Gary, I was just quoting what Tighar wrote.I agree with part of what you said and think the sentence I quoted from Tigher should be clarified. I think they meant the Center of Gravity of the plane was forward of the centerline of the wing and not just the "wing", but I could be wrong.
Brad, Thanks for the link
Of course what parts of the plane were more buoyant is more of a factor in which way the plane would settle than center of gravity. And of course empty tanks are more buoyant than full ones. The article someone else linked to said the plane would sink in 8 minutes but the example they used was a passenger configuration of an electra and not one with big empty tanks in the cabin.
The reason I think discussion of if the plane could float is important to this thread is for salvaging operations after the landing. If it was still on the reef after water rose, then at low tide they may be able to go back out and salvage stuff, even if the plane was flipped over. Of course the force of the tide could move the plane if it floated or not. The buoyancy of the plane could be a factor in which way the tide moved it, closer to the beach or farther away.