Sonobuoys have been in use for close to a century, but the technology behind the underwater tool continues to evolve. An effective, but short-lived, research instrument, sonobuoys are vital components for the U.S. military, for researchers and for those in the oil and gas industry. Curious as to how one works? Take a look at the following to see how this unique piece of equipment functions.
What are Sonobuoys?
People have used buoys, or floats, for a long time, marking locations in water. A sonobuoy is simply a float that utilizes sonar technology in the ocean for a number of different reasons. Sonobuoys were originally manufactured to detect enemy submarines during World War I. The U.S. Navy still uses this technology today for much of the same reasons.
There are generally three different types of sonobuoys: active, passive and special purpose ones. All three serve a particular purpose and are employed for different reasons. Some of the purposes include recording underwater earthquake activity, listening to mammal calls, and researching parts of the ocean unavailable to divers.
How do sonobuoys work?
Sonobuoys are usually housed in canisters and are ejected from aircraft or watercraft into the ocean. A float houses a radio transmitter that sits on the surface of the water, while hydrophone sensors are released below the water. A hydrophone sensor is simply an underwater microphone that records sound. The sensors relay sound information to the radio transmitter, which, in turn, transmits the information back to the users.
Active sonobuoys emit sound into the water and record return echoes. Aircraft can use this information for tracing and tracking submarines. A passive sonobuoy, as indicated by its name, emits no sound. Rather, it tracks sound underwater without revealing its own location.
There are also sonobuoys that are not used for military purposes. The special purpose sonobuoys are utilized most often for search and rescue groups or researchers. These instruments are designed to travel to different depths and collect various types of information, aiding in the tracking of crash sites and sinking ships. Some buoys read salinity levels and barometric pressures, while others include GPS tracking equipment. Essentially, though, all sonobuoys use some type of hydrophone sensors to conduct acoustic readings.
These types of underground instruments, utilizing SONAR technology, have not always been efficient. In fact, most researchers discounted their use in the beginning, finding them quite ineffective. Most research was temporarily halted after World War I.
Today, however, technology has evolved to where sonobuoys are quite effective, taking on a more slimming shape. These instruments can travel to further depths and can transmit signals, via the radio transmitter, at further distances, allowing aircraft to remain removed from the site. Some devices only transmit information, while others are manufactured to store information until retrieval. These instruments have been designed to withstand corrosion, underwater storms, and animal interference. Sonobuoys have become hearty instruments since their day of inception.