Conversion from 3 Nautical leagues to Yards

Information about the Nautical league (nlea)

The nautical league is a unit of length equal to three nautical miles, or exactly 5556 metres. It is longer than the land league by about 728 metres, since it is built from the nautical mile of 1852 metres rather than the statute mile.

The unit belonged to an era when it was the practical measure of coastal jurisdiction. The cannon shot rule, articulated in the seventeenth and eighteenth centuries, held that a state's authority extended as far as it could defend from shore, conventionally taken as three nautical miles. That distance became the standard territorial sea limit and was expressed as one marine league. Many older treaties and statutes define maritime boundaries in leagues for this reason.

The three-mile limit held for centuries before eroding through the twentieth. States progressively claimed wider waters, and the United Nations Convention on the Law of the Sea settled the matter in 1982 by establishing a twelve nautical mile territorial sea and a two hundred mile exclusive economic zone. Both figures are stated in nautical miles rather than leagues, and the older unit fell out of legal use.

Charts and pilot books from the age of sail used the league routinely for describing offshore distances and the visibility of landmarks. Reading those sources accurately requires knowing which league is meant, since the same word could refer to a land league, a marine league or a Spanish or Portuguese variant, and the differences are large enough to matter when reconstructing a historical position.

Today the unit has no navigational role. Charts are marked in nautical miles, and distances at sea are quoted the same way. The nautical league appears only in historical and legal texts.

The unit also underlies a familiar figure in visibility calculations. From a height of about three metres above sea level, the horizon lies roughly one nautical league away, which is why the three-mile limit corresponded loosely to what a lookout could see as well as to what a gun could reach.

One nautical league equals 3 nautical miles, 5556 metres, 5.556 kilometres, or about 3.452 statute miles.

Information about the Yard (yd)

The yard is a unit of length equal to exactly 0.9144 metres, or three feet. The symbol is yd. It is the base unit of the imperial and United States customary length systems, with the foot and inch defined as fractions of it.

That relationship is the reverse of what most people assume. Since 1959 the yard has been defined against the metre, and the foot and inch follow from it, so every imperial length unit is ultimately derived from an SI definition. The International Yard and Pound Agreement fixed the value at 0.9144 metres exactly, reconciling small differences between the American and British yards that had persisted for decades.

The origin of the name is uncertain. Old English gierd meant a rod or measuring stick. The frequently repeated story that Henry I defined the yard as the distance from his nose to his outstretched thumb is not supported by contemporary evidence, though it has proved durable. A physical standard yard bar was maintained in London from 1760, and its destruction in the 1834 Palace of Westminster fire forced a lengthy reconstruction from surviving copies.

Sport keeps the unit prominent. An American football field is 100 yards between goal lines, and the game's vocabulary is built around yardage. Golf course distances are marked in yards in Britain and the United States. Cricket sets the distance between wickets at 22 yards, a figure inherited from the surveyor's chain.

Fabric and carpet are sold by the yard in the United States, and textile widths are quoted in inches alongside. Landscaping materials such as topsoil and gravel are sold by the cubic yard, which is 27 cubic feet or about 0.7646 cubic metres.

Its cube runs the construction trade in North America. Concrete is ordered, delivered and billed by the cubic yard, about 0.765 cubic metres, and a standard mixer truck carries eight or nine of them; excavation, gravel, topsoil and demolition waste are all quoted the same way. Golf keeps the linear unit just as firmly, with every hole on every scorecard measured in yards and every club sold on the distance it carries, so a player who reads a shot as a hundred and fifty yards is using a measurement the rest of the game's arithmetic depends on. Between them the two uses make the yard unlikely to disappear.

One yard equals 3 feet, 36 inches, or 0.9144 metres exactly. It is a little shorter than a metre, by about 8.4 centimetres.