Side Scan Sonar (Sound Navigation And Ranging) search explained

Discussion in 'Caylee Anthony 2 years old' started by whittymom4, Nov 13, 2008.

  1. whittymom4

    whittymom4 New Member

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    Side-scan Sonar (Sound Navigation And Ranging) is capable of producing an image of (lost) objects that are lying on the bottom underwater or floating in the water. Objects that are almost completely buried in the bottom with only small parts sticking out of the botttom can be located. To locate or image objects that are completely buried in the bottom or have no parts sticking out, the side-scan sonar is not appropriate.

    FORGOT TO LIST MY SOURCE: http://www.abc.se/~pa/mar/sidescan.htm

    READ THIS PAGE ABOUT VOLUNTEER SEARCHERS, WORKED LACI P. CASE: http://gralston1.home.mindspring.com/Sidescan.html
     
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  3. mom4321

    mom4321 New Member

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    shouldnt sonar have showed a bag weighted down with bricks?
     
  4. EmMomma

    EmMomma Cleverly disguised as a responsible adult

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    Something weighted down wound sink to the bottom, then down into the bottom...I would think.
    This river, from what I understand, has lots of silt, which makes for a very soft bottom.
     
  5. EmMomma

    EmMomma Cleverly disguised as a responsible adult

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    Thanks for this info. :)
     
  6. kwmred

    kwmred New Member

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    Thanks... this explains a lot!
     
  7. whittymom4

    whittymom4 New Member

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    You are very welcome, I did just edit my post and add a link to where I found the info. and a link to the volunteer searchers who worked on the Laci P. case. Interesting.:)
     
  8. whittymom4

    whittymom4 New Member

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    The website I found the information on is very informative and kind of boring to read, but according to the information listed TM should have picked up on the bricks. Plus it finds metal. Not sure if anything metal was in the bag with the toys.
    On NG tonite when they showed the little girl figure toy in the bag, that is a McDonald's toy that was out in the late spring, early summer. The Barbie line, at least it was here in Iowa. My two little ones both have one. Any other Happy Meal purchaser's see that?
     
  9. MSinIndy

    MSinIndy New Member

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    The Side Scan Sonar I looked up is capable of recording the search with the computer used to navigate the sonar. This company called it an AAR or After Action Report.

    I wonder if Tim has an AAR report that might show the bag there on Sunday. :waitasec:
     
  10. whittymom4

    whittymom4 New Member

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    I wonder if he does. You would think so, it's just one more thing that doesn't make sense in this case. Maybe he did print a report and LE has it?
     
  11. MSinIndy

    MSinIndy New Member

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    I bet he does record searches. LE would want documentation of any bodies found as well as and evidence and where it was found.

    LP needs to check this out.
     
  12. Meagain

    Meagain New Member

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    LOL yea I hear ya.
    And what IF said bag had say, a few REAL bones in it?

    So I guess this sonor only deals with large full bodies?
     
  13. HappyChic727

    HappyChic727 Patiently Waiting

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    Way back when the search for Laci Peterson's body was being done with side sonar, one of our very own members here, Scandi, saw a shot on television of what was seen beneath the water in the form of a woman's body wrapped up in something with a baby's leg and foot coming out of the stomach area. She quickly drew what she saw and that was a good thing because it was never shown again. That was because the team that was using the side sonar didn't do whatever they were supposed to do to locate that body. Scandi was very shy about having done this but I thought she did a wonderful job and sure enough, the bodies surfaced thereafter.

    Just thought I would mention that, for the newbies and the oldies who might remember. I just checked and Scandi is still a member. Her posts only go back to 2007 so I can't find her old post to refer to from 2003.
     
  14. katherine5

    katherine5 New Member

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    we too had the same Happy Meal dolls and they were, in fact, from the early summer.
     
  15. weasel

    weasel New Member

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    <<Just thought I would mention that, for the newbies and the oldies who might remember>>

    I do remember that. I also remember personally seeing a sonar picture that I thought actually was Laci. It showed a body from the back and almost looked like it was slightly bent over. You could see the back of the head and the hair was black. I saw it once and then never again. Wonder what happened to that picture and also the picture Scandi drew?
     
  16. weasel

    weasel New Member

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    <<That was because the team that was using the side sonar didn't do whatever they were supposed to do to locate that body>>

    I thought the reason they didn't recover her body that day was because the water was too treacherous. Then a storm hit and by the time they returned to the spot, she was already gone.
     
  17. mom2chloe

    mom2chloe Member

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    IIRC TM has stated several times recently that Caylee's "body" will never be found and that there is not a "body" in the Econ River?
    Am I just confused by his wording, but at this point, why is anyone looking for a "body", when we know that certainly is not the case at this late date?
     
  18. DianeB

    DianeB Inactive

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    Is it me, or is that an odd position to take without knowing if Caylee's body may have been wrapped in something that would keep her skeleton relatively intact?
     
  19. MADJGNLAW

    MADJGNLAW New Member

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    I figured I would start a thread on this since there is so much bickering between Tim and Padilla.. Yes, Tim used this device in the search for Caylee... Now, most share the success of the sonar devise as yes it is a wonderful useful device. But, there is more to it, it's not all cut and dry.... Mistakes can be made, body's sometimes are not found, items that look like trash and boulder will show up, what is beneath or in them will not for the most part. So, here is the post and all that can share creditable information please do... There is always a positive and negative to all of today's technology. I see why Padilla wants to dive the river and other areas, I see his reason and hope that all will understand why by educating ourselves. The media does not report everything, and people tend to paint a certain picture of how things are being done....

    While doing a bit of research this technique is very useful in finding drowning victims and other. I also have heard and read that at times "things can be missed" and that is why a good dive team and a thorough search should be conducted. At times they see a boulder or other objects, but "without going into the water and pulling the objects out there is no way knowing for sure what is in the package or other"

    I had followed the Peterson case and I did remember reading about them using side scan sonar and also read where at times you can miss things in the water.

    In The Search for Laci Peterson

    UW: What do you look for in the data as telltale signs that you might have found a body? What other
    objects are most often mistaken for bodies with sonar searches?
    GR: Accidental drowning victims are very distinctive and generally quite easy to identify. We can usually
    see arms, legs, and torso. Homicide victims, however, depending upon how they may be "packaged," are a bit more difficult to identify. Quite often they will not display arms or legs, and may be found lying in a variety of positions because of objects attached to them.Also, in homicide cases, it is very critical to
    have an idea of what you are looking for, otherwise, nearly every "out-of-place" object is a potential target of interest.In another homicide case, an ROV was sent down to recover the victim.

    The object appeared to be a large boulder in the video from the vehicle, so the ROV operator moved on. After awhile, the agent in charge told the ROV operator to return to the "boulder" and bump into it. It moved - it was not a boulder!

    UW: What are the biggest factors in a body search of this type being successful?
    GR: Having accurate location information is essential to minimize the search area. Calm water conditions are also a great benefit. Surface wave action from wind or passing boats can cause smearing of the side scan images and render them worthless.

    Of course, the bottom conditions are also important. A smooth, clean bottom with no trees, large boulders, or other debris that can hide the object you are looking for is very desirable.

    UW: Let's talk about equipment. What exactly did you use on the Laci Peterson search?
    GR: We used a customized Marine Sonic Technology side scan sonar. We have a custom-made stainless steel tow body for the 600 kHz transducer. The tow fish is six feet long and weighs about 130 pounds. The extra length makes it more stable and, consequently, the images are better. The
    heavier weight allows us to work in deeper water with less cable.This setup requires the use of a powered hoist to deploy the system. Our hoist has a variable speed electric motor with a remote control and is also equipped with a slip clutch to prevent cable breakage if the tow fish snags on something underwater. We also used an aluminum tow body for the shallow water in San Francisco Bay. The lighter weight of the aluminum gave us greater layback and tended to somewhat de-couple the towfish from boat pitch and heave due to surface wave action.

    UW: Do you use different units for different searches, why or why not?
    GR: We use the aluminum tow body when we have to air freight the equipment and use a boat of opportunity. We have lower and higher frequency transducers available for use in searching for larger or smaller objects. The 600 kHz frequency is the best all-around frequency for most of the underwater
    searches we have conducted.

    http://www.findlaci2003.us/sonar-gene-ralston.html
     
  20. passionflower

    passionflower Just 1 tip to find a killer

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    Did TM do his sonar by the culvert area where LP and divers were? TM said the 'lake or river' did he ever say culvert or sides, banks of river where something could wash up.??
    Though weighted down like Laci, pieces will probably break away.......black bag broke while brought up, did I read that right??
     
  21. HappyChic727

    HappyChic727 Patiently Waiting

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    Oh you might be right about that. My apologies to the search team. It's just weird because it was never show again or spoken of again.
     

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