Sofar bomb

In oceanography, a sofar bomb (Sound Fixing And Ranging bomb), occasionally referred to as a sofar disc,^[1] is a long-range position-fixing system that uses impulsive sounds in the deep sound channel (SOFAR channel) of the ocean to enable pinpointing of the location of ships or crashed planes. The deep sound channel is ideal for the device, as the minimum speed of sound at that depth improves the signal's traveling ability. A position is determined from the differences in arrival times at receiving stations of known geographic locations. The useful range from the signal sources to the receiver can exceed 3,000 miles (4,800 km).

Design

For this device to work as intended, it must have several qualities. Firstly, the bomb needs to

detonate at the correct depth, so that it can take full advantage of the deep sound channel. The sofar bomb has to sink fast enough so that it reaches the required depth within a reasonable amount of time (usually about 5 minutes).^[2]

To determine the position of a sofar bomb that has been detonated, three or more naval stations combine their reports of when they received the signal.

Benefits of the deep sound channel

Detonating the sofar bomb in the deep sound channel gives it huge benefits. The channel itself helps keep the sound waves contained within the same depth, as the rays of sound that have an upward or downward

frequencies

between 30 and 150 Hz, which also helps stop the signal from weakening too much. A side effect of this is that the slightly higher frequencies of sound waves emitted move a bit faster than the lower frequencies, making the signal that the naval stations hear have a longer duration.

History

Dr.

TNT would explode at the correct time for its location (as the deep sound channel's actual depth varies with areas of the ocean). Its main safety mechanism was the detonator that could not trigger without a water pressure that corresponded to at least 750 feet (230 m).^[5]

References

^ YouTube, a Google company. YouTube. Archived from the original on 11 April 2016. Retrieved 28 November 2016.
^ United States. Bureau of Naval Personnel (1953), "SOFAR, Harbor Defense, and other Sonar Systems", Naval Sonar, NAVPERS 10884, Washington, DC: U.S. Government Printing Office, p. 284
^ "Sound Channel, SOFAR, and SOSUS". Robert A. Muller. Archived from the original on 16 May 2007. Retrieved 14 April 2007.
^ United States. Bureau of Naval Personnel (1953), "SOFAR, Harbor Defense, and other Sonar Systems", Naval Sonar, NAVPERS 10884, Washington, DC: U.S. Government Printing Office, pp. 284–286
^ United States. Bureau of Naval Personnel (1953), "SOFAR, Harbor Defense, and other Sonar Systems", Naval Sonar, NAVPERS 10884, Washington, DC: U.S. Government Printing Office, pp. 285–286

United States. Bureau of Naval Personnel (1953), "SOFAR, Harbor Defense, and other Sonar Systems", Naval Sonar, NAVPERS 10884, Washington, DC: U.S. Government Printing Office
http://asadl.org/jasa/resource/1/jasman/v35/i5/p800_s1^{[permanent dead link]}
https://web.archive.org/web/20070516095529/http://muller.lbl.gov/teaching/Physics10/old%20physics%2010/pages/SoundChannel.html

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