Can't believe no one mentioned Sea Hunt here? OK, so it was a TV series and not a movie , but the DVD box set it a MUST own for all divers. They have all 155 episodes, worth every penny to watch the old gear in action. In just about every other episode Lloyd Bridges has to rescue someone underwater and gives them the 10 second SCUBA lesson; "Here, breath on this, oh and don't hold your breath!"
The "hokieness factor" is certainly very high at times, but all in all it is quite amusing. A lot of the stuff he does is spot on accurate and the gear he uses was "state of the art" in 1959 after all.
A lot of the old birds on here will remember this show, everyone else should run, not walk and get the DVD set. If nothing else you will learn where our roots came from as divers.