Nautical units of measurement in current or historical use include:
Unit | Type | Notes |
---|---|---|
Cable length | Length | |
Fathom | Length | |
Knot | Speed | |
League | Length | |
Nautical mile | Length | |
Rhumb | Angle | The angle between two successive points of the thirty-two point compass (11 degrees 15 minutes) (rare) [1] |
Shackle | Length | Before 1949, 12.5 fathoms; later 15 fathoms. [2] |
Toise | Length | Toise was also used for measures of area and volume |
Twenty-foot equivalent unit or TEU | Volume | Used in connection with container ships and ports |
A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol ′, is a unit of angular measurement equal to 1/60 of one degree. Since one degree is 1/360 of a turn, or complete rotation, one arcminute is 1/21600 of a turn. The nautical mile (nmi) was originally defined as the arc length of a minute of latitude on a spherical Earth, so the actual Earth's circumference is very near 21600 nmi. A minute of arc is π/10800 of a radian.
The imperial system of units, imperial system or imperial units is the system of units first defined in the British Weights and Measures Act 1824 and continued to be developed through a series of Weights and Measures Acts and amendments.
The kilogram is the base unit of mass in the International System of Units (SI), having the unit symbol kg. 'Kilogram' means 'one thousand grams' and is colloquially abbreviated to kilo.
Length is a measure of distance. In the International System of Quantities, length is a quantity with dimension distance. In most systems of measurement a base unit for length is chosen, from which all other units are derived. In the International System of Units (SI) system the base unit for length is the metre.
Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events. In other words, measurement is a process of determining how large or small a physical quantity is as compared to a basic reference quantity of the same kind. The scope and application of measurement are dependent on the context and discipline. In natural sciences and engineering, measurements do not apply to nominal properties of objects or events, which is consistent with the guidelines of the International vocabulary of metrology published by the International Bureau of Weights and Measures. However, in other fields such as statistics as well as the social and behavioural sciences, measurements can have multiple levels, which would include nominal, ordinal, interval and ratio scales.
The mile, sometimes the international mile or statute mile to distinguish it from other miles, is a British imperial unit and United States customary unit of length; both are based on the older English unit of length equal to 5,280 English feet, or 1,760 yards. The statute mile was standardised between the Commonwealth of Nations and the United States by an international agreement in 1959, when it was formally redefined with respect to SI units as exactly 1,609.344 metres.
A nautical mile is a unit of length used in air, marine, and space navigation, and for the definition of territorial waters. Historically, it was defined as the meridian arc length corresponding to one minute of latitude at the equator, so that Earth's polar circumference is very near to 21,600 nautical miles. Today the international nautical mile is defined as 1,852 metres. The derived unit of speed is the knot, one nautical mile per hour.
The tonne is a unit of mass equal to 1,000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton in the United States to distinguish it from the non-metric units of the short ton and the long ton. It is equivalent to approximately 2,204.6 pounds, 1.102 short tons, and 0.984 long tons. The official SI unit is the megagram (Mg), a less common way to express the same amount.
The kilometre, spelt kilometer in American and Philippine English, is a unit of length in the International System of Units (SI), equal to one thousand metres. It is the preferred measurement unit to express distances between geographical places on land in most of the world; notable exceptions are the United States and the United Kingdom where the statute mile is used.
A fathom is a unit of length in the imperial and the U.S. customary systems equal to 6 feet (1.8288 m), used especially for measuring the depth of water. The fathom is neither an international standard (SI) unit, nor an internationally accepted non-SI unit. Historically it was the maritime measure of depth in the English-speaking world but, apart from within the US, charts now use metres.
A cable length or length of cable is a nautical unit of measure equal to one tenth of a nautical mile or approximately 100 fathoms. Owing to anachronisms and varying techniques of measurement, a cable length can be anywhere from 169 to 220 metres, depending on the standard used.
The knot is a unit of speed equal to one nautical mile per hour, exactly 1.852 km/h. The ISO standard symbol for the knot is kn. The same symbol is preferred by the Institute of Electrical and Electronics Engineers (IEEE), while kt is also common, especially in aviation, where it is the form recommended by the International Civil Aviation Organization (ICAO). The knot is a non-SI unit. The knot is used in meteorology, and in maritime and air navigation. A vessel travelling at 1 knot along a meridian travels approximately one minute of geographic latitude in one hour.
A unit of length refers to any arbitrarily chosen and accepted reference standard for measurement of length. The most common units in modern use are the metric units, used in every country globally. In the United States the U.S. customary units are also in use. British Imperial units are still used for some purposes in the United Kingdom and some other countries. The metric system is sub-divided into SI and non-SI units.
A shot glass is a glass originally designed to hold or measure spirits or liquor, which is either imbibed straight from the glass or poured into a cocktail. An alcoholic beverage served in a shot glass and typically consumed quickly, in one gulp, may also be known as a "shooter" or “shot”.
The rod, perch, or pole is a surveyor's tool and unit of length of various historical definitions. In British imperial and US customary units, it is defined as 16+1⁄2 feet, equal to exactly 1⁄320 of a mile, or 5+1⁄2 yards, and is exactly 5.0292 meters. The rod is useful as a unit of length because integer multiples of it can form one acre of square measure (area). The 'perfect acre' is a rectangular area of 43,560 square feet, bounded by sides 660 feet long and 66 feet wide or, equivalently, 40 rods by 4 rods. An acre is therefore 160 square rods or 10 square chains.
A system of units of measurement, also known as a system of units or system of measurement, is a collection of units of measurement and rules relating them to each other. Systems of measurement have historically been important, regulated and defined for the purposes of science and commerce. Instances in use include the International System of Units or SI, the British imperial system, and the United States customary system.
A league is a unit of length. It was common in Europe and Latin America, but is no longer an official unit in any nation. Derived from an ancient Celtic unit and adopted by the Romans as the leuga, the league became a common unit of measurement throughout western Europe. Since the Middle Ages, many values have been specified in several countries, ranging from 2.2 km to 7.9 km.
On a vessel's hull, a strake is a longitudinal course of planking or plating which runs from the boat's stempost to the sternpost or transom. The garboard strakes are the two immediately adjacent to the keel on each side.
The obsolete Finnish units of measurement consist mostly of a variety of units traditionally used in Finland that are similar to those that were traditionally used in other countries and are still used in the United Kingdom and the United States.
The hectare is a non-SI metric unit of area equal to a square with 100-metre sides (1 hm2), that is, 10,000 square metres, and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre is about 0.405 hectares and one hectare contains about 2.47 acres.