The nautical mile (symbol M, NM or nmi) is a unit of length that is about one minute of arc of latitude measured along any meridian, or about one minute of arc of longitude at the equator. By international agreement it is exactly 1,852 metres (approximately 6,076 feet).

It is a non-SI unit (although accepted for use in the International System of Units by the BIPM) used especially by navigators in the shipping and aviation industries,^[1] and also in polar exploration. It is commonly used in international law and treaties, especially regarding the limits of territorial waters. It developed from the sea mile and the related geographical mile.

The nautical mile remains in use by sea and air navigators worldwide because of its convenience when working with charts. Most nautical charts are constructed on the Mercator projection whose scale varies by approximately a factor of six from the equator to 80° north or south latitude. It is, therefore, impossible to show a single linear scale for use on charts on scales smaller than about 1/80,000.^[2] The nautical mile circumvents this problem by being equal to a minute of latitude on a chart, which allows any distance measured with a chart divider to be simply converted using the chart's latitude scale.

Definition[link]

The international nautical mile was defined by the First International Extraordinary Hydrographic Conference, Monaco (1929) as exactly 1852 metres.^[1] This is the only definition in widespread current use, and is the one accepted by the International Hydrographic Organization and by the International Bureau of Weights and Measures (BIPM). Before 1929, different countries had different definitions, and the Soviet Union, the United Kingdom and the United States did not immediately accept the international value.

Both the Imperial and U.S. definitions of the nautical mile were based on the Clarke (1866) Spheroid: they were different approximations to the length of one minute of arc along a great circle of a sphere having the same surface area as the Clarke Spheroid.^[3] The United States nautical mile was defined as 1853.248 metres^[4] (6080.20 U.S. feet, based on the definition of the foot in the Mendenhall Order of 1893): it was abandoned in favour of the international nautical mile in 1954.^[5] The Imperial (UK) nautical mile, also known as the Admiralty mile, was defined in terms of the knot such that one nautical mile was exactly 6080 feet (1853.184 m):^[6] it was abandoned in 1970^[6] and, for legal purposes, old references to the obsolete unit are now converted to 1853 metres exactly.^[7]

Sea mile[link]

In English usage, a sea mile is, for any latitude, the length of one minute of latitude at that latitude. It varies from about 1,842.9 metres (6,046 ft) at the equator to about 1,861.7 metres (6,108 ft) at the poles, with a mean value of 1,852.3 metres (6,077 ft).^[6] The international nautical mile was chosen as the integer number of metres closest to the mean sea mile.

American use has changed recently. The glossary in the 1966 edition of Bowditch defines a "sea mile" as a "nautical mile".^[8] In the 2002 edition, the glossary says: "An approximate mean value of the nautical mile equal to 6,080 feet; the length of a minute of arc along the meridian at latitude 48°."^[9]

The sea mile has also been defined as 6000 feet or 1000 fathoms, for example in Dresner's Units of Measurement. Dresner includes a remark to the effect that this must not be confused with the nautical mile.

Geographical mile[link]

The geographical mile is the length of one minute of longitude along the Equator, about 1855.4 m on the International (1924) Spheroid^[6] or about 1855.325 m on the WGS 84 ellipsoid. Bowditch defines it as 6,087.08 feet, which is 1,855.34 metres.^[9] The term "geographical mile" has also been used to refer to the mean sea mile, which would later become the international nautical mile.^[3]

Do not confuse this with the similar-sounding unit the geografische Meile, seen in historical German measurements. This unit was intended to be the length of four minutes of arc along the equator and is standardized as 7421.6 metres. In Germany, the Mile, Uhr or Stunde typically refers to 24,000 of the local foot. This is the distance one might walk in an hour (Stunde).

Tactical mile or data mile[link]

As an approximation, designers of radar systems for ballistic, cruise and anti-ship missiles used by NATO navies use 6,000 feet (1,828.8 m) as their equivalent of a nautical mile. In the Royal Navy, this is also known as a data mile.

Radar mile[link]

In radar theory, the data mile (6,000 feet) is the length unit. A radar mile is the time it takes a radar pulse to travel one datamile forth and a data mile back again, which equals 12.277 μs. This value corresponds with the speed of light (c. 3×10⁸ m/s). A radar's range can be determined by dividing the listening time (pulse repetition time minus pulsewidth) by a radar mile.

Unit symbol[link]

The International Hydrographic Organization, whose membership includes essentially all seafaring nations, and the International Bureau of Weights and Measures use M as the abbreviation for the nautical mile.^[1][10] The preferred abbreviation of the International Civil Aviation Organization is NM.^[11] The abbreviation nm, though conflicting with the SI symbol for the nanometre, is also widely used. The SI symbol for the newton metre is N m (with a space) or N·m, not nm, because only prefixes may abut a unit symbol.^[12]

History[link]

Historical definition - 1 nautical mile

The nautical mile was historically defined as a minute of arc along a meridian of the Earth (north-south), making a meridian exactly 180×60 = 10,800 historical nautical miles.^[5] It can therefore be used for approximate measures on a meridian as change of latitude on a nautical chart. The originally intended definition of the metre as 10⁻⁷ of a half-meridian arc makes the mean historical nautical mile exactly (2×10⁷)/10,800 = 1,851.851851… historical metres. Based on the current IUGG meridian of 20,003,931.4585 (standard) metres the mean historical nautical mile is 1,852.216 m.

The historical definition differs from the length-based standard in that a minute of arc, and hence a nautical mile, is not a constant length at the surface of the Earth but gradually lengthens in the north-south direction with increasing distance from the equator, as a corollary of the Earth's oblateness, hence the need for "mean" in the last sentence of the previous paragraph. This length equals about 1,861 metres at the poles and 1,843 metres at the Equator.^[13]

Other nations had different definitions of the nautical mile. This variety in combination with the complexity of angular measure described above along with the intrinsic uncertainty of geodetically derived units mitigated against the extant definitions in favor of a simple unit of pure length. International agreement was achieved in 1929 when the International Extraordinary Hydrographic Conference held in Monaco adopted a definition of one international nautical mile as being equal to 1,852 metres exactly, in excellent agreement (for an integer) with both the above-mentioned values of 1,851.851 historical metres and 1,852.216 standard metres.

Use of angle-based length was first suggested by E. Gunter (of Gunter's chain fame).^[14] During the 18th century, the relation of a mile of 6000 (geometric) feet, or a minute of arc on the earth surface had been advanced as a universal measure for land and sea. The metric kilometre was selected to represent a centisimal minute of arc, on the same basis, with the circle divided into 400 degrees of 100 minutes.

Conversions to other units[link]

Visual comparison of a kilometre, statute mile, and nautical mile

One international nautical mile converts to:

• 1.852 kilometres (exact)
• 1.150779 miles (statute) (exact: 57,875/50,292 miles)
• 2,025.372 yards (exact: 2,315,000/1,143 yards)
• 6,076.1155 feet (exact: 2,315,000/381 feet or 1,822,831/300 survey feet)
• 1,012.6859 fathoms (exact: 1,157,500/1,143 fathoms)
• 10 international cables (exact)
• 10.126859 imperial (100-fathom) cables (exact: 11,575/1,143 imperial cables)
• 8.439049 U.S. customary (120-fathom) cables (exact: 57,875/6,858 U.S. customary cables)
• 0.998383 equatorial arc minutes (traditional geographical miles)
• 0.9998834 mean meridian arc minutes (mean historical nautical miles)

Associated units[link]

The derived unit of speed is the knot, defined as one nautical mile per hour. The term "log" is used to measure the distance a vessel has moved through the water. This term can also be used to measure the speed through the water (see chip log), as the speed and distance are directly related.

The terms "knot" and "log" are derived from the practice of using a "log" tied to a knotted rope as a method of gauging the speed of a ship. A log attached to a knotted rope was thrown into the water, trailing behind the ship. The number of knots that passed off the ship and into the water in a given time would determine the speed in "knots". The present day measurement of knots and log are determined using a mechanical tow, electronic tow, hull-mounted units (which may or may not be retractable), Doppler (either ultrasonic or radar), or GPS.^[15][16] Speeds measured with a GPS differ from those measured by other means in that they are Speed Over Ground (accounting for the effect of current) while the others are Speed Through the Water, which does not account for current.

See also[link]

Nautical portal

• Conversion of units
• Knot (unit) for the unit of speed
• Mile for the land-based unit of length
• Orders of magnitude (length)
• Nautical airmile for the wind-adjusted unit of length (used in aviation)
• Units of measurement

Notes[link]

• Moritz, H. (1980), "Geodetic Reference System", Bulletin Geodesique 54 (3).  (IUGG/WGS-84 data)
• Taff, Laurence G. (1981), Computational Spherical Astronomy, John Wiley and Sons  (IAU data)

External links[link]

• National Bureau of Standards: Refinement of values for the yard and the pound (1959)
• Measure Distances on a map in Nautical miles
• Nautical Unit Converter Nautical miles converted to and from miles and kilometres

It has been suggested that this article or section be merged into Hydroptère. (Discuss) Proposed since December 2011.

Experimental sailing craft l’Hydroptère

Alain Thébault (born 19 September 1962 in Dijon^[1]) is a French yachtsman and skipper of l'Hydroptère.

With Éric Tabarly, he participated in the conception of a multihull on hydrofoils, named l'Hydroptère, with a team of engineers, many of them from the aeronautics industry.

The project started in 1975 and a model on a one-third scale was expermented between 1987 and 1992. L'hydroptère was launched in 1994 and reaches 35 knots the same year. Since 2005, with the support of Swiss banker, Thierry Lombard of Geneva, he modified his yacht for an attempt to reach the speed of 50 knots.^[2] In September 2009, in Hyères, France, Alain Thébault and his crew managed to break the outright speed record on 500m with 51.36 knots.^[3]

References[link]

1. ^ geboren.am: 19. September
2. ^ Story of the Hydroptère project
3. ^ Records on the WSSRC website

See also[link]

Bibliography[link]

• Alain Thébault, Pilote d'un rêve, Paris, Flammarion, 2005, ISBN 978-2-08-068809-5
• Alain Thébault, "Le mur du vent", Paris, Editions de La Martinière, 2008, ISBN 978-2-7324-3771-2

External links[link]

• Alain Thébault on L'hydroptère website.

Guy Lombardo
Guy Lombardo, photographed by William Paul Gottlieb, 1947
Born	Gaetano Alberto Lombardo (1902-06-19)June 19, 1902 London, Ontario
Died	November 5, 1977(1977-11-05) (aged 75) Houston, Texas
Nationality	Canadian/American
Occupation	Bandleader Violinist
Years active	1924–1977

Gaetano Alberto "Guy" Lombardo (June 19, 1902 – November 5, 1977) was a Canadian-American bandleader and violinist.

Forming "The Royal Canadians" in 1924 with his brothers Carmen, Lebert, and Victor and other musicians from his hometown, Lombardo led the group to international success, billing themselves as creating "The Sweetest Music This Side of Heaven." The Lombardos are believed to have sold between 100 and 300 million phonograph records during their lifetimes.^[1]

Early life[link]

Lombardo was born in London, Ontario to Italian-Canadian immigrants, Gaetano Sr. and Lena Lombardo. His father, who had immigrated to Canada from Italy and worked as a tailor, was an amateur singer with a baritone voice and had four of his five sons learn to play instruments so they could accompany him. Lombardo and his brothers formed their first orchestra while still in grammar school and rehearsed in the back of their father's tailor shop. ^[2] Lombardo first performed in public with his brother Carmen at a church lawn party in London in 1914.^[3] His first recording session took place where trumpeter Bix Beiderbecke made his legendary recordings—in Richmond, Indiana, at the Gennett Studios—both during early 1924.

Career[link]

After that solitary Gennett session, they recorded two sessions for Brunswick (a rejected session in Cleveland in late 1926 and an issued session for Vocalion in early 1927). The band then signed to Columbia and recorded prolifically between 1927 and 1931. In early 1932, they signed to Brunswick and continued their success through 1934 when they signed to Decca (1934–1935). They then signed to Victor in later 1935 and stayed until mid 1938 when again they signed to Decca.

In 1938, Lombardo became a naturalized citizen of the United States.

Although Lombardo's "sweet" big-band music was viewed by some in the jazz and big-band community of the day as "corny", trumpeter Louis Armstrong famously enjoyed Lombardo's music.^[1]

New Year's Eve Radio and TV Programs[link]

Guy Lombardo is best known for almost a half-century of New Year's Eve broadcasts, first on radio, and then on television. Lombardo's orchestra played at the "Roosevelt Grill" in the Roosevelt Hotel in New York City from 1929 to 1959, and their New Year's Eve performances (which continued with Lombardo until 1976 at the Waldorf Astoria). Broadcasts of their performances were a major part of New Year's celebrations across North America.

The band's first New Year's Eve radio broadcast was in 1928; within a few years, they would be heard on the CBS Radio Network before 12 Midnight Eastern time, then on the NBC Radio Network after 12 Midnight EST.

On December 31st, 1956, the Lombardo band did their first New Year's TV special on CBS; the program (and Lombardo's 20 subsequent New Year's Eve TV shows) would include a live segment from Times Square (long the focal point of America's New Year's Eve celebrations) showcasing the arrival of the New Year. During the early years, pioneer broadcast journalist Robert Trout reported from Times Square; in later years, another longtime newsman, Ben Grauer, reported from Times Square.

While CBS carried most of the Lombardo New Year's specials, there were a few years in the late 1960's and early 1970's when the special was syndicated live to individual TV stations instead of being broadcast on a network.

By the middle 1970's, the Lombardo TV show was facing competition, especially for younger viewers, from Dick Clark's New Year's Rockin' Eve, but Lombardo remained popular among viewers, especially older ones.

Even after Lombardo's death, the band's New Year's specials continued for two more years on CBS. The Royal Canadians were noted for playing the traditional song Auld Lang Syne as part of the celebrations. Their recording of the song still plays as the first song of the new year in Times Square.

Other pursuits[link]

Lombardo was also an important figure in hydroplane speedboat racing, winning the Gold Cup in 1946 in his record-breaking speedboat, Tempo VI, designed and built by the legendary John L. Hacker. He then went on to win the Ford Memorial competition in 1948 and the President’s Cup and the Silver Cup in 1952. From 1946 to 1949, he was the reigning US national champion. Before his retirement from the sport in the late 1950s, he had won every trophy in the field. In 1959 Lombardo was attempting a run on the absolute water speed record with the jet engine powered Tempo Alcoa when it was destroyed on a radio controlled test run doing over 250mph.^[4] After the destruction of the Tempo Alcoa, Lombardo retired from hydrofoil racing. A museum which was previously in London, Ontario was dedicated to his musical and hydroplane racing achievements. In 2002 he was inducted into the Canadian Motorsport Hall of Fame for his accomplishments.

Beginning in 1958, Lombardo lent his name to and endorsed The Guy Lombardo Royal Fleet, a line of fiberglass boats manufactured and sold by the United States Boat Corporation of Newark, New Jersey, a division of the US Pools Corporation. The boats were manufactured under license from Skagit Plastics, Inc. of La Conner, Washington. The endeavor was short-lived and ended in 1961 with the closure of Skagit Plastics.^[5]

In his later years, Lombardo lived in Freeport, Long Island, New York, where he kept Tempo VI. He also invested in a nearby seafood restaurant (or clam shack) originally called "Liota's East Point House." It was soon "Guy Lombardo's East Point House." Lombardo later became promoter and musical director of Jones Beach Marine Theater, which is a still-popular concert venue south of Freeport - the venue was built specifically with him in mind by Robert Moses, who regarded himself as one of Lombardo's fans. Lombardo's final production at Jones Beach was the 1977 staging of Finian's Rainbow, with Christopher Hewett in the title role.^[6]

Death[link]

On November 5, 1977 Lombardo suffered a fatal heart attack. Victor took over the band briefly but could not maintain it. When Lebert severed his ties in 1979 the group finally dissolved. The orchestra was later revived in 1989 by Al Pierson, playing a mix of nostalgic tunes and modern arrangements.

Lombardo was inducted into the Long Island Music Hall of Fame in 2007.

Tributes[link]

Guy Lombardo's star on Canada's Walk of Fame.

The Guy Lombardo Society is a society dedicated to preserving the music and history of Guy Lombardo And His Royal Canadians.

There is a bridge named after Lombardo in London, Ontario near Wonderland Gardens, as well as Lombardo Avenue in north London near the University of Western Ontario.

The home where Guy Lombardo and his siblings grew up is still standing in London, Ontario, at 202 Simcoe Street. A plaque to the Lombardos has been moved from the exterior wall of the Labatt Retail Store at Richmond and Horton streets in London to the store's entranceway off the parking lot, denoting the site of a subsequent home of the Lombardos.

In his later home of Freeport, New York there is a major street named for him – Guy Lombardo Avenue.

Guy Lombardo museum[link]

From the mid-1980s until 2007, there was a museum dedicated to Guy Lombardo in London, Ontario, near the intersection of Wonderland Road and Springbank Drive. In September 2007, due to the lack of museum visitors and funding, the museum was closed.^[7] Although the city owned many of the exhibits, most of the collection can be found at the private home of former part-time curator Douglas Flood. City staff have recommended that the museum not be reopened.^[8] The building has been converted into a community rec centre as of 2010.

Media[link]

• Paper Tape Archive: Guy Lombardo at Hotel Roosevelt(1949)
• Radiotapes.com Aircheck of interview with Guy Lombardo that aired on WLOL-FM (Minneapolis/St. Paul) in 1959.

See also[link]

• Music of Canada

References[link]

External links[link]

Wikimedia Commons has media related to: Guy Lombardo

• The Guy Lombardo Society
• Guy Lombardo at the Internet Movie Database
• Canadian Motorsport Hall of Fame
• Gold Cup winners
• 1948 Ford Memorial
• Wonderland Gardens destroyed
• Remembering Mr. New Year's Eve - historical article about Guy Lombardo, his connection with New Year's Eve
• Tempo VI profile & pics, restored in the '90s
• Guy Lombardo's Official Covers Discography at Discoogle.com