How to tell how many knots there are at sea

knots (kn) used to be used by the crew to measure the speed of the ship, and for every 1 nautical mile walked, the crew made a knot on the lowered rope. In the future, knots will be used as a unit of ship speed.

1 knots (kn) = 1 nautical mile hour = (1852 3600) m s is the unit of velocity.

1 nautical mile (n mile) = 1852m is the unit of length.

The speed measurement unit of land vehicles and airplanes in the air, as well as river vessels, is mostly measured in kilometers (kilometers) hours, while the speed unit of sea vessels (including **) is called "knots".

As early as the 16th century, sea navigation was quite developed, but there were no clocks and no voyage recorders, so it was difficult to determine the speed of a ship with certainty. However, a clever sailor came up with a clever trick to throw a float with a rope towed to the surface of the sea while the ship was sailing, and then calculate the speed of the ship according to the length of the rope pulled out in a certain amount of time. At that time, quicksand timers were still used.

In order to calculate the speed of the ship more accurately, sometimes the rope released is very long, so many knots are tied at the equal distance of the rope, so that the whole speed rope is divided into several sections, as long as the number of sections of the rope is pulled in the same unit time, the corresponding speed is naturally measured. As a result, the "knot" became the unit of measurement for the speed of the sea vessel; Correspondingly, the speed measurement units of sea water velocity, sea wind speed, torpedoes and other underwater weapons are also commonly used in the world

A nautical mile is a unit of length in the sea. It originally referred to the length of 1 minute of latitude on the meridian of the earth, and because the earth is slightly ellipsoidal, the radian of 1 minute at different latitudes is slightly different. At the equator, 1 nautical mile is equal to about 1,843 meters; At latitude 45° it is approximately equal to meters, and the poles are approximately equal to meters.

The 1929 International Conference on Hydrography adopted the use of 1 point with an average length of 1852 meters as 1 nautical mile; In 1948, the International Conference on the Safety of Life recognized that 1,852 meters or feet was 1 nautical mile, so 1,852 meters was used as the standard nautical mile length internationally. China recognizes this criterion, which is indicated by the code "M".

The speedometer of modern sea vessels has been very advanced, and some can be digitally displayed at any time, and the "rope throwing knot" has long become history, but the "knot" is still used as a speed unit of sea vessels. Usually look at the sails. There is also a special measure of how many solar terms there are.

People who often go to sea generally look at sails, and there is also an exclusive instrument, which is sold on Jingdong.

Look at the sails. Or replace it with something else.

Wind ratings at sea are classified according to the wind speed at sea, and the commonly used wind ratings are determined according to the Befort Wind Scale Scale. According to this **, the corresponding wind speed range for a category 4 wind at sea is 13 to 17 knots per hour (about 1 meter per second).