The soundtrack for this movie was released on a 7" EP. It sold less than 30,000 copies, making it the worst selling record that Elvis ever released for RCA Victor.
Paramount had originally begun filming a movie with this title starring surf rock musicians Jan and Dean in August 1965, but production was canceled following a serious accident involving Jan Berry and 13 others during a train wreck scene in early days of filming. Studio used same title, but totally different plot, for this Elvis Presley movie released two years later.
Elvis' co-star from Paradise, Hawaiian Style (1966) was offered a role in this film, but according to her interview made in 1998, she turned down the offer and said Tom Parker (Elvis' manager) was one of the reasons why she did so.
The ship Elvis is on in the first part of the movie is the USS GALLANT (MSO-489), an ocean-going minesweeper.