Knot Explained

Highlander, Volume 1, Issue 8, 5 April 1945, Page 2

Knot Explained

A reader writes, asking what is a “knot,” its relationship to distance and how it came to be called such a name.

A knot is a unit of speed and not a measurement of distance travelled. For instance a ship may be travelling at 15 knots, and 10 minutes later at 10 or 20 knots.

In the early days of sail a hand log was used to record the > speed of a vessel. This hand log consisted of a log of wood attached to the end of a line which was knotted at regular intervals according to the seconds of the timing device, usually a sand glass. • The log was tossed overboard, and, as the vessel cruised on, the line raced through the hands of the recording officer. At a certain mark on the line the sand glass was turned and the number of knots passing through during the running of the sand was the speed of the ship. Modern mechanical and electrical logs are used in presentday navigation and these register the nautical miles covered, * with the result that the average speed can be mathematically worked out. A nautical milp is 800 feet further than a land mile.