305 Sentences With "hydrophones" | Random Sentence Generator

Prior to this, they had set up hydrophones all over the world.

The researchers recorded songs annually from 2001 to 2005 using hand-held hydrophones aboard boats.

Officers on deck kept an eye out for aquatic interlopers while using hydrophones to listen underwater.

In this case the data was years of recordings from a dozen hydrophones stationed all over the Pacific.

But this sound was recorded on many hydrophones so it stood out in our mind as being something unique.

Instruments on the seabed include tilt meters, cameras, seismometers, temperature gauges, hydrophones, chemical probes, pressure sensors and fluid samplers.

That may mean towing hydrophones more than a mile below the surface, using specialist devices that are in short supply.

This year the team has deployed another set of hydrophones to find out why the fish make sounds when they spawn.

They compared this to the data they took from Indian Ocean hydrophones to find examples of impacts and seismic events from the real world.

The piece is composed of recordings made in Greenland, where she used hydrophones to capture the noises made by water under the ice sheets.

The sound waves hit the sea floor, penetrating miles into it, and bounce back to the surface, where they are picked up by hydrophones.

The researchers didn't find the airplane, but signals did show up in Indian Ocean hydrophones the day of the disappearance—one in a reasonable location.

At this stage of the search they would typically use acoustic hydrophones, bringing in more advanced robots later to scan the seabed and retrieve any objects once they have been found.

Maritime search experts say acoustic hydrophones must be towed in the water at depths of up to 2,000 meters in order to have the best chance of picking up the signals.

The prosecutors said that from 2015 to 2016, Qin exported 78 hydrophones, devices which can be used to monitor sound underwater, to Northwestern Polytechnical University (NWPU), a Chinese military research institute.

Prosecutors said that Qin sought to illegally smuggle the devices to China and concealed from a U.S. supplier of hydrophones that NWPU was the entity that would be receiving the products.

Maritime search experts say this means acoustic hydrophones are usually towed in the water at depths of up to 2,000 meters in order to have the best chance of hearing the signals.

More sea-traffic data may become available soon as countries consider deploying devices in the water — sonar and camera buoys, as well as low-cost floating hydrophones — to catch ships approaching restricted areas.

The indictment said that from 2015 to 2016, Qin exported 78 hydrophones, devices which can be used to monitor sound underwater, to NWPU, which the indictment described as a Chinese military research institute.

Maritime search experts say this means acoustic hydrophones must be towed in the water at depths of up to 2,000 meters in order to have the best chance of picking up the signals.

The scientists had been using hydrophones to monitor underwater sound levels in the bay, and they realized that the drop in stress had coincided exactly with an equally sudden decline in human-generated underwater noise.

Its newest vessels, Le Laperouse, which made its debut in June, and Le Champlain, an October newcomer, each have a Blue Eye lounge, with oblong portholes, low underwater lighting and hydrophones that transmit the natural sounds at sea.

Maritime search experts say this means acoustic hydrophones must be towed in the water at depths of up to 2,000 metres in order to have the best chance of picking up the signals, which should last for 30 days.

Navy experts explained that the large aperture bow array is water backed with no dome and very small hydrophones able to last for the life of the ship; the new submarines do not have an air-backed array, preventing the need to replace transducers every 10-years.

So his sound recording equipment—hydrophones, bat detectors, lapel microphones—captures a transportative soundscape that has everything from the hum of flies on cow dung to drones flying over the moor, the dawn chorus of birds, cattle, bats, soccer fans cheering and chanting from a nearby stadium, water dwelling insects mating, grass swaying, and the thumping music and screams from the fun fair that comes every year to the moor.

Hydrophones and directional hydrophones using a baffle. Later in the war, the British Admiralty belatedly convened a scientific panel to advise on how to combat U-boats.

Also some experiments have been performed to use CMUTs as hydrophones.

The sonarman bent to his scope and Hank listened intently over the hydrophones.

A hydrophone is a seismic receiver that is typically used in marine seismic acquisition, and it is sensitive to changes in pressure caused by acoustic pulses in its surrounding environment. Typical hydrophones utilise piezoelectric transducers that, when subjected to changes in pressure, produce an electric potential which is directly indicative of pressure changes. As is the case with air- guns, hydrophones are often also employed in groups or arrays which comprise of multiple hydrophones wired collectively to ensure maximum signal-to-noise ratio.

Once detected, other methods such as radar or sonobuoy hydrophones could be used to track and target the contact.

In Heck's concept, a survey ship's crew would drop an explosive charge off the ship's stern, detonate it, and note the time the sound arrived at the ship using a chronograph. Hydrophones installed at known positions would also detect the sound when it arrived at their locations and then automatically send a radio signal to the ship at the instant they detected the sound, recording that time with the ship's chronograph as well. The essentially instantaneous notification of the ship that the sound had arrived at a given set of hydrophones would allow the ship's crew to calculate the distance of their ship from the hydrophones by calculating the difference between the time the ship heard the explosion and the time the sound of the detonation arrived at the distant hydrophones and then multiplying this time by the speed of sound through water. By making these calculations for hydrophones at at least two different known locations, the ship's crew could use triangulation to fix their ship's position.

They were equipped with an array of five hydrophones in the bow to allow them to locate and engage targets while submerged.

Multiple hydrophones can be arranged in an array so that it will add the signals from the desired direction while subtracting signals from other directions. The array may be steered using a beamformer. Most commonly, hydrophones are arranged in a "line array" but may be in two- or three-dimensional arrangements. SOSUS hydrophones, laid on the seabed and connected by underwater cables, were used, beginning in the 1950s, by the U.S. Navy to track movement of Soviet submarines during the Cold War along a line from Greenland, Iceland and the United Kingdom known as the GIUK gap.

Modern hydrophones convert sound to electrical energy, which then can undergo additional signal processing, or that can be transmitted immediately to a receiving station. They may be directional or omnidirectional. Navies use a variety of acoustic systems, especially passive, in antisubmarine warfare, both tactical and strategic. For tactical use, passive hydrophones, both on ships and airdropped sonobuoys, are used extensively in antisubmarine warfare.

Lightweight sound-sensitive plastic film and fibre optics have been used for hydrophones, while Terfenol-D and PMN (lead magnesium niobate) have been developed for projectors.

This system used a second vessel as auxiliary receiver, leading to a considerable increase of the detection range. The omnidirectional hydrophones used resulted in an inability to determine whether signals were coming from the right or left. SACLANTCEN resolved this problem by designing cardioid hydrophones which provided the left-right discrimination. For towed arrays to be effective, the noise problem of the towing vessel needed to be solved.

Identification of signature whistle calls from wild, unrestrained bottlenose dolphins is essential to understand how they are used in their natural environment. Signature whistles of bottlenose dolphins can be recorded in the wild or in captivity. Hydrophones are used in both cases, but the number of devices may vary based on the researcher's preference and methodology. Using multiple hydrophones allows the researchers to better identify which dolphin emitted which whistle.

It carried seven 90-cubic foot high pressure cylinders to provide breathing gas and control buoyancy. The ballast compartment covered the gas cylinders. For communication, the suit used hydrophones.

Stop Fish Bombing USA, a project under the fiscal sponsorship of Earth Island Institute, has adapted ShotSpotter technology with hydrophones to combat fish bombing on coral reefs in Sabah, Malaysia.

The tunnel is equipped with an array of instruments including: Propeller dynamometers, Five- hole pressure probe, Pitot probes, lasers, pressure sensors, hydrophones, planar motion mechanism (PMM), force balances, accelerometers, and acoustics arrays.

Sounds generated by ice quakes are easily determined through the use of hydrophones since sea water, an excellent sound channel, allows the ambient sounds generated through ice activities to travel great distances.

In June 2018, Qin was arrested on accusations that he shipped 78 hydrophones for use in anti-submarine warfare to the Northwestern Polytechnical University, which is affiliated with the People's Liberation Army.

Zirconium hydride phases are also known. Lead zirconate titanate (PZT) is the most commonly used piezoelectric material, with applications such as ultrasonic transducers, hydrophones, common rail injectors, piezoelectric transformers and micro-actuators.

'GHG' (Gruppenhorchgerät) passive hydrophones were fitted to detect submarines and a S-Gerät sonar was also probably fitted. The ships were equipped with a FuMO 24/25 radar set above the bridge.Gröner, pp.

An echosounder installed at Folger Deep shows evidence of a dense zooplankton community and schools of fish in the water column, while hydrophones regularly record the songs of whales and dolphins in the area.

This instrumented fiber optic cabled observatory provides power and communications to the seabed (4728 m). The ACO is currently configured with an array of thermistors, current meters, conductivity sensors, two hydrophones, and a video camera.

The survey and installation focus in that period was on installation of MILS in the Atlantic and Pacific test ranges.The similarity is seen in the 1962 Bell Telephone System advertisement "How the ocean grew 'ears' to pinpoint missile shots". Arrays of hydrophones placed around the target area located the missile warhead by means of measuring arrival times of the explosion at the various hydrophones of a SOFAR charge in the test warhead. During that period an atypical SOSUS system was installed in 1959 at Argentia, Newfoundland to provide surveillance for approaches to Hudson Bay.

The Germany deployed U-boats (submarines) after the war began. Alternating between restricted and unrestricted submarine warfare in the Atlantic, the Kaiserliche Marine employed them to deprive the British Isles of vital supplies. The deaths of British merchant sailors and the seeming invulnerability of U-boats led to the development of depth charges (1916), hydrophones (passive sonar, 1917), blimps, hunter-killer submarines (HMS R-1, 1917), forward-throwing anti-submarine weapons, and dipping hydrophones (the latter two both abandoned in 1918). To extend their operations, the Germans proposed supply submarines (1916).

La Motte-Picquet (D 645). A towed array sonar is a system of hydrophones towed behind a submarine or a surface ship on a cable. Trailing the hydrophones behind the vessel, on a cable that can be kilometres long, keeps the array's sensors away from the ship's own noise sources, greatly improving its signal-to-noise ratio, and hence the effectiveness of detecting and tracking faint contacts, such as quiet, low noise-emitting submarine threats, or seismic signals. A towed array offers superior resolution and range compared with hull mounted sonar.

Macdonald seamount was discovered in 1967, when hydrophones noted earthquake activity in the area. The seamount was named in 1970 after Gordon A. MacDonald. It is also known as Tamarii, while Macdonald appears to be an incorrect capitalization.

'GHG' (Gruppenhorchgerät) passive hydrophones were fitted to detect submarines and an S-Gerät sonar was also probably fitted. The ships were equipped with a FuMO 24/25 radar set above the bridge.Gröner, pp. 203–04; Whitley 1991, pp.

Furthermore, they did not occur on the tectonic plate boundary, but rather in the middle of the plate. The subterranean quakes were detected on hydrophones, and scientists described the sounds as similar to thunder, and unlike anything previously recorded.

A hydrophone being lowered into the North Atlantic The first hydrophones consisted of a tube with a thin membrane covering the submerged end and the observer's ear on the other end. The design of effective hydrophones must take into account the acoustic resistance of water, which is 3750 times that of air; hence the pressure exerted by a wave of the same intensity in air is increased by a factor of 3750 in water. The American Submarine Signaling Company developed a hydrophone to detect underwater bells rung from lighthouses and lightships. The case was a thick, hollow brass disc in diameter.

As technology improved the output of individual Naval Facilities was consolidated at central processing centers designed Naval Ocean Processing Facility (NOPF). The first systems were limited by the commercial telephone cable technology for the application requiring a shore facility within about from the array and thus within that distance from the continental shelf locations suitable for the array. The cable of the time consisted of multi- pair wire connected to the forty hydrophones of the array. New coaxial multiplexed commercial telephone system cable, designated SB, using a single wire for all hydrophones allowed major changes with the prototype installed in 1962 at Eleuthera.

The bottom line is that MASINT cannot identify who is inside a tank or aircraft of interest. Numerous countries produce their own antisubmarine warfare sensors, such as hydrophones, active sonar, magnetic anomaly detectors, and other hydrographic sensors that are frequently considered too "ordinary" to be called MASINT.

Bismarcks clockwise turn on 25 May. Lütjens' tactic was highly successful, shaking free of his pursuers. In the early hours of 24 May 1941, Prinz Eugens hydrophones detected two large ships approaching. Vice Admiral Lancelot Holland in his flagship battlecruiser and battleship were heading towards them.

Hydrophones, a type of underwater microphone, receive acoustic signals and then either store or convert them into radio signals for rapid transmission through the air to receivers on shore. Fixed-site acoustic receiver system used during the late 1950s. Data was recorded on both paper and magnetic tape.

In 1931, the Coast and Geodetic Survey proposed the replacement of manned station ships with "radio-sonobuoys", and placed the new buoys in service beginning in July 1936. These buoys weighed 700 pounds (317.5 kg), could be deployed or recovered by Coast and Geodetic Survey ships in five minutes, and were equipped with subsurface hydrophones, batteries, and radio transmitters that automatically sent a radio signal when their hydrophones detected the sound of a ranging explosion. These "radio-sonobuoys" were the ancestors of the sonobuoys that began to appear in the 1940s.Theberge, Alfred E., "System Without Fixed Points: Development of the Radio-Acoustic Ranging Navigation Technique (Part 1)," hydro-international.com, December 2, 2009.

They carried six torpedo tubes in two rotating triple mounts amidships. The ships could also carry a maximum of 58 to 96 mines and 30 depth charges. They were fitted with a set of Mars hydrophones for anti-submarine work, although these were useless at speeds over .Yakubov & Worth, pp.

The acoustic homing torpedo required a minimum distance of to lock onto the target after launch. The detection range of the hydrophones varied much according to circumstance, but 450 m (500 yards) was considered reasonable for a ship moving at 15 knots.Campbell (1985). Naval Weapons of World War Two, p.

During World War I, a towed sonar array known as the "Electric Eel" was developed by Harvey Hayes, a U.S. Navy physicist. This system is believed to be the first towed sonar array design. It employed two cables, each with a dozen hydrophones attached. The project was discontinued after the war.

Optical fibers are used as hydrophones for seismic and sonar applications. Hydrophone systems with more than one hundred sensors per fiber cable have been developed. Hydrophone sensor systems are used by the oil industry as well as a few countries' navies. Both bottom-mounted hydrophone arrays and towed streamer systems are in use.

General Electric was to design and fabricate propulsion and steering motors and to investigate an active acoustic homing system. David Taylor Model Basin was to assist with hydrodynamics and propulsion. The guidance system consisted of four hydrophones placed around the midsection of the torpedo, connected to a vacuum tube-based sound processing array.

Her Type 96 25 mm AA guns were increased to a total of 11 triple- mounts and 17 single-mounts. Her torpedo launchers were replaced by two quadruple launchers mounted in the stern, along with two depth charge rails. She was given a complete set of the latest radar, hydrophones and sonar.

The transducer elements were cubes of weighing assembled in 72 element modules six elements wide by twelve elements high. Those modules were then assembled on the array in five module components stacked in four horizontal rows. The optimal center frequency of 400 Hz proved in tests to be optimized with the actual modules at approximately 385 Hz and 405 Hz. The array assembly also had electrical equipment required to make the electrical connection between array transducers and the transmission cable and for measurement and control functions that were housed in tanks at the bottom of the array assembly. At the top of the structure were four hydrophones in three coordinate axes that provided array orientation relative to acoustic positioning hydrophones.

In 1996, the Ocean Drilling Program deployed ocean bottom hydrophones and ocean bottom seismometers around Hydrate Ridge. The data from these tools was analyzed in a 2001 study, in which the velocities of refracted seismic waves helped scientists estimate the subsurface contents of the site (e.g. the relative thickness of its free gas zone).

The LSK489 is used in a wide range of front-end signal chain applications, including audio preamps, piezoelectric element preamps and photodiode preamps. The part is also used in high-end sensor systems ranging from hydrophones to the front end of the Large Synoptic Survey Telescope (LSST) being developed by SLAC National Accelerator Laboratory.

Kaiten No.4 sighted again over an hour later and again attacked with depth charges which resulted in a violent explosion, throwing water into the air. I-58 came to periscope depth after her hydrophones reported a distant explosion. In Hashimoto's opinion, the previously sighted destroyer had disappeared. He headed northwards to evade pursuit.

He employed anti-submarine and minesweeping methods. Asdic, depth charges, and the hydrophones used in the Great War could not be used when a ship was underway, however they were used in action against enemy submarines. He was ordered to the Mediterranean Sea in April 1918. He performed convoy, anti-submarine, and rescue work.

Some applications of PVDF are pressure sensors, hydrophones, and shock wave sensors. Due to their flexibility, piezoelectric composites have been proposed as energy harvesters and nanogenerators. In 2018, it was reported by Zhu et al. that a piezoelectric response of about 17 pC/N could be obtained from PDMS/PZT nanocomposite at 60% porosity.

She also had two radar detectors: a metric Type E-27 and a centimetric Model 3 system. The ship had a Type 93 sonar and two Type 0 hydrophones with which to search for submarines. Before the end of the war, a Type 2, Mark 2, Model 4 surface fire-control radar was installed.

237–238 One significant innovation was the Sound Surveillance System (SOSUS), a network of underwater hydrophones and listening posts designed to track the movement of submarines. The first operational test of SOSUS was done during the ASDevEx 1–54 exercise from April 6 to June 7, 1954.Polmar and Moore. Cold War Submarines (2004), p.

By the end of the war, the British had 38 hydrophone officers and 200 qualified listeners, paid an addition 4d per day.Van der Kloot 2014, p. 125. From late in World War I until the introduction of active sonar in the early 1920s, hydrophones were the sole method for submarines to detect targets while submerged; they remain useful today.

The ships carried eight torpedo tubes in two power-operated mounts. A pair of reload torpedoes was provided for each mount. They had four depth charge launchers and mine rails could be fitted on the rear deck that had a maximum capacity of 60 mines. A system of passive hydrophones designated as 'GHG' (Gruppenhorchgerät) was fitted to detect submarines.

Module connection to cable. The receiving array, just as with the source, underwent significant changes from planning to the final test configuration. It was a three dimensional system of hydrophones laid by cable ships on the slope of the Plantagnet Bank seamount. The array cables terminated at Argus Island, the tower erected for the project on the bank.

While TB 81 was refloated and repaired, Viper was wrecked. TB 81 was reboilered in 1905. In April 1913, TB 81 was in commission with a nucleus crew at Portsmouth. TB 81 served as a patrol boat during the First World War, operating out of Portsmouth and Portland, and being fitted with hydrophones and depth charges.

In the figure on the right, a geophone is shown; the conical spike on the geophone is dug into the ground for coupling. As is the case with hydrophones, geophones are often arranged in arrays as well to maximise the signal-to-noise ratio as well as to minimise the influence of surface waves on recorded data.

The ships were armed with one gun, one Bofors guns and two Madsen anti-aircraft cannon. The vessel had three mine dropping rails, and could carry about 100 mines. The ship could also hunt submarines, and was equipped with hydrophones, depth charge throwers and rails. The vessel was also strong enough to be able to tow minesweeping equipment.

NW Rota-1 was discovered to be hydrothermally active by NOAA in 2003 and first mapped by the remotely operated vehicle (ROV) ROPOS in 2004. The volcano has repeatedly been targeted by dives of ROVs. Hydrophones have been placed at the summit and vent during several dives. NW Rota-1 is also known as "Northwest Rota-1".

She had four depth charge launchers and mine rails could be fitted on the rear deck that had a maximum capacity of 60 mines. 'GHG' (Gruppenhorchgerät) passive hydrophones were fitted to detect submarines and an S-Gerät sonar was also probably fitted. The ship was equipped with a FuMO 24/25 radar set above the bridge.Whitley, pp.

She had four depth charge launchers and mine rails could be fitted on the rear deck that had a maximum capacity of 60 mines. 'GHG' (Gruppenhorchgerät) passive hydrophones were fitted to detect submarines and an S-Gerät sonar was also probably fitted. The ship was equipped with a FuMO 21 radar set above the bridge.Whitley, pp.

She had four depth charge launchers and mine rails could be fitted on the rear deck that had a maximum capacity of 60 mines. 'GHG' (Gruppenhorchgerät) passive hydrophones were fitted to detect submarines and an S-Gerät sonar was also probably fitted. The ship was equipped with a FuMO 24/25 radar set above the bridge.Koop & Schmolke, p.

In this context he has been capturing and exploring sounds from, for example, volcanic earth, ice, atmospheric phenomena, nuclear power plants and deserted places."Place and Sound", ABC (Australia), 26 October 2013. Retrieved 10 August 2014 His piece "Labyrinthitis" was created from sounds recorded inside his inner ear. Recording tools used include accelometers, hydrophones and home-built electromagnetic receivers.

Enough depth charges were carried for either two or four patterns of 16 charges each.Whitley, p. 215 Mine rails could be fitted on the rear deck that had a maximum capacity of 60 mines. A system of passive hydrophones designated as 'GHG' (Gruppenhorchgerät) was fitted to detect submarines and an active sonar system was installed by August 1940.

In fact, the opposite proved true: Among other problems, the relatively shallow water along the U.S. East Coast attenuated the sound of ranging explosions and shoals often blocked the sound from reaching shore at all. To overcome these difficulties, the Coast and Geodetic Survey anchored vessels well offshore along the U.S. East Coast to serve as hydrophone stations. In 1931, the Coast and Geodetic Survey proposed replacing the manned station ships with "radio- sonobuoys", and in July 1936 it began to place radio-sonobuoys in service. The 700-pound (317.5-kg) buoys – equipped with subsurface hydrophones, batteries, and radio transmitters that automatically sent a radio signal when their hydrophones detected the sound of a ranging explosion – could be deployed or recovered by Coast and Geodetic Survey ships in five minutes.

It included the Australian physicist William Henry Bragg and the New Zealand physicist Sir Ernest Rutherford. They concluded that the best hope was to use hydrophones to listen for submarines. Rutherford's research produced his sole patent for a hydrophone. Bragg took the lead in July 1916 and he moved to the Admiralty hydrophone research establishment at Hawkcraig on the Firth of Forth.

The hydrophones on Prinz Eugen detected a foreign ship to port at 05:00. The Germans sighted the smokestacks of two ships at 05:45. The British ships started firing at the German task force at 05:53. Vice-Admiral Lancelot Holland planned on targeting Bismarck first, but due to the reversed battle order, and opened fire on the Prinz Eugen instead.

Artemis receiving field array module as implemented 1963. The receiving array was a field of modules forming a three dimensional array laid from 1961 to 1963 on the slopes of a seamount, the Plantagenet Bank (), off Bermuda. The modules, attached to ten lines of cable, were masts with floats on top to keep them upright. Each module mounted sets of hydrophones.

Oberon was the first submarine of the Royal Navy equipped with asdic while under construction, and was additionally equipped with Type 709 hydrophones and a Type SF direction finder. Modifications made during the Second World War included the addition of an Oerlikon 20 mm cannon for anti- aircraft defense and a Type 291W radio direction finder for air and surface warning.

Hydrophones picked up the convoys propeller noises and occasional depth charges but saw nothing. The boat was recalled and arrived in Malta on 27 June, making this her shortest patrol. It was the first patrol in many that Wanklyn could not fly the Jolly Roger to denote a kill. During these patrols, Upholder hosted war correspondent and future actor Commander Anthony Kimmins.

There are several methods of detecting nuclear detonations. Hydroacoustics is the primary means of determining if a nuclear detonation has occurred underwater. Hydrophones are used to monitor the change in water pressure as sound waves propagate through the world's oceans. Sound travels through 20 °C water at approximately 1482 meters per second, compared to the 332 m/s speed of sound through air.

They can also send 20 kHz quality audio recordings from the phone to a studio via FTP. Audio over IP is also used in scientific applications, such as the Neumayer Station in Antarctica, where Barix IP Audio encoders digitize and stream the complete audio spectrum captured by hydrophones under water to the Alfred Wegener Institute for Polar and Marine Research in Germany.

Two reloads were provided for each mount. They had four depth charge launchers and mine rails could be fitted on the rear deck that had a maximum capacity of 74–76 mines. 'GHG' (Gruppenhorchgerät) passive hydrophones were fitted to detect submarines and a S-Gerät sonar was also probably fitted. The ships were equipped with a FuMO 24 search radar above the bridge.

They had four depth charge launchers and mine rails could be fitted on the rear deck that had a maximum capacity of 60 mines. A system of passive hydrophones designated as 'GHG' (Gruppenhorchgerät) was fitted to detect submarines. A S-Gerät sonar was also probably fitted. Z37 was equipped with a FuMO 21 or FuMO 24 radar set above the bridge.

They had four depth charge launchers and mine rails could be fitted on the rear deck that had a maximum capacity of 60 mines. A system of passive hydrophones designated as 'GHG' (Gruppenhorchgerät) was fitted to detect submarines. A S-Gerät sonar was also probably fitted. The ship was equipped with a FuMO 24/25 radar set above the bridge.

Two reloads were provided for each mount. She had four depth charge launchers and mine rails could be fitted on the rear deck that had a maximum capacity of 60 mines. 'GHG' (Gruppenhorchgerät) passive hydrophones were fitted to detect submarines and an S-Gerät sonar was also probably fitted. The ship was equipped with a FuMO 24/25 radar set above the bridge.

She had four depth charge launchers and mine rails could be fitted on the rear deck that had a maximum capacity of 60 mines. 'GHG' (Gruppenhorchgerät) passive hydrophones were fitted to detect submarines and an S-Gerät sonar was also probably fitted. The ship was equipped with either a FuMO 21 or FuMO 24/25 radar set above the bridge.Gröner, pp.

Two reloads were provided for each mount. She had four depth charge launchers and mine rails could be fitted on the rear deck that had a maximum capacity of 60 mines. 'GHG' (Gruppenhorchgerät) passive hydrophones were fitted to detect submarines and an S-Gerät sonar was also probably fitted. The ship was equipped with a FuMO 24/25 radar set above the bridge.

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.

One of key features of ADP reliability 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.

The sonar hydrophones may be towed behind the ship or submarine in order to reduce the effect of noise generated by the watercraft itself. Towed units also combat the thermocline, as the unit may be towed above or below the thermocline. The display of most passive sonars used to be a two-dimensional waterfall display. The horizontal direction of the display is bearing.

The Kil class were designed to counter the U-boat threat posed by the Imperial German Navy during the First World War. They were designed to be equipped with hydrophones and depth charges to detect and destroy enemy submarines before they posed a threat to allied convoys.Rice (1991): p. 7 The class began to be launched towards the end of 1917.

The mapping revealed the existence of four rocky outcrops thought to be former seamounts. The Mariana Trench is a site chosen by researchers at Washington University and the Woods Hole Oceanographic Institution in 2012 for a seismic survey to investigate the subsurface water cycle. Using both ocean-bottom seismometers and hydrophones the scientists are able to map structures as deep as beneath the surface.

Frank Massa (1906–1990) was an American engineer who contributed greatly to the development of the field of acoustical engineering. He is perhaps best known for the development of recorded sound technology for the motion picture industry and, during World War II, the development of the first towed sonar transducers and hydrophones used by the U.S. Navy to detect and defeat German U-boat submarines.

Hydrophones and sonar operating in passive mode can detect acoustic signals radiated by otherwise invisible submarines, and use these signals to target attacks. Modern naval mines and torpedoes such as the CAPTOR mine can be programmed to distinguish the acoustic signatures of different vessels, leaving friendly vessels unmolested and attacking high-value targets when faced with multiple possible targets, e.g. distinguishing an aircraft carrier from its escorts.

That group also recommended a system to monitor low-frequency sound in the SOFAR channel using multiple listening sites equipped with hydrophones and a processing facility that could calculate submarine positions over hundreds of miles.The cited Project HARTWELL report first links arrays with fleet type submarines towing such an array in the GIUK then refers to potential exploitation of the deep sound channel low frequency sounds.

Two reloads were provided for each mount. They had four depth charge launchers and mine rails could be fitted on the rear deck that had a maximum capacity of 74–76 mines. 'GHG' (Gruppenhorchgerät) passive hydrophones were fitted to detect submarines and a S-Gerät sonar was also probably fitted. The ships were equipped with a FuMO 24/25 radar set above the bridge.

257-279, March 2005. There are several ways of employing such communication but the most common is by using hydrophones. Underwater communication is difficult due to factors such as multi-path propagation, time variations of the channel, small available bandwidth and strong signal attenuation, especially over long ranges. Compared to terrestrial communication, underwater communication has low data rates because it uses acoustic waves instead of electromagnetic waves.

Two reloads were provided for each mount. They had four depth charge launchers and mine rails could be fitted on the rear deck that had a maximum capacity of 74–76 mines. 'GHG' (Gruppenhorchgerät) passive hydrophones were fitted to detect submarines and an S-Gerät sonar was also probably fitted. The ships were equipped with a FuMO 24/25 radar set above the bridge.

An inexpensive low fidelity 3.5 inch driver, typically found in small radios A transducer is a device for converting one form of energy into another. In an electroacoustic context, this means converting sound energy into electrical energy (or vice versa). Electroacoustic transducers include loudspeakers, microphones, particle velocity sensors, hydrophones and sonar projectors. These devices convert a sound wave to or from an electric signal.

Launders set about the task, making one risky decision: he decided to switch off Venturers ASDIC (active sonar) and rely solely on hydrophones, to try to detect U-864 without being detected. Wolfram's decision to return for repairs at the U-boat pens at Bergen to fix the abnormal engine noise problem brought U-864 back past Fedje and the area where Venturer was located.

'GHG' (Gruppenhorchgerät) passive hydrophones were fitted to detect submarines and an active sonar system was installed by the end of 1939.Whitley, pp. 71–72 Z20 Karl Galster had a FuMO 21 search radar installed in 1942 and her anti- aircraft suite was upgraded several times over the course of the war. By the end, it consisted of six 3.7 cm guns and fifteen 2 cm weapons.

Acorn remained part of the 2nd Destroyer Flotilla until November 1915, then transferring to the 5th Destroyer Flotilla, part of the Mediterranean Fleet, arriving at Malta on 31 December. Acorn and the were used for trials of hydrophones during 1917. Acorn remained part of the Mediterranean Fleet at the end of the war in November 1918, when she was serving in the Aegean Squadron, based at Mudros.

They were quickly equipped with strengthened bows for ramming, and depth charges and hydrophones for identifying submarine targets. The first submarine casualty to a destroyer was the German , rammed by on 29 October 1914. While U-19 was only damaged, the next month successfully sank . The first depth-charge sinking was on 4 December 1916, when U-Boats Destroyed, Paul Kemp (1997), was sunk by HMS Llewellyn.

A set of depth-charge rails was added on the stern and the ship was fitted with hydrophones at the bow.Friedman, pp. 66, 74 monitor is firing in the foreground, 6 June 1944 Frobisher was assigned to the 4th Cruiser Squadron of the Eastern Fleet after the refit was completed and began escorting convoys and the fleet's capital ships in the Indian Ocean.Morris, p. 169; Rohwer, p.

The explosions were taken to be premature explosions of mines caught in the nets. As dark fell more explosions were heard, two green rockets were spotted at the east end of the net line and more explosions were heard. On 3 October, hydrophones detected a submarine at the west end of the nets, an explosion and then silence. Other boats' hydrophone sets gave similar indications.

The maximum speed at which a ship could travel while using its ASDIC was about 15 knots (~28 km/h), beyond which the noise of its own propeller and engine would drown out the echoes.Brown (2000). Nelson to Vanguard Both the U-boats and the warships also had hydrophones with which they could passively listen for sound in the water. U-boats usually attacked at night.

RESON A/S is a Danish company which provides tools for underwater acoustic applications and survey accuracy requirements. Range of products covers digital multi-beam systems, single-beam sensors, 3D visualization software, high-power transducers, and precision reference hydrophones. The products are used by, among others, the oil and gas industries, marine researchers and naval surveillance teams. RESON is the holding company of the RESON Group.

In 1976, the three brothers, Jens, Claus, and Per Resen Steenstrup pooled their expertise in advanced ultrasonic technology, and consequently RESON A/S was born. At first, they focused on developing homogenisers, but before long their passion for the sea won through. In the 1980s, RESON produced the first transducers and hydrophones, and meanwhile the company opened its first subsidiary, RESON Inc., in California.

U-156 sighted the first steamer in the early afternoon on 12 May, the first of twelve ships—eleven merchantmen and one warship—attacked on this patrol, ten of which were sunk. U-156, positioned near Fort-de-France, was ordered to observe the traffic to and from Martinique. At roughly offshore, the hydrophones detected a ship. Hartenstein attacked from a submerged position firing two torpedoes.

At the distances involved – generally less than – each of these radio signals arrived at the ship at essentially the same instant that each of the remote hydrophones detected the sound of the explosion. The ship's chronograph automatically recorded the time each radio signal arrived at the ship. By subtracting the time of the explosion from the time of radio signal reception, the ship's crew could determine the length of time the sound wave required to travel from the point of the explosion to each remote hydrophone and, knowing the speed of sound in the surrounding sea water, could multiply the sound's travel time by the velocity of sound in sea water to determine the distance between the explosion and the hydrophone. By determining the distance to at least two remote hydrophones in known locations, the ship's crew could use true range multilateration to fix the ship's position.

The passive receive array field consisted of ten parallel cables with 210 modules composed of masts mounting hydrophones. The cables were laid down the slope of Plantagenet BankPlantagenet Bank is often referred to as Argus Bank. in Bermuda. A 1961 array was to the north east of and parallel to array field string number one and a horizontal string, across the slope, was at right angles to the field at about .

While on his fourth patrol, on 3 April 1941, he sighted a convoy but the ships were at extreme range. On 10 April, a second attack went wrong when his torpedoes' tracks were seen and the convoy took evasive action. Upholder was subjected to a sustained counter- attack and was then forced to crash-dive deep when the hydrophones detected a torpedo closing on the vessel.Wingate 1991, p. 53.

The AMAR G3 (Autonomous Multichannel Acoustic Recorder Generation 3) is an underwater acoustic and oceanographic data recorder. It consists of recording electronics housed inside a watertight pressure housing. The AMAR can be connected to up to 8 hydrophones sampled at 24-bit resolution at rates up to 128 kHz, and another high-frequency hydrophone sampled at 16-bit resolution at rates up to 687.5 kHz. Oceanographic sensors (e.g.

Sanders, January 1969, p. 59 Hull turbulence made the U-boat's hydrophones ineffective at the speed U-73 was leaving the area, so she was unaware of the destroyers until Woolseys pattern of depth charges exploded below the submarine at 18:39.Sanders, January 1969, p. 62 Sea water poured in between the bow torpedo tubes and from a salt water inlet valve for the diesel engine cooling system.

Bhangmeters on Advanced Vela satellites detected what is variously called the Vela Incident or South Atlantic Incident, on 22 September 1979. Different reports have claimed that it was, or was not, a nuclear test, and, if it was, probably involved South Africa and possibly Israel. France and Taiwan have also been suggested. Only one bhangmeter detected the characteristic double- flash, although US Navy hydrophones suggest a low-yield blast.

Several new technologies will be needed for shallow-water naval operations. Since acoustic sensors (i.e., passive hydrophones and active sonar) perform less effectively in shallow waters than in the open seas, there is a strong pressure to develop additional sensors. One family of techniques, which will require electro-optical sensors to detect, is bioluminescence: light generated by the movement of a vessel through plankton and other marine life.

She attacked one steamer, but a failure of the echo sounder and the hydrophones forced Onice to return to Cagliari for repairs. During January 31 through February 4, 1938 she carried out her third and last mission, under command of captain Manlio Petroni, off Tarragona but without any results. On February 5, 1938, she left Soller and returned to Italy and assumed her old name of Onice ending her "legionary" career.

Bayerl, Robby; Martin Berkemeier; et al: World Directory of Leisure Aviation 2011-12, page 184. WDLA UK, Lancaster UK, 2011. ISSN 1368-485X The company is a division of Digital Marketing USA. The company's products include autogyros, sailboats, submarines, Scuba diver propulsion vehicle, hydrofoils, off-road motorcycles, amphibious gliders, underwater camera housings, hydrophones, powered paragliders, a line of outdoor cookbooks and a discontinued line of ultralight aircraft and helicopters.

The British and the Americans who examined Graph singled out her Zeiss periscope for particular praise. The American officers who carried out her initial inspection in Iceland recommended it be copied as quickly as possible for possible US Navy use.Report On The German Submarine U-570 Class p.37 Her underwater acoustic equipment was found to be a sophisticated array of hydrophones that was significantly better than the British equivalents.

There are two different types of hydroacoustic stations currently used in the IMS network; 6 hydrophone monitoring stations and 5 T-phase stations. These 11 stations are primarily located in the southern hemisphere, which is primarily ocean. Hydrophone monitoring stations consist of an array of three hydrophones suspended from cables tethered to the ocean floor. They are positioned at a depth located within the SOFAR in order to effectively gather readings.

Bottlenose dolphin (Tursiops truncatus) in the wild. A signature whistle is a learned, individually distinctive whistle type in a bottlenose dolphin's (Tursiops truncatus) acoustic repertoire that gives the identity of the whistle owner. The whistles are identified and studied in the wild or in captivity by researchers using hydrophones. Vocal learning strongly influences the development of signature whistles, which can remain stable for up to at least 12 years.

Although multiple hydrophones are used, signature identification uses a single hydrophone and allows better identification. Variation between signature whistles can be tested by examining the whistle contours frequency modulation pattern. A frequency modulation pattern differs between dolphins, which is usually identified by using standard acoustic parameter measurements, such as beginning, end, maximum or minimum frequency. Combining the measurements of the frequencies will show the modulation pattern of the individuals signature whistle.

Ecomusicological field research of animal behaviours within a particular environment often includes methods of passive recording/listening. This is usually undertaken with the use of multi- directional Microphone which are often hidden and left within a species’ habitat to record the array of sounds created in its environment.Guyette and Post, Ecology 41. Hydrophones (microphones that can be submerged beneath water) may also be used to collect sound data from marine environments.

Acoustic disdrometers, also referred to as a hydrophones, are able to sense the sound signatures for each drop size as rain strikes a water surface within the gauge. Since each sound signature is unique, it is possible to invert the underwater sound field to estimate the drop-size distribution within the rain. Selected moments of the drop-size distribution yield rainfall rate, rainfall accumulation, and other rainfall properties.

After the landslide the volcano became acoustically quiet for some time before sound levels increased again. Between 2009 and 2010 hydrophones recorded numerous acoustic signals, reflecting the steady eruptions, and tremors which may originate in the magmatic conduit although most of the acoustic signals appear to come from the vent. Apart from an increased amplitude in the burst cycles, the acoustic signal in 2010 was similar to that of 2009.

For coastal surveillance, a large receive array of hydrophones is usually deployed close to the shore and connected with cables to a land- based processing center. To enable long range target detection (far away from the shore), one can use a powerful mobile projector, deployable from the ship. A system of this kind exploits the idea of “bringing the projector closer to area of interest and getting the transmission loss down”.

They had four depth charge launchers and mine rails could be fitted on the rear deck that had a maximum capacity of 60 mines. A system of passive hydrophones designated as 'GHG' (Gruppenhorchgerät) was fitted to detect submarines. A S-Gerät sonar was also probably fitted. The ship was equipped with a FuMO 24/25 radar set above the bridge as well as a FuMB 34 radar detector.

Payne and her husband worked at sea to Bermuda in 1968. With the help of a Navy engineer, Frank Watlington monitored hydrophones many miles into the sea to capture the sounds of the humpback whales. After 31 years of analyzing the recordings. Payne discovered the predictable ways in which the whales change their songs each season and, with her colleague Linda Guinee, also discovered that whales use rhymes in their songs.

The Platform and Launch Systems Division (Code GXP) models and simulates: #Components and subsystems of the Submarine, Launch Tube and Missile including missile Launch Test Vehicle (LTV), Ballast Transport Fixtures and Hydrophones. Analyses include Stress, Thermal, Modal and Acoustic using Finite Element Method (FEM). Particular FEM analysis tools include ANSYS and ABAQUS. #Components and subsystems of the Common Missile Compartment (CMC) involving Missile Heating and Cooling (MHC) and Underwater Launch (UWL).

The most common sensor used for acoustic measurement is the microphone. Measurement-grade microphones are different from typical recording-studio microphones because they can provide a detailed calibration for their response and sensitivity. Other sensors include hydrophones for measuring sound in water or accelerometers for measuring vibrations causing sound. The three main groups of microphones are pressure, free-field, and random-incidence, each with their own correction factors for different applications.

The submarine was detected by hydrophones of the force near the island of Suðuroy and the destroyer dropped depth charges twice, but U-151 escaped unharmed. Marksman remained with the Northern Patrol force until the end of the war. On 1 November 1918, Marksman collided with the Naval trawler off Kirkaldy, Scotland. Charles Hammond sank early in the morning of the next day, while Marksman was under repair at Leith until 31 December 1918.

At 13:05 the U-boat estimated that it was now about eight miles ahead of the convoy and submerged to use her hydrophones, proceeding dead slow at a depth of . On detecting propeller noise, the U-boat altered course to approach the convoy. After half an hour the hydrophone operator heard faint propeller noises approaching. The U-boat altered course again and after 15 minutes the operator again reported oncoming propeller noises.

Z2 Georg Thiele had four depth charge launchers mounted on the sides of her rear deckhouse, which was supplemented by six racks for individual depth charges on the sides of the stern, with either 32 or 64 charges carried.Whitley, p. 215 Mine rails could be fitted on the rear deck that had a maximum capacity of 60 mines. A system of passive hydrophones designated as 'GHG' (Gruppenhorchgerät) was fitted to detect submarines.

In September 1914, Viola was requisitioned by the Admiralty (FY 614) armed with a 3 pounder gun and moved to Shetland, patrolling the waters out as far as Fair Isle looking for U-boats and escorting other vessels. Later in the war, Viola was armed with a 12-pounder gun, and transferred to the Tyne for minesweeping duty. She was one of the first vessels to use depth charges. She was also fitted with hydrophones.

Some drifters were equipped with hydrophones and wireless telegraph to improve their anti-submarine detection abilities. However, their 6-pounder guns were deemed inadequate to take on German U-boats. Some drifters in Canadian service were manned by detachments from the Newfoundland section of the Royal Naval Reserve.Canadian drifters were employed at the harbours of Halifax and Sydney, Nova Scotia, usually in concert with naval trawlers either on minesweeping or patrol missions.

This reduction gearing was very noisy, and made the submarine easier to detect with hydrophones. Eighteen late Balao-class submarines received low-speed double armature motors which drove the shafts directly and were much quieter, but this improvement was not universally fitted until the succeeding .Bauer and Roberts, p. 275 The new direct drive electric motors were designed by the Bureau of Ships' electrical division under Captain Hyman G. Rickover, and were first equipped on .

However, Bismarcks forward radar had failed as a result of vibration from the heavy guns firing during this skirmish, and Lütjens was obliged to order Prinz Eugen to move ahead of Bismarck in order to provide the squadron with forward radar coverage.Grützner 2010, p. 179. At the Battle of the Denmark Strait on 24 May 1941, was sunk, probably by Bismarck. The hydrophones on Prinz Eugen detected a foreign ship to port at 05:00.

215 Mine rails could be fitted on the rear deck that had a maximum capacity of sixty mines. 'GHG' (Gruppenhorchgerät) passive hydrophones were fitted to detect submarines.Whitley, pp. 71–72 The Type 34As were equipped with a C/34Z analog fire-control director on the roof of the bridge that calculated the gunnery data using range estimates provided by the two stereoscopic rangefinders, one abaft the rear funnel and the other just behind the director.

215 Mine rails could be fitted on the rear deck that had a maximum capacity of sixty mines. 'GHG' (Gruppenhorchgerät) passive hydrophones were fitted to detect submarines and an active sonar system was installed by the end of 1940.Whitley, p. 72 During the war the ship's light anti-aircraft armament was augmented several times. In 1941, improved 2 cm C/38 guns replaced the original C/30 guns and three additional guns were added.

He had to dive due to the flying boats, but that night, using hydrophones (passive sonar), located the ships and closed in on them. The destroyers were zigzagging in escort; U-32 placed herself between them and Empress of Britain, from where she fired two torpedoes. The first detonated prematurely; the second hit causing a massive explosion. Crews of the destroyers speculated this was caused by the fires aboard the liner reaching her fuel tanks.

McWethy recalled that in 1966, the Secretary of the Navy (SecNav) Paul Nitze was visiting the COSL office when a Soviet November class was detected "snooping around Bermuda." With the aid of the SOSUS hydrophones, "he could see what the submarine was doing and where it was. The SecNav was impressed." SOSUS devices provided critical data in helping locate the submarines and K-129, which both sank with the loss of all hands.

Two attempts to enter the harbour were made by German U-boats during the war and neither was successful: # tried to enter in November 1914. A trawler searching for submarines rammed her, causing her to leak, prompting her flight and surfacing; one crew member died. # made a foray in October 1918 but encountered the sophisticated defences then in place. It was detected by hydrophones before entering the anchorage, then destroyed by shore-triggered mines, killing all 36 hands.

Bottom mounted hydrophones can also be used, with land based processing. A system like this SOSUS was deployed by the US in the GIUK gap and other strategically important places. Airborne ASW forces developed better bombs and depth charges, while for ships and submarines a range of towed sonar devices were developed to overcome the problem of ship-mounting. Helicopters can fly courses offset from the ships and transmit sonar information to their combat information centres.

Sound travels far in water, and underwater loudspeakers and hydrophones can cover quite a gap. Apparently, both the American (SOSUS) and the Russian navies have placed sonic communication equipment in the seabed of areas frequently traveled by their submarines and connected it by underwater communications cables to their land stations. If a submarine hides near such a device, it can stay in contact with its headquarters. An underwater telephone sometimes called Gertrude is also used to communicate with submersibles.

A pair of reload torpedoes was provided for each mount. Leberecht Maass had four depth charge launchers mounted on the sides of her rear deckhouse, which was supplemented by six racks for individual depth charges on the sides of the stern, with either 32 or 64 charges carried. Mine rails could be fitted on the rear deck that had a maximum capacity of 60 mines. A system of passive hydrophones designated as 'GHG' (Gruppenhorchgerät) was fitted to detect submarines.

Since 2014 he works very often with field recordings and hydrophones to use these materials as a sound source for his electro acoustic compositions. The album Dyschronia was part of the A Closer Listening Top Ten 2017. On October the 15th 2018 he released the album Liquid Empires which contains only music made out of underwater recordings. The performance EDIT 1/0/0/0 was a commission work for the 1000 year anniversary of the Moritzkirche in Augsburg.

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 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.

300px Step-Aside was a tactic by which an escort ship could defend itself from a U-boat armed with acoustic torpedoes, specifically the T5 Zaunkönig torpedo, which the German navy began using in August 1943. This torpedo used built-in hydrophones to guide itself to its target by sound. In late 1943, Roberts received reports that the U-boats were regularly targeting the escort ships themselves. Stripped of their escorts, the merchant ships became easy prey.

Advancing lava flows into this crust, forming what is known as pillow lava. Below ocean depths of about 2200 m, where the pressure exceeds the critical pressure of water (22.06 MPa or about 218 atmospheres for pure water), it can no longer boil; it becomes a supercritical fluid. Without boiling sounds, deep-sea volcanoes can be difficult to detect at great distances using hydrophones. The critical temperature and pressure increase in solutions of salts, which are normally present in the seawater.

The linear arrays with hydrophones placed on slopes within the sound channel enabled beamforming processing at the shore facilities to form azimuthal beams. When two or more arrays held a contact, triangulation provided approximate positions for air or surface assets to localize.Before the nature of the arrays became known, many writers assumed SOSUS was a barrier system, rather than arrays giving surveillance of entire ocean basins. An associated program, Colossus, was such a system intended to be installed across straits.

The calls have deepened slightly to around 50 hertz since 1992, suggesting the whale has grown or matured. The track of the 52-hertz whale is unrelated to the presence or movement of other whale species. Its movements have been somewhat similar to that of blue whales, but its timing has been more like that of fin whales. It is detected in the Pacific Ocean every year beginning in August–December, and moves out of range of the hydrophones in January–February.

She was in fact the heavy cruiser , and had sailed from Guam for Leyte the previous day, after having delivered parts and nuclear material for the Hiroshima and Nagasaki atomic bombs to Tinian from San Francisco. Indianapolis was not equipped with sonar or hydrophones, or provided with an escort. I-58 submerged and prepared to attack with Type 95 torpedoes. After manoeuvering into position, at 23:26 (JST) the submarine fired a spread of six torpedoes at 2-second intervals.

It was only after the event that the hydrophones were used, with the purpose being to detect any sound that might indicate the enemy had survived. They heard nothing. Herbert was promoted to the rank of commander and belatedly, in 1919, he was awarded a bar to his DSO when the identity and destruction of UC-66 had been confirmed. Later still, in 1921, he gave evidence at a Prize Court investigating the award of bounties for the sinking of enemy submarines.

Whitley, p. 68 Four depth charge throwers were mounted on the sides of the rear deckhouse and they were supplemented by six racks for individual depth charges on the sides of the stern. Enough depth charges were carried for either two or four patterns of 16 charges each.Whitley, p. 215 Mine rails could be fitted on the rear deck that had a maximum capacity of 60 mines. A system of passive hydrophones designated as 'GHG' (Gruppenhorchgerät) was fitted to detect submarines.Whitley, pp.

Advancements in IoMT technology largely stemmed from military efforts to bolster the development of sensor networks and low-power computing platforms during the 1960s for defense applications. During the Cold War, the U.S. military pioneered the use of wireless sensor network technologies to detect and track Soviet submarines. One example was the Sound Surveillance System (SOSUS), a network of underwater acoustic sensors, i.e. hydrophones, placed throughout the Atlantic and Pacific Oceans to act as underwater listening posts for above-ground facilities.

The underwater sound from the Wigwam explosion was recorded on bottom-mounted hydrophones at Point Sur and Point Arena off California, and at Kāneʻohe Bay off Oahu, Hawaii. The sound emanating from the explosive test began as an intense water shock wave. As the sound travelled away from the test point, it reflected from topographic features, such as islands and seamounts, located throughout both the North and South Pacific Basins. The reflected sound was then recorded as hours-long coda at Kaneohe and Point Sur.

In geophysics, vertical seismic profile (VSP) is a technique of seismic measurements used for correlation with surface seismic data. The defining characteristic of a VSP (of which there are many types) is that either the energy source, or the detectors (or sometimes both) are in a borehole. In the most common type of VSP, Hydrophones, or more often geophones or accelerometers, in the borehole record reflected seismic energy originating from a seismic source at the surface. There are numerous methods for acquiring a vertical seismic profile (VSP).

Batteries which powered the submarines would be recharged during the night and intelligence gathering took place during daylight hours. The submarine was equipped with passive sonar hydrophones which allowed it to record signatures from Soviet vessels, identifying the capabilities of each individual vessel. On 27 September 1980 the Officers and Crew of Orion were granted the Freedom of the City of Wollongong in perpetuity. In 1987, Orion was awarded the Gloucester Cup, for being the RAN vessel demonstrating the greatest overall efficiency over the previous twelve months.

The submarines deployed as a defensive screen for the Operation "Gaudo", an anticipated sortie by the Italian fleet into the Aegean which would end with a catastrophic Italian defeat in the Battle of Cape Matapan. On March 27, 1941, Ambra discovered that her hydrophones did not work. At 2:37 on March 31, 1941, she sighted a large escorted ship moving at an estimated speed of 10 knots. At 2:44 she launched three torpedoes at the target and remained on the surface to observe the results.

Each cable had special takeouts built into it at intervals from which wires to the hydrophones were connected. Each mast was clamped onto the special cable with takeouts. At the upper end of the approximately cable a wire rope was attached and led to an explosively embedded anchor shot into the flat coral top of Plantagenet Bank. Tension of more than 40,000 lb was applied to the wire rope and cable to lay it down the side of the bank in the straightest line possible.

They were fitted with a set of Mars hydrophones for anti-submarine work, although it was useless at speeds over .Yakubov & Worth, pp. 101, 105–106 Fire control for the main battery of the Storozhevoys was provided by a Mina-7 fire-control system that was derived from an Italian Galileo system. It included a TsAS-2 mechanical analog computer that received information from a KDP2-4 gunnery director on the roof of the bridge which mounted a pair of DM-4 stereoscopic rangefinders.

They were fitted with a set of Mars hydrophones for anti-submarine work, although it was useless at speeds over .Yakubov & Worth, pp. 101, 105–106 Fire control for the main battery of the Gnevnys was provided by a Mina-7 fire-control system that was derived from an Italian Galileo system. It included a TsAS-2 mechanical analog computer that received information from a KDP2-4 gunnery director on the roof of the bridge which mounted a pair of DM-4 stereoscopic rangefinders.

Axis air force sank one of the merchants (Clan Campbell) the next day and destroyed three more vessels after their arrival in Malta. At 13:42 on March 23, 1942, Onice detected through hydrophones British Force B that was returning to Alexandria after the battle. She closed in and at 14:15 sighted the ships of Force B (estimated to be composed of 3 or 4 cruisers, plus some destroyers). At 14:33 Onice launched two torpedoes from about 3,000 meters in the position .

During World War II, naval personnel stationed at Point Sur, California conducted experiments with early sonar and radar systems. In 1949, while conducting research into the use of sound to detect submarines, the U.S. Naval Research Laboratory reported it was able to detect submarines at ranges of using SOFAR hydrophones off Point Sur. By the end of that year, they had expanded that range to several hundred miles. During the early period of the Cold War, the Soviet submarine fleet became the largest in the world.

The captain commands the sub to dive much deeper to avoid a surface storm ahead. At this point the submarine travels through a waterfall and enters the hidden ride building, where guests find themselves apparently moving through underwater caverns. The captain announces that, due to advancements in marine technology, they can use "sonar hydrophones" (an homage to the original attraction), to hear the fish talk. The sub passes through a dark cavern where huge eels lunge toward the submarine, and lobsters can be seen as well.

In 2008 and 2009, hydrophones recorded a cyclical activity, with bursts of acoustic signals lasting one to several minutes separated by pauses less than a minute long. Each burst consisted of hundreds of pulses, each several tenths of a second long. An intense acoustic signal recorded between 12 and 16 August 2009 exhibited high amplitudes and low frequencies, with two distinct pulses on 14 August 2009. This signal has been interpreted as an intense explosive eruption which led to the landslide on 14 August 2009.

Blue whales stop producing foraging D calls once a mid-frequency sonar is activated, even though the sonar frequency range (1–8 kHz) far exceeds their sound production range (25–100 Hz). Voyager Golden Records carried whale songs into outer space with other sounds representing planet Earth. Researchers use hydrophones (often adapted from their original military use in tracking submarines) to ascertain the exact location of the origin of whale noises. Their methods also allow them to detect how far through an ocean a sound travels.

Submarine volcanoes are common features of the ocean floor. In shallow water, active volcanoes disclose their presence by blasting steam and rocky debris high above the ocean's surface. In the ocean's deep, the tremendous weight of the water above prevents the explosive release of steam and gases; however, they can be detected by hydrophones and discoloration of water because of volcanic gases. Pillow lava is a common eruptive product of submarine volcanoes and is characterized by thick sequences of discontinuous pillow-shaped masses which form under water.

Silent running is a stealth mode of operation for naval submarines. The aim is to evade discovery by passive sonar by eliminating superfluous noise: nonessential systems are shut down, the crew is urged to rest and refrain from making any unnecessary sound, and speed is greatly reduced to minimize propeller noise. The protocol has been in use since the latter part of World War I, when hydrophones were invented to detect U-boats. The propellers have a characteristic RPM band in which no cavitation noise arises.

Therefore, a few large convoys with apparently few escorts were safer than many small convoys with a higher ratio of escorts to merchantmen. Instead of attacking the Allied convoys singly, U-boats were directed to work in wolf packs (Rudel) coordinated by radio. The boats spread out into a long patrol line that bisected the path of the Allied convoy routes. Once in position, the crew studied the horizon through binoculars looking for masts or smoke, or used hydrophones to pick up propeller noises.

The crew then threw a small TNT bomb off the ship's stern. It exploded at a depth of about , and a chronograph aboard the ship automatically recorded the time the explosion was heard at the ship. The sound traveled outward from the explosion, eventually reaching hydrophones at known locations – shore stations, anchored station ships, or moored buoys – at a distance from the ship. Each hydrophone was connected to a radio transmitter that automatically sent a signal indicating the time its hydrophone detected the sound.

During the Second World War tactical developments became even more closely tied to the development of new weapons and technologies. The war saw the first large-scale tactical use of hydrophones, sonar (or ASDIC) and radar, and the development of new technologies such as high-frequency direction finding (HF/DF). In the North Sea and Atlantic, Germany lacked the strength to challenge the Allies for command of the sea. Instead, German naval strategy relied on commerce raiding using capital ships, armed merchant cruisers, submarines and aircraft.

Anti-aircraft defense was provided by three 34-K AA guns in single mounts on the aft superstructure and a pair of 21-K AA guns mounted on either side of the bridge as well as six DShK machine guns. They carried eight torpedo tubes in two rotating quadruple mounts; each tube was provided with a reload. The ships could also carry a maximum of either 68 or 115 mines and 52 depth charges. They were fitted with a set of Arktur hydrophones for anti-submarine detection.

She studies seals at the Commonwealth Bay and Prydz Bay. The seals are tricky to study as they live in dangerous pack ice off coastal Antarctica, making observations difficult. To identify how the seals respond to a changing ecosystem, Rogers studies them using acoustic technology (hydrophones and retired military sonar buoys). During expeditions, the team take biopsies and collect fur from seals in the wild, which can be used as biomarkers to "capture the changes in an individual's diet, environment, climate, health, and stress levels".

In May 1968, the U.S. Navy's nuclear submarine USS Scorpion (SSN-589) failed to arrive as expected at her home port of Norfolk, Virginia. The command officers of the U.S. Navy were nearly certain that the vessel had been lost off the Eastern Seaboard, but an extensive search there failed to discover the remains of Scorpion. Then, a Navy deep-water expert, John P. Craven, suggested that Scorpion had sunk elsewhere. Craven organised a search southwest of the Azores based on a controversial approximate triangulation by hydrophones.

By dropping the array's 'tail' below the layer, a surface ASW platform can better detect a quiet, submerged contact hiding in cold water below a warm upper layer. A submarine can likewise monitor surface combatants by floating the tail of its array above a thermal layer while lurking below. Akula's towed array is stored in a teardrop shaped container mounted on top of the vertical fin The array's hydrophones can be used to detect sound sources, but the real value of the array is that the signal processing technique of beamforming and Fourier analysis can be used not only to calculate the distance and the direction of a sound source, but also to identify the type of ship by the distinctive, acoustic signature of its machinery noises. For this, the relative positions of the hydrophones need to be known, usually possible only when the cable is in a straight line (stable), or when a self-sensing system (see strain gauges) or GPS or other methods embedded in the cable, and reporting relative position of hydrophone elements, is used to monitor the shape of the array and correct for curvature.

Macdonald is the only known active volcano in the Cook Islands and Austral Islands, unlike in the Society Islands where active volcanism is spread over several volcanoes. The first recorded eruptions at Macdonald occurred in 1967 and was followed by additional activity in 1977, although pumice rafts observed in 1928 and 1936 could have been formed by the seamount as well. These eruptions were recorded with hydrophones; further such activity occurred 1979–1983. Some eruptions, especially eruptions on the southern flank or within a crater, would have passed unnoticed.

The United States Air Force used the island as part of its Eastern Range. NASA established a tracking station on the island in 1967, which it operated for more than 20 years before closing it down in 1990. Ascension was the shore terminal for the furthest down range installation of the Atlantic Missile Impact Location System (MILS), an acoustic system for locating splashdown of test nose cones. The MILS hydrophones that were located in the SOFAR channel for broad area coverage have played a significant role in long range acoustic transmission studies and incidents.

The Gabbianos were designed to be built quickly and in large numbers and began to enter service in May 1942. The ships were fitted with sonar and hydrophones, but the Regia Marina did not consider removing features such as torpedo tubes to reduce topweight or allow the vessels to carry more anti-submarine weapons.Conway p302 These ships were equipped with electric 'creep' motors with an endurance of at for silent running while engaged in anti-submarine searches,Conway p317 Overall, they were well-designed for operations in the Mediterranean and were successful in their role.

They first appeared during World War II, in which they first were used in July 1942 by RAF Coastal Command under the code name 'High Tea', the first squadron to use them operationally being No. 210 Squadron RAF, operating Sunderlands. They were also limited by the use of human ears to discriminate man-made noises from the oceanic background. However, they demonstrated that the technology was viable. With the development of better hydrophones, the transistor and miniaturization, and the realization that very low frequency sound was important, more effective acoustic sensors followed.

An example was reception of coded signals generated by the Navy chartered ocean surveillance vessel Cory Chouest off Heard Island, located in the southern Indian Ocean (between Africa, Australia and Antarctica), by hydrophones in portions of all five major ocean basins and as distant as the North Atlantic and North Pacific.Figure 1 of the reference "The Heard Island Feasibility Test" (Munk) shows ray paths to receiving locations. Table 1 lists the sites with one being a Canadian research vessel with a towed array off Cape Cod. This phenomenon is an important factor in ocean surveillance.

T22s crew finished jettisoning her mines at 00:40 and signaled T32 to see if she was ready to be towed. T32 replied that she was not able to be towed forward, which meant that she would have to be towed stern-first. Around 00:50 T22 began to approach T32 despite being warned that mines were present and struck two of them and blew up at around 01:14. Four minutes later, look-outs reported a motor torpedo boat moving fast aft of the ship and the hydrophones picked up engine noises.

Herbert returned to duty on Q-ships, commanding a flotilla of four trawlers – the Sea King, Sea Sweeper, Nelly Dodds and W. H. Hastie. These were equipped with the recently introduced hydrophone technology and, while patrolling off the coast of The Lizard in Cornwall, they were the first that were thus equipped to have success. That success, however, was not due to the hydrophones: on 12 June 1917, Sea King sighted on the surface and in moving towards it caused the submarine to dive. The flotilla then let loose their depth charges.

They also had eight torpedo tubes in two quadruple power-operated mounts on the centreline, with a pair of reloads for each mount. They had four depth charge launchers mounted on the sides of their rear deckhouse, which was supplemented by six racks for individual depth charges on the sides of the stern, with either 32 or 64 charges carried. Mine rails were fitted on the rear deck, with a maximum capacity of 60 mines. They carried a system of passive hydrophones, designated as 'GHG' (Gruppenhorchgerät), to allow them to detect submarines.

In addition, the noise of the diesel engines made the U-boat's own hydrophones much less effective and it is doubtful U-864 would have heard Venturer running slowly on her electric motors. Combined with the hydrophone reports of the strange noise, which he determined to be coming from a submerged vessel, Launders surmised they had found U-864. He tracked the U-boat by hydrophone, hoping she would surface and allow a clear shot. U-864 remained at snorkel depth, and as the hydrophone plot emerged, she was seen to be zigzagging.

On November 12, 1940, she again detected weak noises through her hydrophones, but again the distant was far too great to attempt an attack. On November 27, 1940, while patrolling south of Sardinia, at 21:35 she sighted three destroyers and submerged to avoid detection. In January 1941 she was deployed to the coast of Algeria and Tunisia. On June 16, 1941, Axum, under command of captain Emilio Gariazzo, was sent to patrol between Ras Uleima, and Marsa Matruh to prevent coastal bombardments by British naval ships conducted in support British troops retreat.

Seventeen stations around the world, including one in the Antarctic, recorded the event as the infrasound reverberated around the world multiple times.Russian Fireball Largest Ever Detected by CTBTO’s Infrasound Sensors, Vienna, 18 February 2013. Recordings from CTBTO hydrophones was analyzed to determine an impact location for Air France Flight 447 and Malaysia Airlines Flight 370, both of which were lost without a known crash site. No data was detected in the event of Flight 447, even after it was reassessed once the location of the wreckage was known.

The ten Montreal-built British H-class submarines launched in 1915 were equipped with Fessenden oscillators. During World War I 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 the electrostatic transducers they used, this work influenced future designs.

An air gun seismic source (30 litre) A seismic source is a device that generates controlled seismic energy used to perform both reflection and refraction seismic surveys. A seismic source can be simple, such as dynamite, or it can use more sophisticated technology, such as a specialized air gun. Seismic sources can provide single pulses or continuous sweeps of energy, generating seismic waves, which travel through a medium such as water or layers of rocks. Some of the waves then reflect and refract and are recorded by receivers, such as geophones or hydrophones.

The ridge is a medium rate spreading center, moving outwards at a rate of approximately 6 centimeters per year. Tectonic activity along the ridge is monitored primarily with the U.S. Navy's Sound Surveillance System (SOSUS) array of hydrophones, allowing for real time detection of earthquakes and eruptive events. The Juan de Fuca Plate is being pushed east underneath the North American Plate, forming what is known as the Cascadia subduction zone off the coast of the Pacific Northwest. The plate does not subduct smoothly and can become 'locked' with the North American plate.

Anti-aircraft defense was provided by a pair of 34-K AA guns in single mounts on the aft superstructure and a pair of 21-K AA guns mounted on either side of the bridge as well as four DK machine guns. They carried eight torpedo tubes in two rotating quadruple mounts; each tube was provided with a reload. The ships could also carry a maximum of either 68 or 115 mines and 52 depth charges. They were fitted with a set of Arktur hydrophones for anti- submarine detection.

Anti-aircraft defense was provided by a pair of 34-K AA guns in single mounts on the aft superstructure and a pair of 21-K AA guns mounted on either side of the bridge as well as six DShK machine guns. They carried eight torpedo tubes in two rotating quadruple mounts; each tube was provided with a reload. The ships could also carry a maximum of either 68 or 115 mines and 52 depth charges. They were fitted with a set of Arktur hydrophones for anti- submarine work.

Anti-aircraft defense was provided by a pair of 34-K AA guns in single mounts on the aft superstructure and a pair of 21-K AA guns mounted on either side of the bridge as well as a dozen M2 Browning machine guns in six twin mounts. They carried eight torpedo tubes in two rotating quadruple mounts; each tube was provided with a reload. The ships could also carry a maximum of either 68 or 115 mines and 52 depth charges. They were fitted with a set of Arktur hydrophones for anti-submarine detection.

Ordered in December 1917, the R class were designed to be faster underwater than on the surface, achieving a submerged speed of versus a surfaced speed of . They were well- streamlined, having no external ballast tanks, casing, or deck gun, and a streamlined spindle-shaped hull of circular cross-sectionFitzsimons, p.2170, "R-1" (not reproduced until the American USS Albacore) which tapered sharply towards the stern and allowed only for a single screw. The bulbous bow contained five sensitive hydrophones and the lightened conning tower was also well-streamlined.

The hydrophones are able to detect even very small earthquakes (~ magnitude 1.8) by listening for the acoustic waves generated by T-waves. These waves can propagate over large distances with minimal loss in power, making them an ideal way to record otherwise unnoticeable submarine earthquakes; over the course of the eruption, only 3 earthquakes were strong enough to register on land-based systems. However, they cannot interpret earthquake depth or what caused them. Between 1991 and 1996 Axial Seamount experienced a single earthquake swarm of over 50 events.

A hydrophone A hydrophone () is a microphone designed to be used underwater for recording or listening to underwater sound. Most hydrophones are based on a piezoelectric transducer that generates an electric potential when subjected to a pressure change, such as a sound wave. Some piezoelectric transducers can also serve as a sound projector, but not all have this capability, and some may be destroyed if used in such a manner. A hydrophone can detect airborne sounds, but will be insensitive because it is designed to match the acoustic impedance of water, a denser fluid than air.

It is claimed that the length of the front wing lets it operate outside the cone of wake that starts at the diver's shoulders. It is claimed to let a scuba diver or swim much faster (250%) than with swimfins for the same amount of bodily effort, if used correctly, and being not motorized, it makes no motor noise to be heard by hostile hydrophones, but noise would occur if the front wings are allowed to hit the diver's hips at end of upstroke. It works somewhat like a penguin's or turtle's front flippers. Its estimated cost is less than $500.

Joseph Harper, Joint United States Military Assistance Group (JUSMAG) chief, and Rear Admiral Edgar A. Cruise, commander US Naval Forces - Philippines, were impressed and praised the conduct of the exercise. Admiral Cruise turned over six amphibious tractors to Commodore Jose Francisco, PN chief, which will be allocated to the Philippine Marines. Maj. General Harper turned over the equipment and facilities used in the harbor defense operations. These equipment and installations include mobile and stationary radar units, magnetic control mines, hydrophones and magnetic indicator loops, which are mostly designed for detecting approaching surface and subsurface vessels, all worth about two million (US-1958) dollars.

The island's location makes it a first point of Atlantic reception for acoustics from the other oceans. As an example the Ascension hydrophones received and the site processed signals generated near Heard Island in the Indian Ocean some from the Ascension arrays and passing around Africa. The Ascension array was one of those involved in the Vela incident acoustic signal in which there were correlated acoustic arrivals with the time and estimated location of the double flash detected by the Vela satellite. A joint Government Communications Headquarters and National Security Agency signals intercept station was also established on Ascension during the Cold War.

The forty hydrophones spaced on the array provided the aperture for signal processing to form horizontal azimuthal beams of two to five degrees wide, each beam with a LOFAR analyzer and capability to do narrow-band frequency analysis to discriminate signal from ocean noise and to identify specific frequencies associated with rotating machinery. The NAVFAC watch floor had banks of displays using electrostatic paper, similar to that used for echograms in depth finders. LOFARgram LOFARgram writers on NAVFAC watch floor. The product of these displays was the LOFARgram which graphically represented acoustic energy and frequency against time.

The attack then started: three depth charges, set to explode at 100, 150, and 250 feet, were dropped from the stern, in accordance with the calculated speed of the submarine. Four explosions were clearly detected. The fourth explosion was so strong that the stern of the Cuban ship was submerged, and water came in through the hatchway of the engine room. At the time, the hydrophones reported a sound that was similar to a liquid bubbling when it comes from a submerged container that is suddenly opened and so indicated that the U-boat had been hit.

During the 1950s, the US Navy tried to use this zone to detect Soviet submarines by creating an array of hydrophones called the Sound Surveillance System (SOSUS.) Oceanographers later used this underwater surveillance system to figure out the speed and direction of deep ocean currents by dropping SOFAR floats that could be detected with the SOSUS array. The mesopelagic zone is important for water mass formation, such as mode water. Mode water is a water mass that is typically defined by its vertically mixed properties. It often forms as deep mixed layers at the depth of the thermocline.

Their Underwater Inflatable Co-prime Sonar Array (UICSA) use low size, weight and power (SWaP) compression. The sonar array is an inflatable structure that can be packed and stowed in a compact space, whilst a sparse co-prime array configuration can resolve a high number of source. The two components in combination can act to reduce the dimensions of the sonar array as well as reducing the number of hydrophones that need to be used. At Temple University Ahmad has expanded her research into healthcare, and started to develop multi-modal sensing devices to monitor patient progress.

The receiving apparatus had evolved from a simple receiver on the ship's bottom to two hydrophones in water-filled sea chests on each side of the ship enabling the ship to determine the direction from which the signal came. The Submarine Signal Company, with branches in Bremen, Liverpool, London, and New York, was both manufacturing the apparatus and collecting data from shipping companies and individual ships on the operation of the signals. The utility of the signals became evident as more stations and ships were equipped. Prominent ship captains, such as James Watt, master of Lusitania, strongly endorsed the system.

Frequently used in combination with coastal artillery and hydrophones, controlled mines (or command detonation mines) can be in place in peacetime, which is a huge advantage in blocking important shipping routes. The mines can usually be turned into "normal" mines with a switch (which prevents the enemy from simply capturing the controlling station and deactivating the mines), detonated on a signal or be allowed to detonate on their own. The earliest ones were developed around 1812 by Robert Fulton. The first remotely controlled mines were moored mines used in the American Civil War, detonated electrically from shore.

For analysis of dissolved organic carbon and total dissolved nitrogen the Southampton-based branch of the NERC NOC is operating a Shimandzu TOV V CPN-TN at NOCS. For seismic studies of the seafloor, sediment packages and sub-seafloor structures the Marine Geophysics group at NOCS operates a wide range of instrumentation, including Chirp, Boomer, Sparker and 3D Chirp sources, single- and multi- channel hydrophones, several multibeam systems and a sidescan sonar. The Ocean Bottom Instrumentation Consortium based at NOCS provides the academic and commercial communities with access to a range of multi-sensor seabed instruments.

The first patent for an underwater echo ranging device was filed by English meteorologist Lewis Richardson a month after the sinking of the Titanic. The First World War stimulated research in this area. The British made early use of underwater hydrophones, while the French physicist Paul Langevin worked on the development of active sound devices for detecting submarines in 1915 using quartz. 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 a prototype for testing in mid-1917.

The time difference, scaled by the speed of sound through water and divided by two, is the distance between 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 submarines identity based on the characteristics of the outgoing ping. For these reasons, active sonar is not frequently used by military submarines.

Pettit at Rothera station Pettit's research is primarily focused on glacial dynamics and exploring the interactions within the ice-ocean-earth system. Pettit is a National Geographic Emerging Explorer who innovated applying acoustic research with hydrophones to calving and melting glaciers reaching the ocean, to examine ice shelf disintegration and the ice-ocean boundary. Her work has been recognized by numerous high-profile sources, including EARTH magazine, and National Geographic, and she was invited to present a TEDWomen talk, on her investigations focused on "listening" to glaciers. Her research on glacier sounds extends to how the underwater noise affects marine animals.

Though Leigh only conducted his tests for ten days in the English Channel his results were resounding. Not only did he show that the American listening devices were superior to anything employed by European navies, but that submarines could be located and hunted by hydrophones. British Naval engineers had been working with this problem since the beginnings of the war, yet Leigh proved the concept practical and revolutionized anti-submarine warfare. Leigh's success in the Atlantic motivated Admiral Sims to direct Leigh to establish an American naval base in the Mediterranean to operate submarine chaser squadrons.

Whitley, p. 68 Four depth charge throwers were mounted on the sides of the rear deckhouse and they were supplemented by six racks for individual depth charges on the sides of the stern. Enough depth charges were carried for either two or four patterns of 16 charges each.Whitley, p. 215 Mine rails could be fitted on the rear deck that had a maximum capacity of 60 mines. A system of passive hydrophones designated as 'GHG' (Gruppenhorchgerät) was fitted to detect submarines and the S-Gerät active sonar system was scheduled to be installed during February 1940.Whitley, pp.

On surface ships, towed array cables are normally stored in drums, then spooled out behind the vessel when in use. U.S. Navy submarines typically store towed arrays inside an outboard tube, mounted along the vessel's hull, with an opening on the starboard tail. . There is also equipment located in a ballast tank (free flood area) while the cabinet used to operate the system is inside the submarine. Hydrophones in a towed array system are placed at specific distances along the cable, the end elements far enough apart to gain a basic ability to triangulate on a sound source.

Similarly, various elements are angled up or down , giving an ability to triangulate an estimated vertical depth of target. Alternatively three or more arrays are used to aid in depth detection. On the first few hundred meters from the ship's propeller there are usually no hydrophones, because their effectiveness would be reduced by noise (cavitation and hull flow noises), vibration and turbulence generated by the propulsion--which would repeat the same problems of ship-mounted arrays. Surveillance Towed Array Sensor Systems used by surface ships have a sonar array mounted on a cable, which pulls a depth-adjustable remote operated vehicle (ROV).

Upon water entry, FIDO performed a circular search at a predetermined depth controlled by a bellows and pendulum system. This continued until the potential target's 24 kHz acoustic signal detected by the hydrophones exceeded a predetermined threshold level, at which point control was then shifted to the passive acoustic proportional homing system. Initially the torpedoes were set to search for a target at a depth of 50 feet (15 m), this was later changed to 150 feet (45 m). To prevent the torpedo accidentally attacking surface ships, it resumed its circling search if it rose above a depth of 40 feet (12 m).

Diagram of SC-1-class submarine chaser Armament was initially planned to be two guns, but the aft gun was usually replaced by a depth charge thrower to attack submerged submarines, with two Colt machine guns completing the armament. Many boats were fitted with hydrophones for detecting underwater noises, with either a K-tube fish-type device of range or SC and MB tubes of range.Moore 1990, p. 152. An initial order of 345 SC boats placed in 1917 was planned to be delivered by the end of 1917, with further orders for the French Navy pushing the total ordered up to 448.

Anti-aircraft defense was provided by a pair of 34-K AA guns in single mounts on the aft superstructure and a pair of 21-K AA guns mounted on either side of the bridge as well as six DShK machine guns. They carried eight torpedo tubes in two rotating quadruple mounts fore and aft of the rear funnel; each tube was provided with a reload. The ships could also carry a maximum of either 68 or 115 mines and 52 depth charges. They were fitted with a set of Arktur hydrophones for anti-submarine detection.

The convoy battles of the First World War had taught the Germans that a single submarine had little prospect of success against a well defended convoy. Instead of attacking the Allied convoys singly, the German U-boats now began to work in packs co-ordinated centrally by radio. The boats spread out into a long patrol line that crossed the path of the Allied convoy routes. Once in position the boats used hydrophones to pick up the propeller noises of the convoys, or used binoculars to try to spot the tell-tale smoke of a convoy on the horizon.

Anti-aircraft defense was provided by a pair of 34-K AA guns in single mounts on the aft superstructure and a pair of 21-K AA guns mounted on either side of the bridge as well as a dozen M2 Browning machine guns in six twin-gun mounts. They carried eight torpedo tubes in two rotating quadruple mounts; each tube was provided with a reload. The ships could also carry a maximum of either 68 or 115 mines and 52 depth charges. They were fitted with a set of Arktur hydrophones for anti-submarine detection.

Experimental work conducted at RNAS Anglesey during the First World War included the use of hydrophones suspended under airships to detect submarines, the use of phosphorus to create smoke screens at sea, and the use of hydrogen from the airship envelope to fuel the engine. At the end of the First World War, Major Thomas Elmhirst, the commanding officer of the station, celebrated the armistice by successfully piloting an SSZ airship under the Menai Suspension Bridge. The act did not harm Elmhirst's career, and he later became Air Marshal Sir Thomas Walker Elmhirst, a senior commander of the RAF. In 1920 the site was bought by Anglesey County Council.

There are 5 versions of the AN/BQQ-5 system, sequentially identified by letters A-E. The 688i (Improved) subclass was initially equipped with the AN/BSY-1 SUBACS submarine advanced combat system that used an AN/BQQ-5E sensor system with updated computers and interface equipment. Development of the AN/BSY-1 and its sister the AN/BSY-2 for the was widely reported as one of the most problematic programs for the Navy, its cost and schedule suffering many setbacks. A series of conformal passive hydrophones are hard-mounted to each side of the hull, using the AN/BQR-24 internal processor.

In this last role, he also undertook early experiments into the use of hydrophones to detect submarines. He was Mentioned in Despatches in December 1918, appointed a Companion of the Order of St Michael and St George in the 1919 New Year Honours, awarded the Greek decoration of Commander of the Order of the Redeemer for his service in the Mediterranean and Adriatic, and was also awarded the United States Navy Distinguished Service Medal. These experiments led to Stephenson's first post-war role, as director of the anti- submarine division of the Admiralty. He found many of his fellow officers conservative in their approach, and struggled to get new techniques accepted.

In the SOFAR channel low frequencies in particular are refracted back into the duct so that energy loss is small and the sound travels thousands of miles. Analysis of Heard Island Feasibility Test data received by the Ascension Island Missile Impact Locating System hydrophones at an intermediate range of from the source found "surprisingly high" signal to noise ratios, ranging from 19 to 30 dB, with unexpected phase stability and amplitude variability after a travel time of about 1 hour, 44 minutes and 17 seconds. Profile showing sound channel axis and bottom at critical depth. Where bottom profile intrudes into the sound channel propagation is bottom limited.

Earthquake monitoring through use of SOSUS after limited civilian access was granted to the Pacific Marine Environmental Laboratory (PMEL) of the National Oceanic and Atmospheric Administration in 1991 revealed ten times the number of offshore earthquakes with better localization than with land based sensors. The SOSUS detection could sense earthquakes at about magnitude two vice magnitude four. The system detected seafloor spreading and magma events in the Juan de Fuca Ridge in time for research vessels to investigate. As a result of that success PMEL developed its own hydrophones for deployment world wide to be suspended in the SOFAR channel by a float and anchor system.

Upon arriving in California, Heck and Guide personnel in consultation with the Scripps Institution developed formulas that allowed accurate echo sounding of depths in all but the shallowest waters and installed hydrophones at La Jolla and Oceanside, California, to allow experimentation in the Pacific Ocean with radio acoustic ranging. Under Heck's direction, Guide then conducted experiments off the coast of California during the early months of 1924 that demonstrated that accurate echo sounding was possible using the new formulas. Experiments with radio acoustic ranging, despite initial difficulties, demonstrated that the method also was practical, although difficulty with getting some of the explosive charges to detonate hampered some of the experimental program.

Seismic data acquisition is the first of the three distinct stages of seismic exploration, the other two being seismic data processing and seismic interpretation. Seismic acquisition requires the use of a seismic source at specified locations for a seismic survey, and the energy that travels within the subsurface as seismic waves generated by the source gets recorded at specified locations on the surface by what is known as receivers (geophones or hydrophones). Before seismic data can be acquired, a seismic survey needs to be planned, a process which is commonly referred to as the survey design. This process involves the planning regarding the various survey parameters used, e.g.

Springer was brought north through Puget Sound and Haro Strait, across the border and then to Campbell River, BC, where locals donated hundreds of bags of ice to help keep the orca cool. To keep her skin from drying out or becoming sunburned during the 13-hour journey, Springer was draped with wet cloths and treated with ointment. The catamaran traveled through the Inside Passage to Johnstone Strait, then to Dongchong Bay, and Hanson Island, not far from OrcaLab. The previous day, high-tech hydrophones were installed in Dongchong Bay by David Howitt and Michael Harris, to monitor acoustic interactions between Springer and wild whales.

In 1949 when the US Navy approached the Committee for Undersea Warfare, an academic advisory group formed in 1946 under the National Academy of Science, to research antisubmarine warfare. As a result, the Navy formed a study group designated Project Hartwell under Massachusetts Institute of Technology (MIT) leadership. The Hartwell panel recommended that spending of annually to develop systems to counter the Soviet submarine threat consisting primarily of a large fleet of diesel submarines. One recommendation was a system to monitor low-frequency sound in the SOFAR channel using multiple listening sites equipped with hydrophones and a processing facility that could calculate submarine positions over hundreds of miles.

The sophistication of influence mine fuses has increased considerably over the years as first transistors and then microprocessors have been incorporated into designs. Simple magnetic sensors have been superseded by total-field magnetometers. Whereas early magnetic mine fuses would respond only to changes in a single component of a target vessel's magnetic field, a total field magnetometer responds to changes in the magnitude of the total background field (thus enabling it to better detect even degaussed ships). Similarly, the original broadband hydrophones of 1940s acoustic mines (which operate on the integrated volume of all frequencies) have been replaced by narrow-band sensors which are much more sensitive and selective.

Using her primary weapon system, her TASS passive sonar system (a system of passive hydrophones towed behind the ship), she was immediately assigned to tracking of Soviet submarines in the Mediterranean. Additionally in September 1982, McCloy was stationed at the entrance to Beirut, Lebanon harbor where an active conflict was ongoing between Israel and the Palestinian Liberation Organization (PLO). She was assigned and completed the escort of nine ships used in the United Nations-arranged PLO evacuation from Beirut, escorting the ships to safe haven ports in the Mediterranean. McCloy received a Meritorious Unit Commendation (MUC) for unsurpassed ASW accomplishments from 8 June to 22 December 1982 during this deployment.

The resulting explosion was spotted by Opossum, which was on a routine anti-submarine patrol nearby. Opossum and several Motor Launches started a search for the submarine using Hydrophones and sweeps. UC-49 was assumed to by lying on the sea bed, and when the submarine restarted motors at 15:20 hr, the noise attracted several depth charges, and more depth charges were dropped at 17:57 hr. Opossum then noisily withdrew a distance of in order to convince the submarine's commander that the hunt had been abandoned, and after 17 minutes the U-boat surfaced, only from one of the Motor Launches and from Opossum, and was brought under a heavy fire.

She was commanded by the 26-year-old Oberleutnant zur See Hans Joachim Emsmann who, since first becoming a U-boat captain in February 1918, had sunk a total of 26 ships. She attempted to enter Scapa Flow submerged by the southern passage, Hoxa Sound, on the evening of 28 October. Hydrophones mounted ashore at Stanger Head, Flotta, alerted the British defenses, and the sea-bed magnetometer loops, designed to detect the magnetic signatures of incoming vessels and thus trigger remote-controlled mines, were activated. Emsmann raised his periscope at 11:30 pm, presumably to check his position, and was spotted by look-outs on shore; the mines detonated shortly thereafter, leaving the submarine disabled on the sea bed.

Two AMAR G4s being deployed near Kitimat, BC, each with a hydrophone surrounded by a yellow shroud to reduce flow-induced noise over the hydrophone The successor of the AMAR G3, the AMAR G4 (Autonomous Multichannel Acoustic Recorder Generation 4) is an underwater acoustic and oceanographic data recorder with 10 TB of removable SD memory cards and Wi-Fi communications. It consists of recording electronics housed inside a watertight pressure housing. The AMAR can be connected to up to 4 hydrophones sampled at 24-bit resolution at rates up to 512 kHz Up to 7 oceanographic sensors (e.g., dissolved oxygen, salinity, acidity, temperature) can be connected, allowing the system to be used as a mini ocean observatory.

The forward Seacat launcher and director was removed, as was the long-range Type 965 radar, allowing the ship's mainmast to be replaced by a smaller mast. The Bofors guns were replaced by lighter Oerlikon 20 mm guns while the ship's boats were removed and the Exocet launchers and torpedo tubes lowered. A large cable reel was fitted to the aft end of the flight deck, while the Type 2031 I towed array sonar consisted of an acoustic array of passive hydrophones which were towed on the end of a cable. The electronics needed to extract and display the sonar data was installed in the ships hangar, which meant that Cleopatra was no longer able to operate a helicopter.

Alternate or dual-use partnerships exist with a number of agencies and institutions. The Applied Physics Laboratory, University of Washington has used the system for Ocean Acoustic Tomography. National Oceanic and Atmospheric Administration (NOAA) Vents program at its Pacific Marine Environmental Laboratory was granted access to the system at the Naval Ocean Processing Facility at Whidbey Island in October 1990 to combine raw analog data from specific hydrophones with NOAA systems for continuous monitoring of the northeast Pacific Ocean for low-level seismic activite and detection of volcanic activity along the northeast Pacific spreading centers. Woods Hole Oceanographic Institute detected and tracked a lone whale with a unique call over a period of years in the Pacific.

On 20 June 1970, Tautog was patrolling the North Pacific Ocean near the city of Petropavlovsk-Kamchatsky, on the Soviet Union's Kamchatka Peninsula, which was a major base for missile-armed submarines of the Soviet Navy. Tautog was attempting to trail the K-108, a Soviet Navy Echo II-class guided missile submarine nicknamed "Black Lila". The Soviet submarine was "close aboard" with Tautog, unaware that Tautog was in the vicinity, and the two submarines were within feet of one another for a lengthy period. Unable to determine the depth of the K-108, as new depth- finding hydrophones had not yet been installed, the American submarine was at a disadvantage in such close quarters.

The only means of subsurface navigation locating a search vehicle or other sensors relative to the ship and bottom is by acoustic navigation. Towed deep vehicles may be half a mile from the towing ship and respond to the ship's movements as much as half an hour after that movement. A capability developed at the University of Washington Applied Physics Laboratory was implemented for Mizar. The system, an early implementation of a short baseline acoustic system, is composed of a triangular array of hydrophones on the ship's hull, a transponder on the towed vehicle with an acoustic pulse triggered by a signal over the towing cable, and a sea floor transponder triggered by an acoustic signal from the ship.

In addition to new construction, several existing old battleships, battlecruisers and heavy cruisers were reconstructed, and anti-aircraft weaponry reinforced, while new technologies, such as ASDIC, Huff-Duff and hydrophones, were developed. At the start of World War II in 1939, the Royal Navy was the largest in the world, with over 1,400 vessels The Royal Navy provided critical cover during Operation Dynamo, the British evacuations from Dunkirk, and as the ultimate deterrent to a German invasion of Britain during the following four months. At Taranto, Admiral Cunningham commanded a fleet that launched the first all-aircraft naval attack in history. The Royal Navy suffered heavy losses in the first two years of the war.

The 1998 eruption of Axial Seamount was preceded by several large earthquake swarms, common indicators of volcanic activity. The swarms correlated to magma movements in the volcano; bottom pressure recorders deployed on the volcano between 1987 and 1992 recorded five instances of deflation in the summit surface (caused by lava movement), ranging from . In 1991, the National Oceanic and Atmospheric Administration (NOAA) was granted access to the United States Navy's SOSUS system, a chain of submerged hydrophones in the North Pacific originally used by the Navy to detect Russian submarines during the Cold War. Since 1993, the NOAA has maintained a real-time monitoring system that alerts the organization whenever an event occurs.

On 22 October, the 4th Torpedo Boat Flotilla, now consisting of T26, T27, and their sisters , and , sortied from Brest to provide cover for the unladen blockade runner Münsterland and her close escort from the 2nd Minesweeping Flotilla as they sailed up the Channel. The British were aware of Münsterland and attempted to intercept her on the night of the 23rd with a scratch force that consisted of the light cruiser and the destroyers , , , , and . T22s hydrophones detected the British ships off the Sept-Îles at 00:25 and Korvettenkapitän Franz Kohlauf maneuvered his flotilla to intercept them before they could reach Münsterland. Limbourne overheard the radio transmissions about 01:20 as the German ships turned, and alerted the other British ships.

The search and rescue operation was carried out under the auspices of the International Submarine Escape and Rescue Liaison Office, an organisation of over 40 countries set up in 2003 following the Kursk submarine disaster. The search area was in size and weather conditions throughout the search and rescue period changed, making the task far more difficult on days with large waves and high winds. Search efforts continued several days, without success. The Argentine ambassador in Austria Rafael Grossi, an expert in security, disarmament and nuclear non-proliferation issues, had the idea to use an international hydrophones network, owned by the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, to search for clues about what could have happened with the vessel.

As a result of the Hartwell group's recommendations, the Office of Naval Research (ONR) contracted with American Telephone and Telegraph Company (AT&T;), with its Bell Laboratories research and Western Electric manufacturing elements, to develop a long range, passive detection system, based on bottom arrays of hydrophones. The system, using equipment termed Low Frequency Analyzer and Recorder and a process termed Low Frequency Analysis and Recording, both with the acronym LOFAR, was to be based on AT&T;'s sound spectrograph, developed for speech analysis and modified to analyze low- frequency underwater sounds. This research and development effort was given the name Project Jezebel. The origin of the project name was explained by Dr. Robert Frosch to Senator Stennis during a 1968 hearing.

On 22 October, the 4th Flotilla, now consisting of T23, T24, and their sisters , and , sortied from Brest to provide cover for the unladen blockade runner Münsterland and her close escort from the 2nd Minesweeping Flotilla as they sailed up the Channel. The British were aware of Münsterland and attempted to intercept her on the night of the 23rd with a scratch force that consisted of the light cruiser and the destroyers , , , , and . T22s hydrophones detected the British ships off the Sept-Îles at 00:25 and Korvettenkapitän Franz Kohlauf maneuvered his flotilla to intercept them before they could reach Münsterland. Limbourne overheard the radio transmissions about 01:20 as the German ships turned, and alerted the other British ships.

On 22 October, the 4th Torpedo Boat Flotilla, now consisting of T27, T26, and their sisters , and , sortied from Brest to provide cover for the unladen blockade runner Münsterland and her close escort from the 2nd Minesweeping Flotilla as they sailed up the Channel. The British were aware of Münsterland and attempted to intercept her on the night of the 23rd with a scratch force that consisted of the light cruiser and the destroyers , , , , and . T22s hydrophones detected the British ships off the Sept-Îles at 00:25 and (Lieutenant commander) Franz Kohlauf maneuvered his flotilla to intercept them before they could reach Münsterland. Limbourne overheard the radio transmissions about 01:20 as the German ships turned, and alerted the other British ships.

On 22 October, the 4th Flotilla, now consisting of T22, T23, T25, and their sisters and , sortied from Brest to provide cover for the unladen blockade runner and her close escort from the 2nd Minesweeping Flotilla as they sailed up the Channel. The British were aware of Münsterland and attempted to intercept her on the night of the 23rd with a scratch force that consisted of the light cruiser and the destroyers , , , , and . T22s hydrophones detected the British ships off the Sept-Îles at 00:25 and Korvettenkapitän Franz Kohlauf maneuvered his flotilla to intercept them before they could reach Münsterland. Limbourne overheard the radio transmissions about 01:20 as the German ships turned and alerted the other British ships.

The sound's source was roughly triangulated to , a remote point in the south Pacific Ocean west of the southern tip of South America. The sound was detected by the Equatorial Pacific Ocean autonomous hydrophone array, a system of hydrophones primarily used to monitor undersea seismicity, ice noise, and marine mammal population and migration. This is a stand-alone system designed and built by NOAA's Pacific Marine Environmental Laboratory (PMEL) to augment NOAA's use of the U.S. Navy Sound Surveillance System (SOSUS), which was equipment originally designed to detect Soviet submarines. According to the NOAA description, the sound "rose" in frequency over about one minute and was of sufficient amplitude to be heard on multiple sensors, at a range of over .

The bank, just off Bermuda, was of particular interest at the time to the Navy's Project Artemis in which an initial installation of a horizontal and a vertical string of hydrophones were installed during 1961. A unique opportunity came on 14 November 1963 when the volcanic island of Surtsey emerged off Iceland when a project aircraft was in the area to fly a survey of the emerging island at altitude. During July 1966 the dormant island was resurveyed revealing a magnetic anomaly not evident in the original survey. By the late 1980s the RP-3D Project Magnet aircraft, specially built using nonmagnetic materials aft of the main cabin door, was named Roadrunner and had the distinctive squadron livery of international orange and white.

The periscope gives away the location of a submarine, and a hull- penetrating periscope greatly weakens a submarine's pressure hull and limits the depths to which it can dive. U-boats also had to come to very shallow depths to use their periscopes, generally about 15 m, leaving them greatly exposed to bombing, depth charging, and even gunfire. With the introduction of Falke, U-boats could remain more deeply submerged and fire at convoys with nothing to give away their position but the noise of their screws. Rather than aiming with a periscope, the torpedo could be roughly aimed at a sound contact as detected by a U-boat's hydrophones, and the homing mechanism could be trusted to find the target without the need for precise aiming.

On 22 October, the 4th Flotilla, now consisting of T25, T22, T23, and their sisters and , sortied from Brest to provide cover for the unladen blockade runner Münsterland and her close escort from the 2nd Minesweeping Flotilla as they sailed up the Channel. The British were aware of Münsterland and attempted to intercept her on the night of the 23rd with a scratch force that consisted of the light cruiser and the destroyers , , , Wensleydale, and . T22s hydrophones detected the British ships off the Sept-Îles at 00:25 and Korvettenkapitän Franz Kohlauf maneuvered his flotilla to intercept them before they could reach Münsterland. Limbourne overheard the radio transmissions about 01:20 as the German ships turned and alerted the other British ships.

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 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 , and ability to survive neighbouring mine explosions.

Although France had never recovered a flight recorder from such depths, there was precedent for such an operation: in 1988, an independent contractor recovered the CVR of South African Airways Flight 295 from a depth of in a search area of between . The Air France flight recorders were fitted with water-activated acoustic underwater locator beacons or "pingers", which should have remained active for at least 30 days, giving searchers that much time to locate the origin of the signals. France requested two "towed pinger locator hydrophones" from the United States Navy to help find the aircraft. The French nuclear submarine and two French-contracted ships (the Fairmount Expedition and the Fairmount Glacier, towing the U.S. Navy listening devices) trawled a search area with a radius of , centred on the aircraft's last known position.

In addition to the main optical detector for cosmic neutrinos, the ANTARES experiment also houses a number of instruments for the study of the deep sea environment, such as salinity and oxygen probes, sea current profilers and instrumentation for the measurement of light transmission and sound velocity. Also, a camera system has been installed for automatic tracking of bioluminescent organisms. Results from these instruments, while also important for the calibration of the detector, will be shared with ocean science institutes involved in the ANTARES collaboration. While the ANTARES detector contains an acoustic positioning system for the alignment of the free-floating detector lines, it also houses a separate dedicated acoustic detection system AMADEUS, which will comprise 6 converted ANTARES storeys with hydrophones to evaluate the possibility for acoustic detection of neutrinos in the deep sea.

The cited Project HARTWELL report first links arrays with fleet type submarines towing such an array in the GIUK then refers to potential exploitation of the deep sound channel low frequency sounds. The Office of Naval Research (ONR) then contracted with American Telephone and Telegraph Company (AT&T;), with its Bell Laboratories research and Western Electric manufacturing elements, to develop a long range, passive detection system, based on bottom arrays of hydrophones. The proposed development was based on AT&T;'s sound spectrograph, which converted sound into a visual spectrogram representing a time–frequency analysis of sound that was developed for speech analysis and modified to analyze low-frequency underwater sounds. The proposed system offered such promise of long-range submarine detection that the Navy ordered immediate moves for implementation.

A hydrogen explosion as the proximal cause for the loss of Scorpion is assessed and analyzed by retired acoustics expert Bruce Rule, a long-time analyst for the Integrated Undersea Surveillance System (IUSS), in his IUSS alumni association blog. Based on his own experiences, Rear Admiral Dave Oliver, who served in both diesel boats and nuclear submarines, provides his assessment in his book Against the Tide that Scorpion was lost as a result of hydrogen build-up due to changes in the ventilation lineup while proceeding to periscope depth. Most recently, following analysis of the ship's battery cells, this is the leading theory for the loss of Scorpion. This is consistent with two small explosions aboard the submarine, a half-second apart, that were picked up by hydrophones.

Radio acoustic ranging had its origins in a growing understanding of underwater acoustics and their practical application during the early decades of the 20th century, and developed in parallel with echo sounding. The first step took place in the early 1900s, when the Submarine Signal Company invented a submarine bell signalling device and a hydrophone that could serve as a receiver of the underwater sounds the bells generated. The crew of a ship equipped with the receiving hydrophone could plot their ship's distance from the submarine bell mechanism and plot intersecting lines from two or more bells to determine the ship's position. The bells were installed at lighthouses, aboard lightvessels, and on buoys along the coasts of North America and Europe, and receiving hydrophones were mounted aboard hundreds of ships.

The aircraft carrier developed into a mature technology, and so did the "Y-range", the term used in this timeline for radar. All of the belligerent powers had Y-range equipment of one sort or another; a U.S. raid on the North Carolina coast in 1942 captured a working Confederate station, in an action similar to the British commando raid on Bruneval, France, in 1942. To fight the submarine, "Hydrophones" was the term used for sound equipment; it did not distinguish between passive listening and active sonar search and ranging of underwater sounds. The North Atlantic was the site of a large-scale naval battle in 1943 between the United States and the Royal and French Navies, during which aircraft carriers were the principal weapons platform; the surface combatants never saw each other, as in our timeline's Battle of the Coral Sea.

Walker then turned his attention to his son, who had drifted during much of his teenage years and dropped out of high school. Walker gained custody of his son, put him to work as an apprentice at his detective agency in order to prepare him for espionage and encouraged him to re-enroll in high school to earn a diploma, then to enlist in the Navy. When Walker began spying, he worked as a key supervisor in the communications center for the U.S. Atlantic Fleet's submarine force, and he would have had knowledge of top-secret technologies, such as the SOSUS underwater surveillance system, which tracks underwater acoustics via a network of submerged hydrophones. It was through Walker that the Soviets became aware that the U.S. Navy was able to track the location of Soviet submarines by the cavitation produced by their propellers.

In 1962 NAVFAC Adak contact reports went to Commander, Alaskan Sea Frontier an that command published a secret report containing the Petropavlovsk contacts presuming they were Soviet. Commander, Submarine Force, U.S. Pacific Fleet (COMSUBPAC) recognized the contacts as their very highly classified operations and immediate changes were ordered for the reporting procedures. In 1973 such contacts were again almost published and stopped only when contact information was matched, on advice by a visiting civilian expert who recognized the signatures, by NAVFAC people to one of the submarine's logs when that submarine put into Adak for a medical emergency. In 1968 a tap on the Adak array for the Air Force Technical Applications Center (AFTAC), a nuclear event monitoring system, combined with AFTAC hydrophones in the Pacific provided time delay analysis for localizing the GOLF II Class Soviet SSB K-129 loss.

Freeman's work has focused on using electronic technologies to ‘translate nature’ – whether it is through the sound of torrential rain dripping on a giant rhubarb leaf, a pair of mobile concrete speakers who lurk in galleries haranguing passersby with fractured sonic samples, or by providing an interactive platform from which to view the flap, twitch and prick of dogs' ears. In 2005 she launched her most known digital artwork, 'The Lake', which used hydrophones, custom software and advanced technology to track electronically tagged fish and translate their movement into an audio-visual experience. The work was developed over three years and was supported by Tingrith Coarse Fishery (which was run by the artist's mother) and a two-year fellowship from the National Endowment for Science, Technology and the Arts (NESTA). It was exhibited at the Tingrith Fishery in Bedfordshire.

The U.S. Navy placed arrays of hydrophones on the ocean floor connected by underwater cables to shore terminals generically called "Naval Facilities" (NAVFACs) within which the low frequency signals were processed and analyzed by means of a Low Frequency Analyzer and Recorder (LOFAR) system. The early SOSUS arrays were positioned at the edge of the continental shelf at a depth of about 650 feet (200 meters) pointed into the deep ocean. At the time, cable lengths were limited to less than 150 miles (241 kilometers) so that NAVFACs had to be placed at coastal sites where the shelf break was close to land allowing access to the deep sound channel close to shore. Point Sur was chosen in part because of its proximity to a deep submarine canyon that cuts into the shelf near the Big Sur coast.

The general principle of seismic reflection is to send elastic waves (using an energy source such as dynamite explosion or Vibroseis) into the Earth, where each layer within the Earth reflects a portion of the wave's energy back and allows the rest to refract through. These reflected energy waves are recorded over a predetermined time period (called the record length) by receivers that detect the motion of the ground in which they are placed. On land, the typical receiver used is a small, portable instrument known as a geophone, which converts ground motion into an analogue electrical signal. In water, hydrophones are used, which convert pressure changes into electrical signals. Each receiver's response to a single shot is known as a “trace” and is recorded onto a data storage device, then the shot location is moved along and the process is repeated.

Marine seismic survey using a towed streamer Plan view of NATS and MAZ surveys Plan view of a WATS/WAZ survey USGS in the Gulf of Mexico Seismic support vessel Traditional marine seismic surveys are conducted using specially- equipped vessels that tow one or more cables containing a series of hydrophones at constant intervals (see diagram). The cables are known as streamers, with 2D surveys using only 1 streamer and 3D surveys employing up to 12 or more (though 6 or 8 is more common). The streamers are deployed just beneath the surface of the water and are at a set distance away from the vessel. The seismic source, usually an airgun or an array of airguns but other sources are available, is also deployed beneath the water surface and is located between the vessel and the first receiver.

It also decided to pursue the development of radio acoustic ranging, a new concept involving a method for determining a ship′s precise location at sea by detonating an explosive charge underwater near the ship, detecting the arrival of the underwater sound waves at hydrophones at remote locations, and radioing the time of arrival of the sound waves at the remote stations to the ship, allowing the ship′s crew to use triangulation to determine the ship′s position. Nicholas H. Heck (1882–1953), a United States Coast and Geodetic Survey Corps officer, took charge of that development process. Both echo sounding and radio acoustic ranging required a precise understanding of the speed of sound through water.NOAA History: The Start of the Acoustic Work of the Coast and Geodetic Survey Guide′s conversion to and fitting out as a survey ship on the United States East Coast was completed in 1923.

Her most advanced feature is the incorporation of acoustic quieting technology to enable NOAA scientists to monitor fish populations without the ships noise altering the behavior of the fish. Her oceanographic hydrophones are mounted on a retractable centerboard, or drop keel, that lowers scientific transducers away from the region of hull- generated flow noise, enhancing the quality of the data collected. To take full advantage of these advanced data-gathering capabilities, she has the Scientific Sonar System, which can accurately measure the biomass of fish in a survey area. She also has an Acoustic Doppler Current Profiler with which to collect data on ocean currents and a multibeam sonar system that provides information on the content of the water column and on the type and topography of the seafloor while she is underway, and she can gather hydrographic data at any speed up to 11 knots (20 km/hr).

As international tensions increased in the mid-1930s the Second London Naval Treaty of 1935 failed to halt the development of a naval arms race and by 1938 treaty limits were effectively ignored. The re-armament of the Royal Navy was well under way by this point, with construction underway on the still treaty-affected new battleships and its first full-sized purpose- built aircraft carriers. In addition to new construction, several existing old battleships, battlecruisers and heavy cruisers were reconstructed, and anti- aircraft weaponry reinforced, while new technologies, such as ASDIC, Huff-Duff and hydrophones, were developed. The Navy had lost control of naval aviation when the Royal Naval Air Service was merged with the Royal Flying Corps to form the Royal Air Force in 1918, but regained control of ship-board aircraft with the return of the Fleet Air Arm to Naval control in 1937.

The DUMAND Project (Deep Underwater Muon And Neutrino Detector Project) was a proposed underwater neutrino telescope to be built in the Pacific Ocean, off the shore of the island of Hawaii, five kilometers beneath the surface. It would have included thousands of strings of instruments occupying a cubic kilometer of the ocean. Diagram illustrating the strings of sensors and detail of one of the sensors The proposal called for two types of detectors: optical detectors to find the Cherenkov radiation emitted by secondary particles traveling faster than the speed of light in water, resulting from collisions by neutrinos, and hydrophones to listen for the acoustic signals generated by the interactions. Sophisticated signal processing would have combined the signals from many optical and acoustic sensors, allowing scientists to determine the direction from which the neutrino arrived, and to rule out false signals arising from other particles or acoustic sources.

Upon arrival in California, Heck and Guide personnel in consultation with the Scripps Institution developed formulas that allowed accurate echo sounding of depths in all but the shallowest waters and installed hydrophones at La Jolla and Oceanside, California, to allow experimentation with radio acoustic ranging. Under Heck's direction, Guide then conducted experiments off the coast of California during the early months of 1924 that demonstrated that accurate echo sounding was possible utilizing the new formulas. Experiments with radio acoustic ranging, despite initial difficulties, demonstrated that the method was practical, although difficulty with getting some of the explosive charges to detonate hampered some of the experimental program. In April 1924, the Coast and Geodetic Survey concluded that both echo sounding and radio acoustic ranging were fundamentally sound, with no foundational problems left to solve, and that all that remained necessary was continued development and refinement of both techniques during their operational use.

Tragedy struck Pioneer on 11 October 1928 when a member of her crew -- Seaman Earl Forsberg—fell overboard and drowned during a survey of Heceta Bank off the coast of Oregon. In 1934 personnel aboard Pioneer developed a deep sea hydrophone in connection with the Survey's work developing radio acoustic ranging, a system in which a small TNT bomb timed to explode at about feet,This was the surface channel, not the deeper SOFAR channel. the explosion's sound wave is registered by a hydrophone aboard and hydrophones at two or more known shore locations that then send a radio signal of arrival time back to the vessel for range calculation, to better establish positions beyond shore signal visibility. Pioneer personnel successfully used the hydrophone to a depth of off the coast of southern California in the work establishing the velocity and path of sound in the sea.

Last photograph of Hood, seen from Prince of Wales When Bismarck sailed for the Atlantic in May 1941, Hood, together with the newly commissioned battleship , was sent out in pursuit along with several other groups of British capital ships to intercept the German ships before they could break into the Atlantic and attack Allied convoys. Hood was commanded by Captain Ralph Kerr and was flying the flag of Vice-Admiral Lancelot Holland. The German ships were spotted by two British heavy cruisers ( & ) on 23 May, and Holland's ships intercepted Bismarck and her consort, the heavy cruiser , in the Denmark Strait between Greenland and Iceland on 24 May.Stephen, pp. 74–76 The British squadron spotted the Germans at 05:37 (ship's clocks were set four hours ahead of local time – the engagement commenced shortly after dawn),Kennedy, pp. 78, 108 but the Germans were already aware of their presence, Prinz Eugens hydrophones having previously detected the sounds of high-speed propellers to their southeast.

In November 1943, U-230 was reassigned to the Mediterranean, for attachment to 29th U-boat flotilla at Toulon. She departed Brest on 22 November, and by 5 December, had arrived at the Straits of Gibraltar Werner reports that the passage through the heavily defended Straits was uneventful; he also describes the boat's hydrophones picking up the sound of dolphins playing and "talking to each other".Werner p181 U-230 arrived at Toulon on 16 December. At this point Werner left U-230 for reassignment to his own command. On 19 January 1944, U-230 left Toulon for a patrol against Allied shipping taking part in Operation Shingle, the Allied landings at Anzio. During this operation U-230 sank two Tank Landing Ships, on 16 and 20 December.Blair p519 She escaped retribution and returned to base at La Spezia on 24 February. In April 1944, U-230 returned briefly to Toulon before departing on 11 April, to undertake another patrol in the Tyrrhenian Sea.

A working model of the Low Frequency Analyzer and Recorder was delivered in May 1951 which operated with real time analysis of a frequency band of 1 to 1/2 Hz. Along with the working model was a proposal for hydrophones, cables, processing systems and beamforming so that a hydrophone array could present multiple azimuthal beams to be displayed. Lofargram writers, one for each array beam, on a NAVFAC watch floor. Each system, from shore facility to the transducer array was a sonar set with the signal processing beginning as the array's signals were amplified, processed into beams by time delay and each beam processed by an electromechanical spectrum analyzer with the display being a sweep of the frequency spectrum's intensity burned across electrostatic recording paper moving on the time axis. The sweeps of the stylus recording the intensity of sound along the frequency axis formed a time record of background noise and specific frequency receptions that formed lines.

Marine survey acquisition is not just limited to seismic vessels; it is also possible to lay cables of geophones and hydrophones on the sea bed in a similar way to how cables are used in a land seismic survey, and use a separate source vessel. This method was originally developed out of operational necessity in order to enable seismic surveys to be conducted in areas with obstructions, such as production platforms, without having the compromise the resultant image quality. Ocean bottom cables (OBC) are also extensively used in other areas that a seismic vessel cannot be used, for example in shallow marine (water depth <300m) and transition zone environments, and can be deployed by remotely operated underwater vehicles (ROVs) in deep water when repeatability is valued (see 4D, below). Conventional OBC surveys use dual-component receivers, combining a pressure sensor (hydrophone) and a vertical particle velocity sensor (vertical geophone), but more recent developments have expanded the method to use four- component sensors i.e.

In deep waters, such as those that prevailed in the Pacific Ocean along the United States West Coast, the Coast and Geodetic Survey could rely upon shore stations to support radio acoustic ranging because the deep water allowed sound to travel to the coast. Along the United States East Coast, where shallower waters prevailed, sound had greater difficulty in reaching the coast, and the Coast and Geodetic Survey relied more heavily on anchored station ships, and later moored buoys, to support radio acoustic ranging. Chronographs recorded times to the hundredth of a second, and the crew of a ship using radio acoustic ranging could determine their ship's distance from the remote hydrophone stations to within , allowing them to plot their ship's position with great accuracy for the time. With sound waves traveling from the point of the explosion to the distant hydrophones at about , ships occasionally used radio acoustic ranging at distances of over between ship and hydrophone station, and distances of were common.

Only the periscope was sighted, and the torpedo was fired in the direction detected by the hydrophones, but no German submarine was in the area. Whilst in service in the Mediterranean, she sank a number of small merchantmen and small naval auxiliary vessels with both torpedoes and gunfire. These included the Italian auxiliary submarine chaser O 97 / Margherita, the Italian merchants Maddalena, Mostaganem and Pasubio, the Italian tugs Genova and Iseo, the Italian sailing vessels Triglav, Albina, Margherita, Sparviero and Ardito, the German auxiliary submarine chasers UJ 2201/Bois Rose and UJ 2204/Boréal, the Italian tanker Bivona, the small Italian merchant Santa Mariana Salina, the Italian auxiliary minesweeper R 172 / Impero and the small Italian vessel San Francisco di Paola A. Unrivalled also damaged the on 3 December 1942, but neither sank or damaged any Axis ships after 28 July 1943. During Operation Husky in July 1943, she was stationed offshore to mark the landing beaches for the 1st Canadian Infantry Division.

In April 1924, the Coast and Geodetic Survey concluded that both echo sounding and radio acoustic ranging were fundamentally sound, with no foundational problems left to solve, and that all that remained necessary was continued development and refinement of both techniques during their operational use. Heck turned over continued development of echo sounding and radio acoustic ranging to Guide's commanding officer, Commander Robert Luce, and returned to his duties in Washington, D.C. Operating off Oregon in 1924, Guide became the first ship to employ radio acoustic ranging operationally. While off Oregon that year, she successfully employed the technique at a distance of 206 nautical miles (382 km) between the ranging explosion and the remote hydrophones detecting its sound and in the process achieved the first observed indication of the ocean sound layer that was later called the sound fixing and ranging (SOFAR) channel or deep sound channel (DSC).Theberge, Alfred E., "System Without Fixed Points: Development of the Radio-Acoustic Ranging Navigation Technique (Part 1)," hydro-international.com, December 2, 2009.hydro-international.

Her oceanographic hydrophones are mounted on a retractable centerboard, or drop keel, that lowers scientific transducers away from the region of hull-generated flow noise, enhancing the quality of the data collected. To take full advantage of these advanced data-gathering capabilities, she has the Scientific Sonar System, which can accurately measure the biomass of fish in a survey area. She also has an Acoustic Doppler Current Profiler with which to collect data on ocean currents and a multibeam sonar system that provides information on the content of the water column and on the type and topography of the seafloor while she is underway, and she can gather hydrographic data at any speed up to 11 knots (20 km/hr). Henry B. Bigelow can deploy CTD instruments to measure the electrical conductivity, temperature, and chlorophyll fluorescence of sea water, as well as specialized gear such as Multiple Opening/Closing Net and Environmental Sensing System (MOCNESS) frames, towed vehicles, dredges, and bottom corers, and she can deploy and recover both floating and bottom-moored sensor arrays.

She also compared echo sounder soundings with those made by lead lines, discovering that using a single speed of sound through water, as had been the previous practice by those conducting echo sounding experiments, yielded acoustic depth-finding results that did not match the depths found by lead lines. Before she reached San Diego in December 1923, she had accumulated much data beneficial to the study of the movement of sound waves through water and measuring their velocity under varying conditions of salinity, density, and temperature, information essential both to depth-finding and radio acoustic ranging. Upon arriving in California, Heck and Guide personnel in consultation with the Scripps Institution developed formulas that allowed accurate echo sounding of depths in all but the shallowest waters and installed hydrophones at La Jolla and Oceanside, California, to allow experimentation with radio acoustic ranging. Under Heck's direction, Guide then conducted experiments off the coast of California during the early months of 1924 that demonstrated that accurate echo sounding was possible using the new formulas.

Operating in the Pacific Ocean off Oregon in 1924, Guide became the first ship to employ radio acoustic ranging operationally. Off Oregon that year, she successfully employed the technique at a distance of between the ranging explosion and the remote hydrophones detecting its sound and in the process achieved the first observed indication of the ocean sound layer that was later called the sound fixing and ranging (SOFAR) channel or deep sound channel (DSC). In 1928, French investigators extended this range, detonating a 30-kg (66-pound) explosive in the Mediterranean Sea between Algiers in French Algeria and Toulon, France, and detecting the sound at a range of . Initially, Heck and others involved in the development of radio acoustic ranging thought the technique would prove least effective along the coast of the Pacific Northwest, where they assumed that the sound of wave action along the coast and the difficulty of setting up shore stations and cables would reduce the success of radio acoustic ranging; in contrast, they thought that conditions along the United States East Coast would pose no challenges.

With his acoustics experience in World War I, Heck, who by then was Chief of the Coast and Geodetic Survey's Division of Terrestrial Magnetism, was the obvious choice to lead this effort. By January 1923, the Coast and Geodetic Survey had decided to install a Hayes sonic rangefinder – an early echosounder – aboard the survey ship USC&GS; Guide, which the Coast and Geodetic Survey planned to commission into its fleet later that year, and when Heck contacted E. A. Stephenson of the U.S. Army Coastal Artillery Corps to inform him of this plan and to inquire further about the Vineyard Sound experiments, Stephenson suggested that a system of hydrophones detecting the sound of underwater explosions could allow Coast and Geodetic Survey ships to fix their position while conducting surveys. Heck agreed, but believed that existing navigation aids would not meet the needs of the Coast and Geodetic Survey in terms of the immediacy and accuracy of position fixes. He envisioned improving on previous concepts by creating what became known as the radio acoustic ranging (RAR) method.

Seismic activity at Axial Seamount virtually disappeared after the 1998 eruption, and monitoring of the volcano was done principally with bottom pressure recorders deployed on the volcano's flanks, supplemented since 2000 by annual measurements using pressure sensors mounted on Remotely operated underwater vehicles (ROVs) and applied to local benchmarks. The sensors have shown that Axial Seamount is slowly reflating; just after the eruption the seamount was swelling at per month, a number that decreased to by 2006. In eight years Axial Seamount recovered approximately 50% of its of pre-eruption swelling, and in 2006, William Chadwick of the Oregon State University and his associates calculated that the next eruption would occur in approximately 2014: In July 2011, a dive using ROV Jason discovered new lava flows on the volcanoes that had not been present a year before. The expeditionary crew recovered two bottom-pressure recorders and two hydrophones (a third was found buried in lava) off the volcano, which together showed that the eruption had occurred during April, starting on 6 April 2011.

If contact was made, they would follow the submarine while summoning surface ships by radio to attack it. Sonar saw extremely limited use and was mostly tested in the Atlantic Ocean with few naval officers seeing any merit in the system. With the end of World War I came the end to serious development of sonar in the United States, a fact that was to be fatal in the early days of World War II. However, considerable development of ASDIC took place in the United Kingdom, including integration with a plotting table and weapon. While the United Kingdom pursued the development of sonar during the interwar period, the United States Coast and Geodetic Survey during the 1920s developed the radio acoustic ranging method of fixing the position of survey ships during hydrographic survey operations by detonating a small explosive at the location of the ship, recording the time it took for the sound of the explosion to reach distant hydrophones mounted at shore stations or aboard manned station ships, and radioing the time of receipt of the sound to the ship, allowing the crew to make precise position fixes by using triangulation.

By January 1923, the Coast and Geodetic Survey had decided to install a Hayes sonic rangefinder – an early echo sounder – aboard the survey ship USC&GS; Guide, which the Coast and Geodetic Survey planned to commission into its fleet later that year; successful operation of the sonic rangefinder would require a precise understanding of the speed of sound through water. When Heck contacted E. A. Stephenson of the U.S. Army Coast Artillery Corps to inform him of this plan and to inquire further about the Vineyard Sound experiments, Stephenson suggested that a system of hydrophones detecting the sound of underwater explosions could allow Coast and Geodetic Survey ships to fix their position while conducting surveys. Heck agreed, but believed that existing navigation aids would not meet the needs of the Coast and Geodetic Survey in terms of the immediacy and accuracy of position fixes.NOAA History: The Start of the Acoustic Work of the Coast and Geodetic Survey He envisioned improving on the Submarine Signal Company's system of underwater noise generators and attached radio transmitters, as well as other previous concepts, by creating what would become known as the radio acoustic ranging method.

Danielson joined the faculty of the University of Virginia in 1968. He moved to the University of California, San Diego in 1979, and to the Naval Postgraduate School in 1985. Danielson is an applied mathematician with contributions to structural mechanics, biomechanics, and orbital dynamics. Publications include: "Dynamic Buckling Loads of Imperfection Sensitive Structures from Perturbation Procedures", AIAA Journal 1506-1510 (1969); "Nonlinear Shell Theory with Finite Rotation and Stress Function Vectors", Journal of Applied Mechanics 1085 - 1090 (1972); "Human Skin as an Elastic Membrane", Journal of Biomechanics 539-546 (1973); "Tension Field Theory and the Stress in Stretched Skin", Journal of Biomechanics 135-142 (1975); "Tension Field Theories for Soft Tissues", Bulletin of Mathematical Biology 161-182 (1978); "A Beam Theory for Large Global Rotation, Moderate Local Rotation, and Small Strain", Journal of Applied Mechanics 179-184 (1988); "Fiber-optic Ellipsoidal Flextensional Hydrophones"; Journal of Lightwave Technology 1995-2002 (1989); "Parallelization of the Naval Space Surveillance Satellite Motion Model", Journal of Astronautical Sciences 207-216 (1993); "Semianalytic Satellite Theory", Naval Postgraduate School Technical Report NPS-MA-95-002 (1995); "The Naval Space Command Automatic Differential Correction Process", Proceedings of the AAS Astrodynamics Conference 991-1008 (1999); "Buckling of Stiffened Plates with Bulb Flat Flanges", International Journal of Solids and Structures 6407-6427 (2004).

Her oceanographic hydrophones are mounted on a retractable centerboard, or drop keel, that lowers scientific transducers away from the region of hull-generated flow noise, enhancing the quality of the data collected. To take full advantage of these advanced data-gathering capabilities, she has the Scientific Sonar System, which can accurately measure the biomass of fish in a survey area. She also has an Acoustic Doppler Current Profiler with which to collect data on ocean currents and a multibeam sonar system that provides information on the content of the water column and on the type and topography of the seafloor while she is underway, and she can gather hydrographic data at any speed up to 11 knots (20 km/hr). Bell M. Shimada has an oceanographic winch with a maximum pull weight of 6,800 pounds (3,084 kg) which can deploy up to 5,100 meters (16,732 feet) of 16-mm wire. She also has two hydrographic winches with a maximum pull weight of 2,600 pounds (1,179 kg), each of which can deploy 3,600 meters (11,811 feet) of 9.5-mm wire, two trawl winches with a maximum pull weight of 7,200 pounds (3,266 kg), each of which can deploy 4,300 meters (14,107 feet) of 28.6-mm wire, and a hydraulic third-wire winch which can deploy 4,700 meters (15,420 feet) of 11.4-mm electromechanical cable.