HarryMann:
I am generally aware of the effect of Reynold's Number on drag regimes, but as this is not my area (I am an EE, as JD says), I can only say that it is my understanding, from having "watched hydrodynamics done"
, that form drag dominates for the conditions of interest here. If anyone still cares at the end of the week, when I return from travel, I will ask an ME who does this sort of work for a more definitive answer.
Outliers:
The target to the north might, as others have suggested, be a piece that drifted on the surface before filling with water and sinking, or it might be something that is not related to AF447.