|Category:||Vintage and Antique|
|Object Name:||Ship's Log Sand Timer|
|Year of Manufacture:||Unknown|
Width (mm): 30
Height (mm): 87
Depth (mm): 30
Weight (g): 73
|Location:||Cupboard CG (Display 2) [Main Store]|
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 is marked '28 SEC' (28 seconds), which is the time taken for the sand to run from one bulb to the other and then, after a swift inversion, to run back.
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.