The distance on the water has always been measured in miles, and the speed of the vessel is calculated in naval knots. Find out how many meters a nautical mile contains and why the nautical knot got its name.
When it comes to the movement of water transport, special units are often used to measure the distance, as well as the speed of the ship. The distance on the water is determined by nautical miles, and the speed of transport is determined by nautical knots. Also nautical mile and nautical knot are used in aviation.
What does nautical mile mean?
A nautical mile is a value approximately equal to two kilometers, or more precisely, 1852 meters. The "Great Soviet Encyclopedia" mentions that this value was approved in 1929 at the International Hydrographic Conference. It is considered correct in the CIS countries and a number of other states, although it is not included in the list of the international system of units.
Where did this meaning come from? It is known that the distance of 1853 meters is the approximate linear length of one minute of latitude, that is, 1/60 of the meridian arc. It should be noted that this length of the meridian corresponds only to the middle latitudes of the globe. We add that a nautical mile contains 10 cables.
The value of the nautical mile in Great Britain was slightly different, where until 1929 it was believed that a mile was equal to 1853 meters. This was due to the convenience of converting an ordinary mile into a sea mile. In this case, it was enough to add 800 to the land mile to get a nautical mile in feet.
What does sea knot mean?
The nautical node displays the specific speed of the vessel. A ship that traveled one nautical mile per hour made one nautical knot. The number of nautical miles that a ship travels in one hour is equal to the number of nodes. Moreover, it is not customary to talk about the ship's speed as the number of knots per hour. If it is indicated that a ship is making twelve knots, it is assumed that it covers the same number of miles in sixty minutes.
Why did the sea knot get this name? It turns out that this concept is associated with a marine device, which previously measured the speed of the vessel - lag. The lag was a load on a long rope that was thrown overboard. The rope was pre-tied with knots in 50-foot increments. After that, the captain or his assistant counted the number of knots on the cable that would submerge in the water in a certain time. Their number also corresponded to the speed of the vessel.
Nowadays, the speed of the vessel in knots is rarely measured, only in Britain it is customary to talk about nautical miles per hour. In most countries, sea transport speeds are measured in kilometers per hour.
