Axel Nordstrom manages a glass-bottom boat tourist operation in the waters of Santa Catalina Island, California. His widowed daughter, Jennifer Nelson, occasionally helps by donning a mermaid costume and swimming underneath his boat for the passengers' amusement.
One day, Jennifer accidentally meets Bruce Templeton when his fishing hook snags her costume. He reels in the bottom half, leaving the irate Jennifer floating in the water without pants. Jennifer later discovers that Templeton is a top executive at her new place of employment, a NASA aerospace research laboratory in Long Beach, where she works in public relations.
Templeton later recognizes Jennifer at the research laboratory and hires her for a new full-time assignment: to be his biographer and write his life story. His real purpose is to win her affections. There is a problem: the laboratory's security chief, Homer Cripps, after observing her mysterious behavior and curious, code-like phone calls, concludes that Jennifer is a Soviet spy. To prove his suspicions, he has Jennifer put under surveillance by everyone at the lab. When she learns of this, Jennifer sets out to turn the tables on the bumbling Cripps by pretending that she is a spy, a charade that eventually exposes a real spy.Doris Day - Jennifer Nelson
Rod Taylor - Bruce Templeton
Arthur Godfrey - Axel Nordstrom
John McGiver - Ralph Goodwin
Paul Lynde - Homer Cripps
Edward Andrews - Gen. Wallace Bleecker
Eric Fleming - Edgar Hill
Dom DeLuise - Julius Pritter
Elisabeth Fraser - Nina Bailey
Dick Martin - Zack Molloy
George Tobias* - Norman Fenimore
Alice Pearce* - Mabel Fenimore
Ellen Corby - Anna Miller
Dee J. Thompson - Donna
*Pearce and Tobias play an inquisitive wife and her disinterested husband, in roles not unlike the ones they played at the time in the television series Bewitched. The film was also released 3 months after the death of Alice Pearce.
Robert Vaughn, famous at the time for playing Napoleon Solo in the TV series The Man from U.N.C.L.E., makes a very brief non-speaking appearance as a sight gag; the theme from his TV series is heard when he is seen onscreen.
Shooting partly took place on Catalina Island. It was Rod Taylor's second film with Doris Day following Do Not Disturb.
The Nautilus boat used in the film sank in the Catalina harbor in 2008. It is currently drydocked in a private part of the island.
The mermaid costume worn by Doris Day in the opening scene is now on display at the Catalina Casino and can be viewed on the Casino tour.
The film stands apart from Day's other 1960s comedies due to animator-turned-director Tashlin's signature penchant for elaborate, cartoon-like gags and humor. This includes Taylor's futuristic, robotic kitchen; a chase scene involving a runaway remote-controlled speedboat; Day accidentally falling into a zero-gravity tank, and a slapstick sequence involving DeLuise as an inept electrician, which closely resembles Tashlin's frequent collaborations with Jerry Lewis.
The film's score was composed by Frank DeVol and includes selections from Beethoven's "Symphony No. 5 in C minor", Mendelssohn's "Wedding March in C major", "Aloha 'Oe" (written by Queen Liliuokalani) and Goldsmith's "Theme from The Man from U.N.C.L.E."
Day sings a shortened version of "Soft as the Starlight" (written by Joe Lubin and Jerome Howard), which she previously sang in its entirety on the 1957 album Day by Night. The song "The Glass Bottom Boat" is a rearrangement of "Soft as the Starlight" with completely different lyrics and is heard twice in the film: over the opening credits, sung by Day, and again as source music sung by Day, Taylor, Godfrey and Fraser. Day also sings a single verse from her signature song, "Whatever Will Be, Will Be (Que Sera, Sera)" (written by Jay Livingston and Ray Evans). Dick Martin sings a brief a cappella rendition of "Be My Love" (written by Sammy Cahn and Nicholas Brodszky).
The film was an attempt to appeal both to Day's traditional fans and to a younger audience. It was a success financially, earning $4,320,000 in North American rentals by the end of 1966.
It drew 21,752 admissions in France.
Day followed up with Caprice (1967), a comedy-thriller more completely in the spy spoof genre, again with Tashlin directing, but it was a critical and commercial failure.
The DVD of The Glass Bottom Boat (released in 2005) includes three vintage featurettes (Catalina Island, Every Girl's Dream, and NASA), as well as the Oscar-Winning cartoon The Dot and the Line.