Those sonar images
Thanks for reminding us of the sonar images 9A+. Looking at the first image it appears that there is a complete blade and the second shows what appear to be several separate segments of the blade arranged in a neat pattern with some segments missing. Critically the missing segments are from the middle of the blade, not the ends. If this had been a blade failure as for DQ-IHE the blade segments would not be co-located as shown in the second sonar scan.The segments would have been thrown well apart.
I suspect that the failure is not related to the blade itself but may be within the root/hub region. In which case even if the blade segments were found they would exhibit consequential evidence, not causal.
However, I agree with Kiwi500 that there should have been a bit more official effort than just offering a paltry reward that would barely cover the costs for S-q-fish.
Regards
Blakmax