Nautical mile how long

Of course, here we are not talking about sailing knots, such as Figure-8 Knot. Similar to the speed and distance measurement on land, the nautical mile and knot explain the movement of a vessel at sea. For instance, a boat or ship travelling at 15 knots could go 15 nautical miles per hour. Since the beginning of ocean navigation, a number of methods have been brought in for making the voyage through long and vast seas easier.

Several traditional practices, using geometry, astronomy and even special instruments, helped sailors to navigate to their destinations for a quite long period. Sometimes, in addition to their know-how tools, it was just luck that protected them when they ventured out into the uncharted, dangerous waters.

In the later periods, the mariners succeeded in developing charts depicting distant shorelines and common features of the sea during voyages. According to historical records, such charts developed in the earlier period were marked with simple outlines of coastlines made to support written or oral directions.

In addition to these, compasses, astrolabes, and callipers were the tools that were in use by ocean navigators in earlier times. Primarily, this compass was used to determine the direction of the wind when the sun was not visible. Similarly, the cross-staff, astrolabe, and quadrant were in use to help sailors determine latitude in several stages of maritime navigation.

Phoenicians are the first Western civilization known to have developed the art of navigation at sea thousands of years ago. Phoenicians relied on primitive charts as well as observations of the Sun and stars to navigate their vessels to destinations.

In the later period, the Phoenicians and their successors, the Carthaginians, also invented a tool known as the sounding weight. Made of stone or lead, this bell-shaped tool had a very long rope attached to the tallow inside. Sailors used to lower this weight into the bottom of the sea to determine how deep the waters were, and, using this measurement, to estimate how far they were from the land. In addition, the tool, with the help of the tallow inside, could pick up sediments from the seabed, which enabled expert sailors to decide the location of their vessel.

However, centuries passed before the use of a standard method to measure the distance and speed during navigation at sea. A number of new techniques and methods were experimented with from time to time, making marine navigation more meaningful. Until the fifteenth century, coastal navigation was mostly in practice, since the open sea voyages were limited to regions of predictable winds and currents. Further ventures by the sailors were enabled by the development of scientific and mathematically-based methods and tools in the following years.

The invention of the sextant, the chip log and Chronometers, etc. And, the modern era saw the replacement of ancient navigational tools with electronic and technological equivalents and also the determination of standard measures including Prime Meridian.

With the help of new technologies, from Gyroscopic Compass to GPS, now marine navigation has become more systematic and easy.

Years after the use of several techniques to determine the position and speed of a vessel, British mathematician Edmund Gunter succeeded in enhancing navigational tools including a new quadrant to define latitude at sea. Gunter claimed that the lines of latitude can be used as the basis for a unit of measurement for distance. 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.

What is a knot? NOS Education. Office of Coast Survey. Nautical Miles Nautical miles are used to measure the distance traveled through the water. If you were to cut the Earth in half at the equator, you could pick up one of the halves and look at the equator as a circle.

You could divide that circle into degrees. You could then divide a degree into 60 minutes. A minute of arc on the planet Earth is 1 nautical mile. This unit of measurement is used by all nations for air and sea travel. A knot is a unit of measure for speed.

If you are traveling at a speed of 1 nautical mile per hour, you are said to be traveling at a speed of 1 knot. A kilometer is also defined using the planet Earth as a standard of distance.