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21-511: Not to be confused with the speed vector unit knots . NOTS may refer to Naval Ordnance Test Station of Naval Air Weapons Station China Lake, US Naval Overseas Transportation Service of pre-1949 US Military Sealift Command Negros Oriental Trade School of Negros Oriental State University , Philippines New Era Dianetics for OTs, an Operating Thetan level in Scientology Nots (band) ,

42-452: A distance in nautical miles on a chart can easily be measured by using dividers and the latitude scales on the sides of the chart. Recent British Admiralty charts have a latitude scale down the middle to make this even easier. Speed is sometimes incorrectly expressed as "knots per hour", which would mean "nautical miles per hour per hour" and thus would refer to acceleration . Prior to 1969, airworthiness standards for civil aircraft in

63-507: A noise punk band See also [ edit ] Knot (disambiguation) Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title NOTS . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=NOTS&oldid=1231259610 " Category : Disambiguation pages Hidden categories: Short description

84-465: A standard nautical chart using Mercator projection , the horizontal (East–West) scale varies with latitude. On a chart of the North Atlantic, the scale varies by a factor of two from Florida to Greenland. A single graphic scale , of the sort on many maps, would therefore be useless on such a chart. Since the length of a nautical mile, for practical purposes, is equivalent to about a minute of latitude,

105-475: A true airspeed of 500 kn in standard conditions. Velocity made good Instead of sailing directly toward a windward mark, the helmsman chooses a point of sail towards the direction of the wind that maximizes velocity made good (either towards the destination - or towards better winds). To actually reach a mark, the boat needs to alternate between courses ( tacks ) where the wind approaches from alternating sides. The helmsman uses VMG to find exactly what

126-465: A value for the knot of 20 + 1 ⁄ 4 inches per second or 1.85166 kilometres per hour. The difference from the modern definition is less than 0.02%. Derivation of knots spacing: 1   kn = 1852   m/h = 0.5144   m/s {\displaystyle 1~{\textrm {kn}}=1852~{\textrm {m/h}}=0.5144~{\textrm {m/s}}} , so in 28 {\displaystyle 28} seconds that

147-497: Is 14.40 {\displaystyle 14.40} metres per knot. Although the unit knot does not fit within the SI system, its retention for nautical and aviation use is important because the length of a nautical mile , upon which the knot is based, is closely related to the longitude / latitude geographic coordinate system . As a result, nautical miles and knots are convenient units to use when navigating an aircraft or ship. On

168-585: Is 1 852  m . The US adopted the international definition in 1954, having previously used the US nautical mile ( 1 853 .248 m ). The UK adopted the international nautical mile definition in 1970, having previously used the UK Admiralty nautical mile ( 6 080  ft or 1 853 .184 m ). (* = approximate values) The speeds of vessels relative to the fluids in which they travel (boat speeds and air speeds ) can be measured in knots. If so, for consistency,

189-506: 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. The length of the internationally agreed nautical mile

210-503: Is different from Wikidata All article disambiguation pages All disambiguation pages Knot (unit) The knot ( / n ɒ t / ) is a unit of speed equal to one nautical mile per hour, exactly 1.852 km/h (approximately 1.151 mph or 0.514 m/s ). 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

231-434: The cosine of the angle between the true wind direction (north) and the sailboat's heading. V M G = V B   c o s θ {\displaystyle VMG=V_{B}\ cos\theta } In this case, the optimal VMG is obtained on a heading of 60 degrees from the true wind (60 degrees NE or 300 degrees NW). Turning up into the wind (more towards the mark) makes less progress towards

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252-652: The United States Federal Aviation Regulations specified that distances were to be in statute miles, and speeds in miles per hour. In 1969, these standards were progressively amended to specify that distances were to be in nautical miles, and speeds in knots. The following abbreviations are used to distinguish between various measurements of airspeed : The indicated airspeed is close to the true airspeed only at sea level in standard conditions and at low speeds. At 11 000  m ( 36 000  ft), an indicated airspeed of 300 kn may correspond to

273-413: The line allowed to pay out. Knots tied at a distance of 47  feet 3  inches (14.4018  m ) from each other, passed through a sailor's fingers, while another sailor used a 30-second sand-glass (28-second sand-glass is the currently accepted timing) to time the operation. The knot count would be reported and used in the sailing master 's dead reckoning and navigation . This method gives

294-520: The mark because the boat slows down too much. Turning downwind speeds up the boat, but yields a course that leads too far away from the mark for the increased speed to be a benefit. Velocity made good is often confused with velocity made good on course (VMC), and often used interchangeably. VMC is the speed component in the direction of a mark. If the course deviation is θ {\textstyle \theta } and speed over ground V o {\textstyle V_{o}} ,

315-405: The optimum angle against the wind is. At the optimum boat speed and angle to the wind, VMG is maximized, steering closer to the direction of the wind will reduce boat speed, while steering further away from the direction of the wind might give a higher boat speed, but at the cost of a larger deviation in heading, so less progress towards a mark. For reaching marks that are towards the direction of

336-492: The speed component toward a mark: V M C , y ^ = V o c o s θ {\displaystyle VMC,{\hat {y}}=V_{o}cos\theta } If the course is directly towards a mark, VMC will be identical to speed over ground (SOG). An ordinary GPS unit will, if it indicates a VMG measurement, of necessity be velocity made good on course. Measurement of wind speed and direction, in addition to boat speed and heading,

357-440: The speeds of navigational fluids ( ocean currents , tidal streams , river currents and wind speeds ) are also measured in knots. Thus, speed over the ground (SOG; ground speed (GS) in aircraft) and rate of progress towards a distant point (" velocity made good ", VMG) can also be given in knots. Since 1979, the International Civil Aviation Organization list the knot as permitted for temporary use in aviation, but no end date to

378-399: The temporary period has been agreed as of 2024 . Until the mid-19th century, vessel speed at sea was measured using a chip log . This consisted of a wooden panel, attached by line to a reel, and weighted on one edge to float perpendicularly to the water surface and thus present substantial resistance to the water moving around it. The chip log was cast over the stern of the moving vessel and

399-401: The wind to a heading of 55 degrees NE causes the boat speed to drop to 4.0 knots. These data indicate the trade-off between speed and progress toward the upwind mark (to the north in this case). Finding the heading that moves the boat most quickly towards the mark requires basic trigonometry . The northward component of the boat's velocity vector is found by multiplying the boat speed (V B ) by

420-418: The wind to create more forward wind pressure on the sails and better balance the boat, which allows it to move with greater speed, but less directly toward the wind (or mark). As an example, assume a boat wants to go north in a wind coming from the north. Assume also on a heading of 60 degrees (NE) the speed of the boat is 5.0 knots. Falling off to 65 degrees NE accelerates the boat to 5.2 knots. Turning up into

441-403: The wind, sailboats need to alternate between headings, "tacks", where the wind angle towards the wind is on opposite sides of the boat. On a tack , the sailor might start by pointing the sailboat as close into the wind as possible while still keeping the winds blowing across the sails in a manner that provides aerodynamic lift which then propels the boat. The sailor can then turn slightly away from

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