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{{short description|Industrial construction in an underwater environment}} ...racticable, the bulk of the work is done out of the water, with underwater work restricted to installation, modification and repair, and inspection. ...

...ion]], especially over long ranges. Compared to terrestrial communication, underwater communication has low data rates because it uses [[acoustic wave]]s instead At the beginning of the 20th century some ships communicated by underwater bells as well as using the system for navigation. [[Submarine signals]] wer ...

===Underwater construction=== {{main|Underwater construction}} ...

{{Short description|Underwater microphone}} ...[microphone]] designed to be used underwater for recording or listening to underwater sound. Most hydrophones are based on a piezoelectric transducer that genera ...

...perated underwater vehicle|remotely operated vehicle]] (ROVs) [[autonomous underwater vehicle]]s (AUVs), [[Submarine communications cable|submarine communication ...o the exploration, drilling and development of oil and gas fields in these underwater locations.<ref>{{Cite web|url=http://subsea.org/subsea.html|title=The Subse ...

[[File:Plongée sous glace VJ.JPG|thumb|Ice diving|alt= A diver is visible underwater in a hole cut in the ice cover of a small lake. Blocks of ice cut to form t ...water]], but [[professional diving]] is sometimes done in other liquids. [[Underwater diving]] is the human practice of voluntarily descending below the surface ...

{{short description|Inspection or measurement in or of an underwater environment}} ...vey performed in an [[underwater environment]] or conducted remotely on an underwater object or region. Survey can have several meanings. The word originates in ...

...rk done out of the water, and where the diving is usually secondary to the work. ...the industry includes maintenance of [[oil platform]]s and the building of underwater structures used in the production process.<ref name="Bevan 2005" /> ...

...arine signals and extension into submarine telegraphy and experiments with underwater telephone communication and eventually sonar. ...ter having become the national leader in underwater sound, sonar and other work with the Navy during the World Wars and branching into other marine systems ...

...Since it doesn't require direct electrical contact with the surface it can work through thin coatings such as paint. This practice is intended for use on w ...be carried out on subsea assets with the assistance of [[Remotely operated underwater vehicle|ROV's]] ...

{{Redirect|Underwater}} ...rvoir]], [[river]], [[canal]], or [[aquifer]]. Some characteristics of the underwater environment are universal, but many depend on the local situation. ...

Development work was started to build a more efficient and powerful second-generation device ...cy to aid its descent into the water. The PCU is almost entirely submerged underwater; only 2 metres of the device poke above the water. The PCU sways back and f ...

{{See also|Underwater construction}} ...xpensive and limited in applications, so when reasonably practicable, most underwater construction involves either removing the water from the building site by [ ...

* [[Thermodynamics]]; [[Heat Transfer]], [[Work (thermodynamics)]], [[Mass Transfer]] ...have distinctive disciplines, naval architects and marine engineers often work side-by-side. ...

...(water is about 1,000 times denser than most gases), the lifting power of underwater gases is very strong. The type of gas used is largely inconsequential becau ...ll with air to lift heavy items like cannons and even whole ships during [[underwater archaeology]] and [[Marine salvage|shipwreck salvaging]]. The air is either ...

[[Image:SCM4 fig11.jpg|thumb|right|300px|Output of a computer model of underwater acoustic propagation in a simplified ocean environment.]] ...ake, a river or a [[Water tank|tank]]. Typical frequencies associated with underwater acoustics are between 10 [[Hertz|Hz]] and 1 [[MHz]]. The propagation of so ...

|uses = Buoyancy correction and trim adjustment of underwater divers Surface-supplied divers may be more heavily weighted to facilitate underwater work, and may be unable to achieve neutral buoyancy, and rely on the diving stag ...

...b | title = International Convention on Tonnage Measurement of Ships, 1969|work =International Conventions | publisher = Admiralty and Maritime Law Guide | ...tion of the hull to a rectangle of the same overall width and depth as the underwater section of the hull. This defines the fullness of the underbody. A low C<su ...

...n SPL of {{nobreak|94 dB}}. In other media, such as [[underwater acoustics|underwater]], a reference level of {{nobreak|1 μPa}} is used.<ref name=Morfey>{{cite b ...ound waves can be present in other [[atmosphere]]s or other media, such as underwater or through the Earth.<ref name="Audio1">{{cite book |last=Winer |first=Etha ...

...ving equipment]] which is worn by divers to establish [[neutral buoyancy]] underwater and positive [[buoyancy]] at the surface, when needed. ...nt pressure divers using underwater breathing apparatus to adjust buoyancy underwater or at the surface within the range of slightly negative to slightly positiv ...