Welcome back Renaud! Glad to have you return to the fold, so to speak!
I am always amazed at how some people get all defensive when they don't like or agree with materials or ideas presented to them. I always figure you should at least evaluate what they have before just outright dismissing them. But you can never tell with some people!

Thank you for your assistance in the past, and hopefully now and in the future!

Thank you Jeff for your kind words. Sorry for the delay in replying but I had my nose buried in my books...

I'm also interested in the mystery of NR16020's disappearance, but it's true that the White Bird has a certain sentimental attachment for me.

I hope to be of some kind of help.

MY two cents.

I showed the sonar picture to my father, an old aviator and sailor. After thirty seconds, he handed it back to me and said, “It's just an anchor with the anchor chain, or even part of the davit with it.” It's true that even iron steamers/liners from the 1870s and 1880s were still equipped with huge conventional anchors carried/secured on the outside of the hull... One should have lost his apparatus during a strong gale.

We don't really know the scale of measurement of this sonar image.

Leaving aside Ric's comment on the strength of the central wings section, I'm having trouble recognizing the aft fuselage and the two vertical fins. And where are the engine fairings/mounts?

As far as I'm concerned, you can say anything and everything about this image, it's like seeing a face in a cloud...

Also on that note and additional question is if a plane uses more fuel on one side of the plane than the other will the weight difference force the wings to either move left or right or angle off. Let me know...thanks

Several nights ago I watched a documentary on Amelia and her life and flying. Very interesting documentary as it covered pretty much of everything. One of the videos shown was her giving a detailed account of her having to circle back when the weather got bad so she could fly the Vega safely. As I thought about that I wandered with the Electra how much fuel would she have lost in the transition. If so what emergency procedures or procedures would she have taken to overcorrect her fuel usage. Also, at the Amelia Conference we talked about how much fuel she would have left in her tanks at the 150 mark. Very interesting topic. So my question is to balance out the Electra in the fuel transition...what standard procedures did they have back in 1937 and with Amelia and the Electra and all those reserve tanks...how did that fuel system work and did she have an emergency resource available should something drastic to happen. Curious to know if she worked from side to side as a balance or worked from left...then right with her fuel usage. It will be interesting to find out from you Ric or Andrew Mckenna as to how this would work with all the changes and modifications it did to the tanks overtime. Let me know...thanks

So perhaps a better question would be has anyone tested to see how quickly the plane would have sunk?

A Lockheed 10E that ditched off Cape Cod in 1967 floated for eight minutes, but it didn't have the large fuel tanks Earhart's airplane had.  How long NR16020 would float would depend on ow intact it was when it went over the reef edge.  The tanks had drain valves on the bell and vents in the filler ports, so if scraping along the reef on its belly compromised the drain valves the tanks would fill quickly.  When the plane slid on its belly in the Luke Field accident it came to stop in a big puddle of gasoline that, fortunately, was quickly washed down by the fire truck that was following the plane.  Bob Brandenburg calculated that with just the two 102 gallon wing tanks compromised the plane would float for 18 minutes.

To wash the airplane into the ocean there had to be a lot of water running across the reef, so it seems safe to assume there was heavy surf at the reef edge when it happened.  Anything that goes over the edge under those conditions does not peacefully float away.  Even on a calm day, a diver in the water at the reef edge gets slammed against the coral.  Having seen that environment first-hand many times, it's hard for me to imagine that airplane not sinking almost immediately in the relatively shallow water near the reef edge.

Personally I never imagined it "flying" underwater, but instead I had always thought that when folks were referencing the "flying" of the plane they meant on the surface. So the tide takes out the landing gear which puts the belly of the plane on the surface of the water. The wings and fuselage allow it to "fly" along the surface of the water. The plane is carried out to sea where it eventually sinks in the way you suggest. I guess float vs. sink might be a more apt comparison. So perhaps a better question would be has anyone tested to see how quickly the plane would have sunk? I guess the longer it's on the surface the farther it could be carried out to sea before it sank.
Don...
 

The flying-underwater thing has never made sense to me.  Water, like air, is a fluid so the wings of an intact airplane sinking nose-first, so the theory goes, should generate "lift" and the aircraft could "glide" for a considerable distance from where it sank before reaching the bottom. 
Let's try an experiment.  Fire up your airplane and climb to whatever altitude suits you.  Now shut off the engine, take your hands and feet off the controls, and don't touch the trim.  Nothing good will happen.   Flying machines remain under control only through human guidance. The Wrights figured that out a long time ago.

Wondering if anyone has done a scale model test of a properly weighted Electra model to see if it would "float and fly" vs. sink. Given that Ballard didn't find anything near the shore the other hypothesis could be that it's much further off the shore if it "flew".
Don...

Ric, I think this hypothesis is sound. We must persevere.

'Recuit' treatment is justified for a laminated ('écrouissage'), bent and stamped part ( that needs to retain its tear strength.

For the moment, I can't go any further on the subject. I'll try to find more studies on French special steels around 1930.

If I see anything else, I'll let you know. We'll be in touch.  

As for the high silicon content, isn't it possible that the artifact had been contaminated by the sand at the bottom of the pond, which has aggregated with it?  You mentioned that the scan was surface scan only.

I had the same thought, but apparently not.  We have a 1975 breakdown (see below) of the elements in Gull Pond (referred to by its topographic map name Goose Pond).

Interestingly, there is no naturally-occurring:
• Silicon
• Vanadium
• Titanium
• Tin
• Phosphorpus

Alll of which were detected in the XRF scans of the artifact.  The titanium (like the cobalt and lead) is probably from the paint. The silicon and vanadium are apparently part of the alloy. The little bit of copper could be from a tiny pocket of sediment. There shouldn't be any phosphorous in alloyed steel so it's probably an impurity.  Ditto for the trace of tin.

If I’m right, the base metal is steel alloyed with manganese, molybdenum, chromium, silicon, zinc, and vanadium.  That’s a complex, very high-quality “special steel’”.

I couldn't find any mention of L2R among French forges in 1918... But if Levasseur uses it in 1929, it's because it's an established standard, and probably a widespread one.

Agreed.

The 'R' reference could be the metal treatment. Perhaps a reference to the French term 'recuit' which is a heat-tratment of the laminated steel (beteween 500 and 800 °C) to restore his original mécanical properties.

That would make sense.