Patented 18th Sept. 1866 Walker’s A2 Harpoon Ship Log Marine Navigation Device

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Patented 18th Sept. 1866 Walker’s A2 Harpoon Ship Log Marine Navigation Device

About the Item

Brass log in the shape of a harpoon, signed Walker’s A2 Harpoon Ship Log Patented 18th Sept. 1866. It is an ancient nautical instrument, very rare and with a characteristic shape, which measured the distance and speed of a ship. He was thrown overboard and dragged behind the ship itself; rotating thanks to its propeller, it transmitted the number of revolutions made on itself to the three dials made on an enameled metal plate placed in the center of the log; the quadrants reported measurements in miles from 0 to 100 in tens, from 0 to 10 in units, from 0 to 1 in quarters. The data was then read every hour to also derive the speed. In very good condition, fully functional and mounted on a custom-made brass wooden base. Length 54 cm - 20 inches, propeller width 16 cm - 5.9 inches, log body diameter 5 cm - 2 inches. Shipping is insured by Lloyd's London; our gift box is free. In the past centuries the attempt to measure the speed of the ships was especially hindered by the lack of tools for the measurement of time of sufficient precision: throwing a piece of wood into the sea from the bow of a ship and measuring the time it took to get at the stern, it was possible to obtain some information on the speed of the ship, but with many errors and inaccuracies. The principle of mechanical patent log was shown to the Royal Society in 1699 by Robert Hooke, but the first model produced for commercial use was patented just in 1802 by Edward Massey, uncle of Thomas Walker, that succeeded him in business. Thomas Walker patented his first Walker log in 1861, patenting the A1 Harpoon Log two years later. His son, Thomas Ferdinand Walker, patented in 1897 the Cherub log, providing a far more accurate reading. Formally completed in 1912, Thomas Walker & Son LLC installed their headquarters in Oxford Street in Birmingham, and the business was continued by the grandson of Thomas Walker, Thomas Sydney Walker.

Dimensions:
Height: 20 in (50.8 cm)Width: 2 in (5.08 cm)Depth: 5.9 in (14.99 cm)
Materials and Techniques:
Brass
Period:
1860-1869
Date of Manufacture:
1866
Condition:
Seller Location:
Milan, IT
Reference Number:
1stDibs: LU1020229060642