and Noctus (voiced by Ray Barrett and David Graham): a pair of undersea beings who appear in the episodes "A Nut for Marineville" and "Trapped in the Depths". Production In late 1962, as production on Fireball XL5 drew to a close, Gerry Anderson decided that an underwater series was the next logical step for production company AP Films (APF): "We had been on land and in space, so where could we go next? One possibility was underwater." He was inspired by childhood memories of U-boats in the Second World War, as well as by the mysteries of the ocean: "I was ... fascinated by trenches in the ocean that are as deep as mountains are high. There are features that man has never seen and pressures that are almost impossible to withstand. I began to wonder if there were areas of the Earth which had been little explored and felt justified in writing some wacky stuff." APF's financial backer Lew Grade, who had bought the company after the success of Fireball XL5, approved the concept and commissioned 26 episodes. Anderson named the new series "Stingray" partly from a belief that stingrays are dangerous animals (in reality, they are docile), but also because it "seemed an exciting title." In preparation for the new series, APF, then based on the Slough Trading Estate's Ipswich Road, moved to a larger site on the nearby Stirling Road at a cost of £75,000.Archer and Hearn, p. 90. The new studios, built inside a converted factory unit, contained three shooting stages: two for puppet filming and one for creating special effects. This arrangement allowed two episodes to be filmed simultaneously by separate crews. Production began in spring or June 1963 and the series was completed in ten months. Each episode required an average of 11 days of puppet filming and five-and-a-half days of effects filming. The total cost of the production was approximately £1 million (£ million in ). The budget per episode was £20,000, which enabled APF, whose earlier productions had been in black and white, to film in Eastmancolor.The opening credits refer to the colour process as "Videcolor". Though Stingray would debut in black and white in its country of origin, the switch to colour filming was intended to increase the series' chances of being bought by a network in the US, where colour TV broadcasts were already common. Sets were re-painted after NBC