Clive Cussler uses SCUBA a lot in his books, which are great, (ever since he got co-writers to help him add some humor), yet only one of his books has been made into a movie. Any Cussler fans in this thread?
I own all the early ones, read and re-read them. Sometime after Dirk became more of a passenger I lost interest. There's one recent book I just can't finish because the inevitable/interminable chase scene was so badly telegraphed a dozen or so pages early.
Back to the topic: not really bad scenes but lots of fun, Fay Wray & Ralph Ballamy in Below the Sea (1933). A hard hat treasure diving movie with one terrible underwater octopus scene, but otherwise a pretty good movie. For me the fun part was about halfway through the movie when I had the sudden realization of "Beaks! Whatever happened to Beaks?" pop into my head. It was Ralph's voice that had been nagging me till that point. (hint: Trading Places).