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Being 'pinged'
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Pax Melmacia



Joined: 19 Nov 2004
Posts: 29
Location: Philippines

PostPosted: Thu Dec 09, 2004 4:12 am    Post subject: Being 'pinged' Reply with quote

Just like everyone else here, I've read quite a number of accounts by U-Boat survivors. The thing is they seem to have different accounts on the sound Asdic makes when it strikes their hull. Some say it sounds like pebbles on a roof. Others, a chain being dragged across the hull. Some say it's like a tuning-fork.

I imagine there's the sound of the pulse first, followed by its contact with the hull, but I'm just guessing here.

I've heard the pings on the subsims, but now I'm wondering if they're accurate.
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Redwine



Joined: 10 Jan 2002
Posts: 1143
Location: Buenos Aires , Argentina.

PostPosted: Thu Dec 09, 2004 10:31 am    Post subject: Reply with quote

Yes i heard the same........

By casuality editing a ping download from the web, using equalizer, i found a effect wich change a little bit the sound of the ping at final of it when it hit the hull........ the ping finish with a "fried" sound.........

I do not know if it is excat real but reproduce that "change" you mentioned.............

I found the effect by casuality editing pings to hear them well at my sound system..................

I put a colection of rare pings from the web and edited at my signature.............
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Catfish



Joined: 21 Sep 2001
Posts: 1248
Location: where the ocean meets the sky

PostPosted: Thu Dec 09, 2004 1:57 pm    Post subject: Pinngg... Reply with quote

Hello there,
i just read a book from a U-boat sailor ('Sharks and little fish') where the detection sound of the ASDIC was described as a 'tack' sound which increased it's frequency the better the destroyer's fix on the U-boat was. If the ship had the boat in it's detection beam (sorry for the transl., it's called 'Ortungsstrahl' in German), it was like lots of pebbles being thrown against the hull of the sub. This sound can be heard quite good in one of the first PC-subsims, 'Wolfpack'.
Greetings,
Catfish
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Heibges



Joined: 26 Feb 2004
Posts: 681
Location: San Francisco, California

PostPosted: Thu Dec 09, 2004 2:56 pm    Post subject: Reply with quote

According to the Uboat Commander Handbook the Germans heard several differnent sounds from several different allied echo sounders.

deeper in tone that German S echo sounder
constant humming
ticking of clock
fluctuating tones between high and low volume
metallic blows on the ship
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Vonotto



Joined: 07 Jul 2002
Posts: 551
Location: Alexandria, Va

PostPosted: Thu Dec 09, 2004 5:42 pm    Post subject: Reply with quote

Yes if you read the several accounts of the sounds then compare the dates you will see that people heard differents sounds in different years. This is due to upgrades and different equipment as it is introduced throughout the war.
The sound is also influenced by the depth of the sub and the amount of salt in the water as well as thermal layers.

If you scuba dive it is easy to understand all these.
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Leif...



Joined: 25 Dec 2001
Posts: 241
Location: Sweden

PostPosted: Thu Dec 09, 2004 5:46 pm    Post subject: Reply with quote

I have never figured out how one can first hear the ping and then hear the contact with the hull. If you hear the sound then you are hit by the sound. What you don’t know, and can’t hear, is if anyone is listening in your direction and hears the echo.

Leif…
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Lanzfeld



Joined: 10 Jan 2002
Posts: 1256
Location: Reston, VA

PostPosted: Thu Dec 09, 2004 5:54 pm    Post subject: Reply with quote

Very good point Leif.... :hmm:
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Sailor Steve



Joined: 22 Nov 2002
Posts: 5433
Location: Salt Lake City, Utah

PostPosted: Thu Dec 09, 2004 6:12 pm    Post subject: Reply with quote

My guess is that the "ping" sound so common in movies comes from the fact that U.S. subs had active sonar themselves. Though not transmitting, the sonar reciever would actually translate the signal transmitted by the enemy, so they would hear a "ping". Any boat not having sonar equipment would only hear the sound waves bouncing off the hull, hence the "gravel" sound.
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Torgen



Joined: 14 Sep 2002
Posts: 454
Location: Tampa FL

PostPosted: Thu Dec 09, 2004 6:21 pm    Post subject: Reply with quote

My father was a contractor visiting a US attack sub in Groton in the 70s, and the destroyer across the river went active andwas pinging the sub's hull constantly. My dad said it made a huge BONG! sound and damned near made everyone deaf. The CO made a *personal* visit to the DD, and the pinging stopped soon after.

Of course, the modern sonar are surely far more powerful and focused than the WWII era ones, and your usually not THAT close to one! :doh:
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Redwine



Joined: 10 Jan 2002
Posts: 1143
Location: Buenos Aires , Argentina.

PostPosted: Thu Dec 09, 2004 7:15 pm    Post subject: Reply with quote

Leif... wrote:
I have never figured out how one can first hear the ping and then hear the contact with the hull. If you hear the sound then you are hit by the sound. What you don’t know, and can’t hear, is if anyone is listening in your direction and hears the echo.

Leif…


The effect was described as a "vibration" or some thing after the ping finish............as if you ping a diapason, you heard the sound and after it finish you still hearing a small vibration...........

May be this "vibration" is present at same time as the ping but covered by the ping sound level and only is audible when the ping sound level down...............

But read some times about this "change in the sound at final of the ping...........wich is avery short time effect, as if there two sound wich finish "gap" by a small fraction of second...........

I never heard it, only read about it................
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Paximus



Joined: 07 Jul 2002
Posts: 44
Location: Miami. FL

PostPosted: Thu Dec 09, 2004 8:39 pm    Post subject: Reply with quote

This "gravel" or "pebbles hitting the hull" sound is what the author of Das Boot heard. Did the movie get it wrong? How does a ping turn into the sound of a bunch of pebbles hitting the hull for those inside the sub?
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Sailor Steve



Joined: 22 Nov 2002
Posts: 5433
Location: Salt Lake City, Utah

PostPosted: Fri Dec 10, 2004 1:49 am    Post subject: Reply with quote

The "ping" is the tone generated by the sonar/asdic transmitter so the operator knows the signal was sent. If it bounces off of something the returning signal is translated by the machine into another tone. By listening to the difference in the tones a good operator can tell the approximate range to the target. The actual signal is supersonic-it can't be heard by the human ear at all. When the signal hits the submarine, the sailors inside are actually hearing the effect the supersonic signal has on the hull itself. Thus, no ping.

Of course I could be completely wrong on that. Ping
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shole



Joined: 28 Jul 2004
Posts: 130

PostPosted: Fri Dec 10, 2004 7:52 pm    Post subject: Reply with quote

supersonic?
i find that hard to believe
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Sailor Steve



Joined: 22 Nov 2002
Posts: 5433
Location: Salt Lake City, Utah

PostPosted: Sat Dec 11, 2004 1:22 am    Post subject: Reply with quote

Sorry, I misspoke...er, miswrote? I meant Ultrasonic, as in higher pitched than the human ear can hear. Obviously sound can't travel faster than the speed of sound... Embarassed
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Drebbel



Joined: 10 Jan 2002
Posts: 6153
Location: Almost at periscope death !

PostPosted: Sat Dec 11, 2004 8:21 am    Post subject: Reply with quote

This is what my babylon says about it

Quote:

- supersonic

adj. greater than than the speed of sound, ultrasonic

- ultrasonic

adj. having a frequency above the range of sound audible to the human ear (of waves, vibrations, etc.)

- supersonic
adj
1. (of speed) greater than that of sound in a given medium especially air; "the concorde is a commercial supersonic aircraft" [ant: sonic, subsonic]
2. having frequencies above those of audible sound [syn: ultrasonic]


So it seems that both are the same in some instances.
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