I have read both threads since they began, but I do not remember seeing any comment regarding which and how many navy subs were used. GB, French, and US are probably givens. Were any Russia subs used. Some Russian boats, with their super tough titanium hulls (as opposed to the steel hulls of the US Navy boats and other Russian boats) can go deeper. How much deeper? The Russians are a little tight-lipped about that. Most think that depths in excess of 3,000 feet were easily accomplished, and one report suggested that 4,000 feet was within the reach of these vessels. If true, then if used at the onset, searching and listening at great depths, perhaps identification and location of the recorders might have been possible.
Not to throw a dart, but it just seems to me that the search effort was behind the power curve from the beginning.
ww