"not knotted and sailors measured the length directly on the line. With the introduction of the nautical mile as a standard unit of measure at sea in the 15th century, they began to mark the line at equal intervals proportional to the nautical mile and to the time interval used for measurement. Initially, the markings were simply knots in the line. Later, sailors worked knotted cords into the log-line. Many ships used knots spaced 8 fathoms (48 feet or 14.6 meters) apart, while other ships used the 7-fathom prescription. The time interval needs to be adjusted according to the distance"
"Nautical mile A nautical mile (also known as an air mile) is a unit of measurement defined as exactly . Historically, it was defined as one minute of latitude, which is one sixtieth of a degree of latitude – i.e. since a minute of a degree is x = , the Earth's polar circumference is approximately 21,600 nautical miles. It is a non-SI unit which today has a continued use in both air and marine navigation, and for the definition of territorial waters. There is no single internationally agreed symbol. While using M itself, the International Bureau of Weights and"
"unit of length used in the expression of the result of the calculation. If one uses Imperial Units, the result for a Six Metre yacht is 19.685 feet. The London Conference preferred the term ""Six Metre"" yachts to ""19.685 Foot"" yacht. For the International rule, the rating number is approximately equal to the sailing length of the hull. These boats have long overhangs which allow the waterline length to increase as the boat heels over. A displacement hull's maximum speed (the hull speed) is directly proportional to the square root of its waterline length. The first rating rules were first"
") is known as the geographical mile. Nautical mile A nautical mile (also known as an air mile) is a unit of measurement defined as exactly . Historically, it was defined as one minute of latitude, which is one sixtieth of a degree of latitude – i.e. since a minute of a degree is x = , the Earth's polar circumference is approximately 21,600 nautical miles. It is a non-SI unit which today has a continued use in both air and marine navigation, and for the definition of territorial waters. There is no single internationally agreed symbol. While using M"
"In the United States, the nautical mile was defined in the 19th century as 6,080.2 feet (1,853.249 m), whereas in the United Kingdom, the ""Admiralty nautical mile"" was defined as 6,080 feet (1,853.184 m) and was about one minute of latitude in the latitudes of the south of the UK. Other nations had different definitions of the nautical mile, but it is now internationally defined to be exactly . The nautical mile per hour is known as the knot. Nautical miles and knots are almost universally used for aeronautical and maritime navigation, because of their relationship with degrees and minutes"
"longitude at the equator is thus exactly 60 geographical miles. It was closely related to the nautical mile, which was originally determined as 1 minute of arc along a great circle of the Earth, but is nowadays defined as exactly 1852 metres. The US National Institute of Standards and Technology (NIST) notes that: ""The international nautical mile of 1 852 meters (6 076.115 49...feet) was adopted effective July 1, 1954, for use in the United States. The value formerly used in the United States was 6 080.20 feet = 1 nautical (geographical or sea) mile."" (6080.2 feet is 1853.24496 meters.)"
"latitude could be used as the basis for a unit of measurement for distance and proposed the nautical mile as one minute or one-sixtieth () of one degree of latitude. As one degree is of a circle, one minute of arc is of a circle (or, in radians, ). These sexagesimal (base 60) units originated in Babylonian astronomy. Gunter used Snell's circumference to define a nautical mile as 6,080 feet, the length of one minute of arc at 48 degrees latitude. Since the earth is not a perfect sphere but is an oblate spheroid with slightly flattened poles, a minute"
"Fathom A fathom is a unit of length in the imperial and the U.S. customary systems equal to , used especially for measuring the depth of water. There are two yards (6 feet) in an imperial fathom. Originally the span of a man's outstretched arms, the size of a fathom has varied slightly depending on whether it was defined as a thousandth of an (Admiralty) nautical mile or as a multiple of the imperial yard. Formerly, the term was used for any of several units of length varying around . The name derives from the Old English word ""fæðm"", cognate"
"accurate because they measure angles from the horizon, eliminating errors caused by the placement of an instrument's pointers, and because their dual mirror system cancels relative motions of the instrument, showing a steady view of the object and horizon. Navigators measure distance on the globe in degrees, arcminutes and arcseconds. A nautical mile is defined as 1852 meters, but is also (not accidentally) one minute of angle along a meridian on the Earth. Sextants can be read accurately to within 0.2 arcminutes, so the observer's position can be determined within (theoretically) 0.2 miles, about 400 yards (370 m). Most ocean"
"Lf represents the waterline length (LWL), S the measured sail area, D displacement. The principal restrictions are: 6.5 Metre The International Six point Five Metre Class is a ""construction class"", meaning that the boats are not identical but are all designed to meet specific measurement formula, in this case the French rule called ""Jauge chemin de fer"". The 6.5m was used as an Olympic Class during the 1920 Olympics. The first formula of the 6.5m, was worked out by Louis Dyèvre, member of the Société des régates de Vannes, naval architect and member of the French delegation to the congress"
"of latitude is not constant, but about at the poles and at the Equator, with a mean value of . Other countries measure the minute of arc at 45 degrees latitude, giving the nautical mile a length of . In 1929, the international nautical mile was defined by the First International Extraordinary Hydrographic Conference in Monaco as precisely 1,852 metres. Imperial units and United States customary units used a definition of the nautical mile based on the Clarke (1866) Spheroid. The United States nautical mile was defined as based in the Mendenhall Order foot of 1893. It was abandoned in"
"Foot (unit) The foot ( feet; abbreviation: ft; symbol: ′, the prime symbol) is a unit of length in the imperial and US customary systems of measurement. Since 1959, both units have been defined by international agreement as equivalent to 0.3048 meters exactly. In both systems, the foot comprises 12 inches and three feet compose a yard. Historically the ""foot"" was a part of many local systems of units, including the Greek, Roman, Chinese, French, and English systems. It varied in length from country to country, from city to city, and sometimes from trade to trade. Its length was usually"
"(equivalent to 914.4 m), depth as ""feet"", and velocity, in some cases, as ""feet per second"". The Navy and Air Force continue to measure distance in nautical miles and speed in knots; these units are now accepted for use with SI by the BIPM. Furthermore, in military aviation NATO countries use feet for flight heights, as they do in the civilian aviation. Illegal drugs and controlled substances are often measured in metric quantities. The federal law prohibiting them defines the penalties in metric masses. In everyday use within its subculture, marijuana is sold using a combination of metric and American"
"Cubic foot The cubic foot (symbol ft) is an imperial and US customary (non-metric) unit of volume, used in the United States, and partially in Canada, and the United Kingdom. It is defined as the volume of a cube with sides of one foot (0.3048 m) in length. Its volume is 28.3168 liters or about of a cubic meter. At , a cubic foot of water weighs . The IEEE symbol for the cubic foot is ft. The following abbreviations are used: cubicfeet, cubicfoot, cubicft, cufeet, cufoot, cuft, cu.ft, cuft, cbft, cb.ft, cbft, cbf, feet, foot, ft, feet/-3, foot/-3, ft/-3."
"6.5 Metre The International Six point Five Metre Class is a ""construction class"", meaning that the boats are not identical but are all designed to meet specific measurement formula, in this case the French rule called ""Jauge chemin de fer"". The 6.5m was used as an Olympic Class during the 1920 Olympics. The first formula of the 6.5m, was worked out by Louis Dyèvre, member of the Société des régates de Vannes, naval architect and member of the French delegation to the congress of London of 1906, is inspired by the formula of the New York Yacht Club in 1903:"
"still use US customary units despite many years of informal or optional metrication. At least two states, Kentucky and California, have even moved towards demetrication of highway construction projects. Air and sea transportation commonly use the nautical mile. This is about one minute of arc of latitude along any meridian arc and it is precisely defined as 1852 metres (about 1.151 statute miles). It is not an SI unit (although it is accepted for use in the SI by the BIPM). The prime unit of speed or velocity for maritime and air navigation remains the knot (nautical mile per hour)."
"length (inch, foot, yard and international mile) were the same in the US, though the US rarely uses some of the intermediate units, such as the (surveyor's) chain (22 yards) and the furlong (220 yards). At one time the definition of the nautical mile was based on the sphere whose surface is the same as the Clarke Ellipsoid. In the US, the full value of 1853.256 metres was used, but in the Commonwealth, this was rounded to 6080 feet (1853.184 m). These have been replaced by the international version, which rounds the sixtieth part of the 45° to the nearest"
"one minute of arc along a meridian of a spherical earth. An ellipsoid model leads to a variation of the nautical mile with latitude. This was resolved by defining the nautical mile to be exactly 1,852 metres. However for all practical purposes distances are measured from the latitude scale of charts. As the Royal Yachting Association says in its manual for day skippers: ""1 (minute) of Latitude = 1 sea mile"", followed by ""For most practical purposes distance is measured from the latitude scale, assuming that one minute of latitude equals one nautical mile"". There are six auxiliary latitudes that"
"latitude is 1 nautical mile. The example above would be given as 40° 11.25′ (commonly written as 11′25 or 11′.25). The older system of thirds, fourths, etc., which continues the sexagesimal unit subdivision, was used by al-Kashi and other ancient astronomers, but is rarely used today. These subdivisions were denoted by writing the Roman numeral for the number of sixtieths in superscript: 1 for a ""prime"" (minute of arc), 1 for a second, 1 for a third, 1 for a fourth, etc. Hence the modern symbols for the minute and second of arc, and the word ""second"" also refer to"
"Many? - A Dictionary of Units of Measurement Shaftment The shaftment is a unit of length, 6 - 6½ inches or 2 palms, i.e. 15.24 cm. A shaftment is the width of the fist and outstretched thumb. The lengths of poles, staves, etc. can be easily measured by grasping the bottom of the staff with thumb extended and repeating such hand over hand grips along the length of the staff. It occurs in Anglo-Saxon written records as early as 910 and in English as late as 1474. After the modern foot came into use in the twelfth century, the shaftment"
"Nail (unit) A nail, as a unit of cloth measurement, is generally a sixteenth of a yard or 2 inches (5.715 cm). The nail was apparently named after the practice of hammering brass nails into the counter at shops where cloth was sold. On the other hand, R D Connor, in ""The weights and measures of England"" (p 84) states that the nail was the 16th part of a Roman foot, i.e., digitus or finger, although he provides no reference to support this. Zupko's ""A dictionary of weights and measures for the British Isles"" (p 256) states that the nail"
"the nautical mile. The are (symbol a) is a unit of area equal to 100 square metres. The litre (symbol L or l) is a unit of volume equal to 10 m. ISO 80000-3:2006 assigns names and symbols to quantities and units of space and time, and defines these quantities and units. For example, Other units of time defined by the standard include the minute (1 min = 60 s), the hour (1 h = 60 min) and the day (1 d = 24 h). The year (1 a = 365 d or 366 d) is defined in an informative"
"more variable: from feet on merchant vessels to either on fishing vessels (from ). At one time, a quarter meant one-fourth of a fathom. A cable length, based on the length of a ship's cable, has been variously reckoned as equal to 100 or 120 fathoms. Most modern nautical charts indicate depth in metres. However, the U.S. Hydrographic Office uses feet and fathoms. A nautical chart will always explicitly indicate the units of depth used. To measure the depth of shallow waters, boatmen used a sounding line containing fathom points, some marked and others in between, called ""deeps"", unmarked but"
"1 sea mile"", followed by ""For most practical purposes distance is measured from the latitude scale, assuming that one minute of latitude equals one nautical mile"". One tenth of a nautical mile is a cable length. The derived unit of speed is the knot, defined as one nautical mile per hour. The metre was originally defined as of the meridian arc from the North pole to the equator passing through Dunkirk. The Earth’s circumference is therefore approximately 40,000 km. The equatorial circumference is slightly longer than the polar circumference – the measurement based on this (40,075.017 km x x ="
"favour of the international nautical mile in 1954. The Imperial nautical mile, often called an Admiralty mile, or more correctly, an Admiralty measured mile, was defined by its relation to the Admiralty knot, 6,080 imperial feet per hour, so 1 imperial nautical mile is about 1,853.181 metres. It was abandoned in 1970 and, legally, references to the obsolete unit are now converted to 1,853 metres. Despite the existence of precise modern definitions, in the early 21st century the old definitions are still in use. The Royal Yachting Association says in its manual for day skippers: ""1 (minute) of Latitude ="
"units used for measurement of length are metres (m) and millimetres (mm). Centimetres (cm) are avoided as they cause confusion when reading plans. For example, the length two and a half metres is usually recorded as 2500 mm or 2.5 m; it would be considered non-standard to record this length as 250 cm. American surveyors use a decimal-based system of measurement devised by Edmund Gunter in 1620. The base unit is Gunter's chain of which is subdivided into 4 rods, each of 16.5 ft or 100 links of 0.66 feet. A link is abbreviated ""lk,"" and links ""lks"" in old"
"(assuming we have 13.6 psi atmospheric pressure and ignoring super compressibility) Standard cubic foot A standard cubic foot (scf) is a unit used both in the natural gas industry to represent an amount of natural gas and in other industries where other gases are used. It is the unit commonly used when following the US Customary System, a collection of standards set by the US National Institute of Standards and Technology. Another unit used for the same purpose is the standard cubic meter, customary when using SI units. A standard cubic foot defines a standard unit of molecular quantity for"
"Shaftment The shaftment is a unit of length, 6 - 6½ inches or 2 palms, i.e. 15.24 cm. A shaftment is the width of the fist and outstretched thumb. The lengths of poles, staves, etc. can be easily measured by grasping the bottom of the staff with thumb extended and repeating such hand over hand grips along the length of the staff. It occurs in Anglo-Saxon written records as early as 910 and in English as late as 1474. After the modern foot came into use in the twelfth century, the shaftment was reinterpreted as exactly 1/2 foot or 6"
"the United States, Australia, Canada, New Zealand, South Africa, and the United Kingdom defined the length of the international yard to be exactly 0.9144 metre. The British Admiralty defined a fathom to be a thousandth of an imperial nautical mile (which was 6080 ft) or . In practice the ""warship fathom"" of exactly was used in Britain and the United States. No conflict in the real world existed as depths on Imperial nautical charts were indicated in feet if less than and in fathoms for depths above that. Until the 19th century in England, the length of the fathom was"
"of water such as in rivers and lakes. A cubic decametre (dam) is equivalent to one megalitre (ML). The ""square decametre"" (dam) also known as the are (a), is the basis for the hectare (100 dam), the standard metric unit of land registry. Decametre A decametre or dekametre (American spelling: decameter or dekameter; symbol dam, sometimes unofficially Dm or dkm) is a very rarely used unit of length in the metric system, equal to ten metres. This measure is included in the SI mostly for completeness: in principle, any combination of prefix and unit can be written, but many are"
"Mile The mile is an English unit of length of linear measure equal to 5,280 feet, or 1,760 yards, and standardised as exactly 1,609.344 metres by international agreement in 1959. With qualifiers, ""mile"" is also used to describe or translate a wide range of units derived from or roughly equivalent to the Roman mile, such as the nautical mile (now 1.852 km exactly), the Italian mile (roughly 1.852 km), and the Chinese mile (now 500 m exactly). The Romans divided their mile into 5,000 roman feet but the greater importance of furlongs in pre-modern England meant that the statute mile"
"determine latitude at sea. He reasoned that the lines of latitude could be used as the basis for a unit of measurement for distance and proposed the nautical mile as one minute or one-sixtieth () of one degree of latitude. As one degree is of a circle, one minute of arc is of a circle – such that the polar circumference of the Earth would be exactly 21,600 miles. Gunter used Snell's circumference to define a nautical mile as 6,080 feet, the length of one minute of arc at 48 degrees latitude. In 1791, the French Academy of Sciences selected"
"volume at 60 degrees Fahrenheit () and 14.7 pounds per square inch (PSI) () of pressure. See Also: Standard cubic foot per minute Cubic foot The cubic foot (symbol ft) is an imperial and US customary (non-metric) unit of volume, used in the United States, and partially in Canada, and the United Kingdom. It is defined as the volume of a cube with sides of one foot (0.3048 m) in length. Its volume is 28.3168 liters or about of a cubic meter. At , a cubic foot of water weighs . The IEEE symbol for the cubic foot is ft."