In response to the poster who asked what major studio owned the show, I am guessing it would be NBC, as California National Productions was run out of the West Coast division of NBC. That said, many California National shows are starting to fall into public domain use; such as many episodes of the William Bendix version of "Life of Riley", "Adventures of Hiram Holliday", and others. I would suspect, based on that, that the "major studio" who is trying to get their hands on the films would be a DVD distributor who wants to release the show. I say more power to them. "The Silent Service" was a great show, I used to stay up very late during the summertime when I was in grade school in the 60s to watch reruns of the show on a local independent station.
Review of The Silent Service
