the Loch Ness Monster is fake, there is nothing there but big Sturgeon...that is Loch Ness...You'll find more evidence of dinos in the Congo than in Loch Ness Lake.
If they really wanted to find something, chum the water, then have sonar and Heat seeking devices (because in order for a large reptile to function in cold water, its going to have to be warmblooded), And there you go. And have Satellites take pics and heat signatures of the whole lake. Problem is that takes money.