Ship's log Rare T Walker's A1 Model

Description

This is a T. Walker's Harpoon Ship's Log. It is a rare A1 model, believed to be circa 1870s. Brass construction with a porcelained enamelled dial plate. 53cm long, body diameter 43mm, propeller width 14cm. With the inscription D Stalker Optician Leith .

The mechanical log recorded the speed and distance run by a ship, which was vital information in recording daily progress. It worked by being thrown overboard into the water and dragged behind the ship.

As it was dragged along, the fins on the log rotated the mechanism, and the revolutions registered on the dials mounted on the enamelled plate.

This example is made of brass with an enamel plate mounted with the three calibrated dials, which are marked in miles from 0 to 100 in tens, from 0 to 10 in units, and from 0 to 1 in quarters. Each of the five fins at the back is inscribed with an anchor.

From the 16th century onwards people had made many attempts to devise a mechanical log which would automatically record speed or distance, but it was only in 1802 that the first commercially successful version was patented by Edward Massey (1768-1852).
It consisted of a brass rotator linked to a geared mechanical recording mechanism.

Massey's design was further refined by Thomas Walker (1805-71) and his son, also Thomas (1837-1921), who took out a patent for the A1 Harpoon Log in 1861.

Condition: As these instruments were designed to be submersed in sea water, they required regular greasing and flushing with fresh water to maintain them in good condition. Few survive in such good condition as this example; remarkable given its 150 years or so of age.

The brasswork is excellent with just a little tarnishing. The calibration markings are clear and unspoiled. With regard to the enamelled dial plate: there is a crack at the top right hand corner and some edge losses, as shown in the images, but it is otherwise in good condition. The fins turn freely. Great piece of history £599

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