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26-557: (Redirected from K-51 ) K-51 or K51 may refer to: K-51 (Kansas highway) HMS  Rockrose  (K51) , a corvette of the Royal Navy Junkers K 51 , a German aircraft design study La finta semplice , by Wolfgang Amadeus Mozart Potassium-51 , an isotope of potassium Russian submarine  Verkhoturye  (K-51) Soviet submarine  K-51 Toyota K51 transmission [REDACTED] Topics referred to by

52-568: A quarter meridian . So ⁠ 10,000,000 m / 90 × 60 ⁠ = 1,851.85 m ≈ 1,852 m became the metric length for a nautical mile. France made it legal for the French Navy in 1906, and many metric countries voted to sanction it for international use at the 1929 International Hydrographic Conference. Both the United States and the United Kingdom used an average arcminute—specifically,

78-406: A degree (5866 ⁠ 2 / 3 ⁠ feet per arcminute ). In 1633, William Oughtred suggested 349,800 feet to a degree (5830 feet per arcminute). Both Gunter and Oughtred put forward the notion of dividing a degree into 100 parts, but their proposal was generally ignored by navigators. The ratio of 60 miles, or 20 leagues, to a degree of latitude remained fixed while the length of the mile

104-469: A degree is a map by Nicolaus Germanus in a 1482 edition of Ptolemy 's Geography indicating one degree of longitude at the Equator contains " milaria 60 ". An earlier manuscript map by Nicolaus Germanus in a previous edition of Geography states " unul gradul log. et latitud sub equinortiali formet stadia 500 que fanut miliaria 62 ⁠ 1 / 2 ⁠ " ("one degree longitude and latitude under

130-571: A minute of arc of a great circle of a sphere having the same surface area as the Clarke 1866 ellipsoid . The authalic (equal area) radius of the Clarke 1866 ellipsoid is 6,370,997.2 metres (20,902,222 ft). The resulting arcminute is 1,853.2480 metres (6,080.210 ft). The United States chose five significant digits for its nautical mile, 6,080.2 feet , whereas the United Kingdom chose four significant digits for its Admiralty mile, 6,080 feet. In 1929

156-575: A patient for an appendectomy and arrived back at Port Elizabeth with only 15 long tons (15.2 t) of fuel remaining. The following year, she participated in Queen Elizabeth II 's coronation celebrations in Port Elizabeth. By the late 1950s, the ship's limitations were becoming apparent, particularly her limited space and electrical power, and Protea was reduced to reserve in January 1957. She

182-488: A survey ship in 1949–50, the ship was disarmed and her interior was extensively reworked to improve her endurance and accommodations. Her bridge was remodelled to improve visibility and a pair of echo sounders were fitted in addition to a navigational radar and direction-finding gear. The changes increased her displacement to 1,080 long tons (1,100 t) at standard and 1,340 long tons (1,360 t) at deep load. Her crew now consisted of 82 officers and ratings. Rockrose

208-531: Is different from Wikidata All article disambiguation pages All disambiguation pages HMSAS Protea (1947) HMSAS Protea was a survey ship of the South African Navy . The ship was originally built as a Flower-class corvette for the Royal Navy during World War II and served as HMS Rockrose ( pennant number : K51 ). Rockrose was initially assigned to convoy escort duties in

234-510: The North Atlantic after her completion in 1941 but was later transferred to South African waters and then to the Far East with the same mission. She returned home in 1945 and was paid off . Two years later the ship was purchased by South Africa and was converted into a survey ship in 1949. Protea was obsolete by the late 1950s and was placed in reserve in 1957. The ship was sold in 1962 and

260-500: The distance along a great circle was 60 miles per degree. However, these referred to the old English mile of 5000 feet and league of 15,000 feet, relying upon Ptolemy's underestimate of the Earth's circumference . In the early seventeenth century, English geographers started to acknowledge the discrepancy between the angular measurement of a degree of latitude and the linear measurement of miles. In 1624 Edmund Gunter suggested 352,000 feet to

286-533: The enemy, but rescued survivors from sunken ships on 8, 10 and 29 October of that year. She was later transferred to the Far East and returned home in 1945, after which she was placed in reserve at Devonport Royal Dockyard . Rockrose was purchased by South Africa in 1947 for conversion into a hydrographic survey ship and was commissioned in the South African Navy on 4 October after a brief refit. Together with

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312-475: The equator forms 500 stadia , which make 62 ⁠ 1 / 2 ⁠ miles"). Whether a correction or convenience, the reason for the change from 62 ⁠ 1 / 2 ⁠ to 60 miles to a degree is not explained. Eventually, the ratio of 60 miles to a degree appeared in English in a 1555 translation of Pietro Martire d'Anghiera 's Decades: "[Ptolemy] assigned likewise to every degree three score miles." By

338-547: The international nautical mile was defined by the First International Extraordinary Hydrographic Conference in Monaco as exactly 1,852 metres (which is 6,076.12 ft). The United States did not adopt the international nautical mile until 1954. Britain adopted it in 1970, but legal references to the obsolete unit are now converted to 1,853 metres (which is 6,079.40 ft). The metre

364-671: The late 16th century English geographers and navigators knew that the ratio of distances at sea to degrees was constant along any great circle (such as the equator , or any meridian), assuming that Earth was a sphere. In 1574, William Bourne stated in A Regiment for the Sea the "rule to raise a degree" practised by navigators: "But as I take it, we in England should allowe 60 myles to one degrée: that is, after 3 miles to one of our Englishe leagues, wherefore 20 of oure English leagues shoulde answere to one degrée." Likewise, Robert Hues wrote in 1594 that

390-430: The measurement based on this ( ⁠ 40,075.017 km / 360 × 60 ⁠ = 1,855.3 metres) is known as the geographical mile . Using the definition ⁠ 1 / 60 ⁠ of a degree of latitude on Mars , a Martian nautical mile equals to 983 m (1,075 yd). This is potentially useful for celestial navigation on a human mission to the planet , both as a shorthand and a quick way to roughly determine

416-466: The newly purchased minesweepers Rosamund and Pelorus , she arrived at Cape Town on 24 December. While awaiting for her conversion to begin, the ship was docked at Salisbury Island, Durban . Gilbert Hamer & Co. of Durban finally began work in mid-1949 and she was recommissioned as HMSAS Protea in February 1950. In late 1952, the ship sailed from Port Elizabeth to Marion Island to bring back

442-403: The poles and 1,843 metres at the Equator. France and other metric countries state that in principle a nautical mile is an arcminute of a meridian at a latitude of 45°, but that is a modern justification for a more mundane calculation that was developed a century earlier. By the mid-19th century, France had defined a nautical mile via the original 1791 definition of the metre , one ten-millionth of

468-448: The same term This disambiguation page lists articles associated with the same title formed as a letter–number combination. 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=K51&oldid=1192292975 " Category : Letter–number combination disambiguation pages Hidden categories: Short description

494-597: The ship was broken up in Table Bay in late 1967. Nautical mile There is no single internationally agreed symbol, with several symbols in use. The word mile is from the Latin phrase for a thousand paces: mille passus . Navigation at sea was done by eye until around 1500 when navigational instruments were developed and cartographers began using a coordinate system with parallels of latitude and meridians of longitude . The earliest reference of 60 miles to

520-520: Was armed with a single BL 4-inch (102 mm) Mk IX gun and two twin mounts for .303-inch (7.7 mm) Lewis light machine guns . For anti-submarine work , she was fitted with two depth charge rails and a pair of depth charge throwers for her 40 depth charges. The ship was equipped with a Type 271 surface-search radar and a Type 123A ASDIC . Rockrose was one of those Flower-class ships that had an extended forecastle and her crew numbered 85 officers and ratings . As part of her conversion to

546-433: Was converted into a fishing trawler with the name of Justin . The company subsequently failed and she was scrapped in 1967. Rockrose displaced 940 long tons (960 t) at standard load and 1,080 long tons (1,100 t) at deep load . The ship had an overall length of 205 feet (62.5 m), a beam of 33 feet 2 inches (10.1 m) and a deep draught of 13 feet 7 inches (4.1 m). She

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572-512: Was listed for disposal in March 1961 and was subsequently purchased by Johannesburg businessman Ernest Bisogno, owner of Maritime Fisheries (Pty) Ltd, for R 4,000. The ship was towed from Simon's Town to Cape Town in October 1963, after having been renamed Justin , for an overhaul and then sailed for Durban to begin conversion into a refrigerated tuna fishing trawler. Her owners were not successful and

598-493: Was named after the rock-rose flower . The ship was ordered on 21 September 1939 from Charles Hill & Sons and was laid down on 28 October 1940 at its Bristol shipyard as yard number 284. She was launched on 26 July 1941 and completed four months later on 4 November. Rockrose was initially assigned to the North Atlantic for convoy escort work, but was transferred to the South Atlantic in 1942. The ship never engaged

624-487: Was originally defined as 1 ⁄ 10,000,000 of the length of the meridian arc from the North pole to the equator (1% of a centesimal degree of latitude), thus one kilometre of distance corresponds to one centigrad (also known as centesimal arc minute) of latitude. The Earth's circumference is therefore approximately 40,000 km. The equatorial circumference is slightly longer than the polar circumference –

650-440: Was powered by a single vertical triple-expansion steam engine using steam provided by two cylindrical boilers . The engine developed 2,750 indicated horsepower (2,050 kW) which gave a maximum speed of 16 knots (30 km/h; 18 mph). The ship carried 230 long tons (234 t) of fuel oil that gave her a range of 5,000 nautical miles (9,300 km; 5,800 mi) at 10 knots (19 km/h; 12 mph). Rockrose

676-449: Was revised with better estimates of the earth’s circumference. In 1637, Robert Norwood proposed a new measurement of 6120 feet for an arcminute of latitude, which was within 44 feet of the currently accepted value for a nautical mile. Since the Earth is not a perfect sphere but is an oblate spheroid with slightly flattened poles, a minute of latitude is not constant, but about 1,862 metres at

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