Talk:Sonar/Archives/2014

Passive Sonar

Passive Sonar is defined in the introductory paragraph of the article as used to monitor the "sound made by vessels" in the introductory paragraph. Passive Sonar has a plethora of use cases and would be more accurately defined as listening for acoustics sources within a prescribed frequency range in its environment. Examples of acoustic sources which are often monitored via passive means include ceteceans and vessels. For vessel detection passive sonar is used to minimize the threat of detecting the sonar system (military application). For cetecean monitoring active sonar may cause injury to the animals and therefore shouldn't be used in this context. — Preceding unsigned comment added by Fflanner (talk • contribs) 18:02, 13 January 2014 (UTC)

The term 'passive sonar' is applied to what were originally called hydrophones and consisted of an underwater microphone outside the ship or submarine's hull and feeding to an operator equipped with headphones so that he could hear any underwater noises.

The term 'active sonar' refers to what was originally called ASDIC, and involves a piezo-electric oscillator under the ship or submarine's hull that emitted the characteristic audible 'ping' that travelled out underwater, and which was reflected back in a similar manner to a radar signal from any underwater target. The bearing of the transmitted signal gave the bearing of the target - the underwater transducer could be rotated - and the time taken for the return of the echo gave the distance from the transmitter, the closer together in time the emitted pulse and the received echo, the closer the transmitting and target vessel were to each other. At close range the operator would receive an 'instantaneous echo', and this is when depth charges would be dropped, as the target submarine would be very near to the attacking ship. There is a very good illustration of the system in use in the film The Cruel Sea

Both hydrophones and ASDIC were in use with the Royal Navy from shortly after the end of WW I - List of British Asdic systems.

Sonar signal processing

Could someone try link to this orphaned page? Gbawden (talk) 11:02, 23 July 2014 (UTC)

Sonar:Origin

The Sonar iis a British, Canadian and German invention. Three inventors from these countries invented Sonar independent from the others. 178.3.28.185 (talk) 23:40, 13 June 2013 (UTC)

Depends on whether you mean active or passive sonar. Active sonar was invented (during WW1) mainly by a French scientist in France, in parallel with but not independently from a Canadian working in UK. Different kinds of passive sonar was also invented during WW1, by US and British scientists. I am not aware of any serious German work on sonar before WW2. Dondervogel 2 (talk) 14:05, 15 June 2013 (UTC)

"Any serious German work"...I suggest using an encyclopedia properly because "Halbbildung stürzt in Sklaverei". The scientist Alexander Behm was granted a patent in Germany for inventing echolot sounding in 1913, this was used for example during the German Atlantic Expedition aka German Meteor Expedition which conducted the first study on the South Atlantic ocean floor in 1925-1927. In WWI german U-Boats used passive Hydrophones. In WWII came the Group Listening Apparatus (Gruppenhorchgerät), the Balkony-Apparatus and the Nibelung-Apparatus which calculated the trajectory of torpedos based on acoustic signals alone. — Preceding unsigned comment added by Lokith99 (talk • contribs) 06:38, 9 September 2014 (UTC)

I was not aware of the German WW1 hydrophones. Can you supply a reference? Dondervogel 2 (talk) 19:29, 10 September 2014 (UTC)

Reverted edit about until now secret about how sonar evolved in Britain

My edit was reverted even I provided good citation. I was told that I have to ask here first. This seems to me odd, because nobody has to ask when writing to Wikipedia when providing good source. So even this is really odd, I'm askig here to please allow me to edit the article this way:

There was a top secret project where [[Ernest Rutherford]] worked at [[University of Manchester]] on submarine detection by what has been later named "sonar".<ref>{{cite web |url=http://www.manchestereveningnews.co.uk/news/greater-manchester-news/manchester-scientist-ernest-rutherford-revealed-8078891 |title=Manchester scientist Ernest Rutherford revealed as top secret mastermind behind sonar technology |author=Alan Selby |date=2014-11-09 |website=http://www.manchestereveningnews.co.uk |publisher=Manchester Evening News |accessdate=2014-11-13}}</ref>

There was similar wording at the web of the University of Manchester (see inside the cited source, however this does now work at the moment). Also this is widely known that British has sonar developed for military purpose on its own. But nobody knows who was behind this development until now. — Preceding unsigned comment added by Milan Keršláger (talk • contribs) 19:29, 23 November 2014 (UTC)

I reverted your edit because it is widely accepted that the main protagonists of the development of sonar in the UK were A B Wood and Robert Boyle. It's true that both worked with Rutherford before WW1, but Rutherford's role during the war is generally considered to be minor, almost anecdotal. What I would like to hear is a description of the contribution made by Rutherford that has now come to light, so I can understand how it differs from or complements the achievements of Boyle (active sonar) and Wood (passive). Can you provide this information? Dondervogel 2 (talk) 22:49, 23 November 2014 (UTC)

I looked up the press release from the Un Manchester website. It is quoted below verbatim from here

Rutherford’s secret war mission helped pioneer ‘sonar’

11 Nov 2014

Manchester scientist Ernest Rutherford – famed for “splitting the atom” – also deserves better recognition for helping to pioneer a system we now know as sonar as part of a top secret World War One defence project.

German U-boats terrorised British ships during World War One (pic: Tom Gerrard) German U-boats terrorised British ships during World War One (pic: Tom Gerrard)

Rutherford, who worked at The University of Manchester, produced a ‘secret report’ during The Great War which was to form the basis of research to develop an acoustic system to detect German U-boats, then terrorising British merchant shipping and Royal Navy battleships.

Rutherford’s great genius was put to the test as he continued his ground-breaking work on nuclear science –successfully “splitting the atom" in 1917 – while also covertly leading a band of researchers to develop an effective method to detect submarines and safeguard Britain’s vital sea routes.

In 1915, the Nobel prize-winner published an historic paper entitled, ‘On methods of collection of sound from water and the determination of the direction of sound’. In this document Rutherford “discussed the possibility of a system of secret signalling by the use of sound waves of frequency beyond the limit of audition”.

“This is the first mention of the system that would one day become modern sonar,” explained Dr Christine Twigg from The University of Manchester, who has researched this less well-known part of Rutherford’s brilliant career.

“This momentous report was the foundation of subsequent anti-submarine warfare and would safeguard thousands of Allied lives in both world wars.”

Rutherford’s team conducted clandestine experiments using water tanks at landlocked labs at The University of Manchester to test hydrophone systems before full-scale testing was conducted using two donated fishing trawlers at a research outpost based at Hawkcraig, on the south coast of Fife, Scotland.

Rutherford attracted the talents of former students and associates, including Albert Beaumont Wood, Harold Gerrard, Robert Boyle and William Henry Bragg. Critically, these exceptional pioneers would share their ideas with their French counterparts, such as Paul Langevin, to produce a working prototype of what the British originally called ‘ASDIC’ and later dubbed sonar.

Early versions of the technology were being installed on Royal Navy war ships just as the war came to an end but would be used to great effect in the following global conflict.

As sonar research progressed, Rutherford led an official British scientific mission to the USA in the spring of 1917 which coincided with America’s entry into the war – partly related to the outcry following a German U-boat torpedoing the liner RMS Lusitania, with the loss of 128 American lives.

As a direct result of this trip a new naval research centre was set up in New London, America’s primary East Coast submarine base, and Rutherford continued to share his expertise with the Americans on naval research into peacetime.

This crucial work was kept from the public – and early biographers – for many years, as it was strictly embargoed by the Official Secrets Act.

However, Dr Twigg believes Rutherford and his team deserves full recognition for the significant contribution they made to science and the Allied war effort, a role that has been long overlooked.

“Rutherford’s role in the development of this field is relatively unknown and was rarely mentioned by his associates as it was one of the greatest official secrets at the time of his death in 1937,” added Dr Twigg.

“Nevertheless, it is believed to be an example of his great genius in an area of intellectual adventure which few had previously entered.”

Ends

Dondervogel 2 (talk) 09:15, 25 November 2014 (UTC)

I took a look at the University web page, which includes the text

"Rutherford’s research devised a means for detecting submarines according to the known laws of physics. He concluded that acoustic detection was the most effective means. As other fields had produced no practical results, the Royal Navy accepted his advice and Rutherford proceeded to set up water tanks in his Manchester laboratory to refine understandings of underwater acoustics which led to much of the basement of the laboratory being turned into a very large concrete water tank. His findings in 1915 were so advanced that they remained largely unsurpassed until the 1980s.

During September 1915, Rutherford travelled to observe experiments and testing of equipment for underwater detection in Scotland. As a result of his technical reports and work in the Manchester laboratory water tanks, Rutherford was able to design diaphragms in water which were ten times more sensitive than previously.

His official report on the tests and findings provided the direction for acoustic research in the remaining years of the war. One of his key recommendations was the ‘possibility of a system of secret signalling by the use of sound waves of frequency beyond the limit of audition’. This was the first suggestion of the system that would one day become modern sonar and present echo-sounding technology. Throughout the war, Rutherford maintained his own research interests and as the war continued, Rutherford became increasingly excited about its direction. Towards the end of the war, Rutherford realised the significance of his work on the atom. In 1917, he was reported late for a joint Allied meeting on anti-submarine warfare and sent a message of apology stating he would be delayed due to laboratory experiments in which he had succeeded in splitting the atomic nucleus."

The main new information here is that Rutherford conducted secret experiments at his Manchester laboratory. The claim that his findings "were so advanced that they remained largely unsurpassed until the 1980s" is of little value when we are not told what the findings were. My proposal is to add a statement about the Manchester tank. The rest seems more relevant to the Ernest Rutherford article than this one. What do others think? Dondervogel 2 (talk) 21:40, 7 December 2014 (UTC)