Lloyd Bridges was soon cast as lead character Mike Nelson. Sea Hunt was intended as a comeback vehicle for Bridges due to his brief blacklisting from acting. Bridges was blacklisted after admitting to the House Un-American Activities Committee that he had been a member of the Actors’ Laboratory Theatre, a group that was tied to the Communist Party.[3][4]
After winning the role, Bridges was given a crash course in scuba diving by Zale Parry and Courtney Brown. Brown served as his underwater stunt double. Bridges was also educated in the art of scuba equipment by Brad 
Pinkernell on the beach in Southern California from 1956 to 1957. It was at a chance meeting when Pinkernell was coming out of the ocean with his scuba gear on. Over the course of the show’s run, Bridges got more involved in the underwater stunt work, graduating from close-ups in the earliest episodes, to doing all but the most dangerous stunts by the end of the series’ run.
After winning the role, Bridges was given a crash course in scuba diving by Zale Parry and Courtney Brown. Brown served as his underwater stunt double. Bridges was also educated in the art of scuba equipment by Brad Pinkernell on the beach in Southern California from 1956 to 1957. It was at a chance meeting when Pinkernell was coming out of the 
ocean with his scuba gear on. Over the course of the show’s run, Bridges got more involved in the underwater stunt work, graduating from close-ups in the earliest episodes, to doing all but the most dangerous stunts by the end of the series’ run.