is complete with original stand, spinner, rope (unfurled with original label) storage box and instructions entitled “Walker’s “Excelsior” IV Patent Log, Outrigger Pattern (For Yachts, Motor Launches and small Fishing Craft). Made in England by Thos. Walker & Son, Ltd, 58, Oxford Street, Birmingham.” The enamelled display dials are marked in nautical miles and tens of nautical miles.

14cm from front to back, 6cm dial, storage case 39cm x 15cm x 18cm. Rope 100ft.

Thomas Walker (pictured, stock image) was an engineer based in Birmingham, England, who patented a number of designs for ships' logs. He was the son of Edward Massey, who pioneered the first commercially viable 'harpoon' log in 1802.