Sonar Target

Ric Gillespie · May 16, 2013, 05:58:56 PM

Quote from: Chris Johnson on May 16, 2013, 03:18:20 PM
From the first image in the thread is it possible to 'scale' the object (or is that something the experts are looking at)?

This is the anomaly with a scale I created by comparing its length to the length of other targets of known dimension in the same imagery. The scale is in meters.

Tim Mellon · May 16, 2013, 07:02:32 PM

Ric, do you remember Will, the Phoenix technician, who had a sonar scan of two meter-cubed aluminum objects connected to each other by four meter-long rods? One could not discern the aluminum cubes themselves, but only their shadows.

Are we looking at shadows here?

Ric Gillespie · May 16, 2013, 08:19:30 PM

Quote from: Tim Mellon on May 16, 2013, 07:02:32 PM
Ric, do you remember Will, the Phoenix technician, who had a sonar scan of two meter-cubed aluminum objects connected to each other by four meter-long rods? One could not discern the aluminum cubes themselves, but only their shadows.

You're speaking of Will O'Halloran, the Bluefin technician. Yes, he was showing us an experiment they did to demonstrate to the Navy that it's possible to construct an aluminum object that is virtually invisible to sonar. All you can see is the shadow.

Quote from: Tim Mellon on May 16, 2013, 07:02:32 PM
Are we looking at shadows here?

Yes. The dark areas behind the anomaly are shadows but remember - these are sound shadows. Interpreting them is tricky.

Walt Holm · May 16, 2013, 08:41:34 PM

Ric:

Do you have the original sonar data of the area around the anomaly in strip-chart ("waterfall") form? The sonar mosaics are great for identifying anomalies, but not so great in trying to figure out what shape the thing actually is. Having the data in a waterfall format would give a lot of clues that the mosaic does not.

-Walt

Ric Gillespie · May 17, 2013, 07:24:46 AM

Quote from: Walt Holm on May 16, 2013, 08:41:34 PM
Do you have the original sonar data of the area around the anomaly in strip-chart ("waterfall") form? The sonar mosaics are great for identifying anomalies, but not so great in trying to figure out what shape the thing actually is. Having the data in a waterfall format would give a lot of clues that the mosaic does not.

I'm not familiar with the term "waterfall" format but I assume you mean the strip chart that shows the original data collected in the particular sonar line in which the anomaly appears. The various sonar lines, like individual photographs, are then used to construct a mosaic. Yes, we have that data in three formats - .swf (Small Web Format), .csf (Content Sealed Format), and .bmp (Bitmap). Reading the first two formats takes software that I don't have but I can read .bmp files. The .csf file provides the best resolution and one of the sonar experts has given me a screen capture of the image from that format. I've attached a detail of the anomaly from the .csf version. As far as I know, in terms of resolution this is the best we have. There's an interesting detail that shows up in this image that is not discernible in the lower-res images. See if you can spot it.

Dan Swift · May 17, 2013, 08:07:43 AM

Not sure what you referring to. I see multiple objects to the left (larger) and just below (smaller) in addistion to many objects casting 'shadows'. Appears to be a lot of debre around this target. The one to the left could be the tail section or a piece of it. The smaller objects in front of the main object (main frame) could be engines and such. Plus, there is a 'shadow' cast all along the 'scar'...which would indicate it was fairly deep?

Douglass D. Benson · May 17, 2013, 09:00:05 AM

For my money, the shadow cast from the small object to the left reminds me of the landing gear from the 1937 photo. That is why I am not a part of the investigation team. I so badly want to see what is probably not there...

Dan Swift · May 17, 2013, 09:11:40 AM

I so want to find this still in "shallow" water when Tighar returns.

Bill de Creeft · May 17, 2013, 09:52:49 AM

Wow, Dan!
Intriguing...I went up to the barn and measured an old aero tire of the same dimension and it measured...as it is supposed to..With no air in it; 29 inches tall, and 13 inches across...the center takes a 6 inch wheel. ("30X13X6" my tire is worn smooth of tread)

All this is known, of course, but if a picture of it leaned against something would help anyone, I could take an iphone pic of it and email it...

Bill

Greg Daspit · May 17, 2013, 12:10:20 PM

Quote from: Ric Gillespie on May 17, 2013, 07:24:46 AM
I've attached a detail of the anomaly from the .csf version. As far as I know, in terms of resolution this is the best we have. There's an interesting detail that shows up in this image that is not discernible in the lower-res images. See if you can spot it.

The smaller shadow to the left. The shadow is an elipse with a line coming from it, extending vertically. Really interesting.

richie conroy · May 17, 2013, 03:13:02 PM

Hi All

Ric

When yous go back possibly 2014 an rov dive to anomaly, If it were to be identified as being Earhart s Electra would it be left in it's resting place or condition pending would it be raised ?

Thank's Richie

Chris Johnson · May 17, 2013, 03:29:17 PM

Quote from: richie conroy on May 17, 2013, 03:13:02 PM
Hi All

Ric

When yous go back possibly 2014 an rov dive to anomaly, If it were to be identified as being Earhart s Electra would it be left in it's resting place or condition pending would it be raised ?

Thank's Richie

If the gun smoked I'd like it to be left in place and then time and resources used to finish off the seven site, look for camp zero and finalize the whole story.

Ric Gillespie · May 17, 2013, 05:37:32 PM

We're getting waaaay ahead of ourselves here, but we've always said that if the plane, or whatever is left of it, is found it should be recovered and conserved - but you can't organize a responsible recovery until you know what there is to recover. So it's a multi-step process - find it; find out as much as you can about it without disturbing it; plan and equip the recovery expedition; execute the recovery; begin the conservation treatment.

richie conroy · May 17, 2013, 08:01:19 PM

Hi Ric

My original question i was going to ask was, Will Tighar take a salvage expert on 2014 expedition to evaluate if recovery is possible if it is confirmed the anomaly is the Electra, Irrelevant what experts say of anomaly as we know it will be 50/50 between yes and no before hand.

As i believe funds permitting, by taking an expert it would hasten the time between, finding, identifying, an retrieving, But thought a more cautious approach would have been better

Ric Gillespie · May 17, 2013, 08:08:23 PM

Quote from: richie conroy on May 17, 2013, 08:01:19 PM
My original question i was going to ask was, Will Tighar take a salvage expert on 2014 expedition to evaluate if recovery is possible if it is confirmed the anomaly is the Electra

We don't do salvage. We do archaeology. There's a big difference. We'll have an underwater archaeologist with us when we go back - just like we did on last summer's trip - but I can't imagine that we'd try to do a recovery at that at time unless there was an immediate "clear and present danger" to the artifact.