Depth sounding
Depth sounding, often simply called sounding, is measuring the
Soundings were traditionally shown on
Terminology
"Sounding" derives from the Old English sund, meaning "swimming, water, sea"; it is not related to the word sound in the sense of noise or tones,[2] but to sound, a geographical term.
Traditional terms for soundings are a source for common expressions in the English language, notably "deep six" (a sounding of 6 fathoms). On the
History
Lead and line
A sounding line or lead line is a length of thin
Measuring the depth of water by lead and line dates back to ancient civilization. It continues in widespread use today in recreational boating and as an alternative to electronic
At sea, in order to avoid repeatedly hauling in and measuring the wet line by stretching it out with one's arms, it is common practice to tie marks at intervals along the line. These marks are made of
Soundings may also be taken to establish the ship's position as an aid in
Mechanisation
During the nineteenth century, a number of attempts were made to mechanise depth sounding. Designs ranged from complex brass machines to relatively simple pulley systems. Navies around the world, particularly the Royal Navy in Britain, were concerned about the reliability of lead and line sounding. The introduction of new machines was understood as a way to introduce standardised practices for sounding in a period in which naval discipline was of great concern.[7]
One of the most widely adopted sounding machines was developed in 1802 by Edward Massey, a clockmaker from Staffordshire. The machine was designed to be fixed to a sounding lead and line. It featured a rotor which turned a dial as the lead sank to the sea floor. On striking the sea floor, the rotor would lock. Massey's sounding machine could then be hauled in and the depth could be read off the dials in fathoms. By 1811, the Royal Navy had purchased 1,750 of these devices: one for every ship in commission during the Napoleonic Wars.[8] The Board of Longitude was instrumental in convincing the Royal Navy to adopt Massey's machine.[7]
Massey's was not the only sounding machine adopted during the nineteenth century. The Royal Navy also purchased a number of Peter Burt's buoy and nipper device. This machine was quite different from Massey's. It consisted of an inflatable canvas bag (the buoy) and a spring-loaded wooden pulley block (the nipper). Again, the device was designed to operate alongside a lead and line. In this case, the buoy would be pulled behind the ship and the line threaded through the pulley. The lead could then be released. The buoy ensured that the lead fell perpendicular to the sea floor even when the ship was moving. The spring-loaded pulley would then catch the rope when the lead hit the sea bed, ensuring an accurate reading of the depth.[7]
Both Massey and Burt's machines were designed to operate in relatively shallow waters (up to 150 fathoms). With the growth of seabed telegraphy in the later nineteenth century, new machines were introduced to measure much greater depths of water. The most widely adopted deep-sea sounding machine in the nineteenth century was Kelvin's sounding machine, designed by
Echo sounding
Both lead-and-line technology and sounding machines were used during the twentieth century, but by the twenty-first,
The first practical
See also
- Depth gauge – Instrument that indicates depth below a reference surface
- Echo sounding – Measuring the depth of water by transmitting sound waves into water and timing the return
- Multibeam echosounding– Type of sonar used to map the seabed
- Fishfinder – Electronic device used in water
- Challenger expedition – Oceanographic research expedition (1872–1876)
References
- ^ "Sounding Pole to Sea Beam". National Oceanic and Atmospheric Administration. Retrieved 2012-07-07.
- ^ "Sound, v2". Oxford English Dictionary (Second ed.). Oxford, England: Oxford University Press. 1969.
- ^ a b c d Hohlfelder, R., ed. (2008). "Testing the Waters: The Role of Sounding-Weights in Ancient Mediterranean Navigation". The Maritime World of Ancient Rome. Ann Arbor: University of Michigan Press. pp. 119–176.
- ^ Kemp, P., ed. (1976). The Oxford Companion to Ships and the Sea. London: Oxford University Press. p. 150.
- ^ a b Hutton, Charles (1795). A Mathematical and Philosophical Dictionary: Containing an Explanation of the Terms, and an Account of the Several Subjects Comprized under the Heads Mathematics, Astronomy, and Philosophy both Natural and Experimental (Volume 2). pp. 474–475.
- ISBN 9780192820846.
- ^ S2CID 40753266.
- ^ McConnell, A (1982). No Sea Too Deep: The History of Oceanographic Instruments. Bristol: Hilger. p. 28.
- ^ Dunn, R (2012). "'Their brains over-taxed': Ships, Instruments and Users". In Dunn, R; Leggett, D (eds.). Re-inventing the Ship: Science, Technology and the Maritime World, 1800-1918. Farnham: Ashgate Publishing. pp. 131–156.
- ^ "Echo Sounding / Early Sound Methods". National Oceanic & Atmospheric Administration (NOAA). NOAA Central Library. 2006.
In answer to the need for a more accurate depth registering device, Dr. Herbert Grove Dorsey, who later joined the C&GS [United States Coast and Geodetic Survey], devised a visual indicating device for measuring relatively short time intervals and by which shoal and deep depths could be registered. In 1925, the C&GS obtained the very first Fathometer, designed and built by the Submarine Signal Company.
External links
- Media related to Depth sounding devices at Wikimedia Commons
- The Lead Line -- Construction and use (retrieved Sept 2006).