Low Flier ... thank for that insightful input. Such a refreshing change from those of the tin-foil hat community.
A question, if I may, as a simple observer.
You refer to side-scan sonar. Without revealing anything sensitive, and as the RAAF Air Marshal noted "we haven't even found the haystack yet', what sort of lateral coverage are we talking about? Surely this implies many months of meticulous (and accurate) scanning over a fairly narrow search band? Wherever such search has as a datum, of course!