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Ship's Log Sand Timer

Technical Information

Catalogue No: C1800
Category: Vintage and Antique
Object Type: Indicator/Instrument
Object Name: Ship's Log Sand Timer
Part No: None
Serial No: None
Manufacturer: Unknown
Year of Manufacture: Unknown
Dimensions: Width (mm): 30
Height (mm): 87
Depth (mm): 30
Weight (g): 73
Location: Cupboard CH (Display 3) [Main Store]

28 SEC


This Sand Timer is used to measure the speed of a ship in 'Knots'.The term knot dates from the 17th century, when sailors measured the speed of their ship using a device called a “common log.” The common log was a rope with knots at regular intervals (usually 7 fathoms), attached to a piece of wood shaped like a slice of pie. Mariners would lower the wood piece into the water and allow it to float freely behind the ship for a specific amount of time (often measured with an hourglass). When the time was up, they would count the knots between the ship and the piece of wood, and that number estimated their speed.
This Timer records 14 seconds and allowing 2 seconds to turn it back over gives o
1 minute of time.
The Timer was donated by the family of the late Ron Howard in 2019. This Timer or one like it had figured in a BBC Television documentary on a Cape Horn Sailing Journey in 1929.

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