What on earth is a nautical mile?
People managed to calculate the distance in sea by some measurement of length but what is it called, aren’t you curious? If you haven’t heard of this please join the voyage with me and I will explicate it on our way. A “minute of arc”; Wow, it’s getting confusing more and more isn’t it. That’s what many say don’t lose hope so quickly. Minute of arc is a unit of angular measurement of length. Why are we talking about some random unit of length here? Well because a nautical mile is about one minute of arc. This was defined in 1929 by the First International Extraordinary Hydrographic Conference which was held in Monaco, they defined it as precisely 1.852 kilometers. Since then it has been the international metric in navigation both sailing and aviation.
Well, we all love to knot up things, don’t we?
Well in maritime terms Knot is the unit of speed whereas nautical mile is for distance. A knot is equal to one nautical mile per hour. This is used not only in maritime but also in meteorology and air navigation. Chip log was the predecessor of knot and was used for the same purpose until the mid-19th century and the chip log consisted of a wooden triangular shaped board which is tied from all 3 edges to a single line of a reel and slanted on one edge to float in a perpendicular manner on the liquid surface. So a knot is allowed to disburse freely until a specific time. When the allocated time runs out the line is pulled back in and the number of knots on the line between the vessel and the triangular shaped wood is set downed. The number of knots specifies the speed of the vessel. So now we are aware of what is a knot and a nautical mile is and where and how it is used.