The song conveys the pleas of a captain on a troubled sea voyage and facing a mutiny from his crew. Its use of an orchestra during the long repeated refrains of the closing movement served to differentiate it from much of Grand Funk's work. Several interpretations of the song have been given; most revolve around the Vietnam War, and "I'm Your Captain" is popular among veterans of that conflict. The song is composed in the compound binary form that was most popular, and used for several well-known songs, in the late 1960s and early 1970s. The first movement opens with an electric guitar riff from Farner, which aspiring young guitarists of the time learned to imitate. This soon changes into a strummed acoustic guitar paired with a distinctive lead bass line from Mel Schacher, set against a steady drumbeat from Don Brewer accompanied with occasional wah wah guitar flourishes. The chord changes go from D to G to G6/C. The story ostensibly deals with a ship's captain on a troubled voyage and facing a mutiny from his crew. Farner's vocal of the pleading lyric begins: Everybody, listen to me, and return me, my ship I'm your captain, I'm your captain, although I'm feeling, mighty sick. I've been lost now, days uncounted ... And it's months since, I've seen home. Can you hear me, can you hear me? Or am I ... all alone. The music has a bass break and then drops down to half time before resuming at its normal tempo. The protagonist's plight becomes worse, with the captain's pleas continuing while the unhappy crew members are approaching the point of murder. At the 4½-minute mark the song switches to the second movement, which begins with the sounds of waves and gulls. The captain's voice is tinged with a sense of hopeless longing, perhaps even indicating that it is his ghost now singing: I'm getting closer to my home ... I'm getting closer to my home ... Again the bass line carries the music, with now a flute line accompanying it. Soon the strings from the orchestra, make their entrance, featuring violins, violas, cellos, and basses. The second movement starts at a fairly slow tempo, before speeding up somewhat into its repeats. The significant chord progression in this part is from C to B♭add9. The movement's single lyric repeats over and over as a mantra, in the style of Van Morrison. Around the 7-minute mark a full orchestra appears to accompany the band to the gradually fading conclusion. Unusually for him, Farner wrote the lyric of the song first, with the words coming to him in the middle of the night after saying prayers for inspiration to write something meaningful. The chord changes to "I'm Your Captain" came to him the following morning between sips of coffee, and the following day he took it to the band. They immediately liked it and began jamming on it and working out their parts at a local union hall in their hometown of Flint, Michigan where they usually did their rehearsals. But after a while they had no ending for the second movement. Inspired by groups like The Moody Blues, they came upon the idea of using an orchestra, and hired Tommy Baker, an arranger and trumpet player who was working on the Cleveland television series Upbeat. He suggested they extend the ending so that his orchestral score would have space to develop in, so the band extended the jam on it. Producer Terry Knight brought in the Cleveland Orchestra to record it. The band members never heard the full version until Knight played it for them back in Flint. Farner nearly cried when he heard it, and Brewer has said of their reactions, "We were just like, 'Wow!'" and "Oh my God, it was magnificent."