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Moore's Patent Ship Log

Datec 1870

Object number00056190

NameMechanical ship log

Mediummetal, wood

DimensionsOverall (including wooden base): 615 × 305 × 305 mm

ClassificationsCeremonial artefact

Credit LineAustralian National Maritime Museum Collection Gift from Joe Kensell

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New to the collection

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DescriptionMoore's Patent Ship Log. It was owned by Joe Kensell, who had extensive experience as a mate on Burns and Philp ships, BP tankers, and as Australasian Commercial Manager for P&Os stevedoring division.HistoryFrom the late 16th century onwards attempts were made to develop a mechanical log which would automatically record speed and distance. Early forms included the Dutchman's log in which a floating object, often a tobacco box made of brass, was dropped over the bow of the ship, the time elapsing before it passed the stern counted by the navigator. This technique was replaced by an approach where the log was attached to a reel of line, dropped over the stern, and as the ship moved away from the log the length of line unfurled in relation to the emptying of a sandglass was the measure of speed. As early as 1688 an English instrument maker Humphry Cole invented a form of the patent log, in which a vaned rotor was towed from the stern of a ship and its revolutions were counted on a register. Edward Massey's log in 1802 was the first to be successfully patented, which consisted of a brass rotator linked to a geared mechanical recording mechanism. Massey's design was refined and widely distributed by Thomas Walker in 1861 under the patent A1 Harpoon Log, the Walker name becoming synonomous with the mechanical log. Moore's log may be seen as a slight variant on the sucessful and long running Massey and Walker models. Moore's patent ship log was developed in the late nineteenth century. It is most likely a product of John Hamilton Moore's legacy. Moore (1738-1807) was in the Royal Navy and later set up his own Nautical Academy in Middlesex. He ran a business selling charts and nautical instruments, further teaching navigation. In 1772 he published 'The New Practical Navigator and Daily Assistant, which aimed to explain the practical concepts of navigation in a concise, practical and accessible way. Moore's work was edited and improved upon by the Salem mathematician Nathanial Bowditch whose own navigational guide became hugely successful and over time replaced Moore's book. Mechanical logs have been superseded by modern electromagnetic logs, doppler logs, and ultrasonic speed sensors. SignificanceThis Moore's Patent log is a rare example of a mechanical log produced by an independent manufacturer. Massey and Walker logs proliferated the market during the nineteenth century, and the Moore's model draws heavily on these designs - with its harpoon shape and display dialls. The log expands upon the design of Massey and Walker, with a slightly longer, narrower, shape and a differing handle mechanism at its tip.