The measurements used in sea shipping. There is over a dozen of them and they origin from old English measurements. The most important and most widely used among them are:

* a nautical mile - a distance defined as a minute of arc along a great circle of the Earth, equalling 1852,8 metres or 6080 feet;

* a knot - one nautical mile per hour or 1,852 metres per hour;

* a cable - a distance equalling 1/10 of the nautical mile or 185,2 metres;

* a foot - a unit of length, primarly equalling the length of human foot and used widely before introducing the metrical system and still used in aviation and sailing. It equals 0, 3038 metre and consists of 12 inches;

* an inch - a distance equalling 1/12 of a feet or 2,54 centimetres;

* a fathom - a measurement taken primarly from the width of outstretched arms, equalling 1,8288 metre or 6 feet.