Less conventional approaches have done no better. Perhaps an earlier exorcism was to blame. We may never find out. And the nature of the loch does not help. The waters themselves are dark, stained with peat.
Visibility is poor.
But, in Loch Ness, finding nothing proves nothing. If Sherlock cannot find the beast, neither, probably, can we. And that is just fine with Drumnadrochit. The tourists will keep coming to the centers, the restaurants, the shops, and the pubs. At the Nessie Shop, the bagpipe muzak will continue to play.