Walker speed log
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.