James Doohan was offered the part of Chief Sharkey, but turned it down, because that same week he was offered and accepted the role of Chief Engineer Montgomery Scott of the Starship Enterprise on Star Trek: The Original Series (1966), for which he became famous.
The season two opener, "Jonah And The Whale", was the first episode to be broadcast in color. Seaview was redesigned with only one set of observation windows and a hatch for the flying sub, although stock footage was used throughout seasons two through four, showing the sub with three or six windows. New uniforms appeared also, as well as the flying sub. Over the course of seasons two through four, there were six different flying sub models used for filming.
Late in the filming of the second season, Richard Basehart fell ill during the filming of the episode "The Monster's Web", and was unable to complete that episode, and work on the next two. "The Monster's Web" was re-written to minimize the part of his character, Admiral Nelson (knocked out of action in the first act), with a stand-in used for many shots with his face hidden and lines dubbed. The next episode, "The Menfish", had Nelson away, and his lines reassigned to guest character Admiral Park (Gary Merrill). The following episode, "The Mechanical Man", had Nelson still away, and reassigned his lines to Captain Crane (David Hedison) and Crane's lines to Commander Morton (Robert Dowdell). Basehart returned in time to appear in the season finale, "The Return of the Phantom".
During the 1965 season of the series, Susan Flannery was considered for a recurring role as Admiral Nelson's secretary, serving both as an on-shore ally to the adventures, and as occasional romantic interest for Captain Crane. The plans were dropped, after demographics showed the series was more popular with children than adults.
Henry Kulky was chosen as a series regular in the role of Chief Curley Jones. The role was cut short when Kulky was stricken by a fatal heart attack in February 1965 that ended his life and career, which included over one hundred features and television episodes.
The final two seasons continued the shift towards paranormal storylines that were popular in the late 1960s. Mummies, werewolves, talking puppets, and an evil leprechaun all walked the corridors of the Seaview. There were also fossil men, flame men, frost men, lobster men, and shadow men. All of them had the same cheesy low budget makeup effects and costume designs of Irwin Allen's other TV shows at the time.
An often referenced running joke is that in many episodes of the series, characters lurch to camera movements on the visibly static set, to give the illusion that Seaview had sustained impact. This was an old movie trick, and was commonly used by other television shows of the period, including Star Trek, but none did it so frequently, nor with such relish as Voyage. Hence, the technique is still commonly known as "Seaview Rock and Roll".
20th Century Fox has released all 4 seasons on DVD in Region 1 in two volume sets. In Region 2, Revelation Films has released the entire series on DVD in the UK in four complete season sets. On March 26, 2012, they released Voyage To The Bottom Of The Sea: The Complete Collection, a 31-disc set featuring all 110 episodes of the series as well as bonus features. In Region 4, Madman Entertainment released the first two seasons on DVD in Australia on August 20, 2014.
The first season's 31 episodes included gritty, atmospheric story lines devoted to Cold War themes and excursions into near-future speculative fiction, involving espionage and sci-fi elements. Aliens, sea monsters and dinosaurs were featured, but the primary villains were hostile foreign governments. While fantastic, the scripts had a recognisably contemporary setting.
Due to ABC's demands for a somewhat "lighter" tone to the series, the second season saw an increase in monster-of-the-week type plots, yet there were still some episodes that harkened back to the tone of the first season, which included story lines devoted to Cold War themes and excursions into near-future speculative fiction.
The most important change in the series occurred during the second season when a notably redesigned Seaview interior was introduced, along with the Flying Sub, a yellow, two-man mini-submarine with passenger capacity. The Flying Sub could leave the ocean and become airborne. The futuristic craft greatly increased the Seaview crew's travel options. It was launched from a bay, access to which was via a sealed hatch stairway at the bow section. The Seaview's private observation deck from the first season was never seen again. The Seaview control room was expanded and a large rectangular panel screen of flickering lights was added. The Seaview also now had a powerful laser beam in its bow light. The small mini-sub from the first season was retained and occasionally still used in the color episodes.
A second-season episode, "The Sky's On Fire", was a remake of the basic storyline of Irwin Allen's 1961 film Voyage to the Bottom of the Sea utilizing considerable film color footage, though several film sequences were removed and had been featured in other first-season episodes such as "The Village of Guilt" and "Submarine Sunk Here."
Though many female characters appeared in Seasons One and Two, in Season Three only two appeared at all: an unseen woman's voice (Sue England) over the intercom in "The Death Watch" and the title character in "The Mermaid" (Diane Webber), who did not speak.
The series' main theme, "The Seaview Theme", was written by Paul Sawtell. A new darker, more serious theme composed by Jerry Goldsmith was introduced at the beginning of the second-season episode "Jonah and the Whale", but this was quickly replaced by the original version.
A paperback novel, City Under the Sea, authored by Paul W. Fairman, was published in 1965, to tie into the series. It had a different storyline than the episode of the same name. The book should also not be confused with the later Irwin Allen film of nearly the same name, which was about the attempts of the world's first under-sea city to prevent the earth from being hit by a rogue asteroid.
Western Publishing published a comic book based on the series. Western's comic company, Gold Key Comics put out a series that ran 16 issues from 1964 to 1970. Most covers were painted, and most had a photo of either Richard Basehart or David Hedison on them.
In 1966, World Distributors, a British publishing company in Manchester, published a hardback book called the Annual. The British-made book used the series characters in all new stories. The book contained a reprint of a story from Gold Key Comics. Both books were mostly prose stories with some illustrations.
Aurora Plastics Corporation released a plastic model kit of Seaview as well as the Flying Sub during the original run of the series. From 1975 - 1977, Aurora reissued both kits; the Seaview (kit #253) was modified with a sea floor base (originally created for the Dick Tracy Space Coupe kit #819) and sub surface details, while The Flying Sub (kit #254) was remodeled in a different base color. The 1975 - 1977 kits--part of Aurora's reissue of 5 of their 11 TV & movie-related science-fiction kits, also included instruction sheets with a detailed history of the TV series or movie plot. Both kits were recently re-released by Polar Lights. The Flying Sub model sold more than the Seaview model.
In 1964, a 66-card set of black-and-white trading cards was released by Donruss. Selling for 5 cents a pack, the set consisted of stills from the first season. Today, a set in mint condition can sell for several hundred dollars.
In the UK, TV Tornado published 14 issues that contained Voyage to the Bottom of the Sea stories, either comics or text with illustrations as per the issue and at least two TV Tornado annuals had original stories as well.