Acoustic mine
Encyclopedia
An acoustic mine is a type of naval mine
which monitors audio activity in its vicinity. Depending on its design, it will either actively send out audio pulses, not unlike a sonar
, listening to the speed at which the echo returns to it or passively listen to its environment, depending only on the noise that is made without its interference.
Further variants exist, as this mine may either freely drift, be moored at a certain location and depth, or lie at the bottom of the ocean floor.
, an acoustic mine is defined as one being equipped with a hydrophone
that functions as a main listening device for the mine itself. This hydrophone listens for particular noises made by any ship or vessel's machinery (propellers) and also detects normal clanks from the hull of any ship. An acoustic mine is mainly operated by its diaphragm
located inside the hydrophone. This diaphragm is actuated when a certain noise reaches a predetermined intensity and time. Therefore this initiates the closing of a switch causing an electrical circuit to then complete and for the mine to detonate. This then leads to the question as to whether or not these mines detonate under false pretenses one being normal oceanic activity? For the majority of the time the answer to this question is simply "no" due to one main reason. Unlike pressure mines that detonate under the circumstance of water displacement caused by the hull
of a ship, acoustic mines have a set range that is determined before it is laid. This means that it is supposed to receive a signal to detonate only when sounds are within this range (normal range intensity usually set close to the noise produced by a vessel's propellers). However, there is one drawback to the invention of the acoustic mine that disturbs its effectiveness. Its ability to accumulate dirt and other sea organisms is quite intense meaning that at anytime it may fail to work or detonate on accident.
Naval mine
A naval mine is a self-contained explosive device placed in water to destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, an enemy vessel...
which monitors audio activity in its vicinity. Depending on its design, it will either actively send out audio pulses, not unlike a sonar
Sonar
Sonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels...
, listening to the speed at which the echo returns to it or passively listen to its environment, depending only on the noise that is made without its interference.
Further variants exist, as this mine may either freely drift, be moored at a certain location and depth, or lie at the bottom of the ocean floor.
Usage
In the broad discussion of naval warfareNaval warfare
Naval warfare is combat in and on seas, oceans, or any other major bodies of water such as large lakes and wide rivers.-History:Mankind has fought battles on the sea for more than 3,000 years. Land warfare would seem, initially, to be irrelevant and entirely removed from warfare on the open ocean,...
, an acoustic mine is defined as one being equipped with a hydrophone
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 electricity when subjected to a pressure change...
that functions as a main listening device for the mine itself. This hydrophone listens for particular noises made by any ship or vessel's machinery (propellers) and also detects normal clanks from the hull of any ship. An acoustic mine is mainly operated by its diaphragm
Diaphragm (acoustics)
In the field of acoustics, a diaphragm is a transducer intended to faithfully inter-convert mechanical motion and sound. It is commonly constructed of a thin membrane or sheet of various materials. The varying air pressure of the sound waves imparts vibrations onto the diaphragm which can then be...
located inside the hydrophone. This diaphragm is actuated when a certain noise reaches a predetermined intensity and time. Therefore this initiates the closing of a switch causing an electrical circuit to then complete and for the mine to detonate. This then leads to the question as to whether or not these mines detonate under false pretenses one being normal oceanic activity? For the majority of the time the answer to this question is simply "no" due to one main reason. Unlike pressure mines that detonate under the circumstance of water displacement caused by the hull
Hull (watercraft)
A hull is the watertight body of a ship or boat. Above the hull is the superstructure and/or deckhouse, where present. The line where the hull meets the water surface is called the waterline.The structure of the hull varies depending on the vessel type...
of a ship, acoustic mines have a set range that is determined before it is laid. This means that it is supposed to receive a signal to detonate only when sounds are within this range (normal range intensity usually set close to the noise produced by a vessel's propellers). However, there is one drawback to the invention of the acoustic mine that disturbs its effectiveness. Its ability to accumulate dirt and other sea organisms is quite intense meaning that at anytime it may fail to work or detonate on accident.