Walker speed log

Practical Boat Owner - - New Gear -

The lat­est in our se­ries of Clas­sic Kit items in­spired by the Golden Globe Race (GGR) 2018 shines the spot­light on the Walker speed log. The GGR chal­lenge sailors are sailing tra­di­tional long-keel yachts de­signed prior to 1988 with non-dig­i­tal kit such as GPS, chart plot­ters and elec­tronic self-steer­ing to mark the 50th an­niver­sary of Sir Robin Knox John­ston’s vic­tory in the Sunday Times Golden Globe solo, non-stop round the world race.

In the book A His­tory of Sailing in 100 Ob­jects, au­thor and GGR me­dia co-or­di­na­tor Barry Pick­thall writes: ‘Sailors have been try­ing to com­pute speed since time was first in­vented. Back in the 16th cen­tury, the best method for cal­cu­lat­ing speed was to time how long a piece of wood dropped in the wa­ter from the bow would take to draw level with the stern.’ Fast-for­ward to 1772, and RH Gower demon­strated the reg­is­tra­tion of a ves­sel’s speed through me­chan­i­cal means.

‘Vis­count de Vaux was first to de­velop a speed log us­ing wa­ter pres­sure in 1807, and CE Kel­way in­vented an elec­tri­cal log in 1876, but it was Thomas Walker’s har­poon or fric­tion­less log, called the Ai Har­poon ship log, that showed the great­est prom­ise. Two years later, Walker in­tro­duced the Cherub, the first model to pro­vide an in­di­ca­tor on the ship’s taff rail showing dis­tance run un­der vary­ing speeds.’

Text © Barry Pick­thall, im­age © Nic Comp­ton, A His­tory of Sailing in 100 Ob­jects, Ad­lard Coles Nau­ti­cal, an im­print of Bloomsbury Pub­lish­ing Plc.

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