This is the only episode in the series that features a speaking female character other than Atlanta.
The "bubble-top" canopy covering the cabin in the Hep Cats' submarine is a recycled canopy section of Supercar (1961), possibly a larger-scale partial prop used for closeups.
This is the only episode in which Marina has any speaking role, though it is only within the dream sequence. Marina speaks telepathically. Sylvia Anderson also provided Marina's voice for the story record Marina Speaks, which described the character's origin story.
This episode was the 16th episode produced and the 9th broadcast.
This episode is one of three episodes in the series that is a dream sequence, the other two being The Cool Cave Man (1965) and Tom Thumb Tempest (1965).