The basic unit of English length is the yard, which is often taken as the distance between Henry I's (1068-1135) nose and the tip of his outstretched arm.
|1 nail||= 2¼ inches|
|4 inches||= 1 hand|
|12 inches||= 1 foot|
|3 foot||= 1 yard|
|5.5 yards||= 1 rod|
|6 foot||= 1 fathom|
|22 yards||= 1 chain|
|100 links||= 1 chain|
|10 chains||= 1 furlong|
|8 furlongs||= 1 statute mile|
|6080 foot||= 1 nautical mile|
The hand is only used to measure horses.
The fathom is only used to measure the depth of water.
A speed of 1 nautical mile per hour is 1 knot. The nautical mile is important internationally, due to air and sea transport. 6080 feet equals 1853.18 metres, but the new International nautical mile is defined now as 1852 metres.
It is obvious from the definition above that the rod is a strange unit - it is only of use in describing areas, as below. The rod is also known as the pole, the perch, and the lugg.
Prior to the 14th century, the league was normally taken as a 1½ statute miles, or (better) as 12 furlongs. After the 14th century, a length of 3 miles became the norm - a league at sea would be 3 nautical miles, and on land 3 statute miles.
Some people say that the plural of 'foot' should be 'feet' - use what sounds best to you.