Echo sounder - Principle and working | Bridge equipment | Merchant Navy knowledge

#lifeatsea #merchantnavy #navy #ship #education #educational
Echo sounder - Principle and working | Bridge equipment | Merchant Navy knowledge
Transmitting Acoustic Signals Through Water: Echo Sounding
APC APC
7 years ago
There are many industries that need to “see” underwater. For example, companies that rely on sea transportation need to know how deep water is to ensure a ship does not run aground. Fishing operations need to find fish, and researchers hunt for shipwrecks.
Not only do they need to have reliable data for what is underwater, they also need accurate information on ports. Although there are many charts for major ports around the globe, for some regions, an up-to-date chart may not exist. For a ship in the middle of the ocean, the charts are not as reliable.
Echo sounding is the solution to these challenges. Echo-sounding technology enables research vessels and others to measure distances underwater by using sound. A form of sonar (SOund Navigation And Ranging), echo sounders can be stand-alone devices or attached to a ship.
Read on to learn more about how echo sounding works, including how it relies on piezoelectricity. You will also learn how it developed into the technology we know today, and how industries today are taking advantage of piezoelectricity.
How Does Echo Sounding Work?
Echo sounders transmit a pulse of energy directly downwards from the bottom of the ship. The pulsation moves through the water and pings off the floor of the sea. It then travels upward until the echo sounder receives the echo.
Once it receives the returned ping, the echo sounder measures how long the pulse took to travel from the seabed and back up to the vessel. Using this data, it can precisely calculate the depth of the water.
The Piezoelectricity Effect and Ultrasonic Sonar
Piezoelectricity is the electric charge that some solid materials can accumulate when mechanical stress is applied to them. Echo sounding is just one of the many commercial and industrial technologies that relies on piezoelectricity.
Jacques Curie and his younger brother Pierre discovered piezoelectricity in 1880 while conducting research into how pressure creates electrical charge in crystals. As they studied tourmaline, quartz, topaz, cane sugar and Rochelle salt (Potassium sodium tartrate), the men found that Rochelle salt produces an electrical charge when stressed.
This discovery facilitated the development of the gramophone (an earlier version of the phonograph) and stress measuring devices. Subsequently, researchers determined that piezo would change dimension or create a force upon receiving an electrical charge. The piezo became the primary force behind the operating principle for ultrasonic transducers.
In 1917, Paul Langevin, along with a team of researchers, developed the first commercial application to take advantage of the piezoelectric property of quartz. They invented an ultrasonic sending and receiving system - the forerunner of modern-day sonar - that solved the problem of transmitting acoustic signals in water.
Sonar in Its Earliest Form
The original sonar device consisted of a hulking gadget that looked like an oversized breadbox. It had a large transducer manufactured from quartz crystal - the resonator for the ultrasound devices - fastened between two steel plates, as well as a hydrophone designed to detect the return echo of submarines.
The device set the quartz piezoelectric crystal into oscillation by sending an electrical signal. The high-frequency mechanical vibration was transmitted through water to a reflecting body, and then to a second quartz crystal, which received the reflected high-vibratory energy or “ultrasound.”
Based on the time lapse between sending the signal and receiving the echo, the crew could calculate the distance from the source to the reflecting body. The top-secret sending and receiving system was initially named an “ultrasonic submarine detector.” Both the British and U.S. governments took advantage of this technology toward the end of World War I. The British Royal Navy used the information to calculate the distance of German submarines and place the depth charges more accurately.
The development of the sonar was instrumental in raising the level of awareness to the potential of piezoelectricity devices in other industries and applications.

[@smdtvX]

❤❤