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85-622: The Wielingen class is a class of four multi-functional frigates constructed for and operated by the Belgian Naval Component . In service from 1976 to 2008 with the Belgians, three of the class were sold to Bulgaria for service with the Bulgarian Navy beginning in 2004. The fourth, Westhinder , ran aground in 1988, was decommissioned in 1993 and was scrapped. The Belgian government began studies in 1969 for

170-531: A NATO reporting name . In addition, the ships of the class would have a number prefixed by a letter indicating the role of that type of vessel. For example, Project 641 had no name, though NATO referred to its members as Foxtrot-class submarines . The ship classification does not completely correspond common designation, particularly for destroyers, frigates and corvettes. Russia has its own classification system for these ships: The British Royal Navy (RN) has used several methods of naming classes. In addition to

255-431: A 2-mile (3.2 km) range). The " Fessenden oscillator ", operated at about 500 Hz frequency, was unable to determine the bearing of the iceberg due to the 3-metre wavelength and the small dimension of the transducer's radiating face (less than 1 ⁄ 3 wavelength in diameter). The ten Montreal -built British H-class submarines launched in 1915 were equipped with Fessenden oscillators. During World War I

340-496: A Mark 29 octuple launcher for eight RIM-7M Sea Sparrow SAMs. These were later upgraded to the RIM-7P model. The frigates also mount a single 100-millimetre (3.9 in)/55 calibre modèle 68 naval gun , one six-barrelled Creusot-Loire 375 mm (14.8 in) anti-submarine warfare (ASW) rocket launcher with Bofors rockets, and two catapults for L5 torpedoes . The class was fitted with two eight-barrelled Corvus chaff launchers ,

425-462: A Sagem Vigy 105 optronic director , a Signaal DA-05 air/surface search radar , a WM-25 surface search radar, SQS-510 hull-mounted sonar , and the SEWACO IV tactical data system with Link 11 capability. They were also given Argos AR 900 intercept electronic support measures and SLQ-25 Dixie torpedo decoy system. The construction programme of four ships was approved on 23 June 1971 and an order

510-407: A central control station. The vessels measured 103.0 metres (337 ft 11 in) long between perpendiculars and 106.4 m (349 ft 1 in) overall with a beam of 12.3 m (40 ft 4 in) and a draught of 5.6 m (18 ft 4 in). The ships had a light displacement of 1,880 tonnes (1,850 long tons ) and 2,283 t (2,247 long tons) at full load . By 2004,

595-411: A hydrophone/transducer receives a specific interrogation signal it responds by transmitting a specific reply signal. To measure distance, one transducer/projector transmits an interrogation signal and measures the time between this transmission and the receipt of the other transducer/hydrophone reply. The time difference, scaled by the speed of sound through water and divided by two, is the distance between

680-486: A letter of intent was signed by the government and the first ship, Wandelaar was acquired. Approval of the purchase came only on 17 March 2005 and Wandelaar was transferred to Bulgaria in October 2005. The ship was renamed Drazki . Drazki was followed by the remaining two frigates of the class, with confirmation of their acquisition on 7 December 2007. Bulgaria took possession of Westdiep on 22 August 2008 and renamed

765-655: A maximum speed of 20 knots (37 km/h; 23 mph) on both diesels or 15 knots (28 km/h; 17 mph) on just one. These turned controllable pitch propellers. The frigates have a range of 4,500 nautical miles (8,300 km; 5,200 mi) at 18 knots (33 km/h; 21 mph). The vessels also had four 500 kW diesel alternators for electric production. They had a complement of 160 including 15 officers in Belgian service. The Wielingen class were armed with four launchers for MM38 Exocet anti-ship missiles , later converted to two twin launchers. They were equipped with

850-539: A means of acoustic location and of measurement of the echo characteristics of "targets" in the water. Acoustic location in air was used before the introduction of radar . Sonar may also be used for robot navigation, and sodar (an upward-looking in-air sonar) is used for atmospheric investigations. The term sonar is also used for the equipment used to generate and receive the sound. The acoustic frequencies used in sonar systems vary from very low ( infrasonic ) to extremely high ( ultrasonic ). The study of underwater sound

935-824: A month after the sinking of Titanic , and a German physicist Alexander Behm obtained a patent for an echo sounder in 1913. The Canadian engineer Reginald Fessenden , while working for the Submarine Signal Company in Boston , Massachusetts, built an experimental system beginning in 1912, a system later tested in Boston Harbor, and finally in 1914 from the U.S. Revenue Cutter Miami on the Grand Banks off Newfoundland . In that test, Fessenden demonstrated depth sounding, underwater communications ( Morse code ) and echo ranging (detecting an iceberg at

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1020-500: A narrow arc, although the beam may be rotated, relatively slowly, by mechanical scanning. Particularly when single frequency transmissions are used, the Doppler effect can be used to measure the radial speed of a target. The difference in frequency between the transmitted and received signal is measured and converted into a velocity. Since Doppler shifts can be introduced by either receiver or target motion, allowance has to be made for

1105-660: A new type of escort that would meet the requirements of escort missions in the North Sea and English Channel during the Cold War . The design would also only be limited to weapon systems already in service with or under development by NATO navies. The design also emphasized seaworthiness, automation and watertight integrity. The weapons systems, with the exception of the Sea Sparrow surface-to-air missile (SSM) were French. The radar and tactical data systems were Dutch and

1190-573: A prototype for testing in mid-1917. This work for the Anti-Submarine Division of the British Naval Staff was undertaken in utmost secrecy, and used quartz piezoelectric crystals to produce the world's first practical underwater active sound detection apparatus. To maintain secrecy, no mention of sound experimentation or quartz was made – the word used to describe the early work ("supersonics") was changed to "ASD"ics, and

1275-487: A pulse to reception is measured and converted into a range using the known speed of sound. To measure the bearing , several hydrophones are used, and the set measures the relative arrival time to each, or with an array of hydrophones, by measuring the relative amplitude in beams formed through a process called beamforming . Use of an array reduces the spatial response so that to provide wide cover multibeam systems are used. The target signal (if present) together with noise

1360-432: A sound wave which is reflected from target objects. Although some animals ( dolphins , bats , some shrews , and others) have used sound for communication and object detection for millions of years, use by humans in the water was initially recorded by Leonardo da Vinci in 1490: a tube inserted into the water was said to be used to detect vessels by placing an ear to the tube. In the late 19th century, an underwater bell

1445-520: A steel tube, vacuum-filled with castor oil , and sealed. The tubes then were mounted in parallel arrays. The standard US Navy scanning sonar at the end of World War II operated at 18 kHz, using an array of ADP crystals. Desired longer range, however, required use of lower frequencies. The required dimensions were too big for ADP crystals, so in the early 1950s magnetostrictive and barium titanate piezoelectric systems were developed, but these had problems achieving uniform impedance characteristics, and

1530-503: A submerged contact before dropping charges over the stern, resulting in a loss of ASDIC contact in the moments leading up to attack. The hunter was effectively firing blind, during which time a submarine commander could take evasive action. This situation was remedied with new tactics and new weapons. The tactical improvements developed by Frederic John Walker included the creeping attack. Two anti-submarine ships were needed for this (usually sloops or corvettes). The "directing ship" tracked

1615-582: A target ahead of the attacker and still in ASDIC contact. These allowed a single escort to make better aimed attacks on submarines. Developments during the war resulted in British ASDIC sets that used several different shapes of beam, continuously covering blind spots. Later, acoustic torpedoes were used. Early in World War II (September 1940), British ASDIC technology was transferred for free to

1700-439: A traditional naming system for its ships. In addition, the ship's type and missions can be identified by the first number on the ship's three-digit hull number , which is placed on the front bows and the back of the stern. The naming convention is: Russian (and Soviet ) ship classes are formally named by the numbered project that designed them. That project sometimes, but not always, had a metaphorical name, and almost always had

1785-473: A training flotilla of four vessels were established on Portland in 1924. By the outbreak of World War II , the Royal Navy had five sets for different surface ship classes, and others for submarines, incorporated into a complete anti-submarine system. The effectiveness of early ASDIC was hampered by the use of the depth charge as an anti-submarine weapon. This required an attacking vessel to pass over

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1870-413: Is bistatic operation . When more transmitters (or more receivers) are used, again spatially separated, it is multistatic operation . Most sonars are used monostatically with the same array often being used for transmission and reception. Active sonobuoy fields may be operated multistatically. Active sonar creates a pulse of sound, often called a "ping", and then listens for reflections ( echo ) of

1955-450: Is a technique that uses sound propagation (usually underwater, as in submarine navigation ) to navigate , measure distances ( ranging ), communicate with or detect objects on or under the surface of the water, such as other vessels. "Sonar" can refer to one of two types of technology: passive sonar means listening for the sound made by vessels; active sonar means emitting pulses of sounds and listening for echoes. Sonar may be used as

2040-453: Is its zero aging characteristics; the crystal keeps its parameters even over prolonged storage. Another application was for acoustic homing torpedoes. Two pairs of directional hydrophones were mounted on the torpedo nose, in the horizontal and vertical plane; the difference signals from the pairs were used to steer the torpedo left-right and up-down. A countermeasure was developed: the targeted submarine discharged an effervescent chemical, and

2125-419: Is known as underwater acoustics or hydroacoustics . The first recorded use of the technique was in 1490 by Leonardo da Vinci , who used a tube inserted into the water to detect vessels by ear. It was developed during World War I to counter the growing threat of submarine warfare , with an operational passive sonar system in use by 1918. Modern active sonar systems use an acoustic transducer to generate

2210-415: Is the source level , PL is the propagation loss (sometimes referred to as transmission loss ), TS is the target strength , NL is the noise level , AG is the array gain of the receiving array (sometimes approximated by its directivity index) and DT is the detection threshold . In reverberation-limited conditions at initial detection (neglecting array gain): where RL is the reverberation level , and

2295-427: Is then passed through various forms of signal processing , which for simple sonars may be just energy measurement. It is then presented to some form of decision device that calls the output either the required signal or noise. This decision device may be an operator with headphones or a display, or in more sophisticated sonars this function may be carried out by software. Further processes may be carried out to classify

2380-402: Is very low, several orders of magnitude less than the original signal. Even if the reflected signal was of the same power, the following example (using hypothetical values) shows the problem: Suppose a sonar system is capable of emitting a 10,000 W/m signal at 1 m, and detecting a 0.001 W/m  signal. At 100 m the signal will be 1 W/m (due to the inverse-square law ). If

2465-526: The Confederate States Navy . Generally accepted by military historians and widely used in the more recent books, webpages and papers on the subject matter (most notably the releases of Osprey Publishing ), these latter-day classifications are sometimes considered "semi-official" (although they are not). Contemporary records, such as the " Official Records of the Union and Confederate Navies in

2550-646: The Weapon rather than Tomahawk class. In European navies, a class is named after the first ship commissioned regardless of when it was ordered or laid down. In some cases this has resulted in different class names being used in European and U.S. references; for example, European sources record the Colorado -class battleships of the United States Navy as the " Maryland class", as USS  Maryland

2635-500: The electrostatic transducers they used, this work influenced future designs. Lightweight sound-sensitive plastic film and fibre optics have been used for hydrophones, while Terfenol-D and lead magnesium niobate (PMN) have been developed for projectors. In 1916, under the British Board of Invention and Research , Canadian physicist Robert William Boyle took on the active sound detection project with A. B. Wood , producing

Wielingen-class frigate - Misplaced Pages Continue

2720-551: The hull or become flooded, the 60 Hz sound from the windings can be emitted from the submarine or ship. This can help to identify its nationality, as all European submarines and nearly every other nation's submarine have 50 Hz power systems. Intermittent sound sources (such as a wrench being dropped), called "transients," may also be detectable to passive sonar. Until fairly recently, an experienced, trained operator identified signals, but now computers may do this. Passive sonar systems may have large sonic databases , but

2805-493: The 1930s American engineers developed their own underwater sound-detection technology, and important discoveries were made, such as the existence of thermoclines and their effects on sound waves. Americans began to use the term SONAR for their systems, coined by Frederick Hunt to be the equivalent of RADAR . In 1917, the US Navy acquired J. Warren Horton 's services for the first time. On leave from Bell Labs , he served

2890-498: The 1970s, compounds of rare earths and iron were discovered with superior magnetomechanic properties, namely the Terfenol-D alloy. This made possible new designs, e.g. a hybrid magnetostrictive-piezoelectric transducer. The most recent of these improved magnetostrictive materials is Galfenol . Other types of transducers include variable-reluctance (or moving-armature, or electromagnetic) transducers, where magnetic force acts on

2975-627: The United States. Research on ASDIC and underwater sound was expanded in the UK and in the US. Many new types of military sound detection were developed. These included sonobuoys , first developed by the British in 1944 under the codename High Tea , dipping/dunking sonar and mine -detection sonar. This work formed the basis for post-war developments related to countering the nuclear submarine . During

3060-586: The War of the Rebellion " (Series 2, Volume 1, Part 1), show that the modern nomenclature was not in use at the time. The unofficial retro-applying of ship classes can occasionally lead to confusion. For example, while American works consistently adhere to the City - and Columbia -class monikers, works of British origin refer to the same classes as Cairo class and Tennessee class respectively, in compliance with

3145-582: The accepted European convention, some classes have been named after a common theme in the included ships' names, e.g., Tribal-class destroyers , and some classes were implemented as an organizational tool, making traditional methods of naming inefficient. For instance, the Amphion class is also known as the A class. Most destroyer classes were known by the initial letter used in naming the vessels, e.g., V and W-class destroyers . Classification by letter also helped to conflate similar smaller classes of ships as in

3230-415: The area near the boat. When active sonar is used to measure the distance from the transducer to the bottom, it is known as echo sounding . Similar methods may be used looking upward for wave measurement. Active sonar is also used to measure distance through water between two sonar transducers or a combination of a hydrophone (underwater acoustic microphone) and projector (underwater acoustic speaker). When

3315-502: The attack had the advantage that the German acoustic torpedo was not effective against a warship travelling so slowly. A variation of the creeping attack was the "plaster" attack, in which three attacking ships working in a close line abreast were directed over the target by the directing ship. The new weapons to deal with the ASDIC blind spot were "ahead-throwing weapons", such as Hedgehogs and later Squids , which projected warheads at

3400-510: The beam pattern suffered. Barium titanate was then replaced with more stable lead zirconate titanate (PZT), and the frequency was lowered to 5 kHz. The US fleet used this material in the AN/SQS-23 sonar for several decades. The SQS-23 sonar first used magnetostrictive nickel transducers, but these weighed several tons, and nickel was expensive and considered a critical material; piezoelectric transducers were therefore substituted. The sonar

3485-525: The case of the A-class destroyers of 1913 whose names spread across the alphabet. Since the end of the Second World War , Royal Navy ship classes have also been known by their type number (e.g. Type 45 destroyer .) For the United States Navy , the first ship in a class to be authorized by Congress is the designated class leader and gives the name to the class, regardless of the order in which

Wielingen-class frigate - Misplaced Pages Continue

3570-444: The characteristics of the outgoing ping. For these reasons, active sonar is not frequently used by military submarines. A very directional, but low-efficiency, type of sonar (used by fisheries, military, and for port security) makes use of a complex nonlinear feature of water known as non-linear sonar, the virtual transducer being known as a parametric array . Project Artemis was an experimental research and development project in

3655-673: The current convention to historical naval vessels sharing similarities, such as those of the American Civil War , where the Union Navy built several vessels in series, which can be termed "classes" as presently understood. Common examples include the Passaic -class monitor and the City-class ironclad , among many others, for the Union side, and Columbia class or Richmond class , for those ironclads in service with

3740-434: The depth charges had been released, the attacking ship left the immediate area at full speed. The directing ship then entered the target area and also released a pattern of depth charges. The low speed of the approach meant the submarine could not predict when depth charges were going to be released. Any evasive action was detected by the directing ship and steering orders to the attacking ship given accordingly. The low speed of

3825-412: The echoes. Since the original signal is much more powerful, it can be detected many times further than twice the range of the sonar (as in the example). Active sonar have two performance limitations: due to noise and reverberation. In general, one or other of these will dominate, so that the two effects can be initially considered separately. In noise-limited conditions at initial detection: where SL

3910-461: The electro-acoustic transducers are of the Tonpilz type and their design may be optimised to achieve maximum efficiency over the widest bandwidth, in order to optimise performance of the overall system. Occasionally, the acoustic pulse may be created by other means, e.g. chemically using explosives, airguns or plasma sound sources. To measure the distance to an object, the time from transmission of

3995-427: The entire signal is reflected from a 10 m target, it will be at 0.001 W/m when it reaches the emitter, i.e. just detectable. However, the original signal will remain above 0.001 W/m until 3000 m. Any 10 m target between 100 and 3000 m using a similar or better system would be able to detect the pulse, but would not be detected by the emitter. The detectors must be very sensitive to pick up

4080-518: The frigate Gordi followed by Wielingen in February 2009 which was renamed Verni . In 2011 Drazki took part in NATO operations against Libya and since then, the vessels have participated in several naval exercises with Turkey. Ship class In the course of building a class of ships, design changes might be implemented. In such a case, the ships of different design might not be considered of

4165-504: The government as a technical expert, first at the experimental station at Nahant, Massachusetts , and later at US Naval Headquarters, in London , England. At Nahant he applied the newly developed vacuum tube , then associated with the formative stages of the field of applied science now known as electronics , to the detection of underwater signals. As a result, the carbon button microphone , which had been used in earlier detection equipment,

4250-473: The hull and machinery were constructed in Belgium. As part of the project, the Belgian government made Belgian shipbuilding participation mandatory in the construction of the new ships. The frigates feature an action information centre between decks and the ships could be split into two independent gas-tight citadels in the case of nuclear, biological or chemical warfare . All machinery could be controlled from

4335-505: The largest individual sonar transducers ever. The advantage of metals is their high tensile strength and low input electrical impedance, but they have electrical losses and lower coupling coefficient than PZT, whose tensile strength can be increased by prestressing . Other materials were also tried; nonmetallic ferrites were promising for their low electrical conductivity resulting in low eddy current losses, Metglas offered high coupling coefficient, but they were inferior to PZT overall. In

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4420-498: The late 1950s to mid 1960s to examine acoustic propagation and signal processing for a low-frequency active sonar system that might be used for ocean surveillance. A secondary objective was examination of engineering problems of fixed active bottom systems. The receiving array was located on the slope of Plantagnet Bank off Bermuda. The active source array was deployed from the converted World War II tanker USNS  Mission Capistrano . Elements of Artemis were used experimentally after

4505-500: The light displacement had increased to 1,940 t (1,910 long tons) and to 2,430 t (2,390 long tons) at full load. The ships are propelled by a two- shaft combined diesel or gas (CODOG) system. This is composed of a single Rolls-Royce Olympus TM3B gas turbine creating 21,000 kilowatts (28,000  shp ) and giving the frigates a maximum speed of 28 knots (52 km/h; 32 mph) or two Cockerill CO 240 V12 diesel engines creating 4,500 kW (6,000  bhp ) with

4590-404: The magnetostrictive unit was much more reliable. High losses to US merchant supply shipping early in World War II led to large scale high priority US research in the field, pursuing both improvements in magnetostrictive transducer parameters and Rochelle salt reliability. Ammonium dihydrogen phosphate (ADP), a superior alternative, was found as a replacement for Rochelle salt; the first application

4675-417: The main experiment was terminated. This is an active sonar device that receives a specific stimulus and immediately (or with a delay) retransmits the received signal or a predetermined one. Transponders can be used to remotely activate or recover subsea equipment. A sonar target is small relative to the sphere , centred around the emitter, on which it is located. Therefore, the power of the reflected signal

4760-598: The modern Royal Navy naming conventions. By the time the United States entered World War II, the current naming convention was in place, though it remains unclear as to exactly how and when the practice originated. Merchant ships are almost always classed by a classification society . These vessels are said to be in class when their hull, structures, machinery, and equipment conform to International Maritime Organization and MARPOL standards. Vessels out of class may be uninsurable and/or not permitted to sail by other agencies. A vessel's class may include endorsements for

4845-548: The need to detect submarines prompted more research into the use of sound. The British made early use of underwater listening devices called hydrophones , while the French physicist Paul Langevin , working with a Russian immigrant electrical engineer Constantin Chilowsky, worked on the development of active sound devices for detecting submarines in 1915. Although piezoelectric and magnetostrictive transducers later superseded

4930-494: The ocean or floats on a taut line mooring at a constant depth of perhaps 100 m. They may also be used by submarines , AUVs , and floats such as the Argo float. Passive sonar listens without transmitting. It is often employed in military settings, although it is also used in science applications, e.g. , detecting fish for presence/absence studies in various aquatic environments – see also passive acoustics and passive radar . In

5015-403: The other factors are as before. An upward looking sonar (ULS) is a sonar device pointed upwards looking towards the surface of the sea. It is used for similar purposes as downward looking sonar, but has some unique applications such as measuring sea ice thickness, roughness and concentration, or measuring air entrainment from bubble plumes during rough seas. Often it is moored on the bottom of

5100-402: The projectors consisted of two rectangular identical independent units in a cast-iron rectangular body about 16 by 9 inches (410 mm × 230 mm). The exposed area was half the wavelength wide and three wavelengths high. The magnetostrictive cores were made from 4 mm stampings of nickel, and later of an iron-aluminium alloy with aluminium content between 12.7% and 12.9%. The power

5185-410: The pulse. This pulse of sound is generally created electronically using a sonar projector consisting of a signal generator, power amplifier and electro-acoustic transducer/array. A transducer is a device that can transmit and receive acoustic signals ("pings"). A beamformer is usually employed to concentrate the acoustic power into a beam, which may be swept to cover the required search angles. Generally,

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5270-861: The quartz material to "ASD"ivite: "ASD" for "Anti-Submarine Division", hence the British acronym ASDIC . In 1939, in response to a question from the Oxford English Dictionary , the Admiralty made up the story that it stood for "Allied Submarine Detection Investigation Committee", and this is still widely believed, though no committee bearing this name has been found in the Admiralty archives. By 1918, Britain and France had built prototype active systems. The British tested their ASDIC on HMS  Antrim in 1920 and started production in 1922. The 6th Destroyer Flotilla had ASDIC-equipped vessels in 1923. An anti-submarine school HMS Osprey and

5355-456: The radial speed of the searching platform. One useful small sonar is similar in appearance to a waterproof flashlight. The head is pointed into the water, a button is pressed, and the device displays the distance to the target. Another variant is a " fishfinder " that shows a small display with shoals of fish. Some civilian sonars (which are not designed for stealth) approach active military sonars in capability, with three-dimensional displays of

5440-399: The same class may be referred to as sister ships . The name of a naval ship class is most commonly the name of the lead ship , the first ship commissioned or built of its design. However, other systems can be used without confusion or conflict. A descriptive name may be used; for example it was decided to group destroyers made to the same design as HMS Tomahawk , all named after weapons, as

5525-558: The same class; each variation would either be its own class, or a subclass of the original class (see County-class cruiser for an example). If ships are built of a class whose production had been discontinued, a similar distinction might be made. Ships in a class often have names linked by a common factor: e.g. Trafalgar -class submarines ' names all begin with T ( Turbulent , Tireless , Torbay ); and Ticonderoga -class cruisers are named after American battles ( Yorktown , Bunker Hill , Gettysburg , Anzio ). Ships of

5610-459: The ships of that class are laid down, launched or commissioned. Due to numbering conventions, the lead ship often has the lowest hull number of its class. (During World War II , the award of construction contracts was not always congruent with completion, so several ships had higher hull numbers than later ships.) Before the 1920s, naval vessels were classified according to shared characteristics. However, naval historians and scholars retro-apply

5695-437: The surfaces of gaps, and moving coil (or electrodynamic) transducers, similar to conventional speakers; the latter are used in underwater sound calibration, due to their very low resonance frequencies and flat broadband characteristics above them. Active sonar uses a sound transmitter (or projector) and a receiver. When the two are in the same place it is monostatic operation . When the transmitter and receiver are separated it

5780-600: The target and localise it, as well as measuring its velocity. The pulse may be at constant frequency or a chirp of changing frequency (to allow pulse compression on reception). Simple sonars generally use the former with a filter wide enough to cover possible Doppler changes due to target movement, while more complex ones generally include the latter technique. Since digital processing became available pulse compression has usually been implemented using digital correlation techniques. Military sonars often have multiple beams to provide all-round cover while simple ones only cover

5865-405: The target submarine on ASDIC from a position about 1500 to 2000 yards behind the submarine. The second ship, with her ASDIC turned off and running at 5 knots, started an attack from a position between the directing ship and the target. This attack was controlled by radio telephone from the directing ship, based on their ASDIC and the range (by rangefinder) and bearing of the attacking ship. As soon as

5950-458: The torpedo went after the noisier fizzy decoy. The counter-countermeasure was a torpedo with active sonar – a transducer was added to the torpedo nose, and the microphones were listening for its reflected periodic tone bursts. The transducers comprised identical rectangular crystal plates arranged to diamond-shaped areas in staggered rows. Passive sonar arrays for submarines were developed from ADP crystals. Several crystal assemblies were arranged in

6035-409: The two platforms. This technique, when used with multiple transducers/hydrophones/projectors, can calculate the relative positions of static and moving objects in water. In combat situations, an active pulse can be detected by an enemy and will reveal a submarine's position at twice the maximum distance that the submarine can itself detect a contact and give clues as to the submarine's identity based on

6120-406: The type of cargo such as "oil carrier", "bulk carrier", "mixed carrier" etc. It may also include class notations denoting special abilities of the vessel. Examples of this include an ice class , fire fighting capability, oil recovery capability, automated machinery space capability, or other special ability. Sonar Sonar ( sound navigation and ranging or sonic navigation and ranging )

6205-481: The very broadest usage, this term can encompass virtually any analytical technique involving remotely generated sound, though it is usually restricted to techniques applied in an aquatic environment. Passive sonar has a wide variety of techniques for identifying the source of a detected sound. For example, U.S. vessels usually operate 60 Hertz (Hz) alternating current power systems. If transformers or generators are mounted without proper vibration insulation from

6290-465: Was a large array of 432 individual transducers. At first, the transducers were unreliable, showing mechanical and electrical failures and deteriorating soon after installation; they were also produced by several vendors, had different designs, and their characteristics were different enough to impair the array's performance. The policy to allow repair of individual transducers was then sacrificed, and "expendable modular design", sealed non-repairable modules,

6375-559: Was a replacement of the 24 kHz Rochelle-salt transducers. Within nine months, Rochelle salt was obsolete. The ADP manufacturing facility grew from few dozen personnel in early 1940 to several thousands in 1942. One of the earliest application of ADP crystals were hydrophones for acoustic mines ; the crystals were specified for low-frequency cutoff at 5 Hz, withstanding mechanical shock for deployment from aircraft from 3,000 m (10,000 ft), and ability to survive neighbouring mine explosions. One of key features of ADP reliability

6460-545: Was being loaded on the cable-laying vessel, World War I ended and Horton returned home. During World War II, he continued to develop sonar systems that could detect submarines, mines, and torpedoes. He published Fundamentals of Sonar in 1957 as chief research consultant at the US Navy Underwater Sound Laboratory . He held this position until 1959 when he became technical director, a position he held until mandatory retirement in 1963. There

6545-669: Was chosen instead, eliminating the problem with seals and other extraneous mechanical parts. The Imperial Japanese Navy at the onset of World War II used projectors based on quartz . These were big and heavy, especially if designed for lower frequencies; the one for Type 91 set, operating at 9 kHz, had a diameter of 30 inches (760 mm) and was driven by an oscillator with 5 kW power and 7 kV of output amplitude. The Type 93 projectors consisted of solid sandwiches of quartz, assembled into spherical cast iron bodies. The Type 93 sonars were later replaced with Type 3, which followed German design and used magnetostrictive projectors;

6630-491: Was commissioned before USS  Colorado . The West German Navy ( Bundesmarine ) used a three-digit type number for every class in service or in advanced project state. Modified versions were identified by a single letter suffix. After the reunification of Germany the German Navy ( Deutsche Marine ) kept the system. Informally, classes are also traditionally named after their lead ships. The Indonesian Navy has

6715-489: Was damaged during an anti-submarine exercise off the coast of Norway in September 1988, striking a rock. The ship was decommissioned on 1 July 1993 and then used as a parts hulk for the other frigates. The hulk was towed to Ghent for scrapping on 7 November 2000. Following the loss of Westhinder , two of the frigates were kept operational while the third was placed in reserve or under refit. The third ship, Wandelaar ,

6800-542: Was decommissioned in 2004 and was sold to the Bulgarian Navy the same year. Wielingen and Westdiep were decommissioned in 2007 sold to Bulgaria in 2008. Bulgaria joined NATO in 2004 and sought out options to replace their older Soviet -era fleet to fulfill their obligations with the organisation. In May 2004 the Bulgarian government agreed to purchase new equipment for the Bulgarian Navy. On 4 December 2004,

6885-426: Was little progress in US sonar from 1915 to 1940. In 1940, US sonars typically consisted of a magnetostrictive transducer and an array of nickel tubes connected to a 1-foot-diameter steel plate attached back-to-back to a Rochelle salt crystal in a spherical housing. This assembly penetrated the ship hull and was manually rotated to the desired angle. The piezoelectric Rochelle salt crystal had better parameters, but

6970-493: Was placed with two Belgian shipyards in October 1973. Construction of the ships began in 1974. The first two ships, Wielingen and Westdiep , were first delivered in December 1976. However, they were both sent back to their yards for an engine overhaul which was completed in 1977. The four ships, including the final two Wandelaar and Westhinder , all entered service in 1978. All four ships were based at Zeebrugge . Westhinder

7055-577: Was provided from a 2 kW at 3.8 kV, with polarization from a 20 V, 8 A DC source. The passive hydrophones of the Imperial Japanese Navy were based on moving-coil design, Rochelle salt piezo transducers, and carbon microphones . Magnetostrictive transducers were pursued after World War II as an alternative to piezoelectric ones. Nickel scroll-wound ring transducers were used for high-power low-frequency operations, with size up to 13 feet (4.0 m) in diameter, probably

7140-512: Was replaced by the precursor of the modern hydrophone . Also during this period, he experimented with methods for towing detection. This was due to the increased sensitivity of his device. The principles are still used in modern towed sonar systems. To meet the defense needs of Great Britain, he was sent to England to install in the Irish Sea bottom-mounted hydrophones connected to a shore listening post by submarine cable. While this equipment

7225-537: Was used as an ancillary to lighthouses or lightships to provide warning of hazards. The use of sound to "echo-locate" underwater in the same way as bats use sound for aerial navigation seems to have been prompted by the Titanic disaster of 1912. The world's first patent for an underwater echo-ranging device was filed at the British Patent Office by English meteorologist Lewis Fry Richardson

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