Assignment: Underwater is an early American television series which aired in NTA Film Network

NTA Film Network

The NTA Film Network was an early American television network founded by Ely Landau in 1956. The network was not a full-time television network like CBS, NBC, or ABC. Rather, it operated on a part-time basis, broadcasting films and several first-run television programs from major Hollywood studios...

 syndication in 1960. It was an adventure series starring prolific B-movie actor Bill Williams

Bill Williams (actor)

Bill Williams was an American television and film actor. He is best known for his starring role in the early 1950 television show The Adventures of Kit Carson.-Career:...

 and Diane Mountford. Williams played Bill Greer, the skipper aboard a charter boat named The Lively Lady. Mountford played his daughter, Patty.

The series was written and produced by Frank De Felitta for Liberty Enterprises and National Telefilm Associates

National Telefilm Associates

National Telefilm Associates was an independent distribution company that handled reissues of American film libraries, including much of Paramount Pictures' animated and short-subjects library.-History:...

.