Loch Ness (1996)

Plot hole: When the monster sinks the boat, there is an underwater shot of the crew drowning. As one of them is struggling to the surface, a bottle of Bells whiskey sinks past him. The bottle is only one-third full, and the top is screwed on, so the bottle should float on the surface, even without a message in it.

Adrian Foot: You couldn't find a dinosaur at the bottom of a whiskey glass.